[Drakelist] AC-4 Sold
Thanks all for your interest! I have a buyer and a backup. I wish I had a few of these. -- *73, Mark, K4SO *www.k4so.com picasaweb.google.com/kfourso picasaweb.google.com/kfourso2 ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] ac-4 supply
Looking for a top cover for a ac-4 supply. Cosmetics not important. 73 dale wt4t ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] AC-4 Supply Needed
Hi All, I am looking to purchase an AC-4 power supply with the AC-4R upgrade kit installed for a Drake station I am putting together. Please call (567) 203-9327 or email. Thanks, Jeff W8CQ ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4 Power Supply
Got it... Thanks, Bill, WB9CAC From: Bill Ellis wb9...@yahoo.com To: Drakelist (Post) drakelist@zerobeat.net Sent: Saturday, May 25, 2013 8:01 PM Subject: [Drakelist] AC-4 Power Supply Does anyone have a voltage chart for the AC-4 by pin on the power supply female connector? Thanks, Bill Ellis, WB9CAC ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] AC-4 Power Supply
Does anyone have a voltage chart for the AC-4 by pin on the power supply female connector? Thanks, Bill Ellis, WB9CAC___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4 Load Bank
Hi folks, I've sent out info to half a dozen folks, and the idea of having a load test has come up more than once. Chris, W7JPG, was the most inquisitive, I've cc'd his note below, and my thoughts on the whole thing. --- my reply: Hi Chris, You're right in everything you say. I had stated originally that this unit did not test under load, and that I was thinking of adding some load features. I did not build the unit, it came from a Collins Guy. I've been thinking about using fixed resistors (large wattage, as you say), probably with a momentary connection, probably thru relays for the HV, just push button switch directly for the bias (low load, maybe 20-30 ma.) and filaments (maybe 3-4 amps). Using, for example, 10 kohms for the HV/LV load, you'd not have to measure current, it'd be the same, in ma., as the indicated voltage divided by 10. Would not be full load, but enough to indicate bad diodes in a doubler ckt, for example. I'd probably use a 50 watt 10k resistor, and for intermittent short duration use that should be OK. I did a little surfing ystdy, that can be found in the $5-15 range (Mouser). A small relay could be used to keep the HV off of a switch. Since the volt meter is switched between HV LV, one resistor could be used for both. I just noticed, the orig. schematic doesn't show a fil. voltage mtr. --- his query: Now, for my question. It looks like your test box measures all voltages under no load conditions. Did I miss something? My interest in the thread on load bank tests was the practical matter of how someone would set up the proper circuit and components to simulate the load presented to a 516F2 by, let's say, a KWM-2A. The info I found on such a load bank for low voltage - high current equipment required a lot of high wattage resistors to dissipate the heat generated for each of the main circuits that would be under a load test: heater, bias, B+ draw. After looking at your fixture, I realized (correct me if I am off base here) that to test a specific power supply (516F2, AC-4, etc.), one would be able to make a comparison check of no load voltages against a properly functioning example of these PSU's or a specification that stated the normal no load voltage levels. So, if a PSU was tested without a load and all the no load voltages were nomimal, what advantage, if any, would a load test provide over a no load test? :-0 I would appreciate any comments. 73, Chris W7JPG --- Any other thoughts from list members would be appreciated by all. 73, Al, W8UT www.boatanchors.org www.hammarlund.info There is nothing -- absolutely nothing -- half so much worth doing as simply messing about in boats Ratty, to Mole On 11/27/2012 1:47 PM, Al Parker wrote: Hi folks, I have scanned the article, one small page, written by K0ZQD in V2 Iss. 16 of The Collins Coll's. MMag. It gives the schematic, leaving construction details to the builder. I also have scanned a skem of the p.s. pinouts for the 516F-2, from the same issue. Make your own adapter(s) for various supplies, if wanted. I'll send the scans to those who have/do request it. Mike brings up a good point, as written, the voltages are unloaded, and will be high. I'd like to switch in the load, so a relay for the HV would be advisable for that. As Mike says, use ohms law for resistor sizing, and you'll know, close enuf, what the currents will be. I've used my test rig on a lot of Collins and Drake supplies, it's a quick test, doesn't show ripple, but ckg ESR on the filter caps will tell you what you need to do there (do it before you power up the supply, so the caps don't do any reforming). Al, W8UT On 11/27/2012 1:06 PM, Mike Bryce wrote: There wouldn't be much too it. all you need would be a hand full of resistors, using ohm's law to calculate the values. The values would be calculated at the max current the TRx series would draw. On would need to load the 6.3 v filament down to the same current as the tubes, if you don't the unloaded transformer would produce more voltage than normal since it's not powering the tubes. a couple of cheap LED digital panel mount meter could be used to monitor the voltages, plate, screen, and bias likewise a meter could be used to monitor current on the plate supply. I don't feel it would be necessary to monitor bias current or screen voltage current either. it would be an interesting project, that would make checking the supply quick. A few test points for an 'oscope to monitor ripple would be icing on the cake later mike, wb8vge On Mon, 26 Nov 2012 11:50:11 -0500 Al Parker anc...@ec.rr.com wrote: hi folks, Some yrs ago there was an article on building a test setup for Collins p.s.'s. I think it was in one of the Collins collector magazines, I can search it out. I came into possession of one of the
Re: [Drakelist] AC-4 Load Bank
I would be very interested in seeing the schematic.. 73 Gene K1NR PS I would not mind having one to check my Collins supply either : - ) On Mon, 26 Nov 2012 11:50:11 -0500 Al Parker anc...@ec.rr.com wrote: hi folks, Some yrs ago there was an article on building a test setup for Collins p.s.'s. I think it was in one of the Collins collector magazines, I can search it out. I came into possession of one of the units, and have made cable adapters for the AC-3/4's, and I think the HP-23's also. It is for voltage only, and did not include a load test, but I have been thinking of adding that to mine. 73, Al, W8UT www.boatanchors.org www.hammarlund.info There is nothing -- absolutely nothing -- half so much worth doing as simply messing about in boats Ratty, to Mole On 11/26/2012 11:30 AM, Hudson, John@CalEMA wrote: That would be a useful test jig. John N. Hudson III, Communications Coordinator 4050 Taylor St, MS 243 San Diego, CA 92110 6192509063 Cell On Nov 24, 2012, at 1:37 PM, Eugene Balinski euge...@nni.com wrote: All, Just wondering if anyone has put together an AC-4 load or test bank ? If so, could you share the plans ? I would like something that would allow one to connect the AC-4. switch on the AC, and measure the various voltage levels on test point, and perhaps even load the supply. Thanks in advance, 73 Gene K1NR - Web mail provided by NuNet, Inc. The Premier National provider. http://www.nni.com/ ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4 Load Bank
There wouldn't be much too it. all you need would be a hand full of resistors, using ohm's law to calculate the values. The values would be calculated at the max current the TRx series would draw. On would need to load the 6.3 v filament down to the same current as the tubes, if you don't the unloaded transformer would produce more voltage than normal since it's not powering the tubes. a couple of cheap LED digital panel mount meter could be used to monitor the voltages, plate, screen, and bias likewise a meter could be used to monitor current on the plate supply. I don't feel it would be necessary to monitor bias current or screen voltage current either. it would be an interesting project, that would make checking the supply quick. A few test points for an 'oscope to monitor ripple would be icing on the cake later mike, wb8vge On Nov 27, 2012, at 10:21 AM, Eugene Balinski wrote: I would be very interested in seeing the schematic.. 73 Gene K1NR PS I would not mind having one to check my Collins supply either : - ) On Mon, 26 Nov 2012 11:50:11 -0500 Al Parker anc...@ec.rr.com wrote: hi folks, Some yrs ago there was an article on building a test setup for Collins p.s.'s. I think it was in one of the Collins collector magazines, I can search it out. I came into possession of one of the units, and have made cable adapters for the AC-3/4's, and I think the HP-23's also. It is for voltage only, and did not include a load test, but I have been thinking of adding that to mine. 73, Al, W8UT www.boatanchors.org www.hammarlund.info There is nothing -- absolutely nothing -- half so much worth doing as simply messing about in boats Ratty, to Mole On 11/26/2012 11:30 AM, Hudson, John@CalEMA wrote: That would be a useful test jig. John N. Hudson III, Communications Coordinator 4050 Taylor St, MS 243 San Diego, CA 92110 6192509063 Cell On Nov 24, 2012, at 1:37 PM, Eugene Balinski euge...@nni.com wrote: All, Just wondering if anyone has put together an AC-4 load or test bank ? If so, could you share the plans ? I would like something that would allow one to connect the AC-4. switch on the AC, and measure the various voltage levels on test point, and perhaps even load the supply. Thanks in advance, 73 Gene K1NR - Web mail provided by NuNet, Inc. The Premier National provider. http://www.nni.com/ ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4 Load Bank
Hi folks, I have scanned the article, one small page, written by K0ZQD in V2 Iss. 16 of The Collins Coll's. MMag. It gives the schematic, leaving construction details to the builder. I also have scanned a skem of the p.s. pinouts for the 516F-2, from the same issue. Make your own adapter(s) for various supplies, if wanted. I'll send the scans to those who have/do request it. Mike brings up a good point, as written, the voltages are unloaded, and will be high. I'd like to switch in the load, so a relay for the HV would be advisable for that. As Mike says, use ohms law for resistor sizing, and you'll know, close enuf, what the currents will be. I've used my test rig on a lot of Collins and Drake supplies, it's a quick test, doesn't show ripple, but ckg ESR on the filter caps will tell you what you need to do there (do it before you power up the supply, so the caps don't do any reforming). Al, W8UT www.boatanchors.org www.hammarlund.info There is nothing -- absolutely nothing -- half so much worth doing as simply messing about in boats Ratty, to Mole On 11/27/2012 1:06 PM, Mike Bryce wrote: There wouldn't be much too it. all you need would be a hand full of resistors, using ohm's law to calculate the values. The values would be calculated at the max current the TRx series would draw. On would need to load the 6.3 v filament down to the same current as the tubes, if you don't the unloaded transformer would produce more voltage than normal since it's not powering the tubes. a couple of cheap LED digital panel mount meter could be used to monitor the voltages, plate, screen, and bias likewise a meter could be used to monitor current on the plate supply. I don't feel it would be necessary to monitor bias current or screen voltage current either. it would be an interesting project, that would make checking the supply quick. A few test points for an 'oscope to monitor ripple would be icing on the cake later mike, wb8vge On Nov 27, 2012, at 10:21 AM, Eugene Balinski wrote: I would be very interested in seeing the schematic.. 73 Gene K1NR PS I would not mind having one to check my Collins supply either : - ) On Mon, 26 Nov 2012 11:50:11 -0500 Al Parker anc...@ec.rr.com wrote: hi folks, Some yrs ago there was an article on building a test setup for Collins p.s.'s. I think it was in one of the Collins collector magazines, I can search it out. I came into possession of one of the units, and have made cable adapters for the AC-3/4's, and I think the HP-23's also. It is for voltage only, and did not include a load test, but I have been thinking of adding that to mine. 73, Al, W8UT www.boatanchors.org www.hammarlund.info There is nothing -- absolutely nothing -- half so much worth doing as simply messing about in boats Ratty, to Mole On 11/26/2012 11:30 AM, Hudson, John@CalEMA wrote: That would be a useful test jig. John N. Hudson III, Communications Coordinator 4050 Taylor St, MS 243 San Diego, CA 92110 6192509063 Cell On Nov 24, 2012, at 1:37 PM, Eugene Balinski euge...@nni.com wrote: All, Just wondering if anyone has put together an AC-4 load or test bank ? If so, could you share the plans ? I would like something that would allow one to connect the AC-4. switch on the AC, and measure the various voltage levels on test point, and perhaps even load the supply. Thanks in advance, 73 Gene K1NR - Web mail provided by NuNet, Inc. The Premier National provider. http://www.nni.com/ ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4 Load Bank
That would be a useful test jig. John N. Hudson III, Communications Coordinator 4050 Taylor St, MS 243 San Diego, CA 92110 6192509063 Cell On Nov 24, 2012, at 1:37 PM, Eugene Balinski euge...@nni.com wrote: All, Just wondering if anyone has put together an AC-4 load or test bank ? If so, could you share the plans ? I would like something that would allow one to connect the AC-4. switch on the AC, and measure the various voltage levels on test point, and perhaps even load the supply. Thanks in advance, 73 Gene K1NR - Web mail provided by NuNet, Inc. The Premier National provider. http://www.nni.com/ ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4 Load Bank
hi folks, Some yrs ago there was an article on building a test setup for Collins p.s.'s. I think it was in one of the Collins collector magazines, I can search it out. I came into possession of one of the units, and have made cable adapters for the AC-3/4's, and I think the HP-23's also. It is for voltage only, and did not include a load test, but I have been thinking of adding that to mine. 73, Al, W8UT www.boatanchors.org www.hammarlund.info There is nothing -- absolutely nothing -- half so much worth doing as simply messing about in boats Ratty, to Mole On 11/26/2012 11:30 AM, Hudson, John@CalEMA wrote: That would be a useful test jig. John N. Hudson III, Communications Coordinator 4050 Taylor St, MS 243 San Diego, CA 92110 6192509063 Cell On Nov 24, 2012, at 1:37 PM, Eugene Balinski euge...@nni.com wrote: All, Just wondering if anyone has put together an AC-4 load or test bank ? If so, could you share the plans ? I would like something that would allow one to connect the AC-4. switch on the AC, and measure the various voltage levels on test point, and perhaps even load the supply. Thanks in advance, 73 Gene K1NR ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] AC-4 Load Bank
All, Just wondering if anyone has put together an AC-4 load or test bank ? If so, could you share the plans ? I would like something that would allow one to connect the AC-4. switch on the AC, and measure the various voltage levels on test point, and perhaps even load the supply. Thanks in advance, 73 Gene K1NR - Web mail provided by NuNet, Inc. The Premier National provider. http://www.nni.com/ ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4
Mark: It is interesting to note that a self proclaimed boat anchor expert with specialization in Collins equipment (Especially the R-390)still insists that the hot lead from the AC mains should always go to the power transformer and the fused side go to the neutral and on-off switch. I can't tell you how many people have written to him and to the trade magazines explaining how dangerous this is but then, I guess, he is the expert. Obviously you know which way is correct. Good luck with the Drakes; Dan K8WOZ - Original Message - From: Mark Nace To: Gary Poland ; John Gartman ; DrakeList Zerobeat Sent: Friday, January 20, 2012 8:02 PM Subject: Re: [Drakelist] AC-4 A number of years ago I bought about four AC4's, and installed 3-prong computer cords, with the ground attached to the AC4 chassis. I used the original strain relief, but carefully cut some of the plastic out of the original, just enough to accomodate the round cord. They all worked great. One thing I did not consider (and I need to go back and look), is the hot lead of the AC cord being on the fuse. I suppose for safety reasons I should have??? 73, Mark N5KAE From: Gary Poland gpola...@cinci.rr.com To: John Gartman johngart...@charter.net; DrakeList Zerobeat drakelist@zerobeat.net Sent: Thu, January 19, 2012 8:43:08 PM Subject: Re: [Drakelist] AC-4 John, As you suggested it would be easiest to just cut it off at the strain relief and re-terminate inside. You will only lose about 6 to 8 inches at best. 73, Gary -- ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4
Mark, Yes. It is vitally important that the fuse be in the hot lead of the cord which should be connected to the _inside_ end of the fuse holder so that when the fuse is pulled part way out with the outside end exposed, the fuse is not hot. 73, Bob AD3K From: drakelist-boun...@zerobeat.net [mailto:drakelist-boun...@zerobeat.net] On Behalf Of Mark Nace Sent: Friday, January 20, 2012 9:03 PM To: Gary Poland; John Gartman; DrakeList Zerobeat Subject: Re: [Drakelist] AC-4 A number of years ago I bought about four AC4's, and installed 3-prong computer cords, with the ground attached to the AC4 chassis. I used the original strain relief, but carefully cut some of the plastic out of the original, just enough to accomodate the round cord. They all worked great. One thing I did not consider (and I need to go back and look), is the hot lead of the AC cord being on the fuse. I suppose for safety reasons I should have??? 73, Mark N5KAE From: Gary Poland gpola...@cinci.rr.com To: John Gartman johngart...@charter.net; DrakeList Zerobeat drakelist@zerobeat.net Sent: Thu, January 19, 2012 8:43:08 PM Subject: Re: [Drakelist] AC-4 John, As you suggested it would be easiest to just cut it off at the strain relief and re-terminate inside. You will only lose about 6 to 8 inches at best. 73, Gary ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4 (bias mod)
in no emission between code elements, but also over part of the cycle. Key clicks could be delt with... The reason they had key clicks was primarily because they were cathode keying high voltages with no shaping as I recall. no? Bias is only on the finals, we don't key those or do we? Junk? Isn't our driver pretty clean? If not, wouldn't we have the same spurs and junk with a linear final? We DO have a tuned output tank circuit for the flywheel effect... no? BUT, if we don't have enough (voltage) drive, that might be a problem, but we don't really need full power... Don't ya think? Changing bias for CW wasn't my idea, but it did sound good to me. TIA, I am trying to learn here... There probably IS some reason nobody did this originally! 73, Gary WB6OGD - Original Message - From: Garey Barrellk4...@mindspring.com To: Gary Winbladgarywinb...@comcast.net Cc: drakelistdrakelist@zerobeat.net Sent: Fri, 20 Jan 2012 15:31:44 - (UTC) Subject: Re: [Drakelist] AC-4 (bias mod) Gary - In a word NO. The PA stage is operated as a LINEAR amplifier, Class AB1, meaning the output signal is a reasonable facsimile of the input signal. The BIAS voltage is carefully chosen to 'center' the operation of the amplifier in the linear portion of the tube's operating region. Increasing the BIAS voltage WILL reduce the IDLE current, (between code elements,) but will shift the PA to a non-linear region. This will result in distortion of the signal, with the potential of spurious signals, clicks, and other 'junk'. This is one reason clicks were so prevalent in the older transmitters. A true Class C amplifier requires considerably more driving power, and relies on the 'flywheel effect' of it's output network to 'smooth' out the 'pulses' of drive that exceed the bias potential. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs Gary Winblad wrote: All this talk of rebuilding AC-4 supplies had me thinking... I have seen a mod(?) that said to turn up(down?) the bias when running CW (and FSK?) to set the finals more to Class C operation to save power dissipation. Is this a good idea? Wouldn't it be easy to add a switch or relay and another potentiometer while you are in there rebuilding? 73, Gary WB6OGD ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4 (bias mod)
All this talk of rebuilding AC-4 supplies had me thinking... I have seen a mod(?) that said to turn up(down?) the bias when running CW (and FSK?) to set the finals more to Class C operation to save power dissipation. Is this a good idea? Wouldn't it be easy to add a switch or relay and another potentiometer while you are in there rebuilding? 73, Gary WB6OGD - Original Message - From: Mark Pilant n1...@arrl.net To: drakelist drakelist@zerobeat.net Sent: Fri, 20 Jan 2012 01:52:42 - (UTC) Subject: Re: [Drakelist] AC-4 Hi John. That I've always done, as suggested by others, is to replace the two conductor cord with a more modern grounded plug and wire. You can see the one I used in the AC-4 rebuild I describe here: http://www.n1vqw.net/ac4rebuild/ BTW, it is a standard computer cord, and I cut off the female end with about 6 inches of cord in case I ever want to use it. 73 - Mark N1VQW ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4 (bias mod)
Gary - In a word NO. The PA stage is operated as a LINEAR amplifier, Class AB1, meaning the output signal is a reasonable facsimile of the input signal. The BIAS voltage is carefully chosen to 'center' the operation of the amplifier in the linear portion of the tube's operating region. Increasing the BIAS voltage WILL reduce the IDLE current, (between code elements,) but will shift the PA to a non-linear region. This will result in distortion of the signal, with the potential of spurious signals, clicks, and other 'junk'. This is one reason clicks were so prevalent in the older transmitters. A true Class C amplifier requires considerably more driving power, and relies on the 'flywheel effect' of it's output network to 'smooth' out the 'pulses' of drive that exceed the bias potential. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com Gary Winblad wrote: All this talk of rebuilding AC-4 supplies had me thinking... I have seen a mod(?) that said to turn up(down?) the bias when running CW (and FSK?) to set the finals more to Class C operation to save power dissipation. Is this a good idea? Wouldn't it be easy to add a switch or relay and another potentiometer while you are in there rebuilding? 73, Gary WB6OGD http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4 (bias mod)
Well yeahh Garey I am not suggesting we change the bias for SSB (or AM), just for CW (and real FSK). So, you would need a switch or relay added and USE it to change modes. Yes, bias it past cut-off, will result in no emission between code elements, but also over part of the cycle. Key clicks could be delt with... The reason they had key clicks was primarily because they were cathode keying high voltages with no shaping as I recall. no? Bias is only on the finals, we don't key those or do we? Junk? Isn't our driver pretty clean? If not, wouldn't we have the same spurs and junk with a linear final? We DO have a tuned output tank circuit for the flywheel effect... no? BUT, if we don't have enough (voltage) drive, that might be a problem, but we don't really need full power... Don't ya think? Changing bias for CW wasn't my idea, but it did sound good to me. TIA, I am trying to learn here... There probably IS some reason nobody did this originally! 73, Gary WB6OGD - Original Message - From: Garey Barrell k4...@mindspring.com To: Gary Winblad garywinb...@comcast.net Cc: drakelist drakelist@zerobeat.net Sent: Fri, 20 Jan 2012 15:31:44 - (UTC) Subject: Re: [Drakelist] AC-4 (bias mod) Gary - In a word NO. The PA stage is operated as a LINEAR amplifier, Class AB1, meaning the output signal is a reasonable facsimile of the input signal. The BIAS voltage is carefully chosen to 'center' the operation of the amplifier in the linear portion of the tube's operating region. Increasing the BIAS voltage WILL reduce the IDLE current, (between code elements,) but will shift the PA to a non-linear region. This will result in distortion of the signal, with the potential of spurious signals, clicks, and other 'junk'. This is one reason clicks were so prevalent in the older transmitters. A true Class C amplifier requires considerably more driving power, and relies on the 'flywheel effect' of it's output network to 'smooth' out the 'pulses' of drive that exceed the bias potential. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs Gary Winblad wrote: All this talk of rebuilding AC-4 supplies had me thinking... I have seen a mod(?) that said to turn up(down?) the bias when running CW (and FSK?) to set the finals more to Class C operation to save power dissipation. Is this a good idea? Wouldn't it be easy to add a switch or relay and another potentiometer while you are in there rebuilding? 73, Gary WB6OGD http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4 (bias mod)
Gary - Obviously the bias would remain in the Class AB1 area for SSB and AM. Applying a keyed signal to a non-linear amplifier is a bad idea. Every time the drive is started or stopped there is the opportunity for additional distortion products to be generated. Some SSB distortion is caused by biasing the amplifier too high or too low, resulting in 'compression' or limiting the waveform to less than it's peak. More distortion. Perhaps we have an amplifier expert on here who can definitively respond to your question. There are no doubt MANY reasons why all transmitters switched to linear operation for CW, in spite of the 'power/efficiency savings. If nothing else than it takes large amounts of drive POWER, more trouble, including greatly increased Grid dissipation. To me, turning an input signal on and off to a Class C amplifier is asking for trouble. A Class C amplifier is essentially a switch, ON or OFF, and relies on the Q of the tank circuits to 'smooth things out'. A lot of potential headaches for a few percent efficiency increase. There are LOTS of 'ideas' on the internet that 'sound' good :-) Let us know what you find out!! 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com Gary Winblad wrote: Well yeahh Garey I am not suggesting we change the bias for SSB (or AM), just for CW (and real FSK). So, you would need a switch or relay added and USE it to change modes. Yes, bias it past cut-off, will result in no emission between code elements, but also over part of the cycle. Key clicks could be delt with... The reason they had key clicks was primarily because they were cathode keying high voltages with no shaping as I recall. no? Bias is only on the finals, we don't key those or do we? Junk? Isn't our driver pretty clean? If not, wouldn't we have the same spurs and junk with a linear final? We DO have a tuned output tank circuit for the flywheel effect... no? BUT, if we don't have enough (voltage) drive, that might be a problem, but we don't really need full power... Don't ya think? Changing bias for CW wasn't my idea, but it did sound good to me. TIA, I am trying to learn here... There probably IS some reason nobody did this originally! 73, Gary WB6OGD - Original Message - From: Garey Barrell k4...@mindspring.com To: Gary Winblad garywinb...@comcast.net Cc: drakelist drakelist@zerobeat.net Sent: Fri, 20 Jan 2012 15:31:44 - (UTC) Subject: Re: [Drakelist] AC-4 (bias mod) Gary - In a word NO. The PA stage is operated as a LINEAR amplifier, Class AB1, meaning the output signal is a reasonable facsimile of the input signal. The BIAS voltage is carefully chosen to 'center' the operation of the amplifier in the linear portion of the tube's operating region. Increasing the BIAS voltage WILL reduce the IDLE current, (between code elements,) but will shift the PA to a non-linear region. This will result in distortion of the signal, with the potential of spurious signals, clicks, and other 'junk'. This is one reason clicks were so prevalent in the older transmitters. A true Class C amplifier requires considerably more driving power, and relies on the 'flywheel effect' of it's output network to 'smooth' out the 'pulses' of drive that exceed the bias potential. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs Gary Winblad wrote: All this talk of rebuilding AC-4 supplies had me thinking... I have seen a mod(?) that said to turn up(down?) the bias when running CW (and FSK?) to set the finals more to Class C operation to save power dissipation. Is this a good idea? Wouldn't it be easy to add a switch or relay and another potentiometer while you are in there rebuilding? 73, Gary WB6OGD http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4 (bias mod)
- Original Message - From: Garey Barrell k4...@mindspring.com To: Gary Winblad garywinb...@comcast.net Cc: drakelist drakelist@zerobeat.net Sent: Friday, January 20, 2012 3:24 PM Subject: Re: [Drakelist] AC-4 (bias mod) Gary - Obviously the bias would remain in the Class AB1 area for SSB and AM. Applying a keyed signal to a non-linear amplifier is a bad idea. Every time the drive is started or stopped there is the opportunity for additional distortion products to be generated. Some SSB distortion is caused by biasing the amplifier too high or too low, resulting in 'compression' or limiting the waveform to less than it's peak. More distortion. Perhaps we have an amplifier expert on here who can definitively respond to your question. There are no doubt MANY reasons why all transmitters switched to linear operation for CW, in spite of the 'power/efficiency savings. If nothing else than it takes large amounts of drive POWER, more trouble, including greatly increased Grid dissipation. To me, turning an input signal on and off to a Class C amplifier is asking for trouble. A Class C amplifier is essentially a switch, ON or OFF, and relies on the Q of the tank circuits to 'smooth things out'. A lot of potential headaches for a few percent efficiency increase. There are LOTS of 'ideas' on the internet that 'sound' good :-) Let us know what you find out!! 73, Garey - K4OAH Glen Allen, VA There is a lot more than changing bias to converting a linear amplifier of any class to a Class-C amplifier. For one thing the plate impedance and thus tank requirements will be different. Its not trivial. There is a lot of information on designing Class-C amps in older handbooks, maybe even on the web, although I have not looked. The difference in output for a tube with given plate dissipation can be considerable. A Class AB linear has less than 66% efficiency and a Class-C amp around 78% (can be made higher with special tank circuits). Essentially, Class-C amplifiers are pulse integration devices. The plate efficiency is partly a matter of the pulse duration. I think if you want a transmitter primarily for CW or FSK building one from scratch might be best. -- Richard Knoppow Los Angeles WB6KBL dickb...@ix.netcom.com ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4 (bias mod)
Hi Garey, Thanks, good explanation. I'm not going to try it any time soon ;-) 73, Gary - Original Message - From: Garey Barrell k4...@mindspring.com To: Gary Winblad garywinb...@comcast.net Cc: drakelist drakelist@zerobeat.net Sent: Fri, 20 Jan 2012 23:24:40 - (UTC) Subject: Re: [Drakelist] AC-4 (bias mod) Gary - Obviously the bias would remain in the Class AB1 area for SSB and AM. Applying a keyed signal to a non-linear amplifier is a bad idea. Every time the drive is started or stopped there is the opportunity for additional distortion products to be generated. Some SSB distortion is caused by biasing the amplifier too high or too low, resulting in 'compression' or limiting the waveform to less than it's peak. More distortion. Perhaps we have an amplifier expert on here who can definitively respond to your question. There are no doubt MANY reasons why all transmitters switched to linear operation for CW, in spite of the 'power/efficiency savings. If nothing else than it takes large amounts of drive POWER, more trouble, including greatly increased Grid dissipation. To me, turning an input signal on and off to a Class C amplifier is asking for trouble. A Class C amplifier is essentially a switch, ON or OFF, and relies on the Q of the tank circuits to 'smooth things out'. A lot of potential headaches for a few percent efficiency increase. There are LOTS of 'ideas' on the internet that 'sound' good :-) Let us know what you find out!! 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs Gary Winblad wrote: Well yeahh Garey I am not suggesting we change the bias for SSB (or AM), just for CW (and real FSK). So, you would need a switch or relay added and USE it to change modes. Yes, bias it past cut-off, will result in no emission between code elements, but also over part of the cycle. Key clicks could be delt with... The reason they had key clicks was primarily because they were cathode keying high voltages with no shaping as I recall. no? Bias is only on the finals, we don't key those or do we? Junk? Isn't our driver pretty clean? If not, wouldn't we have the same spurs and junk with a linear final? We DO have a tuned output tank circuit for the flywheel effect... no? BUT, if we don't have enough (voltage) drive, that might be a problem, but we don't really need full power... Don't ya think? Changing bias for CW wasn't my idea, but it did sound good to me. TIA, I am trying to learn here... There probably IS some reason nobody did this originally! 73, Gary WB6OGD - Original Message - From: Garey Barrell To: Gary Winblad Cc: drakelist Sent: Fri, 20 Jan 2012 15:31:44 - (UTC) Subject: Re: [Drakelist] AC-4 (bias mod) Gary - In a word NO. The PA stage is operated as a LINEAR amplifier, Class AB1, meaning the output signal is a reasonable facsimile of the input signal. The BIAS voltage is carefully chosen to 'center' the operation of the amplifier in the linear portion of the tube's operating region. Increasing the BIAS voltage WILL reduce the IDLE current, (between code elements,) but will shift the PA to a non-linear region. This will result in distortion of the signal, with the potential of spurious signals, clicks, and other 'junk'. This is one reason clicks were so prevalent in the older transmitters. A true Class C amplifier requires considerably more driving power, and relies on the 'flywheel effect' of it's output network to 'smooth' out the 'pulses' of drive that exceed the bias potential. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs Gary Winblad wrote: All this talk of rebuilding AC-4 supplies had me thinking... I have seen a mod(?) that said to turn up(down?) the bias when running CW (and FSK?) to set the finals more to Class C operation to save power dissipation. Is this a good idea? Wouldn't it be easy to add a switch or relay and another potentiometer while you are in there rebuilding? 73, Gary WB6OGD http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4
A number of years ago I bought about four AC4's, and installed 3-prong computer cords, with the ground attached to the AC4 chassis. I used the original strain relief, but carefully cut some of the plastic out of the original, just enough to accomodate the round cord. They all worked great. One thing I did not consider (and I need to go back and look), is the hot lead of the AC cord being on the fuse. I suppose for safety reasons I should have??? 73, Mark N5KAE From: Gary Poland gpola...@cinci.rr.com To: John Gartman johngart...@charter.net; DrakeList Zerobeat drakelist@zerobeat.net Sent: Thu, January 19, 2012 8:43:08 PM Subject: Re: [Drakelist] AC-4 John, As you suggested it would be easiest to just cut it off at the strain relief and re-terminate inside. You will only lose about 6 to 8 inches at best. 73, Gary___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4
Mark, For sure, the hot wire should immediately go to the fuse upon entering the AC4 chassis. I believe that the correct place for it is the tip of the fuse holder. 73, Ron WD8SBB --- On Fri, 1/20/12, Mark Nace n5...@swbell.net wrote: From: Mark Nace n5...@swbell.net Subject: Re: [Drakelist] AC-4 To: Gary Poland gpola...@cinci.rr.com, John Gartman johngart...@charter.net, DrakeList Zerobeat drakelist@zerobeat.net Date: Friday, January 20, 2012, 9:02 PM A number of years ago I bought about four AC4's, and installed 3-prong computer cords, with the ground attached to the AC4 chassis. I used the original strain relief, but carefully cut some of the plastic out of the original, just enough to accomodate the round cord. They all worked great. One thing I did not consider (and I need to go back and look), is the hot lead of the AC cord being on the fuse. I suppose for safety reasons I should have??? 73, Mark N5KAE From: Gary Poland gpola...@cinci.rr.com To: John Gartman johngart...@charter.net; DrakeList Zerobeat drakelist@zerobeat.net Sent: Thu, January 19, 2012 8:43:08 PM Subject: Re: [Drakelist] AC-4 John, As you suggested it would be easiest to just cut it off at the strain relief and re-terminate inside. You will only lose about 6 to 8 inches at best. 73, Gary -Inline Attachment Follows- ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4 (bias mod)
Guess I'll just toss in my 2 cents worth. Converting a Drake to class C in CW mode only by simply changing the bias of the PA may not be a good idea depending upon how it is driven and to a lesser extent how much Q and harmonic filtering is in the tank circuitry. I have not studied the schematic so I'll just leave it at that. But I really don't think class C operation in general should get a bad rap. It's a perfectly legit class of operation and like any mode there is a right way and a wrong way to implement it. It has a major advantage in terms of improving efficiency and thus reduction of heat in the finals. I have measured my Viking II PA with good instrumentation at 79 to 80% over the core bands on multiple occasions. We're talking 144W out for 180W in. The final is parallel 6146's, fixed plus drive-induced bias, and a heavy duty tank with continously optimized Q due to slaving a rollerducter to the plate tuning cap. As for driving power, you generally need a little more with class C, but not a lot more (assuming beam power tubes and assuming we're talking CW, not plate mod AM). To control clicks one should shape the drive signal shoulders softer than what one would normally do when driving a linear amp because the turn-on and turn-off characteristic of class C is more abrupt. There is nothing fundamentally wrong with class C for CW. In fact some cell phones use it. I think modern rigs avoid it simply because the PA is already linear for other reasons and already has a fan to get rid of heat. The maker would have to design the driver stage a little differently and the antenna coupling circuitry as well. I guess that is not worth adverstising additional 10's of watts of CW output power on the brochure. Dennis AE6C On 1/20/12, Garey Barrell k4...@mindspring.com wrote: Gary - Obviously the bias would remain in the Class AB1 area for SSB and AM. Applying a keyed signal to a non-linear amplifier is a bad idea. Every time the drive is started or stopped there is the opportunity for additional distortion products to be generated. Some SSB distortion is caused by biasing the amplifier too high or too low, resulting in 'compression' or limiting the waveform to less than it's peak. More distortion. Perhaps we have an amplifier expert on here who can definitively respond to your question. There are no doubt MANY reasons why all transmitters switched to linear operation for CW, in spite of the 'power/efficiency savings. If nothing else than it takes large amounts of drive POWER, more trouble, including greatly increased Grid dissipation. To me, turning an input signal on and off to a Class C amplifier is asking for trouble. A Class C amplifier is essentially a switch, ON or OFF, and relies on the Q of the tank circuits to 'smooth things out'. A lot of potential headaches for a few percent efficiency increase. There are LOTS of 'ideas' on the internet that 'sound' good :-) Let us know what you find out!! 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com Gary Winblad wrote: Well yeahh Garey I am not suggesting we change the bias for SSB (or AM), just for CW (and real FSK). So, you would need a switch or relay added and USE it to change modes. Yes, bias it past cut-off, will result in no emission between code elements, but also over part of the cycle. Key clicks could be delt with... The reason they had key clicks was primarily because they were cathode keying high voltages with no shaping as I recall. no? Bias is only on the finals, we don't key those or do we? Junk? Isn't our driver pretty clean? If not, wouldn't we have the same spurs and junk with a linear final? We DO have a tuned output tank circuit for the flywheel effect... no? BUT, if we don't have enough (voltage) drive, that might be a problem, but we don't really need full power... Don't ya think? Changing bias for CW wasn't my idea, but it did sound good to me. TIA, I am trying to learn here... There probably IS some reason nobody did this originally! 73, Gary WB6OGD - Original Message - From: Garey Barrell k4...@mindspring.com To: Gary Winblad garywinb...@comcast.net Cc: drakelist drakelist@zerobeat.net Sent: Fri, 20 Jan 2012 15:31:44 - (UTC) Subject: Re: [Drakelist] AC-4 (bias mod) Gary - In a word NO. The PA stage is operated as a LINEAR amplifier, Class AB1, meaning the output signal is a reasonable facsimile of the input signal. The BIAS voltage is carefully chosen to 'center' the operation of the amplifier in the linear portion of the tube's operating region. Increasing the BIAS voltage WILL reduce the IDLE current, (between code elements,) but will shift the PA to a non-linear region. This will result in distortion of the signal, with the potential of spurious signals, clicks, and other 'junk'. This is one reason clicks
[Drakelist] AC-4
My power cord from power supply to radio is a little poor looking at the strain relief, and is more than likely a little brittle. Should I try just cutting it off or replacing it? If I was to replace it any recommendations on where to get this type of cord? Thanks John Gartman AG6GL ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4
Not sure what you mean by round third plug. The wider blade is neutral, not ground. The round blade is ground 73 de W3NU. On 1/19/2012 1525, Kris Merschrod wrote: On the last AC-4 that I upgraded I bought an extension cord with molded three pronged male end about 10 feet long and #12 wire. Then I cut off the female end and carefully tested each wire to see which was the ground (Round third plug); The wider blade is the ground and the narrower blade is the hotwire. I put the main ground to the chassis by a bolt through one of the old Can Capacitor slots. The length of the cord should be to suit your situation to avoid extension cords! Good luck with it, Kris KM2KM - Original Message - *From:* John Gartman mailto:johngart...@charter.net *To:* drakelist@zerobeat.net mailto:drakelist@zerobeat.net *Sent:* Thursday, January 19, 2012 11:20 AM *Subject:* [Drakelist] AC-4 My power cord from power supply to radio is a little poor looking at the strain relief, and is more than likely a little brittle. Should I try just cutting it off or replacing it? If I was to replace it any recommendations on where to get this type of cord? Thanks John Gartman AG6GL ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4
AFAIK, all modern line cords follow the same convention: Green or Green/Yellow is GND, white or blue is neutral, black or brown is hot. Most computer cords I've seen in the last 20 years are GRN/YEL - BLU - BRN - it's an international standard. 73, Steve Wedge, W1ES/4 Live free or die: Death is not the worst of evils. John Stark. All my computers have my signature with various pearls of wisdom appended thereto. From: Charles Ring Sent: Thursday, January 19, 2012 7:08 PM To: drakelist@zerobeat.net Subject: Re: [Drakelist] AC-4 Not sure what you mean by round third plug. The wider blade is neutral, not ground. The round blade is ground 73 de W3NU. On 1/19/2012 1525, Kris Merschrod wrote: On the last AC-4 that I upgraded I bought an extension cord with molded three pronged male end about 10 feet long and #12 wire. Then I cut off the female end and carefully tested each wire to see which was the ground (Round third plug); The wider blade is the ground and the narrower blade is the hotwire. I put the main ground to the chassis by a bolt through one of the old Can Capacitor slots. The length of the cord should be to suit your situation to avoid extension cords! Good luck with it, Kris KM2KM - Original Message - From: John Gartman To: drakelist@zerobeat.net Sent: Thursday, January 19, 2012 11:20 AM Subject: [Drakelist] AC-4 My power cord from power supply to radio is a little poor looking at the strain relief, and is more than likely a little brittle. Should I try just cutting it off or replacing it? If I was to replace it any recommendations on where to get this type of cord? Thanks John Gartman AG6GL ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4
Hi John. That I've always done, as suggested by others, is to replace the two conductor cord with a more modern grounded plug and wire. You can see the one I used in the AC-4 rebuild I describe here: http://www.n1vqw.net/ac4rebuild/ BTW, it is a standard computer cord, and I cut off the female end with about 6 inches of cord in case I ever want to use it. 73 - Mark N1VQW ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4
Excuse, but I understood the question was about the multi-conductor cable from the AC-4 with the Cinch-Jones termination, not the AC cord to the AC-4. My power cord from power supply to radio is a little poor looking. I am guessing his only option is to use single-conductor of appropriate guage and insulation rating to rebuild the cable from the AC-4 to the connector ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4
John, As you suggested it would be easiest to just cut it off at the strain relief and re-terminate inside. You will only lose about 6 to 8 inches at best. 73, Gary___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] AC-4 Voltages
Hello All, I'm a newbie to Drake equipment, I just recently purchased a 4-line. When the equipment arrived one of the tubes had come out of the socket in the R-4B and it was broken so I'm waiting for a new tube. Everything looked good in the transmitter but I thought I would look at the voltages from the AC-4 before connecting things up. The voltages seem a bit high to me, but you're the experts. B+ high 769 VDC (checked at orange wire) B+ low313 VDC (checked at yellow wire) BIAS -76 VDC (checked at green wire) 15 VAC filament voltage (checked between black and white wires) All ripple .004 VAC Too high? v/r Rick Gunderman - WA4RG ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4 Voltages
- Original Message - From: Rick Gunderman wa4rg.r...@gmail.com To: drakelist@zerobeat.net Sent: Sunday, January 15, 2012 9:34 AM Subject: [Drakelist] AC-4 Voltages Hello All, I'm a newbie to Drake equipment, I just recently purchased a 4-line. When the equipment arrived one of the tubes had come out of the socket in the R-4B and it was broken so I'm waiting for a new tube. Everything looked good in the transmitter but I thought I would look at the voltages from the AC-4 before connecting things up. The voltages seem a bit high to me, but you're the experts. B+ high 769 VDC (checked at orange wire) B+ low313 VDC (checked at yellow wire) BIAS -76 VDC (checked at green wire) 15 VAC filament voltage (checked between black and white wires) All ripple .004 VAC Too high? v/r Rick Gunderman - WA4RG Something wrong here. The filament voltage should be 12.5 VAC on a 115VAC power line. The line voltage would have to be nearly 140 volts to produce this filament voltage. All voltages are about 1.2X the correct ones. That makes me suspicious of the meter you are using. What does it measure your line voltage as? I don't think the high voltages are the result of operating without a load although that will raise them somewhat. However, it would not change the bias voltage. -- Richard Knoppow Los Angeles WB6KBL dickb...@ix.netcom.com ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4 Voltages
Thank you for your response Richard. Using the same meter, my line voltage reads 122 VAC. ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4 Voltages
Rick - Pretty close for your line voltage. A little high, but not critical. I assume you are measuring just the supply, no load. 750 VDC 300 VDC -70 to -100 VDC 14.5 VAC The filament voltage is high because of the cable and the heavy load (lotsa filaments) 5.5 Amps. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com Rick Gunderman wrote: Hello All, I'm a newbie to Drake equipment, I just recently purchased a 4-line. When the equipment arrived one of the tubes had come out of the socket in the R-4B and it was broken so I'm waiting for a new tube. Everything looked good in the transmitter but I thought I would look at the voltages from the AC-4 before connecting things up. The voltages seem a bit high to me, but you're the experts. B+ high 769 VDC (checked at orange wire) B+ low313 VDC (checked at yellow wire) BIAS -76 VDC (checked at green wire) 15 VAC filament voltage (checked between black and white wires) All ripple .004 VAC Too high? v/r Rick Gunderman - WA4RG ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4 Voltages
Yes sir Garey, no load, just the supply. On Sun, Jan 15, 2012 at 2:17 PM, Garey Barrell k4...@mindspring.com wrote: Rick - Pretty close for your line voltage. A little high, but not critical. I assume you are measuring just the supply, no load. 750 VDC 300 VDC -70 to -100 VDC 14.5 VAC The filament voltage is high because of the cable and the heavy load (lotsa filaments) 5.5 Amps. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com Rick Gunderman wrote: Hello All, I'm a newbie to Drake equipment, I just recently purchased a 4-line. When the equipment arrived one of the tubes had come out of the socket in the R-4B and it was broken so I'm waiting for a new tube. Everything looked good in the transmitter but I thought I would look at the voltages from the AC-4 before connecting things up. The voltages seem a bit high to me, but you're the experts. B+ high 769 VDC (checked at orange wire) B+ low313 VDC (checked at yellow wire) BIAS -76 VDC (checked at green wire) 15 VAC filament voltage (checked between black and white wires) All ripple .004 VAC Too high? v/r Rick Gunderman - WA4RG ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4 Voltages
- Original Message - From: Rick Gunderman wa4rg.r...@gmail.com To: Richard Knoppow 1oldle...@ix.netcom.com Cc: drakelist@zerobeat.net Sent: Sunday, January 15, 2012 9:56 AM Subject: Re: [Drakelist] AC-4 Voltages Thank you for your response Richard. Using the same meter, my line voltage reads 122 VAC. A puzzle. I have two AC-4's both with the Heathkit shop mods in them. By memory I did not get extra-high voltages on either. One is where I can get to it and will see if I can make some measurements with it unloaded. 122 VAC is typical of current power company practice and is not high enough to account for the differences between specified and measured voltages. I measured the voltages of one of my AC-4's. Measurements with a Triplet 630, 20k ohms per volt DC. I double checked some of the voltages with a Tektronix DMM245 which read essentially the same. Line voltage = 114 VAC HV = +650 VDC Medium HV = +270 VDC Bias, adjustable from about -45 VDC to about -70 VDC Filament, about 13 VAC All measured to chassis ground. All are unloaded voltages, i.e., the supply was not connected to a transmitter. This is pretty close to the values on the schematic. A label on the back of this unit states that it was rebuilt by Jeff Cavelli. My other one is burried a bit but by memory the voltages were nearly the same as this one. I can think of a lot of reasons for the voltages to be _low_ but not many for it to be high, especially by this much. -- Richard Knoppow Los Angeles WB6KBL dickb...@ix.netcom.com ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4 Voltages
Hey, Rick - Welcome to the World-O-Drake. Those voltages sound about right for an unloaded supply. They do drop once you connect a transmitter to the supply. 73, Steve Wedge, W1ES/4 Live free or die: Death is not the worst of evils. John Stark. All my computers have my signature with various pearls of wisdom appended thereto. From: Rick Gunderman Sent: Sunday, January 15, 2012 12:34 PM To: drakelist@zerobeat.net Subject: [Drakelist] AC-4 Voltages Hello All, I'm a newbie to Drake equipment, I just recently purchased a 4-line. When the equipment arrived one of the tubes had come out of the socket in the R-4B and it was broken so I'm waiting for a new tube. Everything looked good in the transmitter but I thought I would look at the voltages from the AC-4 before connecting things up. The voltages seem a bit high to me, but you're the experts. B+ high 769 VDC (checked at orange wire) B+ low313 VDC (checked at yellow wire) BIAS -76 VDC (checked at green wire) 15 VAC filament voltage (checked between black and white wires) All ripple .004 VAC Too high? v/r Rick Gunderman - WA4RG ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4 Voltages
Thank you all for your replies. This week after I receive my 6EH5 in and get the receiver going I'll turn the transmitter on and see what happens. ' 73 Rick - WA4RG ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4 Voltages
Old AC-4 ... no AC-4R rebuild, original parts no load ... 718 vdc 286 vdc -70 vdc 13.8 vac ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4 Voltages
Mark - Interesting. A primary voltage of 121.5 VAC resulted in measured AC voltages out of the transformer at 266 VAC, 108 and 98. The filament measured 14 VAC, all no load. 266 x 2.828 = 752 V peak 108 x 2.828 = 305 V peak Both have very high bleeders, a mA or two so will reach near these peak voltages at no load. 98 x 28.28 = 138 V peak. The divider on the output is nominally 69 VDC at mid-range with NO load. The transmitter is specified as a 33k ohm load. All measurements taken with a calibrated Fluke DMM. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com Mark Nace wrote: When I did an AC-4R board kit replacement with a relatively high serial number (55,000) unit, in the final checkout I got these DC voltages (NO LOAD): 717 (orange) 292 (yellow) -64 (green). This value of course is variable. Did not measure filament voltage, but I have some non-loaded numbers from six unrestored units (two being AC-3's) ranging from 12.6 to 13.3 vac. (119.8 vac power). 73, Mark N5KAE - Original Message From: Richard Knoppow1oldle...@ix.netcom.com To: Rick Gundermanwa4rg.r...@gmail.com Cc: drakelist@zerobeat.net Sent: Sun, January 15, 2012 1:43:20 PM Subject: Re: [Drakelist] AC-4 Voltages - Original Message - From: Rick Gundermanwa4rg.r...@gmail.com To: Richard Knoppow1oldle...@ix.netcom.com Cc:drakelist@zerobeat.net Sent: Sunday, January 15, 2012 9:56 AM Subject: Re: [Drakelist] AC-4 Voltages Thank you for your response Richard. Using the same meter, my line voltage reads 122 VAC. A puzzle. I have two AC-4's both with the Heathkit shop mods in them. By memory I did not get extra-high voltages on either. One is where I can get to it and will see if I can make some measurements with it unloaded. 122 VAC is typical of current power company practice and is not high enough to account for the differences between specified and measured voltages. I measured the voltages of one of my AC-4's. Measurements with a Triplet 630, 20k ohms per volt DC. I double checked some of the voltages with a Tektronix DMM245 which read essentially the same. Line voltage = 114 VAC HV = +650 VDC Medium HV = +270 VDC Bias, adjustable from about -45 VDC to about -70 VDC Filament, about 13 VAC All measured to chassis ground. All are unloaded voltages, i.e., the supply was not connected to a transmitter. This is pretty close to the values on the schematic. A label on the back of this unit states that it was rebuilt by Jeff Cavelli. My other one is burried a bit but by memory the voltages were nearly the same as this one. I can think of a lot of reasons for the voltages to be _low_ but not many for it to be high, especially by this much. ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4 Voltages
- Original Message - From: Garey Barrell k4...@mindspring.com To: drakelist@zerobeat.net Sent: Sunday, January 15, 2012 1:27 PM Subject: Re: [Drakelist] AC-4 Voltages Mark - Interesting. A primary voltage of 121.5 VAC resulted in measured AC voltages out of the transformer at 266 VAC, 108 and 98. The filament measured 14 VAC, all no load. 266 x 2.828 = 752 V peak 108 x 2.828 = 305 V peak Both have very high bleeders, a mA or two so will reach near these peak voltages at no load. 98 x 28.28 = 138 V peak. The divider on the output is nominally 69 VDC at mid-range with NO load. The transmitter is specified as a 33k ohm load. All measurements taken with a calibrated Fluke DMM. 73, Garey - K4OAH Glen Allen, VA I remeasured both supplies. Unloaded and with line voltage at about 120VAC, I get HV= +702 VDC on both. Only measured medium voltage on one and filament on one. MV= +287VDC Filament= 13.8 VAC Didn't remeasure the bias. Meter: Tektronix DMM 254 These were all measured at the end of the power plug with a jumper across the line switch contacts. I actually opened up a supply to measure the first voltages. Not sure where the difference came from. FWIW, wire doesn't work well to short the plug, I used bits of cut-off paper clip and that worked fine. It appears that the original poster's voltages are fine although I still think the filament is high. Since that is a matter of the turns ratio of the transformer it may still be a measurement error. The voltages that count are those measured with the transmitter working. -- Richard Knoppow Los Angeles WB6KBL dickb...@ix.netcom.com ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4 Issue
On Sun, 12 Jun 2011 23:37:44 +, Windows Live Team wrote: AC4 keeps blowing fuses when the power to the T4XB is turned on. Anybody have ideas? Something is shorted somewhere in the power supply or radio. 73 -Jim -- Ham Radio NU0C Lincoln, Nebraska, U.S.S.A. TR7/RV7/R7A/L7, TR6/RV6, T4XC/R4C/L4B, NCL2000, SB104A, R390A, GT550A/RV550A, HyGain 3750, IBM PS/2 - all vintage, all the time! Give a man a URL, and he will learn for an hour; teach him to Google, and he will learn for a lifetime. HyGain 3750 User's Group - http://groups.yahoo.com/group/HyGain_3750/ http://incolor.inetnebr.com/jshorney http://www.nebraskaghosts.org ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4 Issue
First check out the AC-4. Start with http://www.wb4hfn.com/DRAKE/DrakeArticles/TechTips/PowerSupplyTroubleshooting.htm 73,Bob WW3QB --- On Sun, 6/12/11, Windows Live Team wd9...@hotmail.com wrote: From: Windows Live Team wd9...@hotmail.com Subject: [Drakelist] AC-4 Issue To: drakelist@zerobeat.net Date: Sunday, June 12, 2011, 7:37 PM AC4 keeps blowing fuses when the power to the T4XB is turned on. Anybody have ideas? Thanks 73, Jude WD9FUM -Inline Attachment Follows- ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4 Issue
-Original Message- From: y...@aol.com y...@aol.com JUDE Separate the supply from the radio , put in a new fuse, jumper position 1 and 2 on the end of the power cable, a heavy short piece of wire, and plug in the supply. If the fuse does NOT blow, looks like you have a problem in the rig. Get the schematic of the supply and if the supply looks good,check the supply voltages. BE CAREFUL, VOLTAGES ON THE SUPPLY CAN KILL YOU. good luck dale wt4t -Original Message- From: Windows Live Team wd9...@hotmail.com To: drakelist@zerobeat.net Sent: Sun, Jun 12, 2011 7:37 pm Subject: [Drakelist] AC-4 Issue AC4 keeps blowing fuses when the power to the T4XB is turned on. Anybody have ideas? Thanks 73, Jude WD9FUM = ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] ac-4
Bought 2 ac-4s and rebuilt one with the Heathkit shop board. I would like to sell the other ac-4 has full cover ,very clean sn#28901,all cables and line cord like new. asking 99.00 split shipping thanks dale wt4t ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4
I recently rebuilt my AC4 power supply using the AC-4R Replacement Power Supply PCB. I completed the rebuild without errors but not without difficulty. I found the references to the under chassis components and terminal pins to be ambiguous requiring a lot of head scratching to get it right. After the rewiring is complete, you are instructed to jumper pins 1 and 2 of the Jones plug before performing the HV and Bias Voltage tests. The Jones plug pinout with the info that the plug is to be viewed from the solder pin side, is inconveniently missing from the copy of the AC-4 Power Supply Schematic, which is provided in the instructions. Otherwise, the circuit board is of high quality as are the other included components. 73 and good luck with it, ~Damon Raphael, W7MD On 02/24/2011 10:16 AM, Windows Live Team wrote: Looks like it's time to rebuild my AC-4. Does anybody have references or suggestions? TNX ES 73, Jude WD9FUM ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4
This is all you need. Just did one a couple of months ago, works great! _http://www.theheathkitshop.com/page7/page7.html_ (http://www.theheathkitshop.com/page7/page7.html) 73/Paul, K4MSG n a message dated 2/24/2011 12:18:12 P.M. Eastern Standard Time, wd9...@hotmail.com writes: Looks like it's time to rebuild my AC-4. Does anybody have references or suggestions? TNX ES 73, Jude WD9FUM = ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4
Same for meeasy build, easy install, great performanceno-brainer. Dino KL0S On Feb242011, at 1222 PM, ph...@aol.com wrote: This is all you need. Just did one a couple of months ago, works great! http://www.theheathkitshop.com/page7/page7.html 73/Paul, K4MSG ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4
Jude, I too endorse highly the AC4R kit from Heathkit Shop, but would caution you as he will in the literature with the kit to be SURE that you are comfortable with working with the high voltage found in the kit. If so, it's the best!!! 73, Don, WB5HAK ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4
- Original Message - From: Don Cunningham d...@martineer.net To: memberservice...@live.com; drakelist@zerobeat.net Sent: Thursday, February 24, 2011 9:57 AM Subject: Re: [Drakelist] AC-4 Jude, I too endorse highly the AC4R kit from Heathkit Shop, but would caution you as he will in the literature with the kit to be SURE that you are comfortable with working with the high voltage found in the kit. If so, it's the best!!! 73, Don, WB5HAK I've also installed a Heathkit Shop kit. Assembling the circuit board is very easy, and, in fact, installing it was pretty simple but the instructions for the final installation leave a lot to be desired. Nonetheless it all went pretty smoothly. The kit does not change the circuit; it simply replaces the caps with modern radial lead ones and replaces other parts which are likely to have fatigued. The bias circuit everyone warns about remains exactly the same other than the caps are replaced. In fact, you can get the original canned caps from some specialty places but it would probably cost as much as the kit and the kit will make future replacements easier. The high voltage in the Drake supply should be respected. The instructions want you to measure the voltage under unloaded conditions using a jumper to operate the supply without connecting it to the transmitter. Just be careful. While the filter caps have a bleeder on them they will hold a charge for a few minutes after power is removed. A charged cap without a bleeder will knock you across the room, they hold a lot of energy. I found the voltages given in the instructions to be optimistic and higher than the Drake info indicates (this was at the correct line voltage). Also, on mine the ripple was a bit higher than speced but also works fine. The instructions suggest leaving the original caps in place for appearance. I removed them from mine. Partly that is because the resulting holes in the chassis are useful for wiring and also because old electrolytic caps can eventually leak rather corrosive material. Its just as well to get rid of them. While you have the thing open clean the bias pot with some Deoxit, or better with the lubricant-cleaner made by the same people, Caig. Also, if you make any ground connections by soldering directly to the chassis you will need a _big_ iron. Not necessarily high wattage just one with a massive tip. -- Richard Knoppow Los Angeles WB6KBL dickb...@ix.netcom.com ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4
Jude, I just did one with that upgrade kit. Worked super. It will take a while. It is actually fun. Work slowly, carefully and when your not tired around high voltage. If your checking voltages live, keep one hand in your pocket (and don't lean on the chassis) :-) I am doing a L-4B PS now..in either case. One mistake and you may become SK. Oh, I also recommend using a digital camera to capture the before in detail before starting. 73, Lee Lee Simmonds Summit DCS LLC 260-799-4077 Office 260-403-6936 Cell -Original Message- From: Don Cunningham d...@martineer.net To: memberservices-6 memberservice...@live.com; drakelist drakelist@zerobeat.net Sent: Thu, Feb 24, 2011 12:59 pm Subject: Re: [Drakelist] AC-4 Jude, I too endorse highly the AC4R kit from Heathkit Shop, but would caution you as he will in the literature with the kit to be SURE that you are comfortable with working with the high voltage found in the kit. If so, it's the best!!! 73, Don, WB5HAK ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] AC-4 rebuild problem
I'm rebuilding an AC-4 using the heathkitshop kit. I've got it all wired and double (even triple) checked all the wiring. I don't see any problems. When I power it up I get sparks and arching sizzle from where one of the red wires attaches to the PCB pad. This is the 2nd one I've rebuilt... the first one went fine with no issues. I will add that the components of the kit are good quality. However, the instructions are in serious need of attention. I'd appreciate any ideas, fellows? ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] AC-4 rebuild problem (Solved)
Bad solder joint... went back in and reheated the solder connections to the PCB... powers up fine now!! ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] AC-4 Power Cable
I need a 24 inch piece of the AC-4 power cable with or without the Molex connector. Does anyone out there have a drake power supply they have scrapped or know of a source for this cable? Terry, W8NJR ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4 / R-4C Voltage Questions
Jon - See below ... kilo4wit wrote: I'm in the process of getting some c-lines back to life. Befor I even started to delve into these boxes, I am making the assumption that I will need to replace electrolytics. I ordered all new single value cans of near values from Mouser. I have a few questions on voltages: AC-4 Pin #10 is showing 717VDC verse 650VDC Pin #11 is showing 292VDC verse 250VDC These are OK, just at peak because bleeder current only. Pin #9 showing -60VDC - OK This voltage is adjustable with the BIAS pot on the side. Should vary from -50 to -100 VDC with no load. This is the most critical voltage. If this fails, it can cause catastrophic damage to the transmitter, even if it has been left in STANDBY. These filter caps should be replaced, regardless. Watch polarity, as they are upside down. Pin #6/#4 showing 14VDC - OK This should be ~ 14 V AC between these two pins. This is the 12.6VAC filament supply, at no load. No hum is observed with 0 load. What would cause the higher than spec voltages? Should I replace caps on general principal? Best is to use the AC-4R upgrade kit from heathkitshop.com. It replaces all but a couple of components and puts them on one PC board. I think the transformer, fuse and BIAS pot are about all that is not replaced. R-4C Unit burnt transformer on start-up. I don't know the history of this unit. I received a replacement transformer. What would cause it to burn up? Capacitors in the power section? Most likely cause is shorted filter caps. Drop-in replacement caps are available from hayseedhamfest.com, although currently there may be a supply problem. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 4-B, C-Line TR-4/C Service Supplement CDs www.k4oah.com ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] AC-4 / R-4C Voltage Questions
I'm in the process of getting some c-lines back to life. Befor I even started to delve into these boxes, I am making the assumption that I will need to replace electrolytics. I ordered all new single value cans of near values from Mouser. I have a few questions on voltages: AC-4 Pin #10 is showing 717VDC verse 650VDC Pin #11 is showing 292VDC verse 250VDC Pin #9 showing -60VDC - OK Pin #6/#4 showing 14VDC - OK No hum is observed with 0 load. What would cause the higher than spec voltages? Should I replace caps on general principal? R-4C Unit burnt transformer on start-up. I don't know the history of this unit. I received a replacement transformer. What would cause it to burn up? Capacitors in the power section? Thanks...jon k4wit___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] ac-4 rebuild kit
The rebuild kit is back up for sale,brand new never opened. The BUYER, I guess flaked out, on the deal. I would like to get 50.00 for the kit shipped. Its the kit from the heathkit shop.?? Would like to go via pay pal. for payment . pay pal? is?? y...@aol.com Please get back off line. thanks dale wt4t ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] ac-4 kit
I guess its sold ,pending funds. thanks to all? who ?e mailed. dale wt4t ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] AC-4 (First Steps pt2?)
Hi all again, AD5IY still trying to get back on the air with my 4B twins. I have not ordered the AC-4R kit yet. I plan on it soon though. I have been looking inside my AC-4 and stuff, which came up with a question for those that have already installed one of the upgrade kits. I have found that on the original AC-4 that D4 is showing short. On my multimeter on the diode check setting, all B5G5 Diodes are reading somewhere around .5v for forward bias/OL for reverse... standard for diodes, but D4 is reading .08v fwd/rev bias... so the top leg of the 650 line is not held ~1v above ground ( by what I understand on the schematic). Weird, I can read drawings, I can understand flow, but I really cannot understand what this would do to the ckt... Nor do I have a multimeter currently at my new location to see if the 650 is actually at 650 or somewhere else... so I wouldn't doubt that will effect the transmitter in some way. I did take the suggestion of one and setup a lightbulb dummy load seeing how I currently do not have my oil can here yet either(not sure when I can get my can here...) but I wanted to check this out and maybe (hopefully soon) get the AC-4R kit before I really try to start transmitting. So, would repairing this before getting the AC-4R kit be advantagious? or just wait for the kit? and just cause this pinwheel of an antenna that I have made is kinda annoying, anyone got any sites for info or ideas on an good hidden antenna for a 2nd floor apartment? Thanks all! Hope to hear ya on the radios when I get them fully up and running! ET2 Bonnough, Jason A AD5IY ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4 (First Steps pt2?)
Jason - D3 and D4 are connected in series to increase the Peak Inverse Voltage of that leg of the voltage doubler power supply. I would NOT turn on the power supply again! You have just been lucky so far. The B5G5 diode is only rated at 600v PIV, which is why Drake used two in series in this power supply. If the second one (D3) shorts from overload, _hopefully_ the fuse will blow before the power transformer blows. ALL the diodes are replaced, (as is just about everything else besides the transformer and Bias adjust pot,) by the AC-4R kit, so you'll be fine once that is installed. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 4-B, C-Line TR-4/C Service Supplement CDs www.k4oah.com Jason Bonnough wrote: Hi all again, AD5IY still trying to get back on the air with my 4B twins. I have not ordered the AC-4R kit yet. I plan on it soon though. I have been looking inside my AC-4 and stuff, which came up with a question for those that have already installed one of the upgrade kits. I have found that on the original AC-4 that D4 is showing short. On my multimeter on the diode check setting, all B5G5 Diodes are reading somewhere around .5v for forward bias/OL for reverse... standard for diodes, but D4 is reading .08v fwd/rev bias... so the top leg of the 650 line is not held ~1v above ground ( by what I understand on the schematic). Weird, I can read drawings, I can understand flow, but I really cannot understand what this would do to the ckt... Nor do I have a multimeter currently at my new location to see if the 650 is actually at 650 or somewhere else... so I wouldn't doubt that will effect the transmitter in some way. I did take the suggestion of one and setup a lightbulb dummy load seeing how I currently do not have my oil can here yet either(not sure when I can get my can here...) but I wanted to check this out and maybe (hopefully soon) get the AC-4R kit before I really try to start transmitting. So, would repairing this before getting the AC-4R kit be advantagious? or just wait for the kit? and just cause this pinwheel of an antenna that I have made is kinda annoying, anyone got any sites for info or ideas on an good hidden antenna for a 2nd floor apartment? Thanks all! Hope to hear ya on the radios when I get them fully up and running! ET2 Bonnough, Jason A AD5IY ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[drakelist] AC-4 Magazine Article: EPILOGUE
EP Swynar [EMAIL PROTECTED] made an utterance to the drakelist gang -- Good Morning All, Many thanks to Lou, Chuck, Garey, Bill, and Eugene, for steering me in the right direction re. the AC-4 modifications / upgrade article... QST for January 2008 it is...thanks, gentlemen! ~73~ Eddy VE3CUI - VE3XZ -- Submissions:[EMAIL PROTECTED] Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net --
Re: [drakelist] AC-4 PS mod. board
[EMAIL PROTECTED] writes: QST for January 2008 it is...thanks... Just a reminder to all, and there are various pictures of it on line, both AC4 AC3. That kit works nicely on an AC 3 (I have two). Carl WD8NHK **It's Tax Time! Get tips, forms, and advice on AOL Money Finance. (http://money.aol.com/tax?NCID=aolprf000301)
[drakelist] AC-4 plug
[EMAIL PROTECTED] made an utterance to the drakelist gang -- Looking for the plug that mates with the AC-4 Power Supply vox relay. A mfg part number would be great. Tnx for your help. 73, Windy W4ZAA -- Submissions:[EMAIL PROTECTED] Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net --
Re: [drakelist] AC-4 Relay Plug
richard radke [EMAIL PROTECTED] made an utterance to the drakelist gang -- Clair, What I've used for years are pins from a discarded 8 pin (octal) tube base...Break the plastic base apart with pliers...unsolder the pins from the wires of the gird, plate etc., solder the new wires in...the tube pins go all the way into the AC4 jacks, so they can't short...If your using an L4B, they work great on the amp end too Rick W9WS Clair Truax wrote: Clair Truax [EMAIL PROTECTED] made an utterance to the drakelist gang -- Could someone point me to a source for the little two-pole relay plug for the back of the AC-4 power supply, which I use to key an amplifier? At present I am just inserting wires into it and taping it in place with duct tape, not an elegant way to do it, but it works! CUL, CLAIR KJ6NJ ___ Borrego Springs, California 92004 -- Submissions:drakelist@www.zerobeat.net Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net -- -- Submissions:drakelist@www.zerobeat.net Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net --
[drakelist] AC-4 Relay Plug
Clair Truax [EMAIL PROTECTED] made an utterance to the drakelist gang -- Could someone point me to a source for the little two-pole relay plug for the back of the AC-4 power supply, which I use to key an amplifier? At present I am just inserting wires into it and taping it in place with duct tape, not an elegant way to do it, but it works! CUL, CLAIR KJ6NJ ___ Borrego Springs, California 92004 -- Submissions:drakelist@www.zerobeat.net Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net --
Re: [drakelist] AC-4 Relay Plug
Here's how I homebrewed an AC-4 relay connector: http://www.zerobeat.net/drakelist/voxrelayplug.html Tom On 11/29/06, Clair Truax [EMAIL PROTECTED] wrote: Clair Truax [EMAIL PROTECTED] made an utterance to the drakelist gang -- Could someone point me to a source for the little two-pole relay plug for the back of the AC-4 power supply, which I use to key an amplifier? At present I am just inserting wires into it and taping it in place with duct tape, not an elegant way to do it, but it works! CUL, CLAIR KJ6NJ ___ Borrego Springs, California 92004 -- Submissions:drakelist@www.zerobeat.net Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net --
Re: [drakelist] AC-4 measured voltages
Garey Barrell [EMAIL PROTECTED] made an utterance to the drakelist gang -- Al - Sounds good for an unloaded supply. 73, Garey - K4OAH Atlanta Drake B C-Line Service CDs http://www.k4oah.com n7ioh wrote: n7ioh [EMAIL PROTECTED] made an utterance to the drakelist gang -- Hi all, I just installed my 120-240 VAC switch in my AC-4 and replaced R3 with a 100 ohm 10 watt resistor (was burnt). I wanted to be sure I did not have any problems so I checked the voltages to be sure. I think all is OK but thought it wiser to ask those of you with more experience then me if all is well. I just finished checking the voltages as described by Mark Gilger WB0IQK in his AC-4 Trouble Shooting article. I did the test as he described but was wondering if my voltages are close enough or typical of a no load voltage readings at the AC-4 plug. My input voltage is 120VAC, the +650VDC reading is 715VDC, the +250VDC reading is 292VDC, my bias adjusted fine and my filament voltage was 13.86VAC. Thanks, Al, n7ioh -- Submissions:drakelist@www.zerobeat.net Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net --
Re: [drakelist] AC-4 measured voltages
n7ioh [EMAIL PROTECTED] made an utterance to the drakelist gang -- Thanks guys for verifying the voltages are within the acceptable range. Al, n7ioh -- Submissions:drakelist@www.zerobeat.net Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net --
[drakelist] AC-4 measured voltages
n7ioh [EMAIL PROTECTED] made an utterance to the drakelist gang -- Hi all, I just installed my 120-240 VAC switch in my AC-4 and replaced R3 with a 100 ohm 10 watt resistor (was burnt). I wanted to be sure I did not have any problems so I checked the voltages to be sure. I think all is OK but thought it wiser to ask those of you with more experience then me if all is well. I just finished checking the voltages as described by Mark Gilger WB0IQK in his AC-4 Trouble Shooting article. I did the test as he described but was wondering if my voltages are close enough or typical of a no load voltage readings at the AC-4 plug. My input voltage is 120VAC, the +650VDC reading is 715VDC, the +250VDC reading is 292VDC, my bias adjusted fine and my filament voltage was 13.86VAC. Thanks, Al, n7ioh -- Submissions:drakelist@www.zerobeat.net Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net --
RE: [drakelist] AC-4 120-240V switch
Hi, Take a look on http://www.dproducts.be/drake%5FMuseum/ac-4_ps.htm 73s, JM CHERRY De: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] De la part de [EMAIL PROTECTED] Envoyé: jeudi 25 mai 2006 22:18 À: [EMAIL PROTECTED] Cc: drakelist@www.zerobeat.net Objet: Re: [drakelist] AC-4 120-240V switch Hi John, I thought ALL the later model AC-4's were duel voltage units only requiring an internal wiring change. Mine is SN 55719. The latest serial number I have is 58298 and it is a single voltage supply. There are no cououts that don't have a factory connector mounted in them. It doesn't make sense to me that Drake would put a dual primary transformer in the power supply and hot have a way to switch it from the factory. Are you sure that the cutout is for that swith? Is it screened on the supply? It might be possible that someone removed the infamous 2 pin relay connector which would leave a cutout the same size as the switch. Check your schematic against the primary of the trasformer. If there are 2 sets of primary leads, then you have a dual voltage tranny, if there is only one set, it is a 120V power supply. 73, John
Re: [drakelist] AC-4 120-240V switch
Hi John, I thought ALL the later model AC-4's were duel voltage units only requiring an internal wiring change. Mine is SN 55719. The latest serial number I have is 58298 and it is a single voltage supply. There are no cououts that don't have a factory connector mounted in them. It doesn't make sense to me that Drake would put a dual primary transformer in the power supply and hot have a way to switch it from the factory. Are you sure that the cutout is for that swith? Is it screened on the supply? It might be possible that someone removed the infamous 2 pin relay connector which would leave a cutout the same size as the switch. Check your schematic against the primary of the trasformer. If there are 2 sets of primary leads, then you have a dual voltage tranny, if there is only one set, it is a 120V power supply. 73, John
[drakelist] AC-4 120-240V switch
[EMAIL PROTECTED] made an utterance to the drakelist gang -- Hi guys, I have the AC-4R kit I am going to install in my AC-4 and was wondering about installing the 120-240V switch. My AC-4 is the later model and already has the cutout for the switch. Can someone tell me what switch I would need and where I might find them including the lock tab? The reason for wanting the switch is I am now retired and will be doing some traveling and thought it would be more convenient to be able to switch the voltage from the outside. I don't really know if I will be taking the Drake with me to any countries that require 240 volts or not but as long as I have the supply open I thought I would do it. Thanks, Al, n7ioh -- Submissions:drakelist@www.zerobeat.net Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net --
Re: [drakelist] AC-4 120-240V switch
Hi Al, You are going to have to be sure that the transformer has a dual primary. If you have the cutout and there was no switch ever mounted in it, chanses are that you may just have a single primary tranny that will only work on 120V. 73, John, W4AWM Hi guys, I have the AC-4R kit I am going to install in my AC-4 and was wondering about installing the 120-240V switch. My AC-4 is the later model and already has the cutout for the switch. Can someone tell me what switch I would need and where I might find them including the lock tab?
[drakelist] AC-4 120-240V switch
[EMAIL PROTECTED] made an utterance to the drakelist gang -- Hi John, I thought ALL the later model AC-4's were duel voltage units only requiring an internal wiring change. Mine is SN 55719. Al, n7ioh On May 24, 2006, at 9:26 PM, [EMAIL PROTECTED] wrote: Hi Al, You are going to have to be sure that the transformer has a dual primary. If you have the cutout and there was no switch ever mounted in it, chanses are that you may just have a single primary tranny that will only work on 120V. 73, John, W4AWM -- Submissions:drakelist@www.zerobeat.net Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net --
Re: [drakelist] AC-4 Cap values
Ron [EMAIL PROTECTED] made an utterence to the drakelist gang -- These NTC Thermistors are often sold as Inrush Current Limiters They are made by Keystone Electronics, come in a variety of values, and (I think) can still be bought from Digikey. I bought a selection of values from them years ago when I built a 500W 6550 based audio amp. It had 8000 MF of capacitance in the PS, and would blow a 25 amp fuse every other time you turned it on. The inrush limiter solved that problem perfectly: 12 years later I still haven't popped a fuse. At 06:49 PM 3/3/2005, Carl Strode wrote: Carl Strode [EMAIL PROTECTED] made an utterence to the drakelist gang -- What I may do is to install a NTC (Negative Temperature Coefficient) high current thermistor in series with the incoming AC line. These are really cool devices. At room temperature (25C/ 77F) they exhibit a high resistance, as they self heat, the resistance drops. The one I will try starts out at 47 ohms, then slowly drops to less than one ohm in less than a second. Steady state current rating is 4 amps. Perfect for a surge limiter. Gerry wrote: Unfortunately, inserting series resistors in the B+ leads will, depending on the value, adversely affect regulation. It may work fine for static loads such as the +250 supply but is not advisable for HV supplies with dynamic loads. Years ago I tried a home brew power supply constructed with mil surplus components. What I found is that choke input supplies need a critical value resistive load to maintain the voltage below allowable limits. With no load on the +650 volts, it went almost to the rating of the filter caps which I believe was 800 volts. Trying another approach with a capacitive input filter and a choke meant I had to find another transformer. When I did, the 50 Ohms resistance of the choke became somewhat of a problem which all made sense later. At 450 mils, that would be a 22.5 volt drop on top of whatever the drop was in the first place. The thump comes from the transformer and is loudest when power is switched on at the peak of the primary AC cycle. Sometimes you can hit it just right. When I built my Heathkit SB-1000 linear, there was an alignment procedure which called for removing the screws and sliding the case back about an inch or so. This was done per the assembly instructions to align the input coils. When I turned on the amp for the first time, there was a loud KABAM! After changing my underwear, it became obvious what happened: there was a surge at turn on and the steel cover acted like a sounding board. Nothing bad happened to the amp, it was just one of those things that makes you tremble whenever you reach for the ON switch. This brings up another point about the need for slow-start on such devices. I don't use the linear often but it is on my to-do list. -Original Message- *From:* [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] *On Behalf Of [EMAIL PROTECTED] *Sent:* Thursday, March 03, 2005 2:54 AM *To:* drakelist@www.zerobeat.net *Subject:* Re: [drakelist] AC-4 Cap values Carl, Now might be a good time to review some slow-start feature design reviews, looking forward to incorporating one into the turn-on function of the power supply. When you have a thump from turning on a power supply, it generally is indicative of too great of a surge current going into the filter capacitors and stressing them unnecessarily. It doesn't help the rectifiers, either. Also, I'm not sure that it is a leaky capacitor that causes the thump you heard at power supply turn-onI've always been led to believe that the thump was from the large flow of current into an uncharged capacitor, although I've never had it proven to me that this was the actual cause. You could, however, benefit the power supply considerably, by inserting a resistor of the proper resistance and wattage, into the 650 volt output, between D2 and the connection to R1. This would also serve to bring your 650 volt HV (now approx. 700 volts, as you indicated) back down nearer to the correct 650 volt value. Your could also do the similar action with a resistor added between D5 and the connection to C3, and also reduce the 290 volts down to the original design value of 250 volts. Possibly, the original design of this power was slighted somewhat, by not including a choke in each of the two points I noted above. That would have produced a significant reduction in the capacitor surge current at turn-on. Chokes would also have been more effective in reducing the ripple you originally saw on the outputs. I'm naturally assuming, of course, that you do intend to reduce power supply outputs down to their specified voltage levels. I haven't intended to sound critical of your modification efforts here, Carl. Moreso, I am critical that Drake didn't put choke filtered supplies
RE: [drakelist] AC-4 Cap values
Unfortunately, inserting series resistors in the B+ leads will, depending on the value, adversely affect regulation. It may work fine for static loads such as the +250 supply but is not advisable for HV supplies with dynamic loads. Years ago I tried a home brew power supply constructed with mil surplus components. What I found is that choke input supplies need a critical value resistive load to maintain the voltage below allowable limits. With no load on the +650 volts, it went almost to the rating of the filter caps which I believe was 800 volts. Trying another approach with a capacitive input filter and a choke meant I had to find another transformer. When I did, the 50 Ohms resistance of the choke became somewhat of a problem which all made sense later. At 450 mils, that would be a 22.5 volt drop on top of whatever the drop was in the first place. The thump comes from the transformer and is loudest when power is switched on at the peak of the primary AC cycle. Sometimes you can hit it just right. When I built my Heathkit SB-1000 linear, there was an alignment procedure which called for removing the screws and sliding the case back about an inch or so. This was done per the assembly instructions to align the input coils. When I turned on the amp for the first time, there was a loud KABAM! After changing my underwear, it became obvious what happened: there was a surge at turn on and the steel cover acted like a sounding board. Nothing bad happened to the amp, it was just one of those things that makes you tremble whenever you reach for the ON switch. This brings up another point about the need for slow-start on such devices. I dont use the linear often but it is on my to-do list. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Thursday, March 03, 2005 2:54 AM To: drakelist@www.zerobeat.net Subject: Re: [drakelist] AC-4 Cap values Carl, Now might be a good time to review some slow-start feature design reviews, looking forward to incorporating one into the turn-on function of the power supply. When you have a thump from turning on a power supply, it generally is indicative of too great of a surge currentgoing intothe filter capacitors and stressing them unnecessarily. It doesn't help the rectifiers, either. Also, I'm not sure that it is a leaky capacitor that causes the thump you heard at power supply turn-onI've always been led to believe that the thump was from the large flow of current into an uncharged capacitor, although I've never had it proven to me that this was the actual cause. You could, however, benefit the power supply considerably, by inserting a resistor of the proper resistance and wattage, into the 650 volt output, between D2 and the connection to R1. This would also serve to bring your 650 volt HV (now approx. 700 volts, as you indicated) back down nearer to the correct 650 volt value. Your could also do the similar action with a resistor added between D5 and the connection to C3, and also reduce the 290 volts down to the original design value of 250 volts. Possibly,the original design of this power was slightedsomewhat, by not including a choke in each ofthe two points I noted above. That would have produced a significant reduction in the capacitor surge currentat turn-on.Chokes would also have been more effective in reducing the ripple you originally saw on the outputs. I'm naturally assuming, of course, that you do intendtoreduce power supply outputsdown to their specified voltage levels. I haven't intended to sound critical of your modification efforts here, Carl. Moreso, I am critical that Drake didn't putchoke filtered supplies in this equipment. I would sure have liked my T-4XB/R-4B's AC-4 to have been choke filtered. (Guess they figured the cost of the choke, a place to put it, and also a slight change in the secondary output winding in the power transformer secondaries would cost too much to add into the equipment price. Anyhow, and Meanwhile, back at the Ranch (asthey say, somewhere) keep up the good work, and keep us posted. Bill Flowers K5VKL ___ On Wed, 02 Mar 2005 20:37:21 -0800 Carl Strode [EMAIL PROTECTED] writes: Carl Strode [EMAIL PROTECTED] made an utterence to the drakelist gang -- I have completed re-capping the AC-4. After looking at the actual caps installed, and comparing it to my supply of modern electrolytics, I have replaced the 40 mfd caps (shown as 40 mfd on most schematics) with 33 mfd. The HV filter caps were replaced with 150 mfd 450 volt units. ( I had a bunch of these laying around). Since my original late model AC-4 had a 100 mfd cap
Re: [drakelist] AC-4 Cap values
Carl Strode [EMAIL PROTECTED] made an utterence to the drakelist gang -- What I may do is to install a NTC (Negative Temperature Coefficient) high current thermistor in series with the incoming AC line. These are really cool devices. At room temperature (25C/ 77F) they exhibit a high resistance, as they self heat, the resistance drops. The one I will try starts out at 47 ohms, then slowly drops to less than one ohm in less than a second. Steady state current rating is 4 amps. Perfect for a surge limiter. Gerry wrote: Unfortunately, inserting series resistors in the B+ leads will, depending on the value, adversely affect regulation. It may work fine for static loads such as the +250 supply but is not advisable for HV supplies with dynamic loads. Years ago I tried a home brew power supply constructed with mil surplus components. What I found is that choke input supplies need a critical value resistive load to maintain the voltage below allowable limits. With no load on the +650 volts, it went almost to the rating of the filter caps which I believe was 800 volts. Trying another approach with a capacitive input filter and a choke meant I had to find another transformer. When I did, the 50 Ohms resistance of the choke became somewhat of a problem which all made sense later. At 450 mils, that would be a 22.5 volt drop on top of whatever the drop was in the first place. The thump comes from the transformer and is loudest when power is switched on at the peak of the primary AC cycle. Sometimes you can hit it just right. When I built my Heathkit SB-1000 linear, there was an alignment procedure which called for removing the screws and sliding the case back about an inch or so. This was done per the assembly instructions to align the input coils. When I turned on the amp for the first time, there was a loud KABAM! After changing my underwear, it became obvious what happened: there was a surge at turn on and the steel cover acted like a sounding board. Nothing bad happened to the amp, it was just one of those things that makes you tremble whenever you reach for the ON switch. This brings up another point about the need for slow-start on such devices. I dont use the linear often but it is on my to-do list. -Original Message- *From:* [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] *On Behalf Of [EMAIL PROTECTED] *Sent:* Thursday, March 03, 2005 2:54 AM *To:* drakelist@www.zerobeat.net *Subject:* Re: [drakelist] AC-4 Cap values Carl, Now might be a good time to review some slow-start feature design reviews, looking forward to incorporating one into the turn-on function of the power supply. When you have a thump from turning on a power supply, it generally is indicative of too great of a surge current going into the filter capacitors and stressing them unnecessarily. It doesn't help the rectifiers, either. Also, I'm not sure that it is a leaky capacitor that causes the thump you heard at power supply turn-onI've always been led to believe that the thump was from the large flow of current into an uncharged capacitor, although I've never had it proven to me that this was the actual cause. You could, however, benefit the power supply considerably, by inserting a resistor of the proper resistance and wattage, into the 650 volt output, between D2 and the connection to R1. This would also serve to bring your 650 volt HV (now approx. 700 volts, as you indicated) back down nearer to the correct 650 volt value. Your could also do the similar action with a resistor added between D5 and the connection to C3, and also reduce the 290 volts down to the original design value of 250 volts. Possibly, the original design of this power was slighted somewhat, by not including a choke in each of the two points I noted above. That would have produced a significant reduction in the capacitor surge current at turn-on. Chokes would also have been more effective in reducing the ripple you originally saw on the outputs. I'm naturally assuming, of course, that you do intend to reduce power supply outputs down to their specified voltage levels. I haven't intended to sound critical of your modification efforts here, Carl. Moreso, I am critical that Drake didn't put choke filtered supplies in this equipment. I would sure have liked my T-4XB/R-4B's AC-4 to have been choke filtered. (Guess they figured the cost of the choke, a place to put it, and also a slight change in the secondary output winding in the power transformer secondaries would cost too much to add into the equipment price. Anyhow, and Meanwhile, back at the Ranch (as they say, somewhere) keep up the good work, and keep us posted. Bill Flowers K5VKL ___ On Wed, 02 Mar 2005 20:37:21 -0800 Carl Strode [EMAIL PROTECTED] mailto:[EMAIL PROTECTED] writes: Carl Strode [EMAIL PROTECTED] mailto:[EMAIL PROTECTED] made an utterence to the drakelist gang
Re: [drakelist] AC-4 Cap values
Jim Shorney [EMAIL PROTECTED] made an utterence to the drakelist gang -- On Thu, 03 Mar 2005 15:49:52 -0800, Carl Strode wrote: What I may do is to install a NTC (Negative Temperature Coefficient) high current thermistor in series with the incoming AC line. These are really cool devices. I salvage these from dead PC power supplies and monitors. They're usually just about right for an AC4. Here's a good article on inrush limiting, courtesy of the R-390(a) crowd: http://209.35.120.129/Pearls/inrush-current-FAQ.pdf -- Jim Shorney --.--Put complaints in this box jshorney (at) inebraska.com nu0c (at) amsat.org Ham Radio NU0C Lincoln, NE, USA EN10ps http://incolor.inetnebr.com/jshorney/ -- On Behalf of Jim Shorney [EMAIL PROTECTED] Submissions:drakelist@www.zerobeat.net Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: http://www.zerobeat.net Brought to you courtesy of TLCHost.net http://www.tlchost.net/ --
Re: [drakelist] AC-4 Cap values
Carl Strode [EMAIL PROTECTED] made an utterence to the drakelist gang -- I have completed re-capping the AC-4. After looking at the actual caps installed, and comparing it to my supply of modern electrolytics, I have replaced the 40 mfd caps (shown as 40 mfd on most schematics) with 33 mfd. The HV filter caps were replaced with 150 mfd 450 volt units. ( I had a bunch of these laying around). Since my original late model AC-4 had a 100 mfd cap installed at C3 and C4a, and an 80 mfd cap installed at C4b, I decided to keep everything simple and replace these with 150 mfd caps as well. I'll save all of my 82 and 100 mfd caps for some other project. The 150 mfd caps I have are circuit board mount types, with both leads on one end. This made installation above decks a snap. I removed the old caps, and then reamed out one of the holes used for the old cap mounting screws. I installed a 1-1/4 inch long 6-32 machine screw from the bottom so it is sticking straight up near the center of the transformer primary winding. Using nylon tie-wrap, two new caps were attached to the . Just to be safe, I insulated the machine screw with some heavy-wall heat-shrink. This also provided a better grip for the tie-wraps. I soldered the 150K resistors directly across the cap terminals. I used a similar technique with the remaining five caps. Two caps per machine screw, and a single one for C4a. I mounted C3 and C4b right next to each other, and soldered the big 100 ohm power resistor right across the terminals. When I was finished, there was essentially no ripple at all! only about a tenth of a volt on the 650 and the 250 volt, and about 0.2volts on the bias supply. Oh yes, as usual nowadays, the 650 is really closer to 700, and the 250 is about 290. When the power supply is switched on, it thunks a bit harder than it used to, due to the lack of leaky caps and the increased cap values. The supply is much stiffer than before. Very little sag and absolutely no detectable hum. I guess this demonstrates that with brute force, we don't need no steenkin regulators! When I started, the HV was only about 450 volts with lotsa AC. Carl Strode wrote: Carl Strode [EMAIL PROTECTED] made an utterence to the drakelist gang -- I am about to re-cap one of my AC-4s. Looking at several schematics, I note that C5a and C5b are shown as 20 microfarads. I have a parts list dated September 1, 1974 that shows both C5s as 40 microfarads. Looking at the AC-4 I see that indeed there are 40 mic caps installed. What is the scoop here?? Also, I have found a bunch of new electrolytics of larger values that I am planning to use.I will replace an old 125 with a new 150 This is OK, right? What really has me puzzled is the 20 vs 40 mic caps. I was planning on using some 33 mic caps I have on hand. By the way, all of my new caps are 400-450 volt ratings. Please advise. Carl WA7CS R4B, T4XB -- On Behalf of Carl Strode [EMAIL PROTECTED] Submissions:drakelist@www.zerobeat.net Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: http://www.zerobeat.net Brought to you courtesy of TLCHost.net http://www.tlchost.net/ -- -- On Behalf of Carl Strode [EMAIL PROTECTED] Submissions:drakelist@www.zerobeat.net Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: http://www.zerobeat.net Brought to you courtesy of TLCHost.net http://www.tlchost.net/ --
[drakelist] AC-4 Cap values
Carl Strode [EMAIL PROTECTED] made an utterence to the drakelist gang -- I am about to re-cap one of my AC-4s. Looking at several schematics, I note that C5a and C5b are shown as 20 microfarads. I have a parts list dated September 1, 1974 that shows both C5s as 40 microfarads. Looking at the AC-4 I see that indeed there are 40 mic caps installed. What is the scoop here?? Also, I have found a bunch of new electrolytics of larger values that I am planning to use.I will replace an old 125 with a new 150 This is OK, right? What really has me puzzled is the 20 vs 40 mic caps. I was planning on using some 33 mic caps I have on hand. By the way, all of my new caps are 400-450 volt ratings. Please advise. Carl WA7CS R4B, T4XB -- On Behalf of Carl Strode [EMAIL PROTECTED] Submissions:drakelist@www.zerobeat.net Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: http://www.zerobeat.net Brought to you courtesy of TLCHost.net http://www.tlchost.net/ --
[drakelist] AC-4 rebuild ???
Keith Hamilton [EMAIL PROTECTED] made an utterence to the drakelist gang -- I have read about the AC-4R rebuild kit from the Heathkit Shop. This seems like an excellent kit but it brings a question to my mind. I have begun to be a bit paranoid about my current power supply! Has anyone used this kit to rebuild their AC-4? Should I worry about my AC-4 quitting on me? It seems to be working just fine but like I say this kit has made me a bit paranoid about my supply! Should I rebuild it or wait until it quits? What criteria does one use to say when you should rebuild? My AC-4 has a relatively high serial number # 51464 Thanks for letting me ramble on for a bit! 73! Keith Hamilton, W8GX -- On Behalf of Keith Hamilton [EMAIL PROTECTED] Submissions:drakelist@www.zerobeat.net Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: http://www.zerobeat.net Brought to you courtesy of TLCHost.net http://www.tlchost.net/ --
Re: [drakelist] AC-4 rebuild ???
Garey Barrell [EMAIL PROTECTED] made an utterence to the drakelist gang -- Keith - Your supply is probably just fine.. I have several supplies that are considerably older than yours that still work as new. There are too many variables, time in service, storage in humid or dry conditions, electrical and/or physical abuse, etc. to make a definitive statement. That being said, there are a few things you can do to protect your supply. First, and most important, be certain that the AC fuse is the correct size. More than a few power transformers have been fried because someone put in a 10A fuse or in at least one case I have seen, a piece of #10 copper wire!! The most critical circuit in the supply is the bias supply. If this supply (-40 to -90V or so) fails, it can kill a transmitter faster than anything else, and it probably won't even blow the fuse. A good interim step is to replace the filter capacitor and diode for this supply. I'd also examine the two resistors visually and measure them with an ohmmeter. Beyond that, replacing the diodes and caps for the two voltage doubler supplies and checking the resistors will make it good for another 30 years. For these, a shorted diode or shorted filter capacitor will blow the primary fuse pretty quickly. A dried out filter cap on the LV supply will introduce noticeable hum long before it fails catastrophically. The AC-4R kit looks like a good alternative to the difficult to find Twist-Lok capacitors, and certainly makes a neat installation. 73, Garey - K4OAH Atlanta Drake C-Line Service Manual http://hr99.home.mindspring.com/R-4C_Servicez/ Keith Hamilton wrote: Keith Hamilton [EMAIL PROTECTED] made an utterence to the drakelist gang -- I have read about the AC-4R rebuild kit from the Heathkit Shop. This seems like an excellent kit but it brings a question to my mind. I have begun to be a bit paranoid about my current power supply! Has anyone used this kit to rebuild their AC-4? Should I worry about my AC-4 quitting on me? It seems to be working just fine but like I say this kit has made me a bit paranoid about my supply! Should I rebuild it or wait until it quits? What criteria does one use to say when you should rebuild? My AC-4 has a relatively high serial number # 51464 Thanks for letting me ramble on for a bit! 73! Keith Hamilton, W8GX -- On Behalf of Garey Barrell [EMAIL PROTECTED] Submissions:drakelist@www.zerobeat.net Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: http://www.zerobeat.net Brought to you courtesy of TLCHost.net http://www.tlchost.net/ --
Re: [drakelist] AC-4 power supply diodes
The life of an electrolytic capacitor is directly related to applied voltage, ripple voltage, and temperature. It used to be that electrolytics were rated for at least 1,000 hours of operation at maximum specified voltage and temperature. The only way to find this out is to look up the data sheet or catalog information both of which are probably unavailable due to the passing of time. Since the Drake power supply has fuse protection, I say don't fix what isn't broke. Assuming of course that the proper fuse is in place. As long as the measured voltages concur with the specifications in the manual, don't lose sleep over it. - Original Message - From: Eric Webner To: Drakelist Sent: Sunday, December 26, 2004 1:58 PM Subject: [drakelist] AC-4 power supply diodes I am working on my T-4XC (again!). I thought I would check out the power supply first, to make sure all voltages are good. They all measured (with DVM) good DC voltage, with very little AC (except for the filament supply, of course). Will such a measurement be accurate, or do I need a scope to check for AC? There have been some discussions about replacing the electrolytic filter caps and possibly the rectifier diodes. I see no leakage around any of the caps, and would hope to not have to hassle with it. The diodes would be much easier to replace, and I would like to know if it is practical to replace them while the unit is open, or should I "not fix what ain't broke?" If replacement is warranted, is there a suitable replacement or cross-reference for the B5G5 diodes? I'd like to use my 1N400x rectifiers that I have in my junk box, if that is appropriate. Thanks for all your help! 73, Eric KA8FAN Do you Yahoo!?Meet the all-new My Yahoo! Try it today!
[drakelist] AC-4 Voltage Carrying Cable to Radio Needed
Lee Bahr [EMAIL PROTECTED] made an utterence to the drakelist gang -- Does anyone on here have an idea where I can get a replacement power cable for my AC-4 power supply? I'm talking about the cord carrying the filament, B+, bias, and switch voltages going to the Jones plug. (Not the AC power cord). If all fails, I guess I'll have to make up a harness out of discreet wires and bundle them together. I hate thinking of doing that. (The present cord is shot, cut, kaput)! I can't find a wire supplier with the appropriate number of wires and wire size needed to make one up and it appears places like Allied or Mouser either want to sell 100 or 1000 foot spools of control wire if I could even find the right cable. The Jones plug is in OK shape. I think the cable was probably made up special for Drake. (I can live with the wrong `wire colors. I can even live with more wires in the bundle doubled up to handle the filament current if required to do so. I just don't want so many extra wires that the cable diameter becomes to much larger then an original cable). Maybe someone has an AC-4 with a burned out power transformer and bad electrolytics I could purchase. I'd sure appreciate hearing from anyone with ideas on how to handle the problem. I'd prefer either a salvaged old cable from an AC-4, a new piece of power cable that would have the correct wires within it, or a burned up AC-4 supply with a good cable. What have i not thought of on this? Lee, w0vt Houston -- On Behalf of Lee Bahr [EMAIL PROTECTED] Submissions:[EMAIL PROTECTED] Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: http://www.zerobeat.net Brought to you courtesy of TLCHost.net http://www.tlchost.net/ --
Re: [drakelist] AC-4 Voltage Carrying Cable to Radio Needed
Ron Wagner [EMAIL PROTECTED] made an utterence to the drakelist gang -- Lee, If all else fails, you might be able to use discreet wires and heat shrink tubing to make a bundle. Not the best option in my opinion, but something I have done once for a non-obtainable cable. I was actually able to used all the old wires except the one that was history. Biggest issue was getting a long piece of shrink tubing. Most places seem to always cut it into 2 or 3 ft lengths. Might be able to overlap enough to make it work out. Maybe I got lucky with my bundle only loosing 1 wire and finding shrink tube. Good luck and hope this helps. 73, Ron Amateur Radio Station: WD8SBB - Ron and KB8NRP - Joann for my AC-4 power supply? I'm talking about the cord carrying the filament, B+, bias, and switch voltages going to the Jones plug. (Not the AC power cord). If all fails, I guess I'll have to make up a harness out of discreet -- On Behalf of Ron Wagner [EMAIL PROTECTED] Submissions:[EMAIL PROTECTED] Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: http://www.zerobeat.net Brought to you courtesy of TLCHost.net http://www.tlchost.net/ --
Re: [drakelist] AC-4 Voltage Carrying Cable to Radio Needed
Thom R. Lacosta [EMAIL PROTECTED] made an utterence to the drakelist gang -- On Wed, 6 Oct 2004, Ron Wagner wrote: ft lengths. Might be able to overlap enough to make it work out. Maybe I got lucky with my bundle only loosing 1 wire and finding shrink tube. Good luck and hope this helps. I'd be tempted to put on on piece of shrink tube...shrink it down, then overlap the second piece...or just get two pieces of different sizes. Thom http://www.baltimorehon.com/Home of the Baltimore Lexicon http://www.tlchost.net/ Web Hosting as low as 3.49/month -- On Behalf of Thom R. Lacosta [EMAIL PROTECTED] Submissions:[EMAIL PROTECTED] Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: http://www.zerobeat.net Brought to you courtesy of TLCHost.net http://www.tlchost.net/ --
Re: [drakelist] AC-4 Voltage Carrying Cable to Radio Needed
[EMAIL PROTECTED] made an utterence to the drakelist gang -- Heat shrink sticks to itself real well. Put on a piece and shrink it, then overlap an inch or so with the other one and shrink it. It will be fine. unless you plan on tying it in a tree and swinging on it. You might be happier with the end product if you twist the wires and hold them so you have a pretty round bundle before you shrink it. It will look nicer that way. Otherwise it will show the irregular shape of the wires. Michael [EMAIL PROTECTED] wrote on 10/06/2004 08:16:54 AM: Thom R. Lacosta [EMAIL PROTECTED] made an utterence to the drakelist gang -- On Wed, 6 Oct 2004, Ron Wagner wrote: ft lengths. Might be able to overlap enough to make it work out. Maybe I got lucky with my bundle only loosing 1 wire and finding shrink tube. Good luck and hope this helps. I'd be tempted to put on on piece of shrink tube...shrink it down, then overlap the second piece...or just get two pieces of different sizes. Thom http://www.baltimorehon.com/Home of the Baltimore Lexicon http://www.tlchost.net/ Web Hosting as low as 3.49/month -- On Behalf of Thom R. Lacosta [EMAIL PROTECTED] Submissions:[EMAIL PROTECTED] Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: http://www.zerobeat.net Brought to you courtesy of TLCHost.net http://www.tlchost.net/ -- -- On Behalf of [EMAIL PROTECTED] Submissions:[EMAIL PROTECTED] Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: http://www.zerobeat.net Brought to you courtesy of TLCHost.net http://www.tlchost.net/ --
Re: [drakelist] AC-4 Voltage Carrying Cable to Radio Needed
Thom R. Lacosta [EMAIL PROTECTED] made an utterence to the drakelist gang -- On Wed, 6 Oct 2004 [EMAIL PROTECTED] wrote: [EMAIL PROTECTED] made an utterence to the drakelist gang -- Heat shrink sticks to itself real well. Put on a piece and shrink it, then overlap an inch or so with the other one and shrink it. It will be fine. unless you plan on tying it in a tree and swinging on it. You might be happier with the end product if you twist the wires and hold them so you have a pretty round bundle before you shrink it. It will look nicer that way. Otherwise it will show the irregular shape of the wires. But don't make it too prettyI once made it about 1/2 turn too pretty and something broke...but that gave me an opportunity to do a nicer job the second time around (g). thom -- On Behalf of Thom R. Lacosta [EMAIL PROTECTED] Submissions:[EMAIL PROTECTED] Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: http://www.zerobeat.net Brought to you courtesy of TLCHost.net http://www.tlchost.net/ --
RE: [drakelist] AC-4 Voltage Carrying Cable to Radio Needed
Goss, Ed [EMAIL PROTECTED] made an utterence to the drakelist gang -- Try some custom cable fabricators on the Web. I just picked one at random (I have no experience with them): https://www.cablestogo.com/custom_form.asp If their price is not to your liking perhaps they would just sell you three feet of cable. --Ed G-- -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Lee Bahr Sent: Wednesday, October 06, 2004 12:41 AM To: [EMAIL PROTECTED] Subject: [drakelist] AC-4 Voltage Carrying Cable to Radio Needed Lee Bahr [EMAIL PROTECTED] made an utterence to the drakelist gang -- Does anyone on here have an idea where I can get a replacement power cable for my AC-4 power supply? I'm talking about the cord carrying the filament, B+, bias, and switch voltages going to the Jones plug. (Not the AC power cord). If all fails, I guess I'll have to make up a harness out of discreet wires and bundle them together. I hate thinking of doing that. (The present cord is shot, cut, kaput)! I can't find a wire supplier with the appropriate number of wires and wire size needed to make one up and it appears places like Allied or Mouser either want to sell 100 or 1000 foot spools of control wire if I could even find the right cable. The Jones plug is in OK shape. I think the cable was probably made up special for Drake. (I can live with the wrong `wire colors. I can even live with more wires in the bundle doubled up to handle the filament current if required to do so. I just don't want so many extra wires that the cable diameter becomes to much larger then an original cable). Maybe someone has an AC-4 with a burned out power transformer and bad electrolytics I could purchase. I'd sure appreciate hearing from anyone with ideas on how to handle the problem. I'd prefer either a salvaged old cable from an AC-4, a new piece of power cable that would have the correct wires within it, or a burned up AC-4 supply with a good cable. What have i not thought of on this? Lee, w0vt Houston -- On Behalf of Lee Bahr [EMAIL PROTECTED] Submissions:[EMAIL PROTECTED] Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: http://www.zerobeat.net Brought to you courtesy of TLCHost.net http://www.tlchost.net/ -- -- On Behalf of Goss, Ed [EMAIL PROTECTED] Submissions:[EMAIL PROTECTED] Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: http://www.zerobeat.net Brought to you courtesy of TLCHost.net http://www.tlchost.net/ --
[drakelist] Ac-4 power cables
Lee, if all else fails, you might try bundling the rotor cable and the extra conductors needed and then wrap the whole group with the plastic cable protector jackets you can purchase at marine stores. if you are not familiar with the stuff, it is black spiral wound plastic which is used to protect marine wiring from chaffing, salt spray etc. and is sold by the foot. Regards, Mike W4DL
[drakelist] AC-4 late S/N, L4B blower assy and ...
Drake AC-4 power supply, 57239 serial number, with the 120V/240V switch. $75 plus shipping from 46835 Complete blower, motor and mounting assembly for the L4B AP with a GOOD fan. $75.00 plus shipping from 46835. I also have 30+ drake crystals in various frequencies (SWL and HAM Bands) for the R4 (A, B and C)series radios. A few are new (10, 15, 20, 40 and 80 I think ... got these from Sherwood to replace a basic set in an R-4C I no longer have). Let me know what you are looking for and I'll see if I have it. $10 used and $20 for new plus shipping. Mike, W9MWS
[drakelist] AC-4 replacement pcb ready to go
MIKE BRYCE [EMAIL PROTECTED] made an utterence to the drakelist gang -- the pcbs for the new drake ac-4 power supply are now in stock. a very limited number of first run kits will be shipping within a week. (waiting on first run of parts) here's some more information on the project: That old Drake AC4 getting a little rough around the edges? Can¹t locate those high voltage capacitors without taking out a bank loan? Well then perhaps the solution is to install the new AC4R upgrade pc board. No, it¹s not from Drake, and no Drake did not use a pc board in their original AC4 design. Here¹s what we¹ve done for the AC4R upgrade: Increase all the silicon diode ratings to 1.5 amp @ 1000 volts Increase high voltage rating of the electrolytic capacitors Increase wattage of the bleeder resistors Mounted the bleeder resistors, bias resistors and R3 on to the pc board (original bias pot still used) All resistors are flameproof 1 watt Resistor R3 is now rated at 10 watts instead of the original 5 watts With the exception of the bias set trimmer, all parts mount on a single PC board No holes to drill. Easy to assemble with complete assembly instructions PC board is double sided with plated through holes. Solder mask on both sides and component silk screen on both sides. Prices: The pc board only is $15 +$4 shipping A complete kit of parts, including the pc board and all board mounted components is $65+ $4 shipping While the AC4R is an easy to build project, there are a lot of wires that must be cut, moved and reconnected to the new pc board. The project is not for the faint of heart. So I will be offering these two options. Options: 1.For those that don¹t have the time, or simply can¹t see anymore to assemble the pc board, we will stuff the board for an additional $10. 2.And for those that like messing with high voltage or hot soldering irons, we will assemble, install and test your AC4 for an additional $45 above the kit price. Customer to pay for shipping both ways for the AC4 supply. you can call me toll free to order your pcb or kit at 1 888 476 5279 I am in the office from 10am to 2 pm. Mike Bryce, WB8VGE SunLight Energy Systems http://www.seslogic.com http://www.theheathkitshop.com -- On Behalf of MIKE BRYCE [EMAIL PROTECTED] Submissions:[EMAIL PROTECTED] Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: http://www.zerobeat.net Brought to you courtesy of TLCHost.net http://www.tlchost.net/ --
[drakelist] AC-4
Everyone, The AC-4 problem my friend was having where he was having trouble interchanging them turned out to be bad contacts on the connectors! Detox did the trick and all is well thanks to all who answered my question. Dan -- Submissions:[EMAIL PROTECTED] Subscribe: [EMAIL PROTECTED] - subscribe drakelist in body Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Brought to you courtesy of TLCHost.net http://www.tlchost.net/ --
Re: [drakelist] ac-4's
IThe AC-4 that came with the TR-4CW will not fire up the TR-4C (the power won't even come on), and the AC-4 that came with the TR-4C will not power up the TR-4CWrit. It should, it is a compatible supply for all the Drake transceivers. Check the fuse, check to see if there is a 120/240switch on the PS and if so, make sure it is in the 120V position, pull the cap off the interconnecting cable and check for broken leads, pull the bottom off the PS and check the primary of the power tranny. Finally, check around in the PS for broken leads, bad solder jounts, etc. Since you say it will not fire up either rig, it is doubtful that there are 2 bad switches, but if you don't find anything else, check the switches. Please posdt your findings to the list. Thanks, 73 and good luck, John, W4AWM
Re: [drakelist] ac-4's
Did someone modify one of the power supplies and install a relay in it so the on/off switch controlsit rather then the primary of the transformer? If so, they would not be neccessarily compatible depending on the voltage relay used in the mod. Lee, w0vt Houston, Texas IThe AC-4 that came with the TR-4CW will not fire up the TR-4C (the power won't even come on), and the AC-4 that came with the TR-4C will not power up the TR-4CWrit.
Re: [drakelist] ac-4's
I find that the cinch jones connector male pins on the back of the transceivers get really waxy and makeintermittent contact over time. I use some isoproyl alcohol on a Q-tip on the male blades, then use de-oxit, plug in and out about 10 times.that's it. The last time a problem happened was just last week...lost my audio output from a TR-3 to an AC-4 speaker. After a bunch of trouble shooting, I found that the dirty connector was the only culprit. 73, Mark N5KAE - Original Message - From: [EMAIL PROTECTED] To: [EMAIL PROTECTED] Cc: [EMAIL PROTECTED] Sent: Friday, January 30, 2004 11:42 AM Subject: Re: [drakelist] ac-4's IThe AC-4 that came with the TR-4CW will not fire up the TR-4C (the power won't even come on), and the AC-4 that came with the TR-4C will not power up the TR-4CWrit.It should, it is a compatible supply for all the Drake transceivers. Check the fuse, check to see if there is a 120/240switch on the PS and if so, make sure it is in the 120V position, pull the cap off the interconnecting cable and check for broken leads, pull the bottom off the PS and check the primary of the power tranny. Finally, check around in the PS for broken leads, bad solder jounts, etc.Since you say it will not fire up either rig, it is doubtful that there are 2 bad switches, but if you don't find anything else, check the switches.Please posdt your findings to the list.Thanks, 73 and good luck,John, W4AWM
Re: [drakelist] AC-4 Recap Capacitors?
Al, Sherwood made one for the R-4C I think. I just mount terminal strips under the AC-4 chassis and put everything there. With a little planning its not a difficult task. You can leave the original cans in place for appearances if you choose. 73, Gary -- Submissions:[EMAIL PROTECTED] Subscribe: [EMAIL PROTECTED] - subscribe drakelist in body Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Brought to you courtesy of TLCHost.net http://www.tlchost.net/ --
Re: [drakelist] AC-4 Recap Capacitors?
The rumor is that this may work for the Drake AC4 as well. It was written up in qst a few months ago. Im not sure if there are parts differences or not. I need to contact himto confirm because I could use a few. I have 2 supplies that need fixing. If someone has more gumption then I do at the moment to tackle this, please let the group know if it works. 73 Mark W0NCL http://www.theheathkitshop.com/hp23r.html
Re: [drakelist] AC-4 High Volt supply
Bill - At a line voltage of 120 VAC, you should see about 740V no load. With idle current ~70 mA, should read about 715 - 720, and at full load (~350 mA) should be 650 - 660V. The diodes are in a voltage doubler configuration. 73, Garey - K4OAH Atlanta - Original Message - From: Gailey, Bill [EMAIL PROTECTED] In my efforts to update a TR-4 and early AC-4 supply, I've been working in low voltage areas so far (60 and 250). Just discovered that HV line out of the AC-4 is running approx. 740-744 volts D.C. unloaded by the TR-4. The HV line still has original electrolytics. It looks like someone has replaced the rectifier diodes along the way. Now 1N4007s in a bridge arrangement. Does this voltage level sound right? Have not yet measured the voltage under load. Thanks, Bill KG4KKI -- Submissions:[EMAIL PROTECTED] Subscribe: [EMAIL PROTECTED] - subscribe drakelist in body Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Brought to you courtesy of TLCHost.net http://www.tlchost.net/ --
