Re: [Drakelist] Late R-4C 3rd Mixer Changes
Hi Don, All, Yes, that's probably the reason why I did not want to buy the kits. It may be even more fun figuring out something like that myself.. ;-) 73's, Henry - PA0HJA On 2/8/2012 8:04 PM, Don Cunningham wrote: Henry, If we saw the schematics, we probably wouldn't pay the price for the kit, hi. That's his way of selling more. 73, Don, WB5HAK ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] pan adapter
Hi Garey, Curt,All, I was thinking to do the same, assuming the preselector would have a (much) wider pass-band! Is it really that narrow, only 20 kHz ? In that case I think it could be that the reception in the Softrock would benefit a lot from such good preselection! ;-D But that's not the goal here, it's main function would be a panadapter / spectrum display. Although it may be only 20 kHz wide, I think it could give you useful visual info as an extra on the surrounding signals wrt. QRM etc., the radio function as an extra. I will do an experiment tonight, tapping the first IF with my OpenHPSDR Mercury SDR receiver. Curious how this works in my temporary QRM swamped (24/7 S9+ dB! ) QTH. I think the Softrock Ensemble is overkill in this application as a panorama adapter. The now reissued, very cheap ($19), very small Softrock 40, adapted for 5.645 MHz would be adequate to function as a spectrum display. http://www.kb9yig.com/images/srlite2.jpg Good tip about the isolation between the Softrock and the Drake-IF. Regards, Henry - PA0HJA. On 2/9/2012 4:56 PM, Garey Barrell wrote: Curt - OK. Nothing wrong with FUN!! :-) If you're only looking for a 5 - 10 kHz window, then the Preselector won't be a problem except perhaps on 80 / 40M. It's not a steep skirt, so would still be useful further out. The Ensemble really is a cool little receiver. Tony and the rest have done an outstanding job! 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 Curt wrote: Hi Garey: Yes points well taken. In my case, I did this before the ensemble was available. Had I had that availability, I would have chosen to go that way as well. It does work well tho. I didn't see much of an issue at all with the limitation from the preselector. In practice, I was simply looking at perhaps +/- 5-10 KHz when in CW sprint mode. I liked the filtering so well in the SDR, that I worked a couple of CW sprints using the output only from the SDR instead of the Drake mother Rx. Issues there were the delay and lack of a good mute method. Overall, it was a simple thing, no harm done to the Drake, a good learning exercise, but the lack of tracking ability for the center frequency really limits the real Panadapter concept. Mine was in an external, diecast shield box, so I did not have any issues with radiation from the SDR. All over again, would just build the Ensemble like you suggest. Fun tho. Curt KU8L On 2/9/2012 9:44 AM, Garey Barrell wrote: Curt - I guess I'm missing the objective here. I have several SoftRocks, Ensemble, etc., and the biggest 'feature' they offer is the ability to see large chunks ( 48, 96 or 192 kHz ) at a time. If you tap off in front of the roofing filter, 5.645 MHz 1st IF, all you are gaining is an RF stage and mechanically tuned LO. Your widest 'window' is 20 kHz because of the PreSelector bandwidth. It makes sense with one of the modern radios with octave filtering in the front end so you CAN see the entire 48 or 96 kHz capability of the SR. I just can't see the advantage of putting a state-of-the-art, computer controlled receiver BEHIND a mechanically tuned, 50 year old front end. I guess I just don't understand the objective unless it's just all the IF bandwidths, etc. Seems to me a much better option is to just go with the Ensemble and get 1- 30 MHz continuous coverage, tunable from the PowerSDR or other screen. I can't hear anything on any of the Drakes that I can't hear on the Ensemble, being limited by 'atmospherics' rather than noise figure. The Ensemble in it's little QSL sized case just sits there and receives everything, all under the computer control. ?? 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 Curt wrote: Hi Carey: I did exactly that a few years ago with my a version. It works really well and is a excellent way to get involved with SDR, the Software, and get a panadapter along the way. You need to get the proper IF version softrock. The SDR needs to be tapped off of the 1st IF before the filtering. The SDR needs to be able to see unfiltered RF at the IF frequency. You need as good a Soundcard as you can afford. The Delta44 is one of the ones widely used. The connection to the main Rx is a bit touchy. I used a gimmick and a small cap but that is less than ideal. Clifton Labs offers a isolator on a small board that is the real answer. The Softrock for the IF will be different. The coils are different as is the crystal. Tony Parks was good about answering questions and providing info. He can probaly supply the stuff you need to convert the 40M kit since I don't think the IF kit currently being done includes the Drake IF freq. Hope this helps Curt KU8L On 2/8/2012 10:34 PM, Carey Lockhart, KC5GTT wrote: Hello Gang, i have a 13
Re: [Drakelist] Late R-4C 3rd Mixer Changes
Hi, Are there any schematics for these modifications somewhere on the net? (especially the Sherwood mods) Henry - PA0HJA On 2/8/2012 6:06 AM, kc9...@aol.com wrote: Sherwood Engineering ...has a MOD for this to totally fix it. Mix -4$59.00 Mine has it...Mine sure is quiet. http://www.sherweng.com/ham.html 73, Lee -Original Message- From: Steve Wedge w1es1...@earthlink.net To: Drake List drakelist@zerobeat.net Sent: Tue, Feb 7, 2012 8:17 pm Subject: [Drakelist] Late R-4C 3rd Mixer Changes Anyone who has had a late-production R-4C has heard the hiss when listening to a quiet band or a weak signal. Some folks say it sounds like bacon frying (Yum!) but to me it sounds more like the rain setting of one of those noise generators they sell at Brookstone that are supposed to put you to sleep at night. Searching through a lot of stuff, I've located two changes that do fairly similar things on the large scale, but require differing numbers of parts and time in which to do them. I knew there was a Sartori mod and - sure enough - I finally found www.archive.org and found the June 1979 issue of 73 Magazine. This is the change I remember doing back in the '80's. I remember that it helped quite a bit, but the receiver still was never really quiet. It changes the LO feed from the grid of V6 to the cathode. It also adds a series-resonant circuit at the plate to eliminate any excess 50 kHz crud from the output. I've wondered whether or not one could hear this but I suppose there can be products from all that crud that could get into the audible range. There's also another mod that's described on http://www.zerobeat.net/drakelist/drakemod/drmod40.html that involves fewer added parts and looks like an easier change, overall. It does the same overall feed change in that it moves the LO feed from the grid to the cathode, but doesn't use the resonant circuit. It also changes the limiting diodes to 1N4148's removes some capacitors and replaces them with either different values or jumpers. Besides erroneously calling out pin 1 of V6 as the old connection point, it's easy enough to follow. Has anyone out there tried both of these changes and, if so, which one worked better? 73 enjoy those Drakes... 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. ___ 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] Late R-4C 3rd Mixer Changes
Hi Lee, Yes I know. But as the circuits of the Sherwood mods seem to be really not too difficult and critical, at least from seeing the pictures, I would like to evaluate the mods from the schematics a little bit before spending any money. Inquiring minds want to know... ;-) 73's, Henry - PA0HJA On 2/8/2012 3:32 PM, kc9...@aol.com wrote: As to the Sherwood modsit's a board and comes as a kit... Never checked to see if there is a schematic. You just order it and install it. 73, Lee -Original Message- From: Henry Vredegoor henry.vredeg...@gmail.com To: Drakelist Drakelist@zerobeat.net Sent: Wed, Feb 8, 2012 5:08 am Subject: Re: [Drakelist] Late R-4C 3rd Mixer Changes Hi, Are there any schematics for these modifications somewhere on the net? (especially the Sherwood mods) Henry - PA0HJA On 2/8/2012 6:06 AM, kc9...@aol.com wrote: Sherwood Engineering ...has a MOD for this to totally fix it. Mix -4$59.00 Mine has it...Mine sure is quiet. http://www.sherweng.com/ham.html 73, Lee -Original Message- From: Steve Wedge w1es1...@earthlink.net To: Drake List drakelist@zerobeat.net Sent: Tue, Feb 7, 2012 8:17 pm Subject: [Drakelist] Late R-4C 3rd Mixer Changes Anyone who has had a late-production R-4C has heard the hiss when listening to a quiet band or a weak signal. Some folks say it sounds like bacon frying (Yum!) but to me it sounds more like the rain setting of one of those noise generators they sell at Brookstone that are supposed to put you to sleep at night. Searching through a lot of stuff, I've located two changes that do fairly similar things on the large scale, but require differing numbers of parts and time in which to do them. I knew there was a Sartori mod and - sure enough - I finally found www.archive.org and found the June 1979 issue of 73 Magazine. This is the change I remember doing back in the '80's. I remember that it helped quite a bit, but the receiver still was never really quiet. It changes the LO feed from the grid of V6 to the cathode. It also adds a series-resonant circuit at the plate to eliminate any excess 50 kHz crud from the output. I've wondered whether or not one could hear this but I suppose there can be products from all that crud that could get into the audible range. There's also another mod that's described on http://www.zerobeat.net/drakelist/drakemod/drmod40.html that involves fewer added parts and looks like an easier change, overall. It does the same overall feed change in that it moves the LO feed from the grid to the cathode, but doesn't use the resonant circuit. It also changes the limiting diodes to 1N4148's removes some capacitors and replaces them with either different values or jumpers. Besides erroneously calling out pin 1 of V6 as the old connection point, it's easy enough to follow. Has anyone out there tried both of these changes and, if so, which one worked better? 73 enjoy those Drakes... 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. ___ 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] TX-4C 160 Mod ?
Hi All, Is it just me, or is this link not working anymore / has the Ham Radio Magazine archive been removed from the site? 73's, Henry - PA0HJA On 12/21/2011 3:16 PM, Robert Fish wrote: Hi Guys, I am not sure how good the print quality is, but the entire collection of HR magazine (or most of) has recently been made available for download in PDF or just about any format you chose here: http://www.archive.org/search.php?query=collection%3Aham-radio-magazinesort=-publicdate By the way, 73 magazine archives are also available here: http://www.archive.org/search.php?query=collection%3A73-magazinesort=-publicdate I have already spent a bunch of time searching around through this stuff. Lotsa fun. 73, Bob K6GGO ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] Help finding info about alternate FS4 (100 kHz reference version) by W6NBI
Hi Ron, All, Sorry to hear that you seem to have lost your backup of the copy. I sure would like to read Part Two. ;-) I'm thinking about what would be possible with modern (Non DDS technology) components, retaining that same relatively simple, basic synthesizer principle. (A VCO, simple divider chain, a phase comparator, a loop filter and a 100 kHz reference. Simplicity, transparency of its working and much room for experimentation being the advantages of this design.. I still hope someone else can provide the info. 73, Henry - PA0HJA On 12/23/2011 4:21 PM, Ron wrote: Henry, I was in contact with Mr Stein, and am likely the poster of said found reference on this list. He did send me the data electronically. I thought I had a copy on an old backup/archive, but after spending several hours looking, it is not to be found. As I recall the big thing was different buffering and/or filtering to reduce the 100KHz spurs. 73, Ron WD8SBB --- On Fri, 12/23/11, Henry Vredegoorhenry.vredeg...@gmail.com wrote: From: Henry Vredegoorhenry.vredeg...@gmail.com Subject: [Drakelist] Help finding info about alternate FS4 (100 kHz reference version) by W6NBI To: Drakelist@zerobeat.net Date: Friday, December 23, 2011, 9:17 AM Hi All, I followed the link in that other post to an archive of Ham Radio Magazine. This because I too was curious about how the digital alternative for the Drake FS4 frequency synthesizer, as mentioned in this post, looked like in those days. I had a very good time reading! And also, browsing trough the rest of that copy of Ham Radio Magazine was nice, giving a good view on that era in Ham radio. Thanks a lot for that link - I guess I will be reading a lot more there! But. I got really (historically) interested in that alternative for the FS4 after reading I know its design is very dated and nowadays there are far better solutions like integrated circuit DDS's etc. but still... I searched the internet if I could find more about it. I found a follow-up of the article, or better a letter in HRM from the author W6NBI, mentioning additional info and a version with a 100 kHz reference. I could not find this additional info anywhere on the internet though. I did find in a posting from this list that the author had indicated not to be bothered anymore with questions about his (40+ years!) old design . So my question is: Is there anybody on this list who has or knows where to find this additional info? I hope somebody can help with this nice Drake history. (kind of anyway) ;-) 73's, Henry - PA0HJA On 12/21/2011 3:16 PM, Robert Fish wrote: Hi Guys, I am not sure how good the print quality is, but the entire collection of HR magazine (or most of) has recently been made available for download in PDF or just about any format you chose here: http://www.archive.org/search.php?query=collection%3Aham-radio-magazinesort=-publicdate By the way, 73 magazine archives are also available here: http://www.archive.org/search.php?query=collection%3A73-magazinesort=-publicdate I have already spent a bunch of time searching around through this stuff. Lotsa fun. 73, Bob K6GGO I think the discussion is now about the expanded preselector dial that came with the FS4. HR magazine had home brew FS4 in Aug 1972 issue. That article had a copy of the dial in print. That might be where you can pick off a high resolution image if you have an origial. I sold my incomplete set of HR mags when I purchased the entire PDF collection. The PDF of the page that the dial is on is not that great. OTOH you might be able to use it for a starting point to do image restoration and enhancement. Aug 1972 - Ham Radio (Pg. 6) Frequency Synthesizer for the Drake R-4 Receiver Author: Stein, Robert S., W6NBI Sorry if I misunderstood the thread. 73, Ron WD8SBB --- On Tue, 12/20/11, Jim Shorneyjshor...@inebraska.com wrote: ___ 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] Help finding info about alternate FS4 (100 kHz reference version) by W6NBI
Hi All, I followed the link in that other post to an archive of Ham Radio Magazine. This because I too was curious about how the digital alternative for the Drake FS4 frequency synthesizer, as mentioned in this post, looked like in those days. I had a very good time reading! And also, browsing trough the rest of that copy of Ham Radio Magazine was nice, giving a good view on that era in Ham radio. Thanks a lot for that link - I guess I will be reading a lot more there! But. I got really (historically) interested in that alternative for the FS4 after reading I know its design is very dated and nowadays there are far better solutions like integrated circuit DDS's etc. but still... I searched the internet if I could find more about it. I found a follow-up of the article, or better a letter in HRM from the author W6NBI, mentioning additional info and a version with a 100 kHz reference. I could not find this additional info anywhere on the internet though. I did find in a posting from this list that the author had indicated not to be bothered anymore with questions about his (40+ years!) old design . So my question is: Is there anybody on this list who has or knows where to find this additional info? I hope somebody can help with this nice Drake history. (kind of anyway) ;-) 73's, Henry - PA0HJA On 12/21/2011 3:16 PM, Robert Fish wrote: Hi Guys, I am not sure how good the print quality is, but the entire collection of HR magazine (or most of) has recently been made available for download in PDF or just about any format you chose here: http://www.archive.org/search.php?query=collection%3Aham-radio-magazinesort=-publicdate By the way, 73 magazine archives are also available here: http://www.archive.org/search.php?query=collection%3A73-magazinesort=-publicdate I have already spent a bunch of time searching around through this stuff. Lotsa fun. 73, Bob K6GGO I think the discussion is now about the expanded preselector dial that came with the FS4. HR magazine had home brew FS4 in Aug 1972 issue. That article had a copy of the dial in print. That might be where you can pick off a high resolution image if you have an origial. I sold my incomplete set of HR mags when I purchased the entire PDF collection. The PDF of the page that the dial is on is not that great. OTOH you might be able to use it for a starting point to do image restoration and enhancement. Aug 1972 - Ham Radio (Pg. 6) Frequency Synthesizer for the Drake R-4 Receiver Author: Stein, Robert S., W6NBI Sorry if I misunderstood the thread. 73, Ron WD8SBB --- On Tue, 12/20/11, Jim Shorneyjshor...@inebraska.com wrote: ___ 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] A Great Source for Real HC-6/U Crystals
Hello Jim, All It seems my post went directly to you. It was supposed to go through the Drakelist to you! Anyways.. No, it is definitely the better, non contaminating welding process quality. Look for instance at this place: http://www.stabitech.nl/QuartzCrystalHolderTypes.htm I remember reading about this at a number of different places though. It is being used since long before rohs was invented. But agreed, lead-free / rohs compliance could also be a valid reason for using this type of crystal holder for manufacturers. Sending this now to the correct email address, drakelist@zerobeat.net as intended the first time... ;-) Henry - PA0HJA On 12/21/2011 5:47 PM, Jim Pruitt wrote: Hello Henry. You could be right or it could just be industry's way of being rohs compliant. I see this frequently when trying to order any electronic parts. I might have an old part number but later find the part is still available under a different number and the new number uses no lead. Thank you. Jim Pruitt On 12/20/2011 at 12:58 PM, henry.vredeg...@gmail.com wrote: Hi All, I always thought that HC48/U is the preferred, higher quality type than the HC6/U types? Because of the welding process instead of soldering, the crystal material itself is less prone to impurities coming from the soldering process vapors getting into the crystal lattice when sealing the unit? 73's, Henry - PA0HJA On 12/20/2011 4:54 PM, Jim Pruitt wrote: Hello Don and the group. Please do not quote me but if memory serves me correctly the HC-6 and the FT243 have the same center to center pin spacing, just the diameter of the pins is different with the FT-243 being bigger (as in same diameter as a pin from an old octal tube or .093 od). Also I do not think that International Crystal still has HC-6/U holders as they now call then HC-48's. I once tried to have a discussion with International Crystal about that and got no answer but if you look at their web site. That is just a nomenclature difference but it makes it hard to go to a manufacturer's web site and find what you are looking for without knowing that the old nomenclature no longer exists but what you are looking for is called something else and still exists. I think Bry Carling's web site has a crystal socket page that shows them very well. From Bry's web page at: http://www.af4k.com/crystal_holders.htm he lists the HC6 and FT243 as: FT243, 2 pins, spaced 0.486 and .093 dia. HC-6/U - Crystal, metal can, spacing 0.486, pin dia. 0.050 Holder Type Pin Spacing Pin DiameterHeight Width Thickness HC-5/U 0.812 0.156 2.201.821.60 HC-6/U 0.486 0.050 0.780.760.35 HC-10/U (Note A)0.060 1.10- 0.56D HC-13/U 0.486 0.050 0.780.760.35 HC-17/U 0.486 0.093 0.780.760.35 HC-18/U (Note B)- 0.530.400.15 HC-25/U 0.192 0.040 1.530.760.35 FT-243 0.500 0.093 1.100.900.40 FT-243 - Dimensions: 13/16 X 3/8 X 1-1/8 tall Dimensions: 0.8125 wide X 0.375 deep X 1.125 tall plus pins. Dimensions: 20.6mm X 9.5mm X 28.6 mm With 2 pins, spaced 0.486 (12.3mm) and pin diameter = 0.093 (2.4mm) Pin length =3/8 (9.5mm). He lists the HC48 as: HC-48/U - Crystal Unit, thin pins, same as HC-6/U but welded. and that is also what you will get from International Crystal. I just looked at Jan Crystal's web page at http://www.jancrystals.com/chart.html and they still list them as HC-6/U. I found their web site hard to use from an ordering standpoint but they have been around for years. I do not know if that sheds any light on the discussion or not but the HC48 versus HC6 discussion caught me by surprise at International when I was looking for crystals a few years ago. By the same token, HC25 (small plug in crystals liked used in the old Drake crystal controlled 2 meter transceivers) is something like HC50 now and the HC18 wire lead is now the common HC49. Again the HC49 and HC50 or HC25 and HC18 if you will, is like the HC6 and FT243 in that the pin spacing is the same but the pin diameter is different. HC-18/U - Crystal - same as HC-49/U but soldered HC-25/U - Crystal - Same as HC-49 but with rigid pins. (also same as HC50/U but soldered) So I gather from Bry's discussion that the difference between the HC6 and the HC50 is that the HC6 is has a soldered on shell where the HC50 has a welded shell. Same for the HC25 and HC50 in that the HC-25 is soldered and the HC-50 is welded. Why the holder nomenclature is different just because they used a different method to attach the top cover is beyond me but then I am not in manufacturing. Thank you. Jim Pruitt On 12/19/2011 at 7:15 PM, d...@martineer.net wrote: Lee, I'm really not understanding your posts I have seen on several venues today. There's not really a coorelation between the HC-6/U crystal and the FT-243, unless my old
[Drakelist] Don't open this link in (no subject)
The link is a link to a virus/trojan! Henry ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] New to the list, some questions
Hello James, Thank you for the pointers! This sure helps. I did consider to do the upgrade kit for the AC-4R and I think its a fine kit, but I could do it cheaper and had some other ideas/wishes as well so I didn't go that route. 73's, Henry. On 2/12/2011 3:33 PM, james adriansen wrote: Henry, Below are two links to information about Drake sources for parts, materials, etc. The first one is a technical exchange document. The second site has a 3-part document from the Ham Convention about Drake equipment. Some of the info is the same in the two documents. These documents have information about the screws and other items you may need since you said that you purchased the rigs separately. The rebuild on the PS-4 is very doable. I purchased a rebuild kit. http://www.w4ish.net/Manuals/pdf/62-DRAKE_TECH_EXCHANGE02.pdf http://www.wb4hfn.com/DRAKE/DrakeHamvention/2010/Dayton2010-Menu.htm Good Luck and I hope this helps! 73 de James AJ4VP Falls Church, VA. USA ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC4 refurbishment
Hi Garey, All, Thank you Garey for your answer. I did do most of the obvious things for the R4C like some you mentioned, but not with a good result yet :-( I will have to go over it once more thoroughly I guess and follow your tips But for the moment I have put aside the R4C and am concentrating on the AC4 refurbishment. I want to have some status on the T4XC first, because I could not power it up at all yet. The AC4 PSU I bought separately was dead and a mess when I opened it. Leaked capacitors, modifications (repairs?), bad solder joints and loose connections. Fortunately nothing blew up when I tried to power it up to measure its output voltages. (Just the AC4, with a bridge at the plug; not connected to the T4XC!) I have cleaned out the whole inside of the unit, keeping only the transformer, fuse holder, cinch socket, VOX connector and the cable assembly / plug. I first considdered buying the AC4-R refurbishing kit, but got a good deal on some board with HV caps already fitted. I could cut it in two (one half for the 650 Volt supply and the other half for the 250 Volt supply) and to size and they fit nicely to the side panels of the AC4 chassis after removing the old caps fitted to the chassis. . I think I want to also modify it a little bit. Fitting a 3 pin power socket, an extra DPDT mains switch on the unit itself, fuses / fuse holders for all voltages, maybe a safety-relay for enabling the 650 Volt only when bias is present, are some of the ideas. I am waiting now for some parts that did not arrive yet so I think I'll give the R4C another try. As for the tubes 6JF6, I will not use them at this time, if ever. I'll keep you posted. 73's, Henry - PA0HJA On 2/9/2011 6:52 PM, Garey Barrell wrote: Henry - The R-4C probably needs only a good cleaning/DeoxIT treatment. Primarily the rotary switches, but also the tube and crystal sockets. Go through with a screwdriver and check all chassis hardware, tube sockets, PC boards, terminal strips, shields, essentially every screw that goes into the chassis. If not tight, tighten firmly, if tight, loosen slightly and retighten. This should take care of most problems that occur in long term storage. Follow the same process in the T-4XC, then troubleshoot what remains, if anything! I believe the screws in the bottom of the AC-4 are 6-32 x 1/4 pan head. The 6JF6 is a 'potential' replacement for the 6JB6. It is the same base, slightly higher transconductance, BUT considerably higher interelement capacitances. So they 'may' work, especially on the lower bands, but neutralization may be problematic. It may be necessary to increase the value of C65 to bring the adjustment in range. Don't hesitate to post here if you have more questions! 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 Henry Vredegoor wrote: Hello All, I am new to this list, but reading it for some time now. I'm in the process of setting up/restoring/repairing a Drake 4C line: R4C, I own this receiver for 35+ years, proved defective when I recently switched it on after some years of storage T4XC, bought recently, sold as being defective MN4, working OK MS4, working OK AC4, currently being refurbished by me As all items were bought separately, I'm missing bits here and there, like the screws that mount the AC4 PSU in the MS4 cabinet from the bottom side. I assume they are non-metric (M3/M4 do not fit). Can anybody here on this list please tell me what thread/size they are, so I can order the right screws? I could not find any info on this in the documentation. I too have a second question. With the AC4 came four spare tubes, supposedly usable as a replacement for the 6JB6A power tube, type 6JF6 Is this a direct drop-in replacement for the 6JB6A in the Drake T4XC or would I have to change (many-) things in the PA circuit (neutrodynisation etc.) to be able to use these? Any help appreciated. 73's, Henry - PA0HJA ___ 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
