[Drakelist] PS-7 (12 volt) power supply questions
I think I finally have most of the wrinkles worked out of that poor PS-7 I picked up at Findlay. I have the following questions. 1) Based on pg 126 of the book A Family Affair - The R L Drake Story, I see that I should set the current limit trip for ~31 Amp. Does anyone disagree with this figure? 2) Can anyone explain to me how the 2N4402 bias/conduction works for over current shutdown of the LM1723? I've been looking at the the LM1723 circuit and the PS7 schematic. I cannot see how over current will cause the 2N4402 to change states in order to fire the SCR. TNX es 73, Ron WD8SBB ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] Variac
When bringing up a radio on a variac, do I slowly continuously turn the power up or go step by step? I've never used one. ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] Variac
Neil, I'm somewhat compulsive about such things. The older a rig is, or the longer it has set idle, the longer the program or process. In the worst case, I use 10 volts per hour increase. In other cases, I start with 10 volts per 15 minutes. My Variac has three meters---one for voltage, one for current, and one for power in watts. It is easy to see that when the ammeter increase at about the same amount as the voltage, you readily know there is a problem and not to proceed until fault isolation has been completed. 73, Evan, K9SQG -Original Message- From: Neil M Califano cchange...@yahoo.com To: Drakelist Drakelist@zerobeat.net Sent: Sat, Oct 15, 2011 10:25 am Subject: [Drakelist] Variac When bringing up a radio on a variac, do I slowly continuously turn the power up or go step by step? I've never used one. ___ 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] PS-7 (12 volt) power supply questions
On Sat, 15 Oct 2011 11:18:48 -0700 (PDT), Ron wrote: 1) Based on pg 126 of the book A Family Affair - The R L Drake Story, I see that I should set the current limit trip for ~31 Amp. Does anyone disagree with this figure? That matches GW4ALG's notes: http://www.alg.myzen.co.uk/radio/tr7/mods.htm#16 2) Can anyone explain to me how the 2N4402 bias/conduction works for over current shutdown of the LM1723? I haven't studied it that much, but here's how it looks like it will work. The current sense part of the 723 senses the voltage across the emitter ballast of one of the pass transistors. When this goes too high, the internal transistor at pins 3 to 13 goes low impedance, which starves the output circuit of the 723 for bias and decreases the output voltage. Pin 4 will always be at a lower voltage than pin 3, since it is farther down on the voltage divider, so when pin 4 falls below the reference voltage on pin 6 far enough, the 4402 (PNP) fires and kills power to the 723 through the 2N3566. I haven't worked it out completely with real world voltages, so I'm guessing a little. I could be missing something somewhere. 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] PS-7 (12 volt) power supply questions
Jim, Thanks, and see notes in flow. --- On Sat, 10/15/11, Jim Shorney jshor...@inebraska.com wrote: From: Jim Shorney jshor...@inebraska.com Subject: Re: [Drakelist] PS-7 (12 volt) power supply questions To: drakelist@zerobeat.net drakelist@zerobeat.net Date: Saturday, October 15, 2011, 2:53 PM On Sat, 15 Oct 2011 11:18:48 -0700 (PDT), Ron wrote: 1) Based on pg 126 of the book A Family Affair - The R L Drake Story, I see that I should set the current limit trip for ~31 Amp. Does anyone disagree with this figure? That matches GW4ALG's notes: http://www.alg.myzen.co.uk/radio/tr7/mods.htm#16 I should have mentioned that pg 126 is quoting Steve Rawling, GW4ALG. I was kind of looking for second source just to be sure. 2) Can anyone explain to me how the 2N4402 bias/conduction works for over current shutdown of the LM1723? I haven't studied it that much, but here's how it looks like it will work. The current sense part of the 723 senses the voltage across the emitter ballast of one of the pass transistors. When this goes too high, the internal transistor at pins 3 to 13 goes low impedance, which starves the output circuit of the 723 for bias and decreases the output voltage. Pin 4 will always be at a lower voltage than pin 3, since it is farther down on the voltage divider, so when pin 4 falls below the reference voltage on pin 6 far enough, the 4402 (PNP) fires and kills power to the 723 through the 2N3566. I haven't worked it out completely with real world voltages, so I'm guessing a little. I could be missing something somewhere. Just reading what you say and briefly looking back at the PS7 schematic this seems to make the circuit make sense. Thanks. 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 ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] PS-7 (12 volt) power supply questions
On Sat, 15 Oct 2011 13:30:32 -0700 (PDT), Ron wrote: That matches GW4ALG's notes: http://www.alg.myzen.co.uk/radio/tr7/mods.htm#16 I should have mentioned that pg 126 is quoting Steve Rawling, GW4ALG. I was kind of looking for second source just to be sure. Ah... Well, I would say that sounds like a reasonable value (31 Amps). The PS-7 is conservatively rated, like most everything else about the TR-7. Maybe Bill Frost or John Kriner can give you a definitive answer. 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
[Drakelist] R.L. Drake Patents
For those interested, the RV-75 variable rate tuning is described in U.S. Pat. No. 4,352,010, and the infamous TR-7 PA amplifier heat sink located in the cabinet and near the PTO is described in U.S. Pat. No. 4,237,521. These patents are available at www.freepatentsonline.com or other patent websites of your choice. Paul, W5NTQ ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] R.L. Drake Patents
Paul, Thanks for sharing. That patent for the heat sink sure puts an end to the debate of blowing in vs pulling out for the fans :-) TNX es 73, Ron WD8SBB --- On Sat, 10/15/11, Paul pa...@hal-pc.org wrote: From: Paul pa...@hal-pc.org Subject: [Drakelist] R.L. Drake Patents To: drakelist@zerobeat.net Date: Saturday, October 15, 2011, 5:34 PM For those interested, the RV-75 variable rate tuning is described in U.S. Pat. No. 4,352,010, and the infamous TR-7 PA amplifier heat sink located in the cabinet and near the PTO is described in U.S. Pat. No. 4,237,521. These patents are available at www.freepatentsonline.com or other patent websites of your choice. Paul, W5NTQ ___ 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] Drakelist Digest, Vol 40, Issue 25
It doesn't. The SCR is for OVERVOLTAGE protection. On 15/10/11 23:11, drakelist-requ...@zerobeat.net wrote: 2) Can anyone explain to me how the 2N4402 bias/conduction works for over current shutdown of the LM1723? I've been looking at the the LM1723 circuit and the PS7 schematic. I cannot see how over current will cause the 2N4402 to change states in order to fire the SCR. TNX es 73, ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] PS-7 (12 volt) power supply questions - Re: Drakelist Digest, Vol 40, Issue 25
Nigel, There are 2 SCRs in the PS-7. One is the 40 Amp over voltage crowbar which you speak of. The other is a 2N5060 which ultimately drops the power off of the LM1723 and turns off the pass transistors when an over current event gets to a knee in its downward spiral. I believe that the idea is to prevent continual heating and eventual destruction of all the electronic components within the PS-7. I have seen other LM1723 circuit oscillate in an over current situation. Goes from 13 V to 0 V and back again. Current of course follow the voltage. The Drake just go int a locked down kind of powered off state. 73, Ron WD8SBB --- On Sat, 10/15/11, Nigel A. Gunn, W8IFF/G8IFF ni...@ngunn.net wrote: From: Nigel A. Gunn, W8IFF/G8IFF ni...@ngunn.net Subject: Re: [Drakelist] Drakelist Digest, Vol 40, Issue 25 To: drakelist@zerobeat.net Cc: drakelist-requ...@zerobeat.net Date: Saturday, October 15, 2011, 6:53 PM It doesn't. The SCR is for OVERVOLTAGE protection. On 15/10/11 23:11, drakelist-requ...@zerobeat.net wrote: 2) Can anyone explain to me how the 2N4402 bias/conduction works for over current shutdown of the LM1723? I've been looking at the the LM1723 circuit and the PS7 schematic. I cannot see how over current will cause the 2N4402 to change states in order to fire the SCR. TNX es 73, ___ 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] DRAKE SEEN ON TV
Has anyone seen the new Google ad on TV? It is about a girl who discovers a new star with her back yard telescope. The girl and her fathers are interviewed. In the background of the father's interview is some Drake 4 Line gear and also so unnamed test equipment. The clips are fast so you have to look quickly. Maybe someone can get a freeze frame of the commercial. 73, John, W4AWM My hobby is heavy and glows in the dark.___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] DRAKE SEEN ON TV
The full interview use in the ad is at http://www.youtube.com/watch?v=x9-F6dbCIHw There is a 4-line (not C) and MN-4 behind the father's head at 0:58 in. 73, Bob WW3QB From: w4...@aol.com w4...@aol.com To: drakelist@zerobeat.net Sent: Saturday, October 15, 2011 8:06 PM Subject: [Drakelist] DRAKE SEEN ON TV Has anyone seen the new Google ad on TV? It is about a girl who discovers a new star with her back yard telescope. The girl and her fathers are interviewed. In the background of the father's interview is some Drake 4 Line gear and also so unnamed test equipment. The clips are fast so you have to look quickly. Maybe someone can get a freeze frame of the commercial. 73, John, W4AWM My hobby is heavy and glows in the dark. ___ 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] DRAKE SEEN ON TV
Apparently her father is N2IXA. The full interview use in the ad is at http://www.youtube.com/watch?v=x9-F6dbCIHw There is a 4-line (not C) and MN-4 behind the father's head at 0:58 in. 73, Bob WW3QB From: w4...@aol.com w4...@aol.com To: drakelist@zerobeat.net Sent: Saturday, October 15, 2011 8:06 PM Subject: [Drakelist] DRAKE SEEN ON TV Has anyone seen the new Google ad on TV? It is about a girl who discovers a new star with her back yard telescope. The girl and her fathers are interviewed. In the background of the father's interview is some Drake 4 Line gear and also so unnamed test equipment. The clips are fast so you have to look quickly. Maybe someone can get a freeze frame of the commercial. 73, John, W4AWM My hobby is heavy and glows in the dark. ___ 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] Receiver protection lamp
What is this???: http://www.ebay.com/itm/RL-Drake-Receiver-Protection-Lamp-4-Line-Receivers-/360399257957?pt=LH_DefaultDomain_0hash=item53e9784165 ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] Receiver protection lamp
The TR-3/4 had a fuse lamp between the receiver and antenna to protect the receiver. Since these were mobile rigs the large whip antennas could hit light fixtures in garages (my theory). 73, Bob WW3QB From: Neil M Califano cchange...@yahoo.com To: Drakelist@zerobeat.net Sent: Saturday, October 15, 2011 8:54 PM Subject: [Drakelist] Receiver protection lamp What is this???: http://www.ebay.com/itm/RL-Drake-Receiver-Protection-Lamp-4-Line-Receivers-/360399257957?pt=LH_DefaultDomain_0hash=item53e9784165 ___ 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] Receiver protection lamp
- Original Message - From: Robert Ladden rmlad...@yahoo.com To: Drakelist@zerobeat.net Sent: Saturday, October 15, 2011 6:07 PM Subject: Re: [Drakelist] Receiver protection lamp The TR-3/4 had a fuse lamp between the receiver and antenna to protect the receiver. Since these were mobile rigs the large whip antennas could hit light fixtures in garages (my theory). 73, Bob WW3QB More likely to protect the input circuit if someone else fires up a tranmitter nearby, it would also protect the input from static accumulation from friction on the antenna and from driving through a lightening storm. Serves a similar purpose when used in a fixed location. The lamp is a twin-post lamp with similar characteristics to a No.47 but the base arrangement has less reactance at radio frequencies. I managed to pop one while trouble shooting a TR-4 and had trouble getting replacements locally. Keeping a spare available is a good idea even though they are likely to last forever. If the TR-4 receiver seems dead and its nothing else the lamp is worth looking at. If its open or the contacts are dirty the effect is of no antenna being connected. -- Richard Knoppow Los Angeles WB6KBL dickb...@ix.netcom.com ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
