mike stehr Posted September 20, 2022 Share Posted September 20, 2022 Bought this for 50 bucks roughly 17 years ago. Used it for breadboarding lower watt tube amplifier circuits for years in stock form, with the original parts. A conversation regarding these units came up with a local retired AE. He'd been coming across them, rebuilding them and using the supplies around the bench. They can be handy for that sort of thing. I figured then I should go through my Heathkit PS-4, re-cap, check over the resistors, etc... To be honest, while it may not have been completely up to spec in stock form, it was close. All the tubes still tested strong according to my no-go gauge emission tester. 3 Quote Link to comment Share on other sites More sharing options...
mike stehr Posted September 20, 2022 Author Share Posted September 20, 2022 Recapping, etc was rather simple. But of course, I didn't pay enough attention to the schematic and re-oriented the larger diodes backwards. After blowing some fuses I corrected that. Then wondering why, the voltage was wonky, I put a cap on the wrong pin for the control tube. After correcting that, the power supply works as it should. Schematic blunders on my part... 1 Quote Link to comment Share on other sites More sharing options...
mike stehr Posted September 20, 2022 Author Share Posted September 20, 2022 The Heathkit DC tube supplies seem to be a little over-price these days, and it has been mentioned that one could build a high voltage/current B+ supply using transistors for series pass duty, with op-amps or what not for control. Purchase some filament transformers to use for heating the tubes. It's just a cool old school Heathkit built on 04/17/1963. 1 Quote Link to comment Share on other sites More sharing options...
seti Posted September 21, 2022 Share Posted September 21, 2022 That is really cool. I need a few of those!! I have some HP Power Supplies awaiting restoration but I don't think they are as flexible. I've also had my eye on some Lambda Supplies. Quote Link to comment Share on other sites More sharing options...
henry4841 Posted September 21, 2022 Share Posted September 21, 2022 22 hours ago, mike stehr said: Recapping, etc was rather simple. But of course, I didn't pay enough attention to the schematic and re-oriented the larger diodes backwards. After blowing some fuses I corrected that. Then wondering why, the voltage was wonky, I put a cap on the wrong pin for the control tube. After correcting that, the power supply works as it should. Schematic blunders on my part... I make my share. The getter on those tubes look really good. Good indication the tubes are still good without having a tester. 1 Quote Link to comment Share on other sites More sharing options...
mike stehr Posted September 21, 2022 Author Share Posted September 21, 2022 1 hour ago, seti said: That is really cool. I need a few of those!! I have some HP Power Supplies awaiting restoration but I don't think they are as flexible. I've also had my eye on some Lambda Supplies. I have a Lambda C-281M. 325 volts at 200ma maximum operating voltage. The Hewlett Packard 712A would be nice to have... A retired EE friend had a tube power supply he picked up when he was an employee at Magnavox...it was older looking unit that uses 6550 for pass tubes. 600 volts at 200ma. I'd always tried to talk him out of it to no avail. I also have a Lambda LA-100-03BM. Switchable up to 35 volts at 10 amps. An 80–90-pound tank... 1 hour ago, henry4841 said: I make my share. The getter on those tubes look really good. Good indication the tubes are still good without having a tester. It was really a case of paying too much attention to the images I took to reference for rebuilding, and not enough attention to the schematic. I wouldn't be surprised if these are the original tubes that came with the unit. Quote Link to comment Share on other sites More sharing options...
seti Posted September 21, 2022 Share Posted September 21, 2022 7 minutes ago, mike stehr said: I have a Lambda C-281M. 325 volts at 200ma maximum operating voltage. The Hewlett Packard 712A would be nice to have... A retired EE friend had a tube power supply he picked up when he was an employee at Magnavox...it was older looking unit that uses 6550 for pass tubes. 600 volts at 200ma. I'd always tried to talk him out of it to no avail. I also have a Lambda LA-100-03BM. Switchable up to 35 volts at 10 amps. An 80–90-pound tank... It was really a case of paying too much attention to the images I took to reference for rebuilding, and not enough attention to the schematic. I wouldn't be surprised if these are the original tubes that came with the unit. That is cool.. It would be hard to build a tube amp power supply as good as HP or Lambda... Great stuff. My second hobby is restoring test equipment. 1 Quote Link to comment Share on other sites More sharing options...
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