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April 22, 2021, 07:59:17 PM

Author Topic: Voltage Issue Troubleshooting [resolved]  (Read 189 times)

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Offline Paul Birkeland

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Re: Voltage Issue Troubleshooting
« Reply #15 on: March 29, 2021, 06:53:14 PM »
Did the Kreg voltages also end up pulling into line properly?
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline Toobuzz

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Re: Voltage Issue Troubleshooting
« Reply #16 on: March 29, 2021, 08:16:44 PM »
Yes they did!  All voltages, even the bias. I built another amp that used LEDs for high and low to to help dialing in the bias. Those LEDs made me think that clockwise raised the voltage. I checked the bias voltages before I did the other voltage checks and cranked one pot down. I definitely had other issues like the jumper wire and cleaning up the 12au7 pins may have helped (at the expense of some of those wires, oof).

I’ll post some pics of the exterior and some final voltage numbers tomorrow. Perhaps this may help someone in the future.  Thank you so much! I’m so happy right now.

Oh, I just peeked under the chassis and all 8 tube LEDs are lit! I didn’t need to reflow either.
« Last Edit: March 29, 2021, 08:33:58 PM by Toobuzz »

Offline Toobuzz

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Re: Voltage Issue Troubleshooting
« Reply #17 on: March 30, 2021, 02:33:09 AM »
I re-biased after burning in overnight.  Here are my voltages:

275vDC on the Power Supply Board (275V) = 273V
+6.3vDC on the Power Supply Board (55-65V) = 59V
-6.3vDC on the Power Supply Board (50-60V) = 55V
IA on the A side C4S Board (275V) = 273V
IA on the B side C4S Board (275V) = 273V
Breg Regulator Board A (220V) = 216V
Breg Regulator Board B (220V)= 216V
-reg Regulator Board A (0V) = 0V
-reg Regulator Board B (0V)= 0V
Kreg Regulator Board A (8-12V) = 8.6V
Kreg Regulator Board B (8-12V) = 10.2V

Thanks again, Paul!

Best,

Sam

Offline Paul Birkeland

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Re: Voltage Issue Troubleshooting
« Reply #18 on: March 30, 2021, 05:56:21 AM »
Looks good! 
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man