Voltage LEDs [resolved]

diynewbie · 642

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Offline diynewbie

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on: April 24, 2019, 12:04:17 PM
Finished build.  Passed resistance checks and tubes glow.  Failed Kreg voltage and both LEDs on the B side of both c4s boards fail to light.

Voltage Check:
+275 power supply:  282
+6.3 power supply: 6.26
IA on A side c4s board 282
IB on B side c4s board 282
Breg both sides: 216, 218
-reg both sides: -0
Kreg both sides: 5.23, 5.54
« Last Edit: April 25, 2019, 02:02:39 PM by Paul Birkeland »



Offline Paul Birkeland

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Reply #1 on: April 24, 2019, 01:10:41 PM
On the center board, there's a pad on each side labeled with an "X", what voltage do you see there?

Are you able to adjust the OB voltages to spec with the blue trim pots?

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline diynewbie

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Reply #2 on: April 24, 2019, 02:03:28 PM
The pads with X (Upper left and lower right corners) both read 218 VDC.  Neither OB voltage can be adjusted using the blue trim pots - voltage isn't affected; stays ~ 218 VDC.



Offline Paul Birkeland

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Reply #3 on: April 24, 2019, 02:23:08 PM
I would be looking over the wiring on the center board very carefully.  It's fairly common that the step where you fold over the leads on the trim pot and solder two of them together gets skipped.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline diynewbie

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Reply #4 on: April 25, 2019, 01:21:03 PM
Thanks Paul, you saved me a lot time tracking down my error.  I figured I had made the same mistake on one step on the A & B sides , but couldn't see it looking at the top of the boards.  Just too lazy to figure it out myself.

Resistance and voltage checks all fine now.

Thanks again.