Resistance test fail (resolving but with new issues)

phigits · 1449

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Offline phigits

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Right off the bat, I am failing the resistance test.  Grounded to terminal 7 but the meter is reading 0 at terninal 1 and 5. I get a continuity reading seemingly everywhere except terminal 1 and 5.  I've gone over the joints several time, reflowed the solder but to no avail.  I must be missing something obvious but it escapes me.  Any advice as to what to look for?  Thanks in advance.

The fine and course attenuators are set to zero.
« Last Edit: July 17, 2019, 12:27:51 PM by phigits »



Offline Paul Birkeland

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Reply #1 on: July 16, 2019, 05:18:43 PM
Could you post some pictures of the attenuator section of your build?

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline phigits

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Reply #2 on: July 17, 2019, 10:20:50 AM
Apoligize for the delay.  I went back over the wiring for the the boards which took longer than expected.




Offline phigits

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Reply #3 on: July 17, 2019, 12:26:31 PM
UPDATE - Resistance is good.  A faulty battery in the multi-meter was the ultimate cause and a slow brain in the tester was a significant contributing factor.

On to the next issue.  There is no glow from any of the tubes.  None of the LEDS are lit.

Meter shows the following readings getting the following readings:
+275V DC - 339V
+6.3VDC - 0V
IA ON THE A SIDE - 337
IA ON THE B SIDE - 336

BREG Regulator A side - 337
BREG Regulator B side - 0 (need to check the wiring)
-reg Regulator bothe sides - 0
KREG A S-de - 1
KREG B side - 0

Looks like I have more wires to trace.




Offline phigits

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Reply #4 on: July 17, 2019, 12:56:25 PM
Tis is a comedy of errors.  Apparently I clipped many of the plastic shields with the next smallest gauge and that was causing wires to break off as I attached the boards.

I am now getting most readings but they are not to spec:

+275V DC - 339V
+6.3VDC - 0V
IA ON THE A SIDE - 337
IA ON THE B SIDE - 336

BREG Regulator A side - 335
BREG Regulator B side - 335
-reg Regulator both sides - 0
KREG A S-de - 1
KREG B side - 1

The LEDs register 335 volts but are not lighting and there is no glow from the tubes.
« Last Edit: July 17, 2019, 01:05:30 PM by phigits »



Offline Paul Birkeland

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Reply #5 on: July 17, 2019, 01:17:31 PM
You need to resolve the 0V coming out of the 6.3V pad on the power supply board before you worry about anything else.  If you heat up the joint on the power supply board and slip the red wire out of the pad, does the 6.3V supply come back up to proper voltage?

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline phigits

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Reply #6 on: July 17, 2019, 02:06:33 PM
Hi Paul - thanks for the reply and for wading through my nonsense.

Unfortunately, slipping the red wire out of the Power Supply Board does not have any effect.  The voltage still reads zero.

Is the high reading of 337 that I am seeing across the boards something to be concerned about?



Offline Paul Birkeland

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Reply #7 on: July 17, 2019, 02:46:45 PM
You need to focus on the 6.3V being absent before you worry about any of the other voltages.  They will all be way off because none of the tubes are being heated.

On page 38 of the manual there was a check to do on the power supply board before continuing the build.  Did your amp pass these checks at this time?

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline phigits

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Reply #8 on: July 17, 2019, 03:48:30 PM
I'll have to come back to this.  Next step is to pull the power supply board in go through it and make sure it passes all the tests.  Thanks to Paul for the push in the right direction.