Failing Glow test? [resolved]

rhoninkor · 1160

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Offline rhoninkor

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on: September 29, 2019, 03:18:29 PM
Hi Bottlehead community, I just purchased the crack kit and looking forward to putting it together. However when I'm following the instructions, I felt I'm failing the Glow test for the tubes. Here is what I observed:
1. I put in both tubes, turn on the switch, the power tube (larger one?) has very dim light coming from some wires in the tube, but very dim though. Same happens for the smaller tube.
2. I let the tubes stay on for a while, and the larger tube becomes pretty hot, but still with very dim light.
I'm not familiar with tubes in general, so I don't know how bright they should be glowing?

Other information on the other steps during assembly:
1. The voltage I tested was 120 V for input, therefore I followed the >115V < 130V soldering for power transformer.
2. Both first and secondary power transformer tests passed. And I also checked the resistance between most soldering points, and they seem to be <0.2 Ohm, I don't know if that is good enough?
Any debugging comments and inputs are greatly appreciated! Thanks!
« Last Edit: September 30, 2019, 06:34:30 AM by Paul Birkeland »



Offline Paul Birkeland

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Reply #1 on: September 29, 2019, 03:30:30 PM
What AC voltage do you get with your probes on B7 and B8?

The glow doesn't need to be that bright.  If you see about 6V AC between B7 and B8, that would also indicate passage of the glow test.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline rhoninkor

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Reply #2 on: September 29, 2019, 06:48:55 PM
Hi Paul, I tested the voltage when running with tubes on, and between B7 and B8 I'm getting around 6.1V. I guess I will just proceed with the installation?



Offline Paul Birkeland

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Reply #3 on: September 30, 2019, 04:43:37 AM
Yes, the glow you see is very much normal. 

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline rhoninkor

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Reply #4 on: September 30, 2019, 06:27:09 AM
Excellent! I'm anticipating to finish it tomorrow night and finally be able to test it out! Thanks PB for answering my questions!