No sound, no tubes lighting up - did resistance checks

drewhaynes · 6439

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Offline drewhaynes

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on: August 26, 2017, 10:05:53 AM
Hi all,

My Crack has been dead for YEARS and I'm finally trying to get it back up and running. I just did resistance checks and I think the only one that looks wrong is terminal 13 - I believe it is supposed to climb slowly to 270K, but I'm not getting a reading at all.

What does that tell me? And does anyone have a FULL list of the resistance and voltage checks?

Thanks!

Drew


Offline Paul Birkeland

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Reply #1 on: August 26, 2017, 10:14:08 AM
That doesn't really say much.  That terminal has a big cap across it, and your meter may have a hard time reading it.

If the tubes don't light up, did you install the fuse?  What's the AC voltage between the two adjacent power transformer terminals with black wires attached?

Paul "PB" Birkeland

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Offline drewhaynes

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Reply #2 on: August 26, 2017, 10:20:59 AM
Fuse is installed and looks normal. I'm not 100% on which power terminals you are referring to - I tried from 14 to 20 which have a black wire stretching across the transformer, but I just realized you said "adjacent", so I'm assuming those are the wrong terminals.


Offline Paul Birkeland

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Reply #3 on: August 26, 2017, 10:27:45 AM
These two.

Paul "PB" Birkeland

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Offline drewhaynes

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Reply #4 on: August 26, 2017, 10:28:58 AM
Man, you're quick. While I was waiting I checked those two (got ~123V) and checked the other two on the top right in your pic and got ~5.7V


Offline Paul Birkeland

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Reply #5 on: August 26, 2017, 10:51:14 AM
Quote from: drewhaynes on August 26, 2017, 10:28:58 AM
Man, you're quick. While I was waiting I checked those two (got ~123V) and checked the other two on the top right in your pic and got ~5.7V
Your tubes should glow.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline drewhaynes

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Reply #6 on: August 26, 2017, 10:57:29 AM
Hmmm, any other ideas?


Offline fullheadofnothing

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Reply #7 on: August 26, 2017, 11:32:12 AM
• bad/damaged/incorrect tube(s)
• incorrectly installed tubes
• bad solder joint(s) on your heater wiring

Joshua Harris

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Offline drewhaynes

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Reply #8 on: August 26, 2017, 12:09:00 PM
Sorry I'm a newb... heater wire? Can you elaborate?


Offline fullheadofnothing

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Reply #9 on: August 26, 2017, 12:13:47 PM
The twisted wires connecting the low voltage terminals of the power transformer to the tube pins that make it glow. Pictures of your wiring may be helpful.

Joshua Harris

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Offline drewhaynes

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Reply #10 on: August 26, 2017, 12:16:15 PM
Long ago I ordered spare tubes... I just replaced the 6080 big tube with another 6080 and replace the small tube with a JHS 5814A. Still nothing. Let me see if I can get wiring pics...


Offline drewhaynes

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Reply #11 on: August 26, 2017, 12:28:07 PM
Pic 1


Offline drewhaynes

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Reply #12 on: August 26, 2017, 12:28:48 PM
Pic 2


Offline drewhaynes

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Reply #13 on: August 26, 2017, 12:29:12 PM
Pic 3


Offline fullheadofnothing

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Reply #14 on: August 26, 2017, 12:36:47 PM
B7 appears unsoldered, possibly B8 too, I can't really see. Touch up all the solder joints at B7 and B8, then re-test.

Joshua Harris

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