Input tube not wokring and no LEDs [SOLVED]

sjeffrey · 1866

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Offline sjeffrey

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on: October 05, 2013, 11:37:18 AM
I just finished assembling my Crack and going through the resistance tests
all of them are right on except the center pin which I assume is the input tube center pin.  If so resistance goes to 0 and not 90-100k.

I check all solders and circuit and everything looks correct.
I hesitate to continue until I get confirmation or some hint on what could be wrong.

thanks,
Steph
« Last Edit: October 05, 2013, 04:49:03 PM by sjeffrey »



Offline sjeffrey

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Reply #1 on: October 05, 2013, 11:50:50 AM
Looks like center pin is RCA center pin which reads 100k
I had searched before but was searching for LED and resistance  so got nothing that helped.

voltage test is next. Hopefully nothing bad happens to me.  :o



Offline Paul Birkeland

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Reply #2 on: October 05, 2013, 11:59:03 AM
Yes, the center pin is the center pin of the RCA jack.

The LED may or may not give you a resistance reading, which may or may not depend on the orientation of your meter leads ;)

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline sjeffrey

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Reply #3 on: October 05, 2013, 02:47:14 PM
So I did voltage check and all the ones that should be 90V are 140V.  Also the LEDs don't light up. 

Searching forum but haven't found anything yet.

EDIT: voltage at A3 and a8 is 0v.  Input tube is not glowing.  I was too excited about the output tube glowing I didnt notice the input one wasnt at first.
« Last Edit: October 05, 2013, 03:49:30 PM by sjeffrey »



Offline sjeffrey

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Reply #4 on: October 05, 2013, 04:23:49 PM
Well I reheated all solders and this time tube and leds light up.  Voltage was correct as well.
Flipped it over to do sound test and tube went out again.  Looks like I have a cold solder somewhere :(



Offline sjeffrey

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Reply #5 on: October 05, 2013, 04:48:34 PM
So it was A9 that was not soldered correctly.  Fixed the connection and all good now  ;D
Listening with iTouch now just to test it out and sounds great already.  Can't wait to plug it in my Bifrost.

Next up is a bit of tube rolling and then Speedball :)