Help with Crack/Speedball. Voltages way off - 252V or 0V [resolved]

lshaw · 1126

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Offline lshaw

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Hello,

I am a first time builder and definitely need some help. I assembled the Crack kit and everything seemed to go according to plan. The resistance checks were correct as well as the voltages after assembly. After the assembly I listened to it for about 20-30 min, and it had an initial hum at all volumes that went away after about 2-3 minutes and was then silent afterwards and produced great sound. I then proceeded forward with the speedball upgrade. After the upgrade, my voltages (listed below) are way off and there is a loud hum, even though I believe I followed the manual well. Everything is either 0V or 252V. I thought my multimeter was broken so even bought another but it still shows the same readings. I've also gone through and reheated every solder point and added more solder when needed. Both sides of each tube light and get hot. The LEDs are either dimly lit or not lit, it's hard for me to tell, but they are not brightly shining that's for sure.

Voltage readings (with black lead on 12U):
1U: 0V
2U: 252V
3U: 252V
4U: 252V
5U: 0V
6U: 252V
7U: 252V
8U: 252V
9U: 252V
10U: 252V

Small speedball board:
OA: 0V
IA: 252V
B-A/B: 252V
IB: 252V
OB: 0V

Large speedball board:
OA: 252V
OB: 252V
G: 252V
B+: 252V

Attached is a picture of the bottom.

Please help! I have a bad feeling I've ruined the kit.



« Last Edit: June 09, 2022, 10:18:41 AM by Paul Birkeland »



Offline Paul Birkeland

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Reply #1 on: June 09, 2022, 06:55:08 AM
Where the black wires meet on the headphone jack, can you jiggle them and check to see if one is loose?

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline lshaw

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Reply #2 on: June 09, 2022, 07:43:26 AM
Wow...I'm so impressed. It wasn't loose but I just re-soldered it and now everything works perfectly and voltages are all correct. The sound is wonderful, no hum. It must have been a cold joint or something at that spot.

Thank you so much!