Little help: Speedball small board voltage errors

[mferring1]

Been running the standard Crack for a month with no issues. Just started on the Speedball. Built the small circuit board and made it to the first set of voltage checks. The upper right LED did NOT light. Here are the voltages...

OA      150
1A      390
B-A/B  0
1B      390
OB      110

Appreciate any thoughts on my issue.

Mark

 

[mferring1]

If it helps. I took a few pictures.

 

[fullheadofnothing]

B side PN2907 is backwards.

 

[mferring1]

Geez.......

Stupid mistake.....thanks for catching it.

Do you think this will cause the part to fail or can I just swap it around?

 

[mferring1]

Well, I rotated the transistor and now all the LEDs on the small board are on.....a positive step!

However, my voltages are still as indicated above.

Anyone know what that means?

 

[mferring1]

Actually, the voltages are slightly different...

OA      150
1A      380
B-A/B  0
1B      380
OB      150

 

[fullheadofnothing]

Are the LEDs on the 9-pin socket lighting?

 

[mferring1]

Yep, the two on the nine pin are lighting.....as well as all four on the small circuit board.

 

[mferring1]

BTW, I will be out most of tomorrow so won't be able to reply if there is any sage advice. Don't want to seem rude!

 

[Paul Birkeland]

If you have 380V at IA, you have a loose ground wire in the amplifier (black), as there isn't any way to get voltage that high in your amplifier (your meter is struggling to resolve the voltage because of a bad connection in the amplifier).