Speedball Small Board Voltage Check Issue

[onion_breath]

Currently in the process of installing a Speedball and am running into a few issues.

1. LED in position D1 on side B didn't illuminate.
2. Voltage reading on OB is low.

Here are my readings on the Small Board

Terminal    Voltage
OA              70.7V
IA              184.6V
B-A/B          0.001V
IB              184.6V
OB              54.46V

 

[Paul Birkeland]

I would reheat the solder joints.  You're close enough that I would suspect that there's a partial impediment to current flow on the board itself. 

 

[onion_breath]

Upon further inspection it seems as though I installed one of the PN2907A transistors backwards. Currently in the process of desoldering. Hopefully this fixes the issue.


*Update*

Removed the PN2907A and it broke - email has been sent for replacement part.


Would the transistor installation have any effect in the LED illuminating? I did go and reheat the solder joints on both the Small Board and on 5U and the LED didn't illuminate.

 

[Paul Birkeland]

Yes, a backwards PN2907 will cause that kind of issue.  I wouldn't proceed with any other work until the replacement part has arrived.