Bottlehead Forum

Bottlehead Kits => Crack => Topic started by: onion_breath on January 27, 2016, 11:41:20 AM

Title: Speedball Small Board Voltage Check Issue
Post by: onion_breath on January 27, 2016, 11:41:20 AM

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

Title: Re: Speedball Small Board Voltage Check Issue
Post by: Paul Birkeland on January 27, 2016, 12:02:56 PM

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. 

Title: Re: Speedball Small Board Voltage Check Issue
Post by: onion_breath on January 27, 2016, 12:43:30 PM

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.

Title: Re: Speedball Small Board Voltage Check Issue
Post by: Paul Birkeland on January 28, 2016, 06:39:03 AM

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