Speedball Installation - Wrong voltage small board

RSpies · 1435

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Offline RSpies

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on: February 18, 2017, 05:23:24 AM
Hi,
Just started the Speedball upgrade to my Crack and I am not getting the correct voltages when I add the first small board.  The Crack was working well before I started so I suspect the problem is with the board or the attachments. 

Voltage check showed:
OA          78
IA          147
B-A/B      0
IB          147
OB         136

The LEDs on the left (looking from the volume pot end) glow, but much weaker than the two on the right.

Where should I be looking for the problem?

Thanks



Offline Deluk

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Reply #1 on: February 19, 2017, 12:23:45 PM
There are quite a few connections on the board that haven't flowed properly. Should all have a neat little "mountain" with an inverse meniscus. i.e. not a blob. They just need a bit of heat from a properly tinned iron and then just a small amount of solder to reflow them. Can't say which one will cure your problem, maybe none of them, but they need doing. Do the same at the tag strip.



Offline Paul Birkeland

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Reply #2 on: February 19, 2017, 12:31:19 PM
I would agree, more heat, especially on the center legs of those MJE-350's.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline RSpies

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Reply #3 on: February 19, 2017, 04:24:22 PM
Thanks, I resoldered some of the connections and it works now. The second and fourth points are now in around 160-161 instead of 170-190.  I assume that is close enough not to be concerned.  I don't notice any problems listening to it.



Offline Paul Birkeland

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Reply #4 on: February 19, 2017, 07:05:09 PM
Sure, those aren't particularly disturbing.  The important voltages are at T1, T5, T7, and T9, with the rest of the high voltage terminals (2, 4, B2, B5, etc) all dropping a bit more than usual as you install each piece of the Speedball.

-PB

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man