Smoking After Speedball

Tonydatigerr · 1372

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Offline Tonydatigerr

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on: June 22, 2014, 09:06:41 PM
Just finished installing Speedball and began testing voltages. Only got through terminals 1-4 before I noticed it started smoking from somewhere around terminal 16. Also, none of the LEDs on the boards were lit up except for the one closest to the edge of the bottom of the board (big board, with "Top" oriented on the top left). The 2 LEDs on the 9 pin lit up. Only the heatsink on the top right of the board (same orientation) got hot, the other was cold.

Here are the voltages for what I was able to get before shutting down.

1. 69
2. 90
3. 0
4. 90



Offline Paul Birkeland

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Reply #1 on: June 24, 2014, 04:15:09 AM
Check that the 2N2907 and 2N2222A transistors are on the correct board.

9/10 times that we see an issue like this, it is from the TIP50C transistors touching the metal heatsinks, which is prevented by using the included transistor mounting kits. 

-PB

(PS - 69V on T1 means that at least the lower left small PC board is working properly)

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man