Smoking Speedball

StivVid · 1626

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Offline StivVid

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on: August 29, 2015, 01:23:01 PM
Hello, All.

I just finished wiring my Speedball upgrade and was beginning the voltage checks.  Accidentally touched the underside of the main board with the positive probe and got a spark, then a smoking and glowing 31.6 ohm resistor.  My question is, having definitely blown that resistor, is it likely that I've damaged any other components and how do I check to make sure?


Offline Doc B.

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Reply #1 on: August 29, 2015, 05:26:31 PM
If the resistor was smoking and glowing after you removed the probe you have shorted a transistor.

Dan "Doc B." Schmalle
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Bottlehead Corp.

Offline StivVid

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Reply #2 on: September 03, 2015, 07:21:03 AM
I feared that might be the case.  Thanks, Doc.

R


Offline StivVid

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Reply #3 on: September 03, 2015, 08:00:28 AM
So will any TIP50 transistor work, or am I looking for something more specific?


Offline Doc B.

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Reply #4 on: September 03, 2015, 08:33:46 AM
Test your transistors by looking for a low resistance between two of the three legs. It could be the TIP50 or it could be the 2N2222 that is shorted - or both.

Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.

Offline StivVid

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Reply #5 on: September 03, 2015, 10:40:04 AM
I had forgotten to trim the legs of the TIP50's before installing the board.  I definitely touched one leg a TIP50 during the voltage check.  I'm guessing the best way to check these is to remove them from the circuit first?

It was a stupid mistake made late at night when I should have just gone to bed.  We live and we learn.


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