Bottlehead Forum

Bottlehead Kits => Crack => Topic started by: StivVid on August 29, 2015, 01:23:01 PM

Title: Smoking Speedball
Post by: StivVid 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?

Title: Re: Smoking Speedball
Post by: Doc B. 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.

Title: Re: Smoking Speedball
Post by: StivVid on September 03, 2015, 07:21:03 AM

I feared that might be the case.  Thanks, Doc.

R

Title: Re: Smoking Speedball
Post by: StivVid on September 03, 2015, 08:00:28 AM

So will any TIP50 transistor work, or am I looking for something more specific?

Title: Re: Smoking Speedball
Post by: Doc B. 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.

Title: Re: Smoking Speedball
Post by: StivVid 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.