Sunday, October 18, 2009

Damn it

In an attempt to discover what was wrong with my bass amp I further destroyed it. At least before it worked like 60% of the time. Now it's completely fucked.

I set it up to take some voltage readings yesterday. About 5 minutes after I plugged it and turned it on two resistors flamed out. I quickly unplugged it and drained the caps. I poured over the schematic trying to find out what had caused the burnout. Both of the resistors are close in the signal path but not in serial. It seems like if those two components burned out that other resistors should have burned out as well.

The Q13 driver looked suspect in the whole thing so I popped it out to test it. Under one set of testing this transistor indeed looks bad, but under another set of testing (that makes more sense to me) it seemed fine. I decided just to put the driver back in and maybe ship the amp off. Apparently when I de-soldered the driver to test it, the small metal pad that attaches it to the circuit board came loose as well.

This has all gotten quite a bit beyond me. I don't trust myself (especially with the erroneous driver testing) to actually sort this all out. I still can't even figure out why just plugging the amp in and turning it on caused catastrophic failure. And I certainly don't have the money right now to get it fixed. It's a $65 bench fee just to look at it, and on Ebay you can get a new one for $200. It's a shitty amp, but even shitty is better than nothing.

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