Silicon Fuzz Face Collector Voltage Problem?

Started by Jakub421, March 06, 2014, 10:26:48 AM

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Jakub421

Hello everybody.
So just a few days ago, I made a BC 108B silicon fuzz face clone using the original pcb and pretty much all of the original parts as according to the schematic.
At first, it worked great, sounded really awesome, but just yesterday, it started to cut out and eventually stopped working all together.

Took it apart and measured the voltages, and this is what I got.

Q1
E: 0 V
B: .622 V
C: 22 mV

Q2
E: 8.91 V
B: 20 mV
C: 4.6 V

These voltages seem quite a bit off, but I have no idea what could've happened. When I first used it, the voltages were spot on, but for some unknown reason, they got really messed up.

Already went through all the solder joints probably 3 times, and this thing is really starting to get on my nerves. Any ideas as to where the problem may lie?

Thanks a lot!

PRR

> Q2 E: 8.91 V

Q2 E has become shorted to "+9V".
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Jakub421

It can't be, I checked it at least 5 times. It seems like the voltage won't drop over the 8.2k resistor

peterg

The 8.2K resistor should be at the collector of Q2. 4.6V is good at that location but as Paul stated the emitter's voltage is way to high. It should be close to 0.

Jakub421

Solution found, bad ground  :icon_rolleyes:
Thanks for the help!