The pulse after that first 47k would go between 0 and 0.7V maximum. At that point it should turn on the transistor. The output of that transistor usually sits at +VE and will swing down to nearly 0V if that transistor is working correctly. The second transistor works in the same manner, but upside down.
Transistors do NOT need to be matched. Just make sure the first one is an NPN and the output one is a PNP.On Mon, Oct 19, 2015 at 1:52 PM, gerrardjenner@... [cgs_synth] <cgs_synth@yahoogroups.com> wrote:Finally getting around to troubleshooting a few minor problems with my serge panels.
First up was the SWAMP:
The AEP out is sitting at a constant 1.5v and I can't see any pulses.
If I scope the D line I can see the spikes - but when it hits the B board after the first 47k resistor they're gone.
The transistor before the AEP out is at 5v and after the 2k2 resistor it's 1.5v.
I tried swapping out the transistors which didn't make a difference - do they need to be matched at all?
Every other function is working fine.
Cheers
Gerrard
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