Mad Mouse Troubleshooting

[tomg]

Hi Jay, 

> I am having trouble getting tomg's mad mouse synth working.
> I know a lot of people have put this together and I was wondering if
> there was a checklist of tests to isolate problems.
> Such as outputs to check for on pins A-Z, AA-DD, and LED1+2.
> I haven't had much time to test but what I have found is as follows.
> The led lights up.  It is always on no matter what position the on
> switch is in.  I don't think this is supposed to happen.

Uhh no. If the led doesn't go out. You are not turning it off.

> I have checked for +12 and -12 in the smoke test section and this seems
> ok.  (11.94V and -12.16V)

That's ok....

> With or without a cv input the mad mouse always makes a low frequency
> low volume noisy growling sound.  The controls have minimal effects on
> this sound but the minimal effect appears close to what it should be.
> eg the volume pot makes it louder, resonance changes the sound a bit
> right near the max position.  cutoff frequency appears to change the
> sound a little etc.

You have a ground loop. Try using separate transformers.
Make sure no x-former leads go directly to a metal case.
Run your gnd from the pc-board to the chassie instead. Not
from the same place the x-former leads connect thought. 
You might end up with the same problem.

> I also have a midi2cv8 in the same box.  Both boards run off a single
> 12VAC 500mA transformer (is this ok?)

Sometimes this is ok. Not so with a MM. Populate and use the on-board
power supply. If you did this and are powering the CV8 with it, separate
them.  

> The midi2cv8 output test works.  MIDI data causes the MIDI Activity LED
> to blink.  I haven't done the MIDI In test yet but I think this will
> work.
> Thankyou in advance for any help.
> 
> Jay

Sure. Good luck and let me know how it goes.

-tg




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