[sdiy] juno 60 death

[R. D. Davis]

Will reply more later tomorrow... it's getting late, sleepy, but I'm
curious about something.

Quothe gregory zifcak, from writings of Sun, May 09, 2004 at 09:51:46PM -0700:
> i measured correctly this time, and i'm getting 0 volts ac at the outputs 
> of the transformer. i am getting 120 volts going in, so i'm pretty sure the 
> problem is the transformer itself. nothing looks burnt though. it seems 

Interesting to see which windings may be open.  If you're getting some
small voltage, then the primary perhaps isn't open, or somethings
shorted somewhere, etc.  Did you do a quick check with an ohmmeter, or
RCL bridge, (with everything unplugged, and the transformer
disconnected from the circuit) to see if anything is open or shorted?

Would disconnect the PSU board from the rest of the synth, in any
case, just to be on the safe side, before any further testing:

I'd be tempted to try a different transformer, or transformers (18V CT
and something between 6V and 12, or just use another half of an 18V CT
to get approx. 9V... just watch component voltage ratings before the
7805; looks like they should be ok... 12V in _before_ the rectifier
will probably be a little too high after it and filtering, for the
7805, giving that more thought.  You want to keep it below 13 to 14 V
there at the input to the 7805, and getting up to those levels (have
done that before, with a car battery), a lot of heat sinking on the
7805 be a good idea, if I recall correctly.) and see what happens.

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