[sdiy] Cheetah MS6 Help

[Keith Winstanley]

Hi All,

just picked up a Cheetah MS6 which is a little bit more deaded
than I was hoping and I could do with a little help or experience.

Firstly, anyone got any schematics for this synth, cant find them
and they would help?

What is apparent is that the unit powers up with the code
FE - FF briefly and then settles on the initial bank - tone config
11 - 1 so it seems that some sort of boot is happening. After that
there is nothing. no button responses or response over midi and
no audio output apart from a bit of noise.

Now someone had tried replacing the battery on this unit and pulled
a few tracks which I have repaired. I am getting some low voltages
from two of the regulators, +12 +5, I tried replacing them but this
made no difference. The +5V reg is outputting about +2.6V which I
find on a rail running to the switch matrix.
I did find a DAC0800 running very hot, I replaced it but it still runs hot.

Now I have found that one of the two transformers running quite hot
and the other at room temp. I am guessing that this hot tranny
has shorted internally and is the root of the problems. I have read
on the MS6 resource site http://www.maad.net/ms6/ that the
transformers can be a problem. I just need some confirmation that a
hot transformer is a bad transformer before pull it I order another.
Without the schemos I am a bit unsure of which is what at the moment.

Hope someone can offer some advice?

Cheers....

Keith

http://home.freeuk.net/lowpass