[sdiy] sh-101 progress :)

[Seb Francis]

nN AAt e e wrote:

>i don't have my scope setup right now, so i was doing ye olde 'cable to pin'
>test to see if i got any output from the CEM... didn't sound very VCO-y...
>can someone tell me what the output directly from the CEM3340 should sound
>like? just like any raw waveform i would assume. i'd also like to know what
>kind of symptoms the synth would have if it it was a case where just the
>CEM3340 was dead.
>
>  
>
Yes, the CEM should output raw waveforms .. listen to pins 4 and 8 for 
square and saw respectively.  See whether the outputs track the keyboard 
pitch.  In a 101 I fixed the other day the CEM was outputting proper 
waveforms, but at non-audio frequencies (above audio IIRC) and not 
tracking changes in input CV.  In this case it was the CEM chip that was 
faulty (expensive to replace!)

I have the datasheet for the CEM3340 and schematics for the SH101 
(contact me off list if you want them).

Seb