Yamaha CS80

slammah2006 wrote:
> I am down 2 Oscillator cards in Bank 2 (# 3 and # 5) I believe it is 
> the Waveshape chips that are faulty.....
> Does anyone have any spares,
Good luck
>  or is know if there is a way to drop a 
> voice out of the rotation giving 2 banks of 7 Oscillators???...If that 
> were the case I could move one from my first bank to bank 2...
>   
This is pretty easy - I've done it before for someone while waiting for 
an oscillator chip. Move the bad parts to the highest voice cards (e.g. 
voice 8, then 7). Then you just jumper on the KAS board.  If you look at 
the KAS chip description 
(http://www.therogoffs.com/cs80/manuals/CS80_Service_Manual/06%20-%20KAS%20ICs.jpg), 
you can see that changing pin 40 (MODE)  from -6.5 to +8.5v skips voice 
8. If you have to disable more voices, then you need to change the 
K01-K08 pins. Look at the difference between the CS80 KAS board 
(http://www.therogoffs.com/cs80/manuals/CS80_Service_Manual/04%20-%20KAS%20schematic.jpg) 
and the CS80 KAS board (page 3 of 
http://www.therogoffs.com/cs80/manuals/CS50_Service_Manual/Yamaha%20CS-50%20Service%20Manual%202%20of%202%20(%2011%20x%2017%20-%20Double%20Sided%20).PDF).

Note: when I did this, I just changed the MODE pin (by cutting the far 
end of the resistor attached to it and connecting it to +8.5v) and 
didn't tie the K08 pin.  This caused the 8th voice to be on all the time 
and screwed up the trigger to the Ring-Mod EG.  I ended up pulling the 
oscillator chips on the 8th voice M Cards to mute them.  However, this 
created a really weird side-effect. The waveshaper chip was still there 
and picked up the signal from the PWM oscillator.  When the PWM rate was 
raised, it triggered the WSC and the oscillator was audible all the 
time!  Confused the hell out of me at the time.

 David