Archive of the former Yahoo!Groups mailing list: Yamaha CS80

Congrats on getting the CS60!  The sub-osc problem should be pretty easy to trace if you are comfortable opening it up and can read a schematic.  I have the service manual on my website here: http://therogoffs.com/cs80/manuals/CS60_Service_Manual/index.html

If you look at the bottom left of the giant schematic, you’ll see the sub-osc goes to the front panel controls and then to the R6 board.  The R6 is just a bunch of resistors that mix the mod voltages and sends them to the voice cards.  Sounds like the problem is there - probably just a broken wire.  If it’s just voice 7 for VCO mod, then it would be the VB7 output.  If you look at the R6 board page, you’ll see that VB7 is pad 10 on the right and has a grey wire that goes to pad 36 on the 7th voice card.  Check that this wire is solid on both ends.  You can check it easily with an oscilloscope or even just an amplifier if you set the sub-osc to its fastest rate.

  David