Yamaha CS80

Hi, thanks for the group, lots of good info!

I recently acquired a CS60, that mostly works pretty well. 

The first, and easiest issue is to find out a modern replacement for the Touch Response light bulb. I'm having some trouble finding a 24v5w equivalent. The #1864 seems close, but is 28v, and I'm not even sure it is the correct base size. 


The only other issue I've found (other than the need for a good tuning touch-up) is that the 3rd voice does not pass Square, Saw, or Noise. The Sine wave works great, and all other cards work fully. 

Where can I start? I've read a few posts here about it possibly being the Wave Shaper or maybe the VCF or VCF master level?

Thanks!
lee.