Hi guys,

I'm trying to figure out how a circuit works on this old Wavetek 166 function generator (see attachment). Specifically, there is square wave generating circuitry (selected using switch SW3-D located near left side of screenshot - the bottom three terminals of the switch select between three different types of square waves) running into the MC1496 Modulator/Demodulator IC and I'm not too familiar with this part and also not quite sure how it's being used here or how the circuitry is intended to function together.

I appreciate any help, thanks!

(If you need to see any additional pages of the .pdf let me know and I'll add them, the original pdf is quite large and too big for the uploader.)

 

no help?

 

Is it broken, or are you just curious about how it's supposed to work?

 

Both of those actually. The problem is that one of the lower three functions (square waves) isn't working correctly and I don't see any pulses coming out.