[ICOM] IC37a Lost it's pl tones

[Ray Keefe]

I've got an old IC37A that apparently lost it's PL tone. They did work, 
now I can't access any repeater that requires PL tones now.

I found a schematic online but the pin numbers for the PL chip are just 
short of looking like Sanskrit to my aging eyeballs.

After probing all the pins with a scope, I have been able to determine 
that the CPU is requesting pl tones, by watching the inputs to the chip 
I see the request change when the pl tone is changed.

I don't see any sinewave signals coming from this chip on any pin, just 
steady state voltages or grounds. I have a suspicion that the xtal has 
gone south.

Anybody have an idea of what pin is the sinewave output pin and what 
sort of signal level should be there?

Other than the flakey volume control, all the segments in the display 
are solid and not burned out it's a nice little radio. I'd like to keep 
the radio or else it's up for sale.

Tnx
Ray