Thanks for the tips!

I've seen the preselector, and it's a 72A2 (bummer, I guess)
Can someone confirm that this is the "wrong" module for ham band coverage? Didn't see any "61A" modules...

But, I did manage to remove the pin!

My four-channel is now a 12-channel.

It was much easier, once I ...

I note from the N2 call that you're in the Northeast.

With the classic "whip into the socket & clamp with setscrew", there
is a constant problem with corrosion from road salt, etc.

I find that coating the setscrew hole and whip socket with "antiseize"
(lubricant with metallic flakes used to ...

Having built more than a few DTMF decoders, I would heartily recommend the 8870 part. It's multi-sourced & works well. The AY-5 number is a VERY old General Instruments number, and I would advise against using it.

I found one in my junk box if you want it, email me with your address
& I'll mail it ...

Thanks to both of you. I understand about the plug not being reprogrammable. What I meant was what you suspected, use another zone & rejumper, which I gather is the "standard trick". The space where the zone switch goes on the top panel is inhabited by a noise squelch adjustment knob, which I think ...

My ham club recently received a donation of some H43SSU3140AN MX340 portables. Assuming we can get the code plugs reprogrammed at a reasonable cost, and of course, new batteries, they could be useful!

I'm curious if anyone knows whether the channel switch can be unblocked to allow rotation to 12 ...