Thanks Harry.

I do have a service manual for the system published
by Piper, however it has no details of the electronic
compoents, only the electro-mechanical stuff. It does
have enough overall theory of operation information
to help get me started with the electronics. I'm also
trying to find out what help the orginal manufacture
can be. They are still in business, although operating
under a different name. So far, all I'm getting is their
hold message, but if I can ever get someone on the phone
I might get some help there.

Concerning your follow-up post, another gentleman has
already emailed me a scanned datasheet for the 2N1192
and the general info you provided on the MA900 like
devices should get me going there.

Thanks again for the help.
Ronnie

wrote in message
oups.com...
Ronnie, just as a suggestion, (although you've likely already tried),
try and obtain a technical or service manual for the system. Many of
these will included a cross-reference from the manufacturer's part ID
to a and industry standard.

Even a Sams folder would help you here, if one was ever published. Nice
thing about Sams folders is that they almost never go away once
published, only become a bit brown with age! :-)

Harry C.