"Jay Somerset" wrote
My two KX 170B NavComs are getting a bit tired. The tuning gears have been
replaced, and after several years are now getting really stiff and hard to
turn again. Apart from the mechanical parts, the radios both work just
fine.

I am looking at three alternatives; having them repaired again, getting the
MAC 1700VTX conversion, or replacing them with TKM MX-170B units. The
conmversion and the TKM units seem to be about the same price.

What is the collective wisdom of this newsgroup? Does anyone have direct
experience with both the MAC and TKM products?

Actually, since your 170B's are still worth $300+ each on eBay (and
that's being conservative - I've seen them go for $400+) you better be
saving at least that much by going with the TKM over the MAC. And
then there's the downtime of having your radios worked on. And the
fact is, the electronics are still old. I would avoid the MAC. BTW,
the MAC conversion was made by McCoy, and they are out of business. I
understand someone else picked up the support.

Realistically, if the only problem is that the mechanical parts are
getting stiff and hard to turn, a good cleaning may solve your
problems.

I used to have a MAC and a KX-175B in my plane. Once I had an
overvolt condition due to a short in the field line. The KX-175B was
fine. The MAC could still transmit and receive, but the digital front
end got fried beyond repair, so no display. I now have a 170B where
the MAC used to live.

Michael