On Tue, 09 May 2006 11:10:03 -0700, Dunkirk
wrote:

Hi, Chuck -- thanks for your response...

Chuck Harris wrote:

Dave Hildebrand wrote:
I have a 22-year old Icom 02-AT that has worked reliably until now, when
it ceased putting out any transmitter power whatsoever.

Does it still receive correctly?

...yes -- the only thing that's changed is that the little bar-graph
(along the bottom) doesn't appear; as though there were nothing to be
measured. And, I fell out of the repeater while in QSO (full-quieting),
having to sign clear on another radio.

What usually happens, is the synthesizer quits, and it stops sending,
or receiving.

...in my case, I can dial-up any repeater and listen -- I just can't
transmit any more.

The output transistor is a T05 (TO39) type package, and is soldered to the
metal frame that surrounds the radio. It is very special, in that the case
of the transistor is connected to the emitter. Most transistors in that
package have the case connected to the collector. This is done so that
they
could run the emitter grounded (as is usual) and not need any insulated
heatsinking hardware.

...are they (the transistors) a real bitch to replace?

The usual way of blowing the output transistor in an 02AT is to use a
battery
pack that supplies more than 9v, or to try and power the rig directly from
your car battery. ISTR that a short on the antenna is a third way.

...the jack on the top's supposed to have an internal regulator, and
I've used it in my truck on occasion since the radio was new with no
negative consequences (not like the HTX-202, which was made by Maxon
under license by Icom for Radio Schlock, and had issues with its
external power-jack).

Maybe infrequent long-winded transmissions over the last 22 years is the
culprit for the transmitter's untimely demise? (It's kept my hands warm
in the cool outdoors more than once.) I've long since misplaced (or
lost) the original manual, which had a schematic.

If I crack it open, I should be able to measure the voltages on the
device, itself to see if it's blown. Right now, the final seems like the
prime suspect. Thanx...

...Dave, N6BHU
Icom never had a thing to do with the HTX-202. No license, design
etc. Radio Shack choose accessories that were popular and happened to
choose the Icom battery design. You are correct Maxon made the HTX-202
for Radio Shack.

I had many calls while working at Icom over that rumor Many wanted
Icom to repair the HTX-202. Icom America asked IJ if they were making
the HTX-202 and they said no but found out Maxon was building the
HTX-202. all water over the dam now.

It was true that Icom did private label the H and U-16 for Midland
Land Mobile for a while.

Gary K8IZ