[222mhz] TM-631A Problems

[Dr. Gerald N. Johnson, electrical engineer]

No audio could easily be a broken wire in the microphone connector or
the microphone end of the cable. Microphone cables have been failing
that way for as long as radios have been used mobile.

The lithium back up battery is probably soldered to the control PC
board. Finding it is the biggest task of replacement. Kenwood parts
tends to want $10+ for a $3 battery with solder tabs. Kenwood parts
books and service manuals tend to ignore its presence and so don't help
the parts search. Changing it is a matter of finding the suitable
replacement, then unsoldering the old battery, and soldering the new
battery in its place, standard PC board repair except that its worth
while to unplug the iron while soldering in the new battery to prevent
shorting it with a grounded iron tip. I'd think a shop would charge
their minimum shop time service fee, likely more than $50 for only 5
minutes of work.

73, Jerry, K0CQ

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Entire content copyright Dr. Gerald N. Johnson, electrical engineer.
Reproduction by permission only.