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From: chris@hplvla.UUCP (chris)
Newsgroups: net.ham-radio
Subject: Kenwood TW-4000A Problems.
Message-ID: <2800012@hplvle.UUCP>
Date: Thu, 21-Nov-85 16:09:00 EST
Article-I.D.: hplvle.2800012
Posted: Thu Nov 21 16:09:00 1985
Date-Received: Thu, 28-Nov-85 23:40:47 EST
Organization: HP Loveland Instrument Division
Lines: 24


I have recently had the opportunity to fix one of two problems
in my Kenwood TW-4000A, and thought the fix might be of interest.

Problem 1: On cold mornings, no transmit modulation evident.
Freeze-mist on the workbench could not duplicate the problem.
Solution: replace the gain and deviation pots with higher quality
units. The pots are very cheap in design, contacts (soldertails)
were crimped on, evidently loose, and would lose contact in cold
conditions. Freeze mist caused condensation which masked the problem.

Problem 2: Very infrequently, the microprocessor appears to go to 
never-never land. Display is fluctuating meaningless characters, or
blank. No controls work, including PTT, beeper may sound. Resetting
the micro by power off/on seldom works. Resetting by shorting out the
reset contacts under the lower cover sometimes works. Removing
power for several hours always works (unplugging, not just turning off
the switch).

If anybody has info about problem 2, please reply.

Thanks and 73, 
Chris Kelly, WD5IBS
hpfcla!hplvla!chris