[Premium-Rx] WJ Optical Tuning Encoder Failures

[Ahmet G.]

I have seen several WJ8718 s Encoders needing cleaning. In my case it was
easy to open the encoders and simply clean them carefully with cleaning
alcohol and air spray the dust and dirt off. they worked fine
afterwards.  i also replaced an Encoder of another non-WJ set which could
not be saved by simple cleaning. Encoders are expensive but i found a
very low cost source for them.  I have seen major failure problems with
HP test equipment encoders that used regular lamps and high current would
burn the series resistors which were low wattage ones.  WJ encoders that
i have worked on have open contsruction without hermetic seal which makes
them easy to get dust and dirt but also makes them easier to open and
clean.  careful cleaning takes care of it in most cases.
as i mentioned if anyone needs new encoder i can recommend a source. 

regards

ahmet


Several list members experienced problems with their optical tuning
encoders in WJ radios. Unfortunately I now understand what can go wrong.
My 8716/MFP started to malfunction 2 weeks ago. Scanning and key pad
entry were fine. The tuning wheel started operating erratically.  Pre
Failure Symptoms:1) Sticking shaft2) Clicking once on reversing tuning
direction3) Heavy drag Failure Symptoms:When the wheel was turned the
displayed frequency would1) Jump randomly 2) Run in reverse3) Do nothing
Failure Analysis:1) Factory glue from the locator shaft flaked off and
migrated to the encoder wheel blocking the apertures2) Grease on the main
shaft between the O rings had increased in viscosity with age and was
binding the shaft3) Front and rear halves of the encoder
housing separated when the plastic palls lost tension and released I have
two other radios that are in pre failure mode, so I will either need
parts, a procedure, or to develop a procedure. I use the tuning wheels a
lot. This type of failure will be a problem for me. I repaired the
original 8716/MFP encoder. I believe it was done reliably, but a special
epoxy is required to secure the locator and palls. The thermo plastic
used in the encoder case is very hard and difficult to bond with. We
shall see how the encoder holds up. I would like to hear from others
would had similar problems. If you have been into the encoder you know
what a job it is to work on. I would rate the complete rebuild as a
factory job, high difficulty. Best Regards,Steve PCS Associates
949 Glenneyre Street
Laguna Beach, CA. 92651-2706
Phone: (949) 376-7844
FAX: (949) 376-7866
http://www.pcsassociates.net/
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