[Premium-Rx] WJ Optical Tuning Encoder Failures

[stephous]

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 shaft
2) Clicking once on reversing tuning direction
3) Heavy drag

Failure Symptoms:
When the wheel was turned the displayed frequency would
1) Jump randomly 
2) Run in reverse
3) Do nothing

Failure Analysis:
1) Factory glue from the locator shaft flaked off and migrated to the encoder wheel blocking the apertures
2) Grease on the main shaft between the O rings had increased in viscosity with age and was binding the shaft
3) 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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