Saturday, 18 January 2020

Servicing of a Yaesu FRG 7700 receiver radio

I have posted on the FRG7700 before, some success was the result, then the thirty eight year old set that I own went silent, like no sound at all.

As many of us do I searched forums to see who have seen similar issues and what was done to repair the fault?

Some were very helpful, others went in a wrong direction or not suitable for my sets repair?

The lack of audio volume was repaired by the application of a cleaning fluid made by CRC, the cost in Rands was R139.00 it would be about U$10.00 I think?

I applied the plastic safe spray to the various control knobs, that was front and back.

To start with there was no change, no audio at all, I switched the set off and then after a half hour switched it back on, the result was an audio that was so strong and loud that I nearly fell off my chair.

With a set that was working well as far as its sound was concerned I turned myself to try and reolve the twelve channel memory which was stuck on all channels and showing a frequency around 6.190Mhz ?

There had been an issue with the memory battery pack, I had used so called " Leak Proof " Duracell batteries, so much for that claim ?

I had found a mention in one forum that to remove the six plugs ( difficult ) in the memory pack can in most cases ( they said 90% ) clear and repair the memory, in my case this did not work.

On joining a forum named Antique Radios I was given various suggestions, one was that while the three AA batteries I had by then fitted showed some 3.9 volts they may not power the memory correctly?

With a new pack of Varta AA batteries installed I tried the memory function again, nothing had changed.

The white presstick putty is holding the batteries in place.

What I now had was new batteries and a memory which was locked, I had  not been able to clear the twelve memories. I next went through each memory, then switched the set on and off, I did that twelve times then tried to enter Cape Talks 567 AM radio frequency into a memory channel, it worked!

I saw that as the memory saved before it was off frequency some, I corrected that by saving the frequency slight off the correct one, it would then save correctly, I can fine tune using the M Fine control if required.

I then saved selected frequencies.

I hope my fix will be of use to others, having this thirty eight year old set is a delight  to use, next I need some LED bulbs to fit in the S meter and the tuning dial indicator.

How hard was this?

Not really but it took some time I must admit.

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