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Impossible Circuit Board Repair?

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Oakton

New Member
Many years ago I purchased a GE SuperRadio. It was considered an "expensive" radio, but I think it was the
best portable AM/FM radio ever made. Because it has external connectors, you can pick up AM stations
thousands of miles from your location with a decent antenna.

For decades it functioned perfectly. A few days ago the volume control was damaged in a freak accident. I
opened the case and was immediately impressed by the construction. All the components look brand new!

There are three square pots soldered to the circuit board for treble, bass, and volume. Pot number four is a
traditional round unit. It's fastened through a hole in the board with a control nut.

There are seven guide wheels for the dial cord. The shaft for the round pot supports the two larger drive wheels.
I have a spool of replacement dial cord, but that is not the problem. Pulling the board so I can unsolder the
damaged volume pot will make this SuperRadio unusable.

It's a classic "Catch-22," if you know what I mean. The drive wheels are buried under the board (solder side).
Pulling the board will instantly remove the dial cord from the wheels. When the board is reinstalled you cannot
run new dial cord, because the wheels are inaccessible.

When this radio was assembled in the factory, several of the plastic structural components must have been
glued or heat sealed after the dial cord was wrapped around the wheels. Obviously, reversing this process
is impossible.

I can think of a possible workaround, but it's not something I really want to try. If I can find an ultra tiny
cut-off wheel for a Dremel tool, I could cut the volume control pins. Using conductive adhesive, I might be
able to bond a replacement volume pot to the cut pins left on the board. The cut-off wheel would have to
be extremely small so it doesn't damage nearby components. Maybe 1/8" maximum. Manufacturers of
custom jewelery use tiny cut-off wheels. The cost for this type of precision bit is probably more than I
want to spend.

If you can think of a more rational solution, please let me know.
 
Last edited:

jpanhalt

Well-Known Member
Most Helpful Member
The small, round burr (about 1/16") that comes with Dremel will do what you suggest. However, I have a hard time imagining a situation where you can get the burr there but cannot get a soldering iron to the same place.

Maybe a picture would help.
 

tomizett

Active Member
It's hard to believe that a radio of such apparent quality would have been constructed in such a way that it could not be taken apart for repair - but I suppose it is possible.

As John suggests, a picture would be great.

<edit>
As John again alluded to above, trying to glue a new pot in place would likely be a non-starter - it would have to be soldered. You may be able to un-solder the cut-off pins from the front side of the board.
 

jpanhalt

Well-Known Member
Most Helpful Member
Let me add that you can solder a component on the copper side from the back side, even when there are not plated through holes.
This bridge rectifier sits flush on the copper side. It is a one-sided board and was soldered from the side back side:
upload_2017-9-18_17-54-31.png

John
 

Nigel Goodwin

Super Moderator
Most Helpful Member
I've repaired radios professionally for many decades, and even cheap crap ones usually come apart for repair, and decently made ones are pretty well guaranteed to be designed to be repairable.

I can't comment on GE (as they are presumably USA specific?), but it's most likely that you're 'missing something', and not disassembling it correctly.

It's fairly common for the dial drive to stay as part of the cabinet, while the PCB is pulled away from it - and you have to make sure that the dial drive engages in the right place when you reassemble it.

Have you tried google?

http://www.davidmoisan.org/radio/superadio/gesr_app_A.html
 

BobW

Active Member
Also quite a bit of info on this site:
http://earmark.net/gesr/
It covers the original Superadio, the Superadio II, and the Superadio III, including disassembly instructions and service manuals.
 

Oakton

New Member
Thanks for all your replies!

I examined this radio with a very powerful headband lamp (1000 lumens) and dental inspection mirrors. For at
least two hours I searched for hidden screws, clips, or any weird fastener that would allow access to those
drive wheels after reinstalling the circuit board. I found nothing.

There is a four diode bridge, capacitors, and a jumper wire very close to that damaged volume control. Heating
those pins on the "wrong side" of the board will not accomplish much. The solder must be vacuumed up with a
sucker or wicked away with a desoldering braid.

Perhaps this radio should be given to a collector who has a lot of experience wrapping dial cord around those
wheels. I would like to keep it, but I'm afraid anything I try might cause more damage.
 
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