Panasonic RX-C45 AM/FM/Casette Boom Box Repair

[Guest]

I managed to get a service manual from an on-line vendor for less than $10. There were problems with printing pages due to built-in watermark, but I managed to use the schematic and printed circuit lay-out diagram enough to make repairs. The left channel was dead on all functions, however the output was OK from the volume control through to speakers. There was a mouse nest inside when I opened it up. It turned out that the pee from the mouse ate away a circuit trace between C115 and R129 (a carbon film deposited resistor on the top circuit trace). One end of R129 was connected to C146 a .001 mfd tubular ceramic capacitor. I found a through-hole near this junction that allowed me to add a jumper wire to replace the copper trace that had eroded away. A general clean-up of controls and circuit board left most all of the unit in good shape again and fully functional. The upper circuit traces are made from a copper paste/film deposited on the board. They are very difficult to repair and usually best to find a throug-hole near a component and jumper with a wire as I did. Solder will not adhere to this copper paste/film at all.

I plugged a hole in the battery compartment where the mouse had gained entry using a piece of white plastic from a discarded computer glued it in place with some Liquid Nails. Mice will no longer be able to get inside.

[Pentode]

I repaired a Sonab vertical type speaker once, they look like wooden stools with a grille at the top.... all distorted!

A mouse was trapped between the speaker cone and the speaker chassis... they guy was absolutely delighted when I removed the dead mouse, apparently his cat went ballistics one night and he thought he saw it chase a mouse but wasn't sure!

We know now.... what we don't know if the mouse was deafened first!

I remember GEC equipment around the 1960/70's they used the same technique in their music centers etc. using carbonized resistor tracks and silver traces... they just disappeared should you try to solder them.

On one occasion I used a couple of 8BA brass screws and washers, drilled slightly off-center, relying on the washers to make contact - only thing I could do at the time.

Dave