Repairs

This is a very simple project indeed: add a line-in input feeding the amplifier in my sister’s CD/Tape/Radio, which has much better sound than the ‘device’ she mainly plays music from. How hard can it be to find the amplifier IC and feed in directly?

Taking the thing apart was none too hard, and it’s cheap ’90s hardware so all through-hole and single-sided PCB. I found the mode switch, traced it back to the amplifier, paid careful attention to the pinouts and soldered a small cable onto one input, the other end going to a 555 ‘signal generator’ kit I had lying around. Power up: the signal generator exploded and the lcd backlight died.

This posed something of a problem: what do you do when a pinned tenon breaks? The joint was too broken just to glue, neither surface was flat, and the dowels were in the way. In the end I decided to dowel it with three dowls, to leave as much of the broken tenon intact as possible. Dowled joints are easy on flat, square workpeices. On jagged tapering workpeices, now… With a quarter-inch chisel I cut flats to mark on and marked the three holes on both mortice and tenon. Then I made a jig to make drilling square a bit easier. This wood—generic African hardwood—is like fibreboard. The lip and spur bit just spun on the surface:

There is a nasty thing out there called ‘built in obsolescence’, which is supposed to cure the fact that most things are actually made quite well and would last a long time if left to themselves. Here is a microwave: