28 February 2016

Saba Compact Clock A - washed up - no joy

As announced, I washed with hot tap water the Saba Compact Clock A PCB covered with NiCd electrolyte spill.

I would say that 80% of the alien material has gone away and most tracks shine again. A ceramic capacitor was split in half and I had previously removed a trimmer that was badly damaged.

I reconnected the transformer and, unfortunately but expectedly, the clock does not power up at all. Not even a mildly reassuring sequence of "000".

Probing around with the DVM I spotted open diodes in the area closest to the was-backup-battery. And since I have no pinout of the microchip, let alone a datasheet, I have no idea which pin is not being fed correctly.

I might replace few 1N4148 here and there and fit a new 100k trimmer. If nothing happens I will leave a note to the future myself inside the device of what has been found and done, and the Saba Compact Clock A will join my collection of electronic items from 1980's.

It can be fixed. With patience and time. Do I really want to?

PS: the display is not a simple LED, and I need the microchip to work again so that I can measure voltage values!

PPS: according to the blogging platform, this is my 500th post!