My 25 year old radio/alarm stopped working. Always resistant to throw stuff out I decided to try and fix it.
I'd expected to find a few obviously dead capacitors, but no… all looked well. I did however manage to find online data sheets for the long obsolete radio chip, and also the clock chip, and have convinced myself that (surprisingly) the clock chip itself is the culprit; the alarm output pin is meant to be intermittent 900Hz modulated yet it is just DC. That is consistent with the symptoms, it just 'pops' when it should be 'beeping'. Most amazing of all, I have found an ebay seller willing to ship the suspect chip, long disappeared from normal supply channels, for under a fiver. It's on its way.
Disassembly & diagnosis was non-trivial and included bravely unthreading the cord that connects the tuner 'pointer' from various tiny pulleys, shafts & springs, separating two pcbs that were soldered together, and temporarily desoldering several interconnect wires that were too just too much in the way. Plus of course countless digital photos to aid reassembly. Spent about 4 hours on this so far, and budget another 2 or 3 hours to install & reassemble when the new chip arrives. Not sure how much a new clock would cost, but I'm certain it would be hard to justify my efforts in comparison, and a modern clock would probably a better clock too.
Plus of course the risk that I may have misdiagnosed, or that the chip failure may have been secondary to some other fault, or that I may damage the pcb swapping the chips, or may fail to reassemble correctly. Ah well, they say it keeps us out of mischief.