Well, the not working timer did work, as long as the start/reset bar was pushed.
Since I had nothing to lose, I asked my neighbor (retired electronic engineer) what could be wrong and he told me to open it and look at the board
Peeling the rubber feet gave me access to 4 screws in the back, and then had to do a bit of coaxing to remove the front dials and this showed up:
Gralab 450 Board - built as a tank
His recommendation was to look in this order
1 Start/Reset switch (corrosion due to humid environment)
2 Capacitors (useful life)
3 Ribbon cable (broken)
4 Voltage regulator (broken)
I ruled out 3 and 4 because the timer-panel was doing what it was supposed to
I started on (1); which seemed the more logical one. I guessed it needed a good contact cleaner treatment (spray, actuate, spray, actuate) . Tested and that seemed to do the trick.
Just in case I also cleaned all the other contacts, and measured the capacitors (2) which seem ok for now but expect to replace them in 3-5 years as they naturally lose the electrolyte liquid inside of them.
So now I have 2 working timers.
