those are 1000pF polystyrene caps they are all of the same value. Only the caps with the yellow holders should be suspect on a first inspection.Those are the Aluminium Electrolytic capacitors, they dry out over time or start leaking out electrolyte ...Rufer wrote:Thanks. Would it make sense for caps of different values to be labeled 'mial 1000 5%'?
all the other caps are either polypro or polyester, they rarely break down. polystyrene also falls in the "rarely breaks down" category. However they are very easily harmed by overheating when soldered.
The most suspect components on these boards are the transistors and the lytics. The germanium transistors are very sensitive to moisture. from the outside or from bad manufacturing.
easiest way to test if the main oscillator or any of the other frequency divider transistors are broken is to hook up a 9V battery to the circuit and listen to the individual output tabs with a headphone attached with some alligator clips between ground and each tab. ground goes to sleeve and the tab under test goes to the tip.
greetings,
Thomas