24-11-2020, 09:53 AM
Hi.
There are many new to this hobby that are unaware that silver mica capacitors are usually perfectly OK.
It's not their fault as we talk about waxies, so seeing a wax covered capacitor it's usually change on sight.
Many of us experienced restorers will tell others that.
A 9volt operated transistor radio really doesn't need this across the board advice, the low impedance of transistor devices is not going to be effected by a few Meg ohms leakage. My advice is only replace if there is a fault like noise or hiss on the audio. The biggest issue is dried out electrolytic caps or leaky ones. Measure the quiescent current on the set and if out of spec then investigate. Restoration is less of a word with these sets it's more like fault finding and service, a different kettle of fish.
There are many new to this hobby that are unaware that silver mica capacitors are usually perfectly OK.
It's not their fault as we talk about waxies, so seeing a wax covered capacitor it's usually change on sight.
Many of us experienced restorers will tell others that.
A 9volt operated transistor radio really doesn't need this across the board advice, the low impedance of transistor devices is not going to be effected by a few Meg ohms leakage. My advice is only replace if there is a fault like noise or hiss on the audio. The biggest issue is dried out electrolytic caps or leaky ones. Measure the quiescent current on the set and if out of spec then investigate. Restoration is less of a word with these sets it's more like fault finding and service, a different kettle of fish.
