10-05-2020, 10:27 AM
(This post was last modified: 10-05-2020, 10:30 AM by Mike Watterson.)
BRT165 sounds wrong, almost all GEC are BCnnnn (four digits), at least 1935 to 1960. Though some "Commercial" sets (Military, Marine and others) might be BRTnnn
Replace any paper dielectric caps between anodes and grids (leakage destroys following stage / audio transformers), screen grids to 0V (reduces gain dramatically) and across mains or HT or audio transformer primary (can short).
I'd do "bluetooth" by using a Gram input (2 x33 Ohms and a 3.5mm socket), or for live chassis sets a low power AM TV with loop beside it fed by 3.5mm jack. Sets with FM are no problem as a €6 FM TX to connect phone/MP3 to an FM Radio can be higher quality than Bluetooth and can be fed with a €10 BT receiver.
Leakage on the HT Electrolytics can be a problem. One strategy is to remove valves and feed them via 30V current limited PSU (< 50mA) and only replace if leakage doesn't drop to less than 1mA (leave in place and cut + lead, solder small new one to -Ve tag and sleeve +ve connection).
Replace any paper dielectric caps between anodes and grids (leakage destroys following stage / audio transformers), screen grids to 0V (reduces gain dramatically) and across mains or HT or audio transformer primary (can short).
I'd do "bluetooth" by using a Gram input (2 x33 Ohms and a 3.5mm socket), or for live chassis sets a low power AM TV with loop beside it fed by 3.5mm jack. Sets with FM are no problem as a €6 FM TX to connect phone/MP3 to an FM Radio can be higher quality than Bluetooth and can be fed with a €10 BT receiver.
Leakage on the HT Electrolytics can be a problem. One strategy is to remove valves and feed them via 30V current limited PSU (< 50mA) and only replace if leakage doesn't drop to less than 1mA (leave in place and cut + lead, solder small new one to -Ve tag and sleeve +ve connection).
