The only thing I'd add to what Al has said is that often in older test gear, the HT is rectified either by a stick rectifier or contact cooled rectifier. (EG, Hunts CRB3 etc). Over time, if those rectifiers don't fail, they often give low HT. Easy enough to rectify ('scuse the pun!) by replacing with a modern silicon rectifier diode.
Some test gear did use high stability wirewound resistors in the divider chain, (usually recognizable by their black painted appearance) which often retain their values, but any carbon composition resistors tend to drift high over time. Maybe not so important in a radio, but if they're in the measuring circuit of test gear, obviously they throw the calibration right out. The good news Joe is that it does actually work, if only after a fashion!
Some test gear did use high stability wirewound resistors in the divider chain, (usually recognizable by their black painted appearance) which often retain their values, but any carbon composition resistors tend to drift high over time. Maybe not so important in a radio, but if they're in the measuring circuit of test gear, obviously they throw the calibration right out. The good news Joe is that it does actually work, if only after a fashion!
Regards, David.
BVWS Member.
G-QRP Club Member 1339.
'I'm in my own little world, but I'm happy, and they know me here'
BVWS Member.
G-QRP Club Member 1339.
'I'm in my own little world, but I'm happy, and they know me here'
