01-31-2015, 09:21 AM
Madmurdok
In the way back machine (Rocky & Friends) we always tapped the meter in the tube testers in the drug & grocery stores while testing. They always stuck a little.
Look on BAMA for manuals and other data.
The best tune up I've seen uses an isolated Variac to inject voltage and set results. IMHO the "reference" tubes are just an OOC problem being propagated.
You noted a diode replacement for the 83 and may or not have filament supply load resistor to get current up enough to get line voltage down to adjustable range.
I have a 800 that I cleaned up and calibrated (voltage injection) and have been thinking about doing a front end regulator or voltage control to deal with the reduced current of ripping out the old tubes (no filament current) and replacing with diodes. No filament load resistor heat & I don't burn up a lot of current for nothing. My hesitation is what happens in the test data charts on power tubes. Little ones don't draw enough line current to worry me about the readings.
Yea my meter sticks a bit also and I always tap it and would even if it didn't stick - old habits don't die.
DO NOT use any lube on meter pivots - as was already said.
I've been rebuilding meters for years and the best advise I can offer if you decide to learn the art is buy a bunch of old meters you don't care about to learn on. You WILL make mistakes even if you have a meter Tech looking over your shoulder and whacking you on the head. As was said get plenty of light and a magnifying head band - Harbor Freight or other.
Testing tubes will find shorts or opens. One that is "Good" will probably work anywhere, while ? or "Bad" might work fine also. You just gotta try em in the circuit and see. Might work in one circuit and not another. Testers are also good for matching parallel or push pull output pairs. Not just the 2 best ones if you have several to choose from - the 2 closest matched.
An unsubstantiated SWAG if tubes have survived this long, they will soldier on unless abused. The Getter will only capture so much Oxygen the rest will deteriorate the tube. The few old tubes that got the best vacuum pulled have survived while the others are long gone.
In the way back machine (Rocky & Friends) we always tapped the meter in the tube testers in the drug & grocery stores while testing. They always stuck a little.
Look on BAMA for manuals and other data.
The best tune up I've seen uses an isolated Variac to inject voltage and set results. IMHO the "reference" tubes are just an OOC problem being propagated.
You noted a diode replacement for the 83 and may or not have filament supply load resistor to get current up enough to get line voltage down to adjustable range.
I have a 800 that I cleaned up and calibrated (voltage injection) and have been thinking about doing a front end regulator or voltage control to deal with the reduced current of ripping out the old tubes (no filament current) and replacing with diodes. No filament load resistor heat & I don't burn up a lot of current for nothing. My hesitation is what happens in the test data charts on power tubes. Little ones don't draw enough line current to worry me about the readings.
Yea my meter sticks a bit also and I always tap it and would even if it didn't stick - old habits don't die.
DO NOT use any lube on meter pivots - as was already said.
I've been rebuilding meters for years and the best advise I can offer if you decide to learn the art is buy a bunch of old meters you don't care about to learn on. You WILL make mistakes even if you have a meter Tech looking over your shoulder and whacking you on the head. As was said get plenty of light and a magnifying head band - Harbor Freight or other.
Testing tubes will find shorts or opens. One that is "Good" will probably work anywhere, while ? or "Bad" might work fine also. You just gotta try em in the circuit and see. Might work in one circuit and not another. Testers are also good for matching parallel or push pull output pairs. Not just the 2 best ones if you have several to choose from - the 2 closest matched.
An unsubstantiated SWAG if tubes have survived this long, they will soldier on unless abused. The Getter will only capture so much Oxygen the rest will deteriorate the tube. The few old tubes that got the best vacuum pulled have survived while the others are long gone.
