[kd4pqf]

who can i get to repair a tube tester? The filament voltages are all over the place.

[Alan Douglas]

Filament voltages come from taps on the power transformer, and there's not much you can do to change them. It's not unusual for some of them to be off a little, either high or low, though high is more common. They will drop somewhat under load, so you should be measuring them with a suitable tube plugged in.

[kd4pqf]

I thought about that but most of them are way high or way low. thought about replacing the rheostat . but it seems to work ok maybe a little jumpy...but it has fried two tubes form the voltage being so high

[DCASAZZA]

Alan is right. The taps pretty much determine the voltage. The rehostat takes care of the little high/ little low after the load of the tube is brought to bear. Ive never had to fix one but it might be worth you taking a realy good look to make sure there is no "creative wiring" form a previous owner. I would suspect if the transformer was bad there would be a noticable loud hum, unusual heat, smoke, or all of the above. Good luck

Dave

[Alan Douglas]

Is the switch knob installed correctly on the shaft?

[kd4pqf]

as far as i can tell the knob is fine. There dosent look like anyone has ever been in it before. The voltage are all over the place like the windings are missed up, but the transformer looks fine no funny smells or anything. The transformer has about 10 taps coming off of it.....I am probable going to junk it and try to find another one.

[Jim Berg]

I have a few testers I use and the readings do vary, but not enough to blow a tube. What tubes did it blow? Any chance of a shorting wire or debris on the selector switch?

[Alan Douglas]

There must be a pattern to this. Read the voltage on pins 1 and 4 of the 4-pin socket, while turning the filament selector through its range. They'll be somewhat high, with no load, but they should match the knob settings pretty well. Do they start at 1 or 2 volts and increase in step with the knob position? 6V at the 5V position, 7V at the 6V position, 13V at the 12V position, and so on? Or do they really jump around?