This is a Hickok 534 tube tester that I repaired and calibrated for a Customer. The Customer asked me to wire a Bias fuse bulb and test points for checking plate current.
The Hickok 534 tube tester has a built in multi-tester with VOM capability. This model has a common failure in the multi-tester circuit that switches the meter. It switches from tube testing to multi-meter testing that causes the meter to not operate when testing tubes.
The plate current test points have a precision resistor so a millivolt meter can be used to measure plate current. You then measure the voltage across the resistor that is proportional to the current in the plate circuit. A current meter is not required to measure the plate current and a jumper is not required to test tubes when not measuring plate current.
It is a good idea to install a Bias fuse bulb in tube testers that don’t have a fuse bulb. Over current through the Bias pot can cause damage and there are no replacements available for the custom wire wound Bias pot.
Contact me if you have a tube tester you want calibrated.
Just curious how you got the surface so shiny. And…do you repair and calibrate Jackson 648? If so, how much? Thank you!
I didn’t do any cleaning of the deck. It came to me from the Customer looking like that. Contact me through the contact form and we can discuss your Jackson 648.
I have a TV-3A that has a similiar problem, the bias mMho’s adjustment is off causing meter reading to be very low, not reaching the tube test side of the scale, are the 534 and TV-3 related in a similar way. Just scratching my head red and losing hair.
They both use the Hickok mutual conductance circuitry. Your TV-3A probably needs to be checked and calibrated.