Accurate Instruments Co, model 157
 

Hi,

Does anyone know how to calibrate one of these tube checkers? Every tube I check seems to read in the high part of the "replace" range on the meter. I noticed today that when I rubbed my hand over the meter, it went up into the "good" range but was still erratic. The meter has full range if I lightly shake the box. I don't know if it need's a new meter or a calibration. I opened it up today and it has three or four resistors and a transformer. I don't know where i'd ever find a replacement meter unless I found a boatanchor for parts so I want to try to calibrate it... but i don't know how.

Thanks!!

Julien

Old tube testers are pieces of old electronic equipment, just like an amp. They need to have out of spec components replaced before they can be calibrated. I'm not familiar with that model, but the testers I have sure have a lot more components than a few resistors. If yours is that simple underneath, I would suggest not putting much money into it. Otherwise, check whether or not the resistors are still good, clean sockets, do a visual check of wiring, etc. If the meter is bad, nothing will fix that. There are guys who work on old meters, but again, the cost will be more than the tester is worth.

Thanks. I was thinking that if the meter is bad it would be junk. I will try replacing the resistors. It has three resistors and one cap and a transformer.

It is a simple emissions tester. I'd like to have a Hickock but cannot justify the price.

In case I buy another one can you recommend a decent tester that can be had for under 200 ?

Thanks,

J