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B&K 700 question
I just bought the B&K 700.seemed to work fine until all my 12volt tubes were reading very low.I tried what I know are a couple of new tubes.They test 30 as well,Im not really sure if this is a problem that can be fixed without getting it completely overhauled.Any one have any suggestions.Im new to this tube tester thing.
Thanks
Follow Ups:
A reading of 30 would be normal for a 12AX7 on this tester. Anything above 22 is good. Good 12AT7s should test 65+ though.If the tester is in good shape you can get it repaired and calibrated by William Waters, ts6550@yahoo.com. He has a SS rectifier mod that works, can add meter protection circuitry, modify the tester to read plate current, and numerous other enhancements.
I think I have a B & K 700 and a 707. I've been inside the 707, and it has an 80 rectifier. If you're lucky, it's just the 80 getting weak, which happens about every 50 years (they last a long time in this application). The 80 is a moderately priced tube, I think. If it's not that, it could be some resistor has drifted badly.
Actaully ,I did open it up ,and there was no rectifier in the socket.Now ,some one was telling me it could have been re wired with a solid state component.Or maybe thats the problem.I dont assume it would even work if the tube was just missing.Im really clueless about this stuff.Most other tubes seem to test normally.Just the 12ax7s and 12ats all test low.
Anyways thanks for you feedback.If you have any other ideas or resources let me know.
Cheers
Bob
Check the calibration! Not that this is a 'gimme', but I've yet to have luck calibrating a 700/707 with a SS rectifier.
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