rawk_chawk asked:
I have a Motorola console hi-fi from the 60’s that uses vacuum tubes in its amplifier. The right channel is starting to cut out and waver in volume. I suspect one of the tubes is starting to become weak, but I have no way of telling which one it is without buying lots of expensive replacement tubes. I’ve tried every electronics and guitar repair shop in town and nobody owns a tube tester or even knows where to find one anymore. My question is: Can vacuum tubes be tested at home with a multimeter?
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Sphere: Related ContentI have a Motorola console hi-fi from the 60’s that uses vacuum tubes in its amplifier. The right channel is starting to cut out and waver in volume. I suspect one of the tubes is starting to become weak, but I have no way of telling which one it is without buying lots of expensive replacement tubes. I’ve tried every electronics and guitar repair shop in town and nobody owns a tube tester or even knows where to find one anymore. My question is: Can vacuum tubes be tested at home with a multimeter?
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No, vacuum tubes cannot be tested with a multimeter. You need to apply operating voltages to them in order to test their operation. The heater needs to get hot to emit electrons, the grid needs voltage applied and the plate needs B+.
If you want to keep and use the hi-fi, you might have to have your tubes tested by mail. The link below might be of help. They seem to offer tube testing. If you do it, just send them all in. It’s pointless to replace one tube if another is going to go bad in a few months.