Kevin_Kaas
New Member
After restoring a Teac A-6300 for a customer I powered it up for calibration while listening to my AM radio. Whenever I raised the auto shut-off lever to thread up a tape I heard a "frying" noise come out of the radio's speaker. When I released the lever the noise stopped. Simple reasoning revealed the microswitch that powers the capstan motor was arcing and was about to drop dead.
Nearly every time I raised that arm to activate the capstan motor the frying noise would start back up and the noise would sometimes stop after a few seconds, but it became obvious the switch needed replacing.
I would never have known that switch was about to die had I not been listening to an AM radio. So here you go all your techs out there, the old AM radio with all its static has become a handy tool for detecting bad A.C. power switches/relays. Tune your radio to the low freq end, around 530 KHz at a spot where there are no stations for best detection. Radios plugged into your bench's A.C. power strip have the best detection. Also, if you do most of your work at night like I do when the band is crammed with stations due to the ionosphere, just tune to the weakest clear-channel station such as 640 and 650 Khz. Some older radios can tune a bit below 530 Khz where there may not be so many carriers at night.
Kevin Kaas
Nearly every time I raised that arm to activate the capstan motor the frying noise would start back up and the noise would sometimes stop after a few seconds, but it became obvious the switch needed replacing.
I would never have known that switch was about to die had I not been listening to an AM radio. So here you go all your techs out there, the old AM radio with all its static has become a handy tool for detecting bad A.C. power switches/relays. Tune your radio to the low freq end, around 530 KHz at a spot where there are no stations for best detection. Radios plugged into your bench's A.C. power strip have the best detection. Also, if you do most of your work at night like I do when the band is crammed with stations due to the ionosphere, just tune to the weakest clear-channel station such as 640 and 650 Khz. Some older radios can tune a bit below 530 Khz where there may not be so many carriers at night.
Kevin Kaas
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