Mcintosh MHT200, where do i put the multimeter points to adjust the power supply volts to 5.3

CozmoCramer

CozmoCramer

Enthusiast
I recently bought a mcintosh mht200 and a month later it started shutting down when I turned it on. The guy that sold it to me came over and adjusted the multimeter to 5.3v and worked great after. I've moved since then and now having the same problems all over again. I know where the potentiometer is to to adjust the volts but I don't know where to set the multimeter points to get a volt reading. Can anyone please help me out. Would be very much appreciated.
 
TLS Guy

TLS Guy

Seriously, I have no life.
I recently bought a mcintosh mht200 and a month later it started shutting down when I turned it on. The guy that sold it to me came over and adjusted the multimeter to 5.3v and worked great after. I've moved since then and now having the same problems all over again. I know where the potentiometer is to to adjust the volts but I don't know where to set the multimeter points to get a volt reading. Can anyone please help me out. Would be very much appreciated.
I managed to find a service manual. This adjustment is for the backup power supply of the digital processing board. This will be the board the potentiometer to do the adjustment is on. The test point is pin 2 of connector CN2. The manual says this is a critical adjustment and should be done by a service tech. My strong hunch is that the voltage should not be set with a cheap multimeter from Home Depot or the like.

Critical adjustments on solid state gear should be done with a high impedance amplified meter. This can be a tube voltmeter or a FET VOM. I use a FET VOM for critical work on equipment.

The problem is that a non amplified meter loads the circuit and results in an erroneous reading. A FET VOM has a loading impedance in the megohm range.

I suspect you are having trouble, as previous adjustments have been done with improper test equipment.
 
CozmoCramer

CozmoCramer

Enthusiast
I managed to find a service manual. This adjustment is for the backup power supply of the digital processing board. This will be the board the potentiometer to do the adjustment is on. The test point is pin 2 of connector CN2. The manual says this is a critical adjustment and should be done by a service tech. My strong hunch is that the voltage should not be set with a cheap multimeter from Home Depot or the like.

Critical adjustments on solid state gear should be done with a high impedance amplified meter. This can be a tube voltmeter or a FET VOM. I use a FET VOM for critical work on equipment.

The problem is that a non amplified meter loads the circuit and results in an erroneous reading. A FET VOM has a loading impedance in the megohm range.

I suspect you are having trouble, as previous adjustments have been done with improper test equipment.
Really appreciate the gold response advice. I've checked with more places than I can count and never got any response close to yours. Yes I picked a multimeter up from Walmart and will be setting that aside for this adjustment. I'll either be picking up a FET VOM or tube multimeter or make sure a repair tech is able to use one. Thanks my friend .
 
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