#138138  by Searing75
 Tue Apr 08, 2014 5:40 am
I have an MC50 that I have recapped, and got into wonderful working order. I now want to try the sentry monitor lift mod, but have no idea how to? I have looked through the forum but cannot find the answer. Waldo? Brad? Again, for the MC50 circuit. Thanks!

 #138153  by Jon S.
 Tue Apr 08, 2014 1:51 pm
Am I the only one for whom opening pages on this forum has slowed to a snail's pace lately?
The McIntosh Sentry Monitor

Although the autoformer provided an efficient match between the power transistor output and a variety of load impedances, a short circuit at the amplifier output or a load that was much lower than the selected autoformer tap could cause excessive current to flow in the output transistors. To complement the new transistor amplifiers, the McIntosh Sentry Monitor circuit was developed which prevented destructive current levels from occurring under any conditions. This circuit sensed the dynamic operating time, voltage and current of each amplifier output stage and controlled the current flow, confining it to non-destructive limits. The arrangement assured complete circuit reliability for all load conditions. The Sentry Monitor did not limit the rated power output available from the amplifier in any way. McIntosh power amplifiers continue to use the Sentry Monitor circuitry.
Mine is staying right where the McI engineers placed it.