Couldn’t wait to post this photo of this McIntosh MC901 during Bench Test at Bob the Tech Audio. It takes up every inch of the bench and weighs so much this McIntosh MC901 is literally a Bench Test! This unit is failing to come up all the way out of standby.
We’ve completed our analysis at this point and have isolated the startup issue to a failed startup timer. After replacing that part the unit is reliably coming up out of standby. A KT-88 tube failed with an internal short during testing. This resulted in some nasty oscillation and high current draw, and the unit shut itself down. We tested the tubes and identified the failed one. With a replacement tube in place this unit performed great with distortion measurements within spec to full power.
Now that we’ve proven the bench can literally handle McIntosh MC901 test, contact Bob the Tech Audio for your McIntosh MC901 service needs.
