I have a Mcintosh C28 that works very well apart for an annoying issue. One the preamp warms up, the volume will increase by its self, and the volume control can't lower the volume. The volume control does work and can additionally increase the volume, but if the volume control is turned down to zero, it does not cut off the sound. Even if the preamp is turned off and on, the problem still exists.
Once the problem occurs, I unplug the inputs, and plug them back in and allow the center un-grounded phono plug to cause a hum at the stuck volume level, and I do this a few times, and the volume control is restored.
This preamp is stock and has not been recapped, and I'm wondering if this can be a capacitor issue, based on what temporally fixes the problem.
Any ideas?
Once the problem occurs, I unplug the inputs, and plug them back in and allow the center un-grounded phono plug to cause a hum at the stuck volume level, and I do this a few times, and the volume control is restored.
This preamp is stock and has not been recapped, and I'm wondering if this can be a capacitor issue, based on what temporally fixes the problem.
Any ideas?
Most likely this is an intermittent connection to the volume control itself.
Otherwise the volume should go to zero at the minimum setting.
Otherwise the volume should go to zero at the minimum setting.
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Yes its likely a dodgy ground connection - blasting it with hum breaks through the corrosion/oxide as temporarily restores the ground by the sound of it.