[Robin]

Recently, my RM-5 II makes pop noise when RM-5 II recovers from power on mute. And at a phono position, a speaker cone moves backwards and forwards as I turn volume from left to right and from right to left.

After some turning volume from left to right and from right to left, the speaker cone did not move.

I wonder that coupling capacitors leak current shortly after power on.

Does someone know a symptom like this?

[gerald porzio]

This sympton is older than you. A cap needs replacement & you might need a subsonic filter to deal w/ the phono/woofer issue.

[Roger A. Modjeski]

Recently, my RM-5 II makes pop noise when RM-5 II recovers from power on mute. And at a phono position, a speaker cone moves backwards and forwards as I turn volume from left to right and from right to left.

After some turning volume from left to right and from right to left, the speaker cone did not move.

I wonder that coupling capacitors leak current shortly after power on.

Does someone know a symptom like this?

I'm not quite sure I understand the part about turning the volume control. As to the pop it could be a leaky cap but I have never replaced one yet. They are very good.

If you are saying the woofer continues to move at moderate volumes after the first few minutes that indicates a loss of power supply regulation.  That would also explain the pop at turn on.