JVC RC-M70 MMS issue

marcus1598

New Member
Hi everyone,

I’m having an issue with the Multi Music Scanner (MMS) circuit on the JVC RC-M70 and wondered if anyone has seen this before.

During playback (on any source) there is a constant noise through the speakers, and the MMS green light flickers very rapidly as if it’s constantly trying to trigger. If I press MMS search, the noise disappears while it’s searching. The noise is a very fast tapping / ticking sound through the speakers, exactly in sync with the green FF light flickering.

Cassette playback also seems quieter than radio or phono.

A few things I’ve checked:
  • The auto-stop switch works when tested separately with a battery (removed the deck from the M70).
  • Sometimes the tape stops but the mechanism doesn’t fully click off (buttons stay depressed and can hear squealing).
  • If I disconnect the cassette deck, the noise disappears completely.
This makes me think the problem is somewhere on the deck/MMS circuit.

Has anyone experienced this? Or could point me to some trouble shooting?

Any advice would be much appreciated.

Thanks,
Marcus.