At least my MZ-R2 had a problem of unexpected "resets" occasionally when the top cover was touched. Because the operation buttons are on the top cover, this problem was very irritating.Especially pressing PAUSE might cause the device to reload the disc. It was not so common, and very difficult to make it happen repeatedly. But, of course, when I have unsaved TOC in the device, it "reset" itself when I pressed PAUSE while recording -- practically losing all recorded tracks.
The device "resets" (reloads the disc) every time when the
top cover is closed, or actually, when the OPEN lever is restored to
the default position even if the top cover is kept closed. I suspected
similar "grease problem" in the switch indicating the state of the
cover locking mechanism: When the top cover is touched, it is moved
slightly which may cause the contact of the indicator switch to fail.
And even the shortest contact failure in the indicator
switch causes the unit to think that the cover was opened and causes
the disc to be reloaded. This happens also when the unit is in the
playing or recording mode -- although it is impossible to actually
open the cover in those modes!
CAUTION! You can damage the device seriously when opening it. You are doing everything at your own risk. This solution that helped my MZ-R2 may not help yours.
fix the problem, the locking indicator switch must be cleaned. (If you
have problems with the HOLD switch, you may use similar procedure to
clean it. For the HOLD switch, you need to disassemble the bottom part
instead -- see the optical block fixing
instructions for disassembling instructions.)
Now you can
see the locking indicator switch below the STOP button. The switch
senses the cover locking with the spring-tightened lever. In my unit
the grease from the lever had soiled the circuit board noticeably.
The grease around the switch is not the problem but the grease
switch is. To clean the switch you need to disassemble this miniature
After successful opening, clean the internals of the switch
carefully but completely from the grease. If you fail to clean the
switch internals completely, the grease you left starts soiling the
contacts immediately. Bend the spring contacts in the switch slightly
up so that the contact with the moving part is ensured.
After the actual cleaning you need to re-assemble everything in the reverse order. Closing the switch is little tricky. I recommend to work in such place that you will find the small spring even if it jumps out accidentally. Remember to re-solder the switch cover to the PCB. Use as little solder as you can -- it helps reopening some day...
Good luck. I hope that this helps you too. At least it helped my MZ-R2 -- it has worked now for several months without any unexpected "resets"!