Servicing fixed the
they probably replaced the optical block (the whole device was not
replaced as the covers had same scratches as before servicing). Fixed
unit worked (surprisingly) long but after several years it started to
behave similarly. However, it was not worth of the expensive service
price. By turning the unit on its sides, and adjusting MO_FCBIAS
in the service mode I could still use it.
I used the Walkman only as a desktop player and in my car. So I could forget the problem completely after buying a desktop MD recorder and a car MD player few years ago.
Finally now, in 2003, more than seven years after the service visit, one day I needed a portable recorder. However, my MZ-R2 was (almost) completely unless and service mode adjustments didn't help at all. Every disc generated lots of seeking noise and finally a . As I had nothing to lose, I tried to fix the problem by myself.
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. Also, you can make the device useless by adjusting (incorrect) values in the service mode. Be careful when working in the service mode!I found some discussions in www.minidisc.org about Sony optical block problems. My problem was exactly same. The focusing lens attachment is connected to the optical block with a nylon spring. The system moves the focusing attachment using the coils in it. However, nylon spring characteristics probably change gradually and finally the device fails to control the laser beam focusing.
I could not find any instructions how to open the device to get a good view to the optical block so I had to found it out by myself. The easiest way to tune the optical block is:
You can see several thin parts on the nylon spring. They allow moving the focusing attachment slightly in two directions. First I tried to add some glue drops on those thin parts of the spring to make it stiffer. It helped a for a while but the device started to fail in a few hours, showing even for every disc. So I had to remove the glue.
My working (at least until now) solution is to add a stripe of PVC tape on the four-pin membrane cable. I used standard electrician's PVC tape. The tape stripe is about as wide as the membrane cable and starts where the cable goes into the focusing attachment and ends on the large metallic structure around the attachment. The tape changes the vibration characteristics of the focusing attachment so that the device will work!
However, you have to assemble the device before you can try it... Be careful to check that the main board is well in its place before tightening the screws. (My board was not easy to install correctly. Check especially the mic, line, and phone jacks.) Also check that the membrane cables go straight into the connectors after locking the locking levers, otherwise they may be short-circuited.
Finally you may need to adjust MO_FCBIAS in the service mode to fine-tune the operation of the unit. Try values from 7A (default in my unit) to 90 (suggested by Graham Baker). For reference, my MO_FCBIAS is now 8A. To adjust the setting do the following: