The repair saga's details (for those interested)

• July 2000: I inherited an MDS-S30 minidisc recorder deck from my brother. He told me that it no longer ejected discs and that the AMS rotary encoder was missing its knob; if I could fix it I could keep it. Other commitments meant it was a few weeks before I could investigate further.

• August, September 2000: I addressed the problems with the unit in spare time and by the beginning of September 2000, after some relatively minor mechanical repairs to the front panel, repairing of a couple of dry joints in the power supply and replacement of the rotary encoder, the deck was back in working order.

• Mid-September 2000: While in use one day the deck suddenly stopped recording. It would go through the motions of recording but on playback the new recording was nowhere to be found. Playback of previously recorded discs was fine. Because of the deck's age I did not want to take the unit into a service centre and pay a quote fee only to be told that some major component had failed, making repair uneconomical. (This seemed likely since reports on the internet generally indicated that these symptoms were due to a failure on the BD board which is uneconomic to repair for a deck of this age.) Therefore, armed with the service manual of an MDS-JE510 I set about determining what might have failed.

  Although the MDS-JE510 differs substantially from the MDS-S30, the descriptions and circuits in the former's manual gave sufficient detail to deduce what should be occurring within the MDS-S30. I was able to determine that the overwrite head definitely had its required signal and that the laser was also being driven correctly by the electronics. This left two possibilities: either the laser was not emitting correctly when switched to `record' power, or there was a problem with the overwrite head itself. Upon close inspection of the overwrite head in the `record' position it appeared that it was not actually resting on the disc correctly, so I concluded that a mechanical fault with the overwrite head was the most likely problem.

• 9 October 2000: Having determined that the replacement cost for an overwrite head for this model is of the order of AU$75 I decided that a repair would be economic, given the new price of comparable decks is around AU$400. Lacking the necessary equipment to fully test either the laser or the overwrite head in order to positively identify the faulty component, I took the unit to Digital Domain - an Authorised Sony repair centre here in Adelaide. I explained what I had found and that I suspected either a faulty overwrite head or laser assembly.

• 12 October 2000: I was contacted by Digital Domain regarding the repair. To my surprise I was told that `corrosion' had `caused damage to all circuit boards' and that therefore repair was uneconomic. During my repairs of the unit I had noted a white deposit in a few places within the unit but after inspection had decided that it was harmless. I mentioned this and was told I could talk to the technician about the details when I came to pick the unit up.

• 16 October 2000 : I returned to Digital Domain to claim the unit. Once again I expressed my surprise at the news. Despite what I was told earlier I was not allowed to talk to the technician. A conversation with with the manager was ineffective at convincing Digital Domain that perhaps a reconsideration was warranted. With sincere doubts about their diagnosis I reluctantly paid their quote fee (AU$55) and departed with the unit, determined to investigate this supposed corrosion.

• Late October 2000: Within a short time I had discovered two things. Firstly, when the unit was tested on arrival home, it failed to play discs whereas playback functioned perfectly on 9 October 2000. Secondly, upon removing the cover, the alleged corrosion turned out to be simply a non-conducting white deposit which was easily wiped off with a cottonbud dipped in methylated spirits - not even the circuit board lacquer was damaged underneath. The extent of the deposit's distribution within the unit did not appear to match the diagnosis given.

  Once again, armed with the MDS-JE510 service manual I set about finding out why playback no longer worked. The problem was traced to a microswitch (the sled `limit in' switch) which had a broken lever. I found this very surprising, knowing that there was no way this could have been broken in transit and that playback worked fine on 9 October. Arrangements were made to acquire a replacement switch.

• 5 January 2001: After an inexplicable delay, the microswitch finally arrived on 5 January 2001.

• 8 January 2001: After fitting the new switch the unit was able to playback correctly once more. With little to lose I decided to have a go at manipulating the overwrite head back into a more likely looking position. After about thirty minutes of trial and error I succeeded in restoring the record function to the deck, proving beyond doubt that the cause of the fault was indeed the overwrite head. Clearly the spring elements had weakened over the years and a replacement was deemed necessary to guarantee reliable operation. This was demonstrated in the weeks following this `fix'.

• 29 January 2001: Ordered a replacement overwrite head from Speedy Spares in Melbourne for a cost (including shipping) of AU$72.20.

• 5 February 2001: New overwrite head arrived and was fitted by myself. Because the new unit was slightly longer than the original it caught on some metalwork associated with the disk loading mechanism. The offending metalwork was trimmed with a nibbling cutter. Correct operation of the record function was then verified.

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