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fourbanks

Sony MDS-JB 940 Static Mini Disc Player (fault)

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Hi friends 

I have just noticed on my new Sony MDS-JB 940 Static Mini Disc Player that on inserting the disk it says reading TOC and plays well . however on ejecting the disc it says eject then goes straight to the message reading TOC without ejecting 

The unit has only been used once before storage many years ago. hopefully i will be able to fix it as our good friend Jim is no longer here ?

 

Edited by fourbanks

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Dead easy. Just make sure you don't leave the belt twisted if it ends up that way after you first put it on.

If I recall correctly, this is roughly the sequence

1. Remove lid.

(EDIT) If there is any disk in the unit, persuade it very gently to come out, using whatever tools you have to do the work of the belt that's not working (i.e. push the eject button and "help" it to eject). Probably easiest with the power on. (EDIT)

2. disconnect ribbon cables making sure you know where they go back (it should be obvious) leading to the mainboard from the MD unit. ONLY DISCONNECT ONE END OF EACH.

3. Undo the grounding straps (they are push fit), I think there are only 2 you care about, making sure you know where they came from.

4. Remove/loosen the front panel (6 screws or so), only enough to remove the MD unit. See the service manual. If you're smart you won't completely undo it.

5. Undo the 4 "flying saucer" screws anchoring the MD unit into its rubber bushings.

6. Now you can take the MD unit into your hand with no wires or anything. Prise the plastic mechanism by squeezing just enough to let it open past the (plastic) stop and open the main hinge very very carefully making sure not to bend or stretch anything particularly the overwrite head. You should be able to replace the belt now.

Putting it back together is easy. The service manual shows it all (the DISassembly of course). Nota bene: you should not have to disassemble the MD unit itself. Particularly if you get to something that says "remove solder" stop immediately and reconsider your fate.

Good luck

Stephen

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i still have this work to do but will get round to it. if i need to eject the disc i just have to put some pressure in the opening and it ejects but as i say i'll get round to it 

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well well well. I thought I would check my store of mindisck decks jb940 and one also  now shows the same problem! Does time  deteriorate the belt esp when not in use or maybe the storeage conditions?  This is the first time this has happened to me. is it common? as it was fine when stored away and never gave any trouble of any kind. By the way where is the service manual referred to above as it seems I will have to do the same job!!

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well I started to dismantle mine. it is nt necessary to undo the front at all as once the  saucer screws are undone it lifts out clean. re the grounding straps - cant see any. Now just got to get to the belt,  the instructions above a bit un clear. I can see the little  belt from the front? only one belt? What should I expect to see? a broken belt? Mine is still intact and in place.Just slipping then? and a new one will do the job?

Edited by freddyjollo

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well I started to dismantle mine. it is nt necessary to undo the front at all as once the  saucer screws are undone it lifts out clean. re the grounding straps - cant see any. Now just got to get to the belt,  the instructions above a bit un clear. I can see the little  belt from the front? only one belt? What should I expect to see? a broken belt? Mine is still intact and in place.Just slipping then? and a new one will do the job?

Mine is still intact and in place.Just slipping then? and a new one will do the job?

hopefully freddy that is all it will be ?

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to open the "main hinge" I think you have to remove a small spring at the side that otherwise keeps it closed. This is a very small spring with not too much tension that I think could easily be damaged so do with care. I havent got to that state yet, as I am waiting for a spare belt to arrive.

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to open the "main hinge" I think you have to remove a small spring at the side that otherwise keeps it closed. This is a very small spring with not too much tension that I think could easily be damaged so do with care. I havent got to that state yet, as I am waiting for a spare belt to arrive.

i will follow your lead we can do this together when your new belt arrives 

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to open the "main hinge" I think you have to remove a small spring at the side that otherwise keeps it closed. This is a very small spring with not too much tension that I think could easily be damaged so do with care. I havent got to that state yet, as I am waiting for a spare belt to arrive.

The spring is no big deal, but you may want to remove it early just to make sure it doesn't get bent out of shape (it's easy enough to bend back). The belt, on the other hand can slip quite easily and no amount of adjusting springs etc. will make any difference to the mechanism functioning properly.

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A lot of the decks around that time use the same mechanism. However there are different cable widths (17,19,21,23 pins on the principal cable from MD to mainboard). So one must check AT LEAST that the 2 cables have the same number of pins. It has to do with the extra control lines related to M-Crew/NetMD support (remote), IIRC.

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i'm afraid this did not go well as the piece of the laser broke off so if possible will need to put the rest of this unit into a old 920 uk model like the lighting unit ? and the belt i have just brought  ?

i have a tv electronic engineer who works close by so he may be able to swap some of the parts over ?

 

 

Edited by fourbanks

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Can you take a picture?

i have dropped the units over at the at the engineers so i'll leave it up to him as the best way forward. the laser unit of the old 920 did work but has been heavily used. He might just swap that over but failing that he will if able just swap the main light unit over as it's new and will just keep all parts for a later date 

these things happen and if i came across the same model will get another this was just bad luck

will keep you posted  

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