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MDS-JB940 problems.. please assist minidisc addict

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semmyroundel

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Hi there, I'm a newb to this forum but veteran minidisc user. I was given an MDS-JB940 along with a 120 odd Radio 4 plays and concerts on disc which I look forward to getting through. When I first fired up the machine, I could insert a blank disc but it wouldn't play, then it wouldn't eject, and now all I get is the power LED (little red light) and nothing else, Won't even turn on. I opened up the case and found a constant whirring sound from transport mech like it was trying to do something.

Obvious questions come to mind: anything I should look for? On Ebay I've seen an engineer's manual and drive belts quite reasonable £4, £8. respectively, should I invest in these?

I have also bought an MDS-JB980 (waiting for it, and am looking to bid on another 940 to use or have spares of but these are currently going for aropund £140

I have also two MZ-N510 portables and recently bought an MZ-RH1 for son's drumming recording, and of course music appreciation on my system.

Keep banging the minidisc v ipod drum!

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Hi. On the JB940, sounds like there could be two problems. Is there a disc actually stuck in the drive? This model uses a variant of the MDM-7 drive, and one of the common problems is bad eject caused by a slipping drive band. It's the only rubber drive band in the unit, and easy enough to swap once you know how to remove the upper slot mechanism. If you can manually help the disc to eject, it may spring back into life. Sometimes just by touching the top of the jammed in disc with a finger or tool is enough to give the drive band a jog to help eject the disc.

If you manage to eject it, and reinserting brings you an error (usually C13 error), then chances are the spindle motor is also goosed, or maybe but less likely the optical pickup. When a disc is inserted the mechanism first tries to focus to determine if a disc is inserted, then spins up the spindle motor to read the TOC. If either of these fails then a C13 error is shown.

Jim

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Thanks fgor that speedy reply Jim, I did tap on the disc which is indeed stuck inside but to no avail. I noticed that the disc alu sleeve was pulled back like it was going to be read, but the disc is not spinning, that I can tell. I'm sure I first saw a c13 code, but now there is no display, the machine doesn't even turn on the display although there is something going on with the drive mech. I did notice the flap at the back of the top of the drive, is this a manual eject assist? How do I do it otherwise? and is the display meant to be off? Thanks.

Julian.

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Jim, I think it's time you put some sort of Ebay URL into your signature?

Anyway here he is (decks cost a little more than portables, but that's between you and him): http://www.ebay.co.uk/itm/Sony-Portable-Minidisc-Recorder-Player-Repair-Service-/220859657553

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Always fancied one of these myself. There is a possibility I even have one somewhere - I have so much stock stored away I have actually forgotten exactly what I do have! The only Denons I remember looking at had Sharp drive units, but this one looks to have a Sony drive that I don't recognise. The laser unit is certainly Sony, as is the ATRAC chip. But the rest of the electronics looks to be pure Denon? The drive may be a Denon unit using a Sony laser and overwrite head, of course.

Those errors you are experiencing lead me to think you have a spindle motor error, probably the servo control for that motor. Are you in the UK? The unit is heavy I believe, but if you are willing to courier it over to me I am willing to take a look, so long as you realise it will not be a priority repair so may take some weeks.

Jim

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Thanks for the reply Jim,

I recorded a full 80min MD on the 1050 on Friday, I then ejected the disc and inserted it into the machine again but it would not play error 73 came up on the display.

I have played the disc on a couple of other machines without any problem.

I purchased this machine to do backup recordings, I use Denon DN-991R as playback machines I have 3 off these http://elektrotanya.com/denon_dn-m991r.pdf/download.html Also a Denon DN-2000R http://elektrotanya.com/denon_dn-m2000r.pdf/download.html

These are all Denon pro machines, I also have a number of Sony MD machines but they are all consumer machines. A couple MDS-302 and an MDS-303

The 302's both had to go back to Sony for repair about a year after I got them they cost £500 each to buy and then sony would not stand over them for repair and cost a further £200 each for repair, needless to say that was the end of my purchasing Sony products so I moved to Denon.

I am in the UK only problem is not the mainland as I'm in NI.

I'll be in touch.

Regards

H4rry.

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Believe it or not, the read adjustment of Laser Power (LP) is much more sensitive than the write adjustment. It sounds like it's simply in need of adjustment if you can write perfectly good disks.

However you may need an LP meter to check it out - currently Jim doesn't have one. I do, but I'm 5000 miles away in Canada.

You never answered my question about Tom Lehrer, so rather than ask it again, I will say that your name reminds me of him talking about his friend Hen3ry ("the 3 was silent, you see").

Stephen

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With the extra info I tend to agree with Stephen. If you can record ok and replay on another unit, most likely there's nothing wrong with the motors. It does sound like the play on MO discs laser power needs adjustment. I take it play on CD-type factory recorded discs is ok, assuming you have one of these?

Jim

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Believe it or not, the read adjustment of Laser Power (LP) is much more sensitive than the write adjustment. It sounds like it's simply in need of adjustment if you can write perfectly good disks.

However you may need an LP meter to check it out - currently Jim doesn't have one. I do, but I'm 5000 miles away in Canada.

You never answered my question about Tom Lehrer, so rather than ask it again, I will say that your name reminds me of him talking about his friend Hen3ry ("the 3 was silent, you see").

Stephen

Hi Stephen,

I was not sure if you were referring to me on the Tom Lehrer as he means nothing to me, never heard of him. My first name is Harry this is used on many forums so the nearest I can get to that is H4rry 4 looking almost like the letter A...

There could well be a problem with the play as I had a disc in playing the other night it played ok until the last couple of tracks it started to freeze.. When I checked the disc in another machine it played perfect.

I have a couple of rerecorded discs around somewhere but where! If I find them I'll try one out.

I shall try a few more recordings the disc that was recorded on Friday was recorded as one 80min track, So this time I shall try a few different tracks.

Regards

H4rry

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Don't :)

It's pretty clear that adjustment is the thing. You've told us data from two different events that indicates what Jim and I are saying is correct. Continuing to use the machine makes it more and more likely that the laser WILL mess up somehow, or some motor may burn out trying to servo to the right part of the disk when it can't read properly.

Keep the disk (if you remember) that didn't fail until the last two tracks, around. This may be a very reasonable substitute for an LP meter. Somehow we'll try and figure out how to get you to adjust it yourself. It may be as simple as one notch on the read power, and then you see if that makes the disk with the 2 tracks bad better or worse.

Stephen

PS here's the Hen3ry reference

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I had a look at the manual. Page 54 looks interesting. This machine evidently dates from the mid to late 90's, so some of the sophistications of the firmware are not present yet, that make the later decks easy indeed to adjust. However the firmware menus are recognisably Sony's since this is mostly Sony technology in a Denon box. Right, Jim?

To cut to the chase, the key adjustment seems to be the pot shown RV102. But without a meter, it's going to be difficult

I might suggest you try to get one (a meter), as compared to the wealth of equipment you seem to have, it's a relatively small investment. This is a very nice machine (Pro, so no SCMS, as an example) and you wouldn't want to mess it up.

S

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That probably is not a CD, although I've never seen one.

If you adjust the LP with no way of checking the results (other than "it works") you run a great risk of burning out the laser, destroying disks, etc etc.

If I was totally desperate, that's what I might do. Sounds like you are going to have to wait to get it serviced, though.

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The problem with sending something of to get serviced is that it would cost as much as the price of the meter I'm guessing.

I work with Canon camera gear and every time it has to go to canon it's almost £100 for a check and clean and twice it's had to go back for repair at the cost of almost £400 each time, and there's no reason that if the Denon has to go back to them that this will be a low cost fix.

Regards

H4rry

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By "get it serviced" i did NOT mean the manufacturer. Not Sony, nor any other mfr wants, or even currently offers, to service MD equipment, which is considered an obsolete technology.

That is one reason we folks cluster here, because we, like you, try to keep the technology alive and fresh past its sell-by date, to coin a phrase.

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By "get it serviced" i did NOT mean the manufacturer. Not Sony, nor any other mfr wants, or even currently offers, to service MD equipment, which is considered an obsolete technology.

That is one reason we folks cluster here, because we, like you, try to keep the technology alive and fresh past its sell-by date, to coin a phrase.

Point taken Stephen.

OK I called with a friend today and got a factory minidisc from him the best of Eric Clapton.

so 30 seconds after putting it into the 1050 error 2b came up.Eric refused to sing!

I then tried the disc in my 3x 991 machines

Machine #1 cued in 5 seconds #2 in 10 seconds and # 3 came up with error 2b

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OK I called with a friend today and got a factory minidisc from him the best of Eric Clapton.

so 30 seconds after putting it into the 1050 error 2b came up.Eric refused to sing!

I then tried the disc in my 3x 991 machines

Machine #1 cued in 5 seconds #2 in 10 seconds and # 3 came up with error 2b

Jim's point is that the CD adjustment is separate. In theory you could have MO (rewriteable) disks adjusted perfectly and still not be able to read a CD, AND VICE VERSA. In practice this won't happen. But the borderline behaviour tends to suggest some adjustment is needed. Obviously if you get the gear to do one, you can do them all - equally obviously the shipping on 3 machines is probably as much or more than the meter. Note, #2 (10 seconds) is clearly also borderline.

Cheers

S

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I was speaking to a friend of mine this morning who worked in the BBC engineering dept. He is now out working on his own but still does work for them from time to time.

He hasn't got a meter but said he would check and see if the BBC had one.

Another option I have is to return the unit to the company I purchased it from for a full refund, I've been told one of there engineers checked the unit out on rec & play with a number of different discs & it worked fine.. They think the machine may have got a knock during shipping & this may have knocked the laser lineament out.

H4rry

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The fact you report trouble in 3 machines out of 4 (that you mentioned) is (wouldn't you think?) unrelated to shipping.

I went through the same as you asking about a meter like this from an institution here. I think the specific tool is unlikely to be forthcoming, TBH - someone will have charge of it (if they have one) and it will be in regular use. Or there won't be one. Prove me wrong by all means.

The fact it (your original machine) isn't dead means (just as with the machine that I ended up buying the LP-01 for) it works a lot of the time. But the reading of MD's is a servo (feedback) system, and continuing to use it after it's become iffy is precisely how to ensure it eventually burns out.

Just my 3.14159p.

Stephen

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I think you have taken me up wrong in part.

I tried a factory disc in four machines yesterday three of them I've owned for about three years the denon 991r's

The machine which I am concerned about at this minute in time is the Denon 1050 this was the machine that I have just purchased.

It was checked before it was shipped and found to be ok but as I stated above the seller is willing to give me a full refund and send a courier to come and collect it from me.

He thinks maybe it has been dropped by the courier and this may be part of the problem.

H4rry

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