kgallen

There will probably be an actuator somewhere ie a bent piece of the case metal, that presses a switch. Maybe this is bent slightly so it slips off the switch with a bit of pressure? Or is there anything fouling the mechanism that could cause the motor to be impeded (the motor stall current may be enough to drop the battery voltage too low which makes the electronics reset). So have a look round to see if mechanically anything looks out of true.

The E12 SM only lists one belt. That supplier above confuses things by not being clear on what they mean by "length" in their table - "length" or "total length" per their measurement description. As it happens we can use some simple maths to interpret their data, but they could have been clearer... So let's take their "37X1.4" belt listed with "length 116". Diameter is 37. Circumference of a circle is diameter x pi, so 37 x 3.1415 = 116mm. So what they list in the table as "length" is actually what they describe as "total length" (i.e. circumference) in their measurement instructions (i.e. double the measured squeezed-together length). So you're looking at their 17X1.4 - or 19X1.4 if you really think the 17mm dia belts are too small.

List of Sony machines using Sony loading belt part number 4-227-025-01: belt_4-227-025-01.pdf

If you really want genuine belts then having a search around Japanese sites might be worth a try.

OK, listen up, this is how to read your micrometer from what I can glean from your pictures and references. So on your micrometer main shaft: the main scale is in 0.1" (so 100 thou). the incremental scale is thus 25 thou (there are 4 per main scale) On the micrometer ring, I'm assuming it goes 0 to "100" as the "20" looks like about a fifth of the way round so the ring is in thou When you read the main scale, you ignore any "part" increments because that extra bit is taken from the ring (which should be on 0 when you're exactly on an incremental mark). So only count increment marks you can actually see. So your 1/4" rod is 2 *100thou (main scale) + 2 *25thou (main scale increments) + 20thou (on the ring) = 270thou (so about 1/4" which would be 250thou). Your screwdriver is 1 *100thou + 1 *25thou + 10thou = 135thou - so 135thou which is pretty much 1/8" So back to the belts. The thin one (the "old" one?) is 55 thou = 1.4mm The thick one (the new 17mm?) is 70 thou = 1.75mm A European teaching an American (?) to read an imperial tool - what next - Boris Johnson as UK PM?!

1.5mm is about 60 thou (1.5/25.4). Your micrometer reads 2 graduations (what is one graduation - a 1/32? a 1/64? something else?) plus 20 (20 what - thou?). You're gonna have to help me out here with your tools. Whilst I use both metric (millimeters etc) and imperial (inches) all of the time depending on the work I'm doing, I don't think I've ever used an imperial (i.e. inches) micrometer. Some other poor soul might chip in here and help us out...

11/16 * 25.4 = 17.5mm So if the thickness and cross-section shape of those 17mm belts is ok for the pulley groove then they should be perfect.

They might if I had the vaguest of ideas of how to read an imperial micrometer and what the scale of the graduations are!

What device is 499953701 for? It''s square section. Anyway 47.43 Polish Zloty's is about 12.50USD (July 2019). (VAT is EU sales tax, "Value Added Tax"). Kris references 422702501 for JB980 etc (which is also square-section) and that is about 13USD. But nothing more to be gleaned on the spec from this site... and I'm certainly not going to be spending that sort of silly money on a single belt!

Maybe you could mark up your paper with any other info you can determine from the belts - "old" and "new", cross-section shape (square, round, flat), thickness if you can measure it (1mm? 1.5mm? etc) and then circumference - or diameter if you can get the belt roughly circular. Then re-take a photo. This would be a useful back-reference for old/stretched belts at least given we don't have any Sony data. Also if you have some new belts - those 17mm ones for example. Maybe they could be added to the picture and marked up accordingly (17mm new, round) as an A-B comparison? If you have some 5mm gridded paper or graph paper to lay out your whole specimen collection on that would be even better!

Which of those belts are ‘old’ from your machines and which are new (big one is new, understood). E12 and 940 are both MDM7 variant drives so they’ll use the same belt. Can't really tell from the picture but a square section or round section belt is needed not a flat section one. Kevin

Confirmed from an independent source that Sony also use EM-30L: https://pl.eetgroup.com/i/871997696-Sony-GREASE-EM-30L-P02E009

Can add MDS-E10 and MDS-E12 to that list too, since they are also MDM7 variant drives. 440,640,940,S50,470,770 = MDM-7A 480,780 = MDM-7S1A E10, E12 = MDM-7SC

The E12 got the gig over the Tascam! Also a first outing for my newly acquired Behringer X-Air XR16 if you readers are in to live sound. E12, XR16, 6 small diaphragm condenser mics and 2 boundary mics. Great concert run for charity with some close theatre friends. E12 faultless and a Godsend to have. Doing lighting at the same time as sound, so having that E12 just working perfectly at a touch of a button is why I’m back using minidisc for my theatre work! Hoping to get another look at that E10 soon...

Most Sony MD service manuals are on manualslib, minidisc.org or elektrotanya and come up pretty readily with a google search. Here: https://elektrotanya.com/sony_mds-e12_md_recorder.pdf/download.html also note that depending what information you're after many of the service manuals are very similar in content. What varies of course is the exact drive model, optical pickup (OP), additional features (like say the RS232 on the E12 not on the E10), and the button combinations to get into service mode. OP = optical pickup - the laser and focus module. KMS260A, KMS260B and KMS260E are the usual types found in the Sony MD drives. Sometimes they are interchangeable, but often there are caveats like exactly how they are set up for e.g. Laser power. Plenty of threads on this site on this!

I did start a bit of a drive list on a spreadsheet - I just went around the service manuals and noted what was specified. But I haven’t done all (Sony) machines as there are many and I didn’t have the need. Also on the list I added the OP type (A/B/E).

Also note many drives are the same mechanically. So for example 440, 480, E10 and E12 are all variants on the MDM7 drive and mechanically identical. So the same belt - the 17/1 worked for me in all these machines. But for some reason not in your E12. I don’t understand the reason. Other drives like the MDM5 in the 520 and 530 I think are all gears, no belts at all.

The eBay seller I used has a pack with 17, 19, 22, 25 mm belts plus bigger https://ebay.us/d1v7nU At the moment he’s not asking for your life savings. You say the 17 is too small so is it worth getting this pack and trying the 19 or maybe the 22? But you do say the disk binds early on so I’m not sure how the 17 can be causing this! I know this is hit and miss but we don’t have a Sony spec or a pristine example to measure. I’m sceptical these high price belts are known to be the correct diameter and thickness. How do they know this? Do they actually have a spec or are they guessing by trial and error like the rest of us. If you’re sick of black belts then I like others tried those denture bands. This gave me a clue to the size but I didn’t want a rough cut piece of elastic in my machines hence hunting for some true drive belt of a usable size. Kevin

Molykote EM-30L You can buy 10 gram/ml portions for a few pounds (UK). Something like this. Apply sparingly with a cocktail stick or similar fine applicator: https://www.ebay.com/itm/Molykote-Em-30L-Grease-for-audio-equipment-UK-Seller-Free-Del-100-Genuine/192930369139?hash=item2ceb8bce73:g:ROIAAOSwiPBc6-zg ETA: Just read back through the earlier stories in this thread. Very impressed and kinda proud that people are repairing and using these beautiful machines! I’m all emotional!

Nice to see those 1U vent panels in there too!

Hmmm, that might come back to bite you. But I think you already said you're a bit nervous about fitting a machine with a crude elastic band and I agree you're right to be wary! There is no guarantee that those black belts we can get these days are top-notch quality but at least they were intended for this particular job. I'd be interested if you can see why the belts I've recommended are not working - do you think they are too loose or too tight in your drives? Discussions on this belt come up a lot and various users (including myself) have sought to find suitable replacements - but none of them are the actual component that Sony used - and we don't have a spec for a new/perfect example of one - so we're all guessing a bit and looking for suitable (if not exact) replacements. I'm not sure I could settle with an elastic band in such a valuable machine. More investigation would be worthwhile if you have the time/inclination!

There is no "white lever", it's a black tab (as previously advised). Your flat blade screwdriver is pointing at it. Anyway, glad you got the belts changed. Doing it through the MD slot is a bit of a challenge though - far easier to just remove that spring and flip up the upper frame in my experience - but whatever works for you and gets the job done! I'm confused you say the 17mm belts "don't work" - having done at least 3 machine myself and fixed this exact problem. I can't see how they could bind with any of the mechanism - the white nylon wheels that it travels around have quite deep grooves in them and the replacement belt (as seen side-by-side with the original in your photo) aren't that much thicker (assuming they are the 17mm/1mm belts). Working machines - that's the outcome we want and it sounds like you're nearly there. So good work! Kevin

Start from the beginning. Mains socket ok? Plug fuse ok etc

At the rear there is a tab that can move up and down in a slot. There’s only one and it’s that one! On your top photo, it's above (when the drive is the right way up on a table) the "SCE 535" label. Yes 17mm belts work perfectly. Did you look at the Russian video? In my link above I give time stamps for each step - but in a slightly later post in that thread. If your symptoms, as you describe, are that the disk will load and eject but with a little manual help, then the load belt really is the culprit! That is unless you are only trying a disc that has a label that is lifting or is covered in sticky nail varnish (the disk in your picture does look like the label is "decorated" with some lumpy stuff!). So did you really get a second E12 from an eBay seller for free just because of this load issue? Oh I wish I was so lucky!!! Those E12s are pretty valuable... Where are you - can I have one of your "spare" E12s? :-D

See my post here on the belt and fitting. As above the belt can look fine but when you take it off it will look ‘lifeless’ and will have no stretch