NGY

Thought I would post these photos. I was listening to some music the other day on my recently acquired JA20ES, and towards the end of the disc it suddenly dropped the sound and the same time a strange rattling noise came from the deck. My blood froze, such a nice unit and damaged? I had no proper time to check it immediately, so I just put it aside with a bad feeling, but today I decided to open the unit and try to fix it. It took quite a while to take the drive apart, for the complex loading mechanism and shielding. Then it turned out that the same part is "guilty" as in bluecrab's JA22ES: the toothed rack that moves the OP. It lost one tooth at the same position, but the lost tooth got stuck in the grease on a farther part of the rack. Looks like this loose/stuck tooth caused the drive malfunctioning, when it blocked the gear that drives the rack. I quickly took the same part out from another deck (will certainly repair the broken one later), and reassembled the drive, also cleaned and greased all moving parts with fresh new grease. And while I was there, I checked the OP settings too. The whole repair took almost three hours, but now the deck works flawlessly again, so my pulse is back to normal. So the question that bothers me is how on earth these racks broke in drawer loading drives (of expensive models), i.e., where the disc cannot be forced in or out manually, like on the slot loading units. And strange enough that this has happened - again - on a fairly new or hardly used machine. .

Without any offense, but there should be some sense made, or at least showing some sign of consistency (in terms of wishes, objectives and willingness). Because then does not compute for me (in terms of "not spending any more".) 10 GB of mp3 is about 3k songs, that translates into ~150 pcs. of 74min. md discs, that cost too. Unless he gets the discs for free or for less than ten cents each, it would make better sense buying a 16GB mp3 player for about 15 dollars, copy the whole stuff onto it in about twenty minutes or so (keeping all the directories etc.), and avoid a serious amount of man hours spent on transferring mp3 to md. But anyhow.

After the MZ-R30 fully charged the battery, I have run a full discharge-recharge cycle: MZ-R30 laid on the desk, earphones attached, volume turned at 50%, play mode "repeat". I checked back at the end of every hour what the unit's display showed for remaining battery % (grey squares represent the segment blinking very slowly): At the end of the 8th hour it was still playing, with some juice left in the battery, but I did not want to squeeze it more, so I stopped the device. Recharge took few minutes less than 5 hours, again inside the MZ-R30. These values are very reasonable, even do match the specs in the UM (although conditions were very forgiving, compared to what a units gets during jogging for example) - that tells me that this particular battery pack had not yet achieved it's lifetime before it had been put down and forgot about. My other try today on a Li gum stick battery failed though. I managed to get the "revitalized" cell accepted and charged by the device, but the battery did not hold charge, it dropped voltage in less than a minute. End of story.

Thank you.

When you enter Test Mode, select "Service", then "ErrDisp". First variable is "total rec", next is "total play. Reaching into test mode can vary by model. It is fairly similar for the decks, and the process is usually described on the 2...3. page of the SM. I am not - yet - familiar with the portables though. These counters are not available on decks prior the MDM-5 mechanisms. Also, some of the MDM-7 mechanisms seem not using these odometers. Some models use a third value, for the spindle running hours.

With all due respect - moving mp3 onto minidisc is not that much sensible (except one leverages on 1GB HiMD as a storage option). Regardless md being dead or not. ATRAC encoding is superior to mp3 in sound quality.

Finally, I bought a JA20ES on ebay.de, and it arrived today. Deck is in very nice shape, no scratches, looks near new. Display is bright, buttons/knobs are not worn. I could not resist to open it, and it is totally clean inside. And yes, indeed it has the CXD2656R ATRAC chip (Type-R). Error display shows 36 and 183 hours of total rec/play times respectively - this is the least used deck I have ever possessed (besides the one I bought new - nearly twenty years ago). Damage was 167 Euro, including shipping and original RM-D19M remote included. . . . . . .

Yes, there are risks here (as always are when "tinkering" stuff), and whether or not it is worth it, that is certainly subjective. For better understanding those risks, let me add some more insight. In my post above I wanted to be as brief as possible (unsuccessfully), and left out the physics part completely (most of it will still be missing below though, but gooogle is there anyway). But before that, supplement to the DISCLAIMER part: the thoughts below (just as the process above) are not meant to suggest/convince anyone, that they can/should repair their battery packs this way. Yes, it is generally not recommended to recharge Li batteries, if the cell's voltage dropped below ~2,5V (according to most manufacturers). And the reason for this is the risk of overheating the cell during the charge process (and as we know, Li batteries can even catch fire if handled improperly, i.e., terminals shortcut, overcharged, etc.). How can it happen? Very simply put (without much of the chemistry part): the cell's internal resistance drops dramatically as the voltage lowers (and not even linearly). Regular charging current (in case it can be up to 1/1 of the cells nominal capacity in mAh, or more in quick charge mode) over this low resistance can overheat (or burst) the battery, and heat is one of the biggest enemies of the Li cells. However, there is a reasonable range of this undervoltage in which a deeply discharged battery can be brought back to life, using an appropriate pre-charging process (GOTO DISCLAIMER). 800...900 mV is about the limit (or say ~25% of nominal voltage), when it still can be attempted to recharge the battery (highly depends on the cell itself though). And in the lights of the above, the first precaution is the initial charging current. (Advanced chargers do this anyway: at the very beginning of the charging process they apply a very low current, and as the cell voltage rises, increase the current). The 1/10th (or 1/5...1/6th for the impatient) constant current is low and safe enough in most cases, not to burn the battery (GOTO DISCLAIMER). And yes, during the whole process the temperature of the battery must be monitored (I indeed forgot to emphasize this, but here it is now). Those short impulses are still fairly below of a regular charging current, in terms of mA and the duration. I am using them for "pumping" some energy into the cell, to increase cell voltage to a level that the controller board would accept and happy to take charge. From this point, if the battery's own charger accepts again the pack and begins charging it, the rest is business as usual. Heat still needs to be monitored, but if the cell was cold during those impulses, it should be OK (GOTO DISCLAIMER). PS.: the MZ-R30 is running now in loop cycle after the "treatment" of this LIP-12 pack, I will report back, how the battery performs.

It is, indeed. And the reason I reply to a fairly old thread, is a similar experience, but with a little addition - a little hint (but a long story, apologies). It might work in some cases. Li-ion batteries are delicate on one hand, but on the other hand, due to the built in electronics, they can survive better, than the NiMH batteries for example. (I understand in some places of the world it is advised to use disclaimers - without repeating his words here, please refer to the OP's disclaimer at the top of this thread.) Few days ago I bought a small bunch of junk minidisc walkmans (for peanuts really), just out of curiosity, to see how they look like inside. I can tear them down without any fear, and I maybe able to learn new things. One of these was a Sony MD-R30, little beaten, but it turned out being fully operational, and just run nicely plugged on my MZ-R3's power adapter (even it was only 5V, while the R30 would have needed 6V, according to the sign next to the inlet). Then I noticed, that there is a battery in the unit. It looked completely dead, no voltage on the terminals, and it did not take any charge either. I decided to check it inside - I did not have any replacement battery, but I had an experience, that suggested I should try it again. Few years ago, I once accidentally left a battery of my tiny Sony camera (DSC-T7) in the watch pocket (coin pocket) of my jeans. My wife did not notice it, and put them into the washing machine. It took me some time to realize where I left the battery, but by then the washing program was almost complete. Needless to say, the battery was completely drawn, worse than that, even the external charger indicated it was faulty. I had nothing to loose, opened the miniature case, and disconnected the internal controller board from the battery. It showed only a few hundred mV, but it was a sign, that it is not yet completely dead. Then I connected the battery to a CC PSU (constant current power supply). At about 5 Volts, I began charging the battery with ~100mA current (* more about the value below), and monitored the voltage. It soon jumped up to ~3V, then I gave a couple of 5-10s impulses of 200...300mA, with equal length of "breaks" with 100mA in between. After this treatment I reassembled the battery, glued the case, and I have been using that battery since then, just like a normal one. Based on this story, I gave a chance to this LIP-12 pack too. I assumed the unit has not been in use for many years, and it depleted the battery. An alkali or a NiMH battery would have certainly died, but the Li-ion is protected from completely discharged, by the internal controller board. When I desoldered the 18650 cell from the controller board, it showed (what a coincidence) a similar 8...900mV. Then I performed the procedure above. I chose 200mA charging current, and 500mA for the impulses. The 200mA is about the 1/6th of the nominal capacity of the pack in mAh - the rule of thumb is 1/10, but while that is appropriate for regular charging a healthy battery, here I wanted to get some quick results. After a few minutes the voltage went up to 3V, then I repeated the impulses, finally, left the battery on ~150 mA for about ten minutes. At this time, it showed ~3,7V - that is good, as the nominal voltage of the pack is 3,6V. I resoldered the cell on the board, reassembled the pack, a few little drops of superglue on the edges of the case, and it looks as before. When I slipped the pack back into the compartment, the unit immediately showed ~50% remaining charge (that instant value was a bit "fake", but definitely a good sign), and after plugging the wall adapter in, it began charging. Playback did not stop when I unplugged the power adapter, so the battery was back in life. I will experience a bit around the real capacity of the "revitalized" cell, but so far so good. . . . .

They are essentially the same. But using a cleaning disc is probably not the best idea. More thoughts here.

Thanks for the information, it strengthened my confidence. The particular unit I was after got sold unfortunately (for about 80€ ...). It then removed any ambiguity.

Education and intelligence are two different things, and mostly independent of each other. An undereducated person can be very intelligent, and vice versa, a highly educated person can be less intelligent than others with way less education. I have met many of both kind. This site is not run by the vendor you are referring to. There are enthusiasts here, who sacrifice their spare time for sharing their invaluable knowledge to help others, without getting any compensation from the company. I have not seen any Sony employee posting here yet.

I wish he was still around. Few months ago I sent him a PM, an e-mail, and an ebay message. No reply, unfortunately. Might be as well, that he is not interested anymore. But I doubt it.

This is the frame around the display, or on other models, the front face of the disk drawer:

I think I am then looking at a different version of SM. This is what I see on the front page: I have seen the "Type-R" written (or embossed) on the middle plastic plate, but only on the 33ES, 333ES and 555ES. Have not yet seen an 20ES or 30ES with such a sign. Anyhow, I am certainly convinced the JA20ES is a Type-R machine, just wanted to somehow get hold of those photos.

Ha... I am afraid, I missed your point. Which photo are you referring to?

Thanks Stephen. The 2656 chip being Type-R is familiar, I met this chip in several models. What confusing me is that the sign on the front panel of the JA20ES does not reflect this fact (seems a few ES models 'disguise' their ATRAC version). What I wanted to check on those photos, if any revision number was visible on the BD board. I would not expect though such a change in a device already in series production, I admit. Type-R or 4.5 for SP: my understanding is that Sony originally developed Type-R for JA22/33ES (I read it here), to increase encoding quality, and as none of these are MDLP machines, I would expect it being better in SP too (I can imagine though, that Sony already had MDLP in mind when began developing Type-R, and doubled the encoding power). I took your point on power amplifiers, and buying a JA20ES is not really about buying better sound quality, as both my 930/940 QS decks are already good enough for my ears :-) . Instead, I am really impressed by the "half a ton" type build quality of the device itself, and some other features on it. Such a "tank" in my mini md "collection" would also be nice :-) .

I understand this is an old thread, but if someone could help me please, how can I see these pictures? Only the placeholders appear in my browser. I have read the forum back and forth about the JA20ES being Type-R or not, and Azureal's quoted post took me the closest, and raised my hopes. There is a unit I would like to buy, but if there is any probability, that there were JA20ES units also made with the 4.5 chip, I would rather not chance it.

Just a thought. The toothed rack positions the laser over the tracks of the md. The black part moves the OP, and the white part compensates the backlash. Backlash is a small amount of play or gap between the gear and the toothed rack, that is needed for smooth and easy transmission, but results a decrease in the precision of positioning, especially when reversing direction. This gap in our case can be up to two orders of magnitude (!) larger, than the actual track pitch. The white part is tensed against the black one with the help of a spring, thus the actual tooth of the gear is pressed from both sides, and the force of the spring (that is, larger than the force needed to move the OP) eliminates the backlash (to a decent degree, and the rest is taken care of the OP's lens mechanism, see below). Now, the reason why I mentioned this. The laser keeps trying to focus and keep in the groove, and even with virtually zero backlash, it may require repositioning a few or more times, depending on different conditions (you can observe this, if you take a look at the OWH of an open drive, while playing a disc). Although the tracking mechanism and the electronics of the drive are designed for this, the focusing part of the OP is also given a load of repositioning and refocusing, that can dramatically increase, if those conditions getting worse (in this case, although the white part's teeth take over the role of the black's broken teeth, without compensation backlash reappears, plus uncertainty in positioning adds, for the white part is not firm on the arm). Therefore, even if your drive may be able compensate for the missing two teeth without audible errors, in fact the OP must work heavily to find the track and read the information. This extra work can wear the laser way faster, than the normal use. (Same happens, when the disc itself hits, radial or lateral. Using such discs can speed up the wear of the OP. Certainly, everyday users won't open their decks to check their discs for hitting - I actually began doing it, and am proactively sorting out those, also, if I accidentally drop an md, I immediately check if it still runs true.) So my point is, to preserve the laser head, it might make sense to have this part replaced, the earlier the better.

Hi, I dropped a reply to your pm.

I wish I could - but my hobby-level knowledge (though I am learning every day) is limited to those "bulky" decks. (Not least because those having "easy-to-see-and-pick" kind of parts - that seems getting more of a constraint for me, as time goes by). Update: Having said that, if anyone was about to part their broken HiMD gear, I am interested to buy, just out of curiosity, to have a feeling how these little gems look inside.

"Dental implants" :-) . Where the two teeth were missing, I cut a "notch" into the rack (see second photo). Then I cut a small block of plastic that would fit tight this notch, from a piece of plastic part I took from another broken Sony drive, so it would match the material. I pressed this block into the opening on the rack, also used a drop of super glue. I kept it in a vise under pressure for a few hours, letting the glue do its job properly. Finally, I shaped the teeth with a precision file. Done. It holds nicely, and strong enough, because the two teeth have a "root", that can transmit forces to the base of the rack. If I had glued back the teeth only, it would have not held sufficiently, I guess. On the third photo, if you enlarge it, you can notice the outlines of the implanted block.

Great update, thanks for keeping us informed. I was actually waiting for your news, see below why. What a coincidence, a few days ago I just fixed a deck with a similar error. It was a little S40, that had multiple troubles, C13 was one of them, the one I could fix as the latest, as I kept insisting on it was the laser, without much success. And yes, at the end of the day it did relate to the laser, but just as you wrote, mechanically, not electronically. I guess you saw something similar, like this below. Lacking an immediate replacement part, I had to take the time to fix the toothed rack - and it went well. The deck is fully operable since then. I doubted your hi-end machine suffered the same error, so I was reluctant to advice to take this path, and potentially drive your friend crazy. But it seems, he found his way, congratulations.

The MDLP capable decks: 440/640/940, 470/770, S50, PC3. Also, the 480/780/980 have a very similar drive, though not fully identical to the MDM-7A.

Sold. Anybody from here? I would love to see some good close-up photos of the drive.