NGY

I completed the repair of this 480 during the weekend. This involved installing a new OP. However, for some reasons yet to know the drive did not accept the new OP for the first time. I had to reset all settings in Service Mode, and perform a full adjustment process with the new OP in. Now all seems fine, machine works like before. I plan to experiment with the faulty OP in another device, because based on the total record/play hours this 480 was hardly used, for I would have not expected the OP die (or make the deck irresponsive). Petter, I just wonder how far you got with your repair.

You may want to read my post here. That's all I can add to the "how to". I put my best knowledge and all my experiences into that list, so it will probably give you an idea, how to progress with your repair. Apart from a spare OP or a spindle motor (whichever turns out to be the faulty one, if at all), there is not much cost involved for most of those checks. But you cannot avoid having (borrowing) the necessary tools. Rest you can find here on this forum, and as Kevin put it very nicely, the success depends on you too, big time:

I don't have any experience with swapping complete drives between an x70 and an x80 family deck. I have just sold my 470 some days ago, so cannot even try - I wish I could and give an exact answer. I can only speak for the 330/520/720/920 vs 530/630/730/930 compatibility. Both families have MDM-5 drives, and both type BD boards have the exact same pinouts on all three cable connectors (although the switch board is not part of the BD board). Nevertheless, swapping drives between the two families did not work, and I tried quite a few combinations. I suspected it was due to the different DSP chip. This difference is certainly there between the x70 and x80 families too (being Type-R and Type-S respectively). Therefore, if I was in Alex's shoes, I would be cautious before spending yet another 38 Euros on a 780 (or 480) drive for my 770, until somebody can firmly confirm that such a swap works. On the other hand, 38 € for a drive that has several important compatible parts (OP, OWH, sled, spindle motor, etc.) is not a bad deal.

Thanks for your additions. If I may, I cannot 100% agree with this part (noting that I did not write that switches should be desoldered, except the protection switches, and those only in order to remove the BD when needed). In essence: I cannot make sure if someone follows my "advices" here, cannot go wrong and make a bigger trouble, but my intention is to reduce the risk as much as possible. An "amateur" might not be fully aware of all the risks of poking around on a PCB, with a "loaded gun" DMM. What I mean is a DMM provides a certain DC voltage (in the range of 1...3 Volts) on its probes for resistance (and continuity, and diode) measurements. A wrong pick with those probes can burn vital components. It can be the voltage level itself or a reverse polarity (or ESD related). The switches are directly connected to the respective legs of the main system controller IC. Although the I/O ports of the cpu are certainly able to handle bidirectional voltages and currents (to certain levels) by design, my recommendation to those without such a deep technical understanding is do not touch the BD with a DMM in resistance (continuity, diode) mode. Luckily, the position switches are on separate boards on most of the drives but the MDM-7 variants, therefore no soldering is necessary to test them safely, enough pulling the respective cables out. In case of the drives with the switches directly soldered on the BD board my recommendation is using an ESR meter. Why? Because ESR meters work with very low voltage signals (couple of 10 mVolts only), that is way too low to result any semiconductors to "switch on", thus risking a potential silicon damage. Regarding the spindle motor: I agree an H-bridge drive would not influence the resistance measurement of a DC motor's coil (as long as we can exclude the fault of the driver IC itself). Also agree that these DC motors are simple and very robust. My recommendation for testing a motor is still desoldering and probing it from an external power source (the best would be a PWM generator, but let's just stay on the ground of the amateurs :-) ). Based on Jim Hoggart's notes, even with a proper (looking) ohmic value that motor can still have a fault (as he wrote once, "a blind spot", if I recall it properly).

We have seen here on the forum quite a few C13 errors recently. There is one thing that is more true than ever before: lots of possible causes can led to the actual C13 error (or "DISC ERROR" on certain models). For this reason, there is no generic recipe, how to solve a C13 issue. I decided to post here my silly little "itinerary". This is not a magic formula, not even a nice, polished, completed flowchart. It is just a brief list of steps and comments I collected based on previous cases (mostly Sony MD decks), and that I normally follow when facing a C13. Although this text below is still in "rough" format, I tried to build up a - sort of - logical order, coming from trivial to complex, from "outside" to "inside", from easy to hard to perform. Some checks do not require any tools (OK, maybe a screwdriver), while some do require at least a DMM and a soldering iron (with adequate soldering skills), and as soon as one deals with the OP, those special tools are a must. I encourage you to add/comment based on your experience. C13.txt

Short answer: yes, it is possible. Long answer: I know my opinion is only one, and it does not count, nevertheless, here is what I think (no offense!): It is not yet known, what caused your C13 error. First you said you knew that it was the spindle motor. Now you say it is the OP to replace. In between you said you are done with "reset and reseat". This way you certainly will not be able to find the real problem and the real solution, unless you are very lucky. As I wrote above: systematic approach is the name of the game. Replacing the OP is certainly on the list, but there are several others well before it. You still want to replace the OP? I guess then you are aware of what it takes to perform such a delicate service process. But why do you want to begin with replacing the OP, without actually checking the existing OP first? There is a reasonably good level of technical expertise here on this very forum, when it comes to repairing MD gear. You can have some directions where to begin, good advices when and what to touch and what not, etc. As well, as what minimum knowledge/understanding and special tools required in a given case. Now: I don't know anything about your technical preparedness, this is why I am hesitant to take you any further. I don't want to be responsible for any damage to your valuable MD deck. I am very sorry if I sound kinda negative. I hope somebody else with much better senses can jump in and help you through this repair.

The 18650 cell is slighlty shorter and ”thinner" than the original battery. I do not know this Denon model, but it probably has a spring contact at one end. If that spring cannot make a firm contact with the 18650, with a (clean, oxide-free) coin you can "extend" it. A few turns of some adhesive tape around the 18650 can help to fit the diameter - it is enough at the top and at the bottom. Alternatively, you can use multiple rings of heat shrink tube, layered on each other until you reached the needed diameter. Just make sure you do not overheat the cell during the process.

Can you measure the length and the diameter of the battery? That is a good basis for finding a replacement. Alternatively, you can search for compatible batteries from other, similar devices (i.e., Sharp MD-S100, MD-S200, Kenwood DMC-F5R, DMC-G7R; Pioneer PMD-R1, PMD-R2 and alike.) Edit: dimensions are 70,0mm x 19,5mm if I got it right. If it is not avaialble, I would just use a standard 18650 cell, with a little "trick".

I always had trouble with "silicon" and "silicone", which one is the correct spelling in written English, and whether they are actually different in some way. Now I took the time and looked after it. Here is what I found: "silicon is a naturally occurring chemical element, whereas silicone is a synthetic substance." So actually, there is a difference between silicon and silicone, and it is quite essential. Interesting, as in many languages those two expressions are more distinct than just a single letter (for example in German: Silizium vs. Silikon). I did not go back and edit all my posts above, but please consider silicone wherever I wrote silicon in the context of lubrication :-) .

Now, I am a little familiar :-) . Here is some good reading.

You're welcome. Enjoy your 940, it is a good one :-) !

Here is the thing: the TOC of a recordable MD can contain a lot of other information besides the track marks and titles. (Unfortunately, I am not able to give you more details on that because I am not familiar with how the TOC structure looks like.) If, for example, an - unknown - device previously wrote the TOC in a "non-standard" way (containing some non-standard data), your deck might just consider that TOC invalid that it cannot write to, and stops there with an error. If the deck does this with some of the discs but performs well with others, I would not be too much concerned. As long as the test above shows a "cleaned" disc now works properly. If it is not the case, then you can begin worrying :-) . Yes, just use your portable to blank those discs, before recording in the deck.

I think it is probably the disc then. If you can record a blank disc and play it back, then your deck must be OK. The 940 is a very solid machine. I had a similar case in the past, when discs recorded in one device I could not erase in another one, but finally I could erase them in a third one. If your portable can erase those discs, then that is the way to go. You can then check back, once you erased a questionable disc in the portable, try the A scenario with that blanked disc. If it works (records, plays, erases), the deck must be OK. If you want to go a step further, you may want to check the decks internal error messages, whether or not it detected something erratic behaviour.

I am afraid I lost track. These are the two scenarios: a.) you record one track on a blank disc, then you can eject and it writes the TOC back properly. (Side question: can you playback that track, before attempting "all erase"?) Then you reinsert that same disc, and do an "all erase", and again, TOC is written and you get back your blank disc. b.) you put in a disc that already has music on it, then after doing an "all erase", TOC is not written back, disc not spinning, sled not moving. What other difference is there between the two discs in case a.) and b.)? I mean, both already have music on them before the "all erase", so there must be something else. Was disc b.) previously recorded on this same machine?

20 minutes TOC writing is not good ... When you open the machine, you may want to check the magnetic head first. I mean, after you took a look at what happens when the deck gets stuck in TOC writing: disc spinning or not, sled moves back to the TOC area or it does not, etc. Without the TOC written back after the recording session the only way to check if the actual recording is on the disc and it has no problems is via "TOC cloning". You would need access to another deck and clone another, good disc's TOC onto this one. If the recording was OK, then you can play it back (track marks, titles will not match obviously). I am trying to separate the possible laser issue from the magnetic head problem. But a quick visual check on the magnetic head will certainly tell the "obvious", if that's the culprit.

May I ask a few questions: - when recording, do you see the seconds ticking? Does recording a track/disc take the same amount of time as the total time of that track/disc (i.e., when you record from a CD)? - if you take a non-blank disc, and change only one character in the title of the disc or a track, do you experience the same TOC error? - when you see the machine is locked up, do you still hear the disc spinning? - what happens if you leave the deck in TOC writing for more than a minute or so? - can you open the lid and observe, what the deck is actually doing while it displays "TOC writing"? If playback works fine, then chances are something is wrong with recording/writing. To figure out whether it is the magnetic head, the laser, or else, some more information is needed on the actual behaviour. Usual first suspect is the magnetic head, second is the laser.

Before you adjust anything, first check the error levels. Error levels can indicate (without "turning any knobs") whether or not it is necessary to undergo the focus bias adjustment process. FB adjustment is not foolproof, it is rather tricky. Apologies if I created an expectation that this the "thing" that will solve the problem. Proper FB setting is necessary for the laser to operate optimally - this is true. However, all other adjustments (laser power, traverse, auto gain, etc.) must also be checked and done.

I used the term "picky" meaning "hard to please". In other words, sensitive to smallest details [being in strict order]. We all wish if it was just that much. Do take a quick look around that topic I linked above .... I wrote reseat ... You probably are, but not your deck, it is still far from it. But certainly, it is your choice. This forum is meant mostly for amateurs, not pro service people. Some of us (similarly amateur folks) hang around here trying to help people fixing their precious MD gear, using the collective experience and knowledge documented here. In this particular case, there are still a few items that can be checked before turning the case down for good, even for a non-pro user. But again, if that's your decision, then who am I to force you to attempt reparing your device :-) .

I would not say that, those are very good drives. Just the main cpu-s of those models equipped with MDM7 variants seem being kinda ”picky”. But your case is amongst the better ones, because your deck is at least "alive" after the belt replacement. Many people struggle with "stuck in standby", and that one is really a hard nut to crack. Dozens of causes can result the C13 error. It needs a systematic approach, and take one step at a time to find the real one. We normally begin with the "trivial" things, like resetting the machine, reseating all the ribbon cables, cleaning the OP lens. Then we go deeper - and here where the need for some technical knowledge and experience as well as some special tools begins, otherwise one can ultimately ruin an otherwise good machine. But again, your deck is not (yet) dead, and it might just be a small, easy to fix cause of that C13.

I am getting the impression, that these decks with the MDM7 flavours are very sensitive. Lots of people are experiencing (sometimes serious) trouble after a simple belt replacement. Just scroll through this topic quickly ... Anyhow, you can try to reset your deck before doing anything else. Locate the reset jumper, remove it for about 10...20 seconds (with the AC cord pulled out beforehand).

Well, it sounds similar to how a laser degrades. First some skipping happens during recording, then it skips playing back a good recorded track/disc, then cannot find some tracks, then does not read the TOC, finally not able to read premastered MD-s either, lastly cannot even recognize the disc. When a disc is loaded, the drive attempts to read the lead-in area of the disc. This is a non-recordable area, very similar to the CD-s. In fact, it is much '"easier" for the laser to read it, than reading the recordable areas, like the TOC and the actual tracks. (And this is why sometimes a deck still can play the factory pressed MD-s without any problems, but cannot play the recordable MD-s). Probably the safest method is to use a Sony (or other, brand make) MD lens cleaner. Alternatively, as most of us do with a Q-tip, a drop of isopropyl alcohol, and very gentle hands. Best if you take a look at a few videos on-line - cleaning cd/dvd/md lenses are practically the same thing. When opening a deck, make sure you ground your body's/cloth's electrostatic charge before touching anything inside (a radiator, or a water pipe/tap can make a good ground).

You may want to replace the spindle motor then. I would be interested to know, how did you detect it, I mean, how do you know it is dead? The spindle not spinning is only half the equation. Even if the laser does attempt looking for the disc, still there is a chance that it is not a dead spindle motor. It might just as well be the OP. In some cases it is just a little dust on the lens. In other cases it is just a matter of a slight change in the laser's settings. And certainly it can be a faulty laser too. (BTW, from 100€ you can have the whole unit shipped back and forth within Europe to a real pro and also have it fixed. Or just buy a donor machine for half that much or even less, and swap the drive by yourself.)

Glad to hear that you got at least halfway in clearing those noises. The mechanism will probably survive us all. It is more the OP that can fail, for the excess focusing/tracking efforts. Those very thin, flat copper springs that hold the focusing lens can lose their flexibility. Also, the laser diode itself can age faster. Playback is less of an issue (still counts though), recording is where the laser will have most of the extra load. I am afraid, you cannot adjust the traverse settings with a DMM only, or by trial and error. There is a specific waveform you must literally see in order to properly adjust. You can try to check the error rates and adjust the focus bias according to the SM, just make sure you follow it word by word. It is kind of a pain job, as you may need multiple attempts and the process can take an hour or even more to complete. It may also happen, that the factory recommended settings cannot be achieved - a probable sign that the OP itself has already an issue.

Thanks for the video. I can hear both noises, the ticking one and the high pitch. The ticking sounds like coming from the sled motor's gear chain. It is visible, that the laser has very hard time to keep in the groove. The high pitch - most probably - is coming from the disc itself, sounds like a friction noise. You can hear this noise "slowing" as the disc spins down after you hit the stop button. As for the first one, it definitely calls for some checks and fine adjustment. I can give you a checklist, what to begin with, but as Stephen already pointed out, if you feel 100% comfortable going into that depth technically. Based on the result of these checks, it is probable, that your traverse and focus mechanisms need readjusment, but then that will require special gear, such as a test jig and an oscilloscope as a bare minimum. As for the second one, I lean toward the spindle having an issue. The magnetic hub might have "descended" a bit on the shaft, causing the disc touching the shell somewhere while spinning. Not that easy to prove or disprove. Nevertheless, a quick (and "dirty") check: cut a 10mm dia circle from self adhesive paper (printable label, for example), and stick it into the disc's metal hub. This will raise the disc just a bit, the magnet on the spindle will still grab it properly. Check if the noise changes. You may need a second one on top of the first. Maybe a third. If the noise changes audibly, then we are on the right path.

If you choose one good and one "noisy" MD, you can do a quick comparison. Observe the cogs by looking at the drive from behind (see photo below). The leftmost, smallest one would show the most visible "oscillation":