jim.hoggarth

It is a standard USB A to Mini-B, but make sure you get a good quality one. The NH900 has a high data transfer rate and I wouldn't want to try just about anything.

This adjustment should never be touched - it is factory set. You are in danger of just making things worse. There is a good chance the laser pickup is damaged and no amount of adjustment of the laser drive current or the servo EEPROM drive settings is going to change that. The laser unit has an internal regulator photodiode, the 'sensor' you mention, but if this is giving incorrect feedback info only replacement of the whole laser unit will help. You say the drive unit gets very hot. Possible damage to your skin hot, or very warm, or mildly warm? After the drive has been working for some time - and especially during record sessions - there is a certain amount of heat generated. You need to quantify this level of heat somehow, so we can compare it to our experiences. But anyhow, if the drive fails with the top on it is definitely not right. Jim

Yes, very true. I am more inclined to think the regulation photo-diode in the laser emitter itself is at fault, causing the foldback laser current to be way too high and generating excessive heat. Only fix is a replacements optical pickup. Jim

It doesn't happen often, but sometimes a totally dead gumstick battery will appear to accept a full charge, but the outcome is as good as a totally flat battery. Probably about one in every 25 bad batteries I come across show exactly this problem. In your case though, a new battery shows an identical problem. I suggest there is a fault on the charging controller IC. It may be something as simple as a bad resistor or solder joint, of course, but it will be very difficult to find and prove. Personally I would start by swapping out the main board, assuming the battery contacts are in pristine condition. I would also check the batteries out in another unit to confirm these are fine, which they presumably are if the fault is electronic. But then again, I have the parts and test gear which you do not, I guess. My advice is to get the batteries checked on another unit first. Time to contact a local friend with an MD or CD player which uses gumsticks? Jim

In the last two weeks I have bought very little stock, primarily two off Sony MZ-N707s in partial completeness. My intention is to list a complete one with the best of the bits tonight. I was jotting down serial numbers, and thought I had entered one incorrectly as the last digit was a '5' not a '6' as I had previously seen. To my utter surprise it then dawned on me that the two main units are immediate siblings - one serial number is 5166786, the one I bought earlier 5166785. How amazing is that? I guess they may have even been in the same batch, from the same shop (probably Argos?), and bought around the same time. Yet one came to me from South Wales, the other Byfleet in Surrey. I'm not sure I want to sell them now - after being separated since 'birth' they are finally together again! Anybody else seen an amazing coincidence like that? Jim

Actually, they are quite important in order that electromagnetic radiation is kept in check. With the proliferation of electronic devices, it is imperative that they do not interfere with each other. More specifically, that non-essential equipment does not have an adverse effect on essential installations. You know, important things like life-support equipment and avionics. These filters are designed to reduce very- and ultra-high-frequency emissions which can easily cause interference. If we look at the minidisc recorder as an example, even those made from plastic parts include a degree of shielding using ground planes, metallised plastic guards and so on. However, it is not possible to protect the external cabling from EMI (electromagnetic interference). Some may say 'ah yes but these cables only carry low frequency audio signals'. Not so. High frequency signals are always present due to inductive and capacitive effects. The control processors found in most modern electronics run at GHz, and clock and signal frequencies will always make their way ultimately onto external connections. The way around this is filtering HF signals, which can be done to some extent internally but is far easier (and cheaper) by adding filters to the cables - including the power cables as these digital clocking signals can also propagate back through the supply. Hence the chunky filters around which the cable should be looped several times. And of course the problem is cumulative. One badly shielded device may be ok, but a whole aircraft full of them and I for one would prefer not to fly in it, thank you. And I am sure bodies such as the FCC and the EU equivalent wouldn't spend millions/billions researching and implementing these requirements unless there was a definite need. Jim

I wish I had! I have yet to find a decent source for tiny rubber feet like these. Whereabouts In South Yorks are you? I am in Bradford, just off the M606 motorway (the spur off the M62 into Bradford). Jim

If the Sharp MD-MT80H is what you are definitely looking at (bear in mind it is SP only), then I have a complete boxed unit in *very* good condition. It didn't cost me too much either, so I could let you have it at a good price. Send me a personal message if you are interested. Jim

Make sure the seller describes it as definitely working. Any possibility of uTOC errors and give it a miss. The majority of Sharp units are famous for this, and getting hold of the part is hard as so many suffer from it (caused by the splitting of a small plastic gear on the sled drive shaft). Jim

Trying to look like Apple?

Stephen, we can't rule out a busted overwrite head flexible cable. I have seen similar faults when the cable is just about to go and the contact is intermittent. Especially were recording to the start of disc is ok, but part way along it suddenly fails. Jim

You can do worse than the N510/520. It is a superb unit, although a bit bulky due to the battery compartment. The N710 is basically the same machine with a gumstick and metal front, although it has a shorter life due to limitations in the design of the control buttons and lower casing (plastic parts cracking). I tend to prefer MD80 discs for long-term listening, as it seems more satisfying to replace the disc at the end of an album, somewhat like changing vinyl. Hi-MD smacks too much of MP3s - half your music collection on one disc? For me, stuff gets lost in the crowd. Much better to make a conscious choice about which artist/recording to play next. When you have too much to chose from, there is a possibility of 'surfing' tracks, just like when you have a proliferation of TV channels. Another analogy is like a kid in a candy shop - just can't make their mind up. Consequently I don't use Hi-MD for general use, much preferring the N510 as already said. Sony sold *lots* of these, and they are still one of the most common models to appear on sales listings. And because they are so reliable, and easily repaired, I can confidently say this: When almost every Hi-MD recorder has seen its day and been scrapped, I will still have a large stock of parts for the N510 etc and will hopefully still be refurbishing them for years to come yet! Jim (And I can seen the supply of MD80 discs outlasting the 1GBs too!)

If it is in good physical condition and does not suffer from the usual problem - the FF/REW control not working properly - now may be a very good time to sell as resale values are surprisingly high. Also check the battery storage capacity is reasonable, and that the two halves of the display are balanced and bright. And if there is little in the way of physical marks, and perhaps it even still has its rubber feet fixed firmly, and if it includes the mains-to-USB power converter, it will be snapped up. Some folk are paying daft prices at present, as these recorders get harder to come by month on month. Jim

I second that. Using a known blank disc, transfer just one track, complete the process (you may need to press STOP on the recorder), and disconnect it. Physically removing the media and reinserting won't do any harm. Check that this new track still exists on the disc, and if possible do this on another recorder, player, or deck. The solutions will depend on the outcome of this test. Jim

To be honest, I can't fully remember what I did with them. I do seem to remember fixing one, and then scrapping the rest. For units which do not meet the grade for refurbishing, I tend to strip them for parts. Every so often I go through candidates for stripping, test all the individual parts and label them up with the cost. I reckon yours went this way mostly. Jim

Not taking away anything from your obvious sheet-metal working skills, but the write head on the decks is far less critical than the portables (and there is the write power to consider too - the decks pump out a hell of a lot more juice). And with the Hi-MD units, the head alignment is so critical as to make it almost an art swapping one out and another in. I recall that when Sony still supplied parts for these, you were forced to buy the optical pickup and write head as one pre-aligned item. Getting the write head wrongly set-up can cause *lots* of problems when it comes to aligning Hi-MD units, especially on the MD3 (ie 3-layer) 1GB discs. Jim

That's a very common problem. The Hi-MD units have a tendency to crap out during a panic TOC update due to a failing battery, and leaving the write head in the loaded position. Instead of putting in a fresh battery or mains adapter, and pressing STOP, as described in the manual (or the separate addendum insert), users prise the unit open to get the disc out. Removing the disc and/or inserting another in this state just rips the head off. And because of this, any units I purchase for spares have around a 50/50 chance of having a damaged write head already. Which means I need to buy two 'spares or repairs' units before getting a good working head. As these can cost over 20 GBP each, I need to fork out a lot of money to get good working parts. True, I may also have a good optical pickup or main board in the bundle, but it is write heads I particularly look for. Consequently, even though I make no profit on parts, I need to charge a minimum of 16 to 20 GBP each time I fit one of these. Customers don't realise this, though, and often baulk at the cost of parts, perhaps thinking I am making a killing on supplying them. Which I am most definitely not. Jim

Due to the repair attempt on the write head (not down to Rob, but the prior owner), and the other fault I assumed to be the optical pickup, I simply replaced the drive unit with a known good worker. I have yet to try fix the original fault. Jim

Definitely seen better days. Incidentally, any attempts I have made in the past to 'straighten' such write heads have always failed dreadfully. I no longer even try - just swap them out. Damned expensive part too. Jim

Yes, you might. But then again this does sound like it may just be the disc-in switch at fault. Original poster, please send me a personal message or email me at jim.hoggarth@blueyonder.co.uk Jim

Yes, definitely a Frankenstein unit built from all the broken parts lying around. I get them every now and then, but never this blatant and complete a rip-off. I wish I could locate the other three units I bought in that batch, to see what state they are in, but they could be anywhere now. Anyhow, I am kind-of attached to this recorder now, and I don't know if I want to sell it. Perhaps I should put it in a glass case as a reminder to look at stuff as and when it comes in! I would love to be able to leave feedback for it now... Jim

No, just less than £5. But it was so unexpected I actually found it funny. It is quite obviously a bundle of faulty bits thrown together to sell for whatever can be got. Actually, the guy would probably have got more if the unit had been sold on its own - not too bad looking, but with a sting in the tail. Whoever worked on this before was a total amateur. But then so was I, the first time I opened up a portable MD unit!!!

This will give you a chuckle: Started work on a Sony MZ-N510 yesterday, and have just completed it now. I chose it as a possible B-Grade sales unit, thinking once the damaged display window plastics were swapped it would only need a tweak or two. I originally bought it in a job lot off eBay in February last year (2012), so I assumed there would be some problems as lots of 'spares or repairs' gear had often been messed with. The original stated fault was dead, but I should have realised what was to come when I spotted the display board had deliberately been left disconnected (the seller is unsurprisingly no longer a registered user on eBay.co.uk): Display window plastics - badly marked Key plastics - broken Display board - LCD matrix fault Outer chassis metalwork - bent (especially lid lock latch) Sub-chassis disc lock release arm - bent Head load transmission shaft - final gear slipping Main circuit board - no motor drive Optical pickup unit - laser fault Motors assembly - inconsistent spindle motor speed Upper slot mechanism and overwrite head - head tampered with and misaligned Lower plastic casing - eject button hinge pillar broken Sub-chassis step screw missing Lid pop-up spring missing Lower casing screws missing - all four of them So, other than the plastic sub-chassis and top case, just about every other part needed or adjusting. Did you think I was seen off with this one? Jim

Did you get a second mortgage, or sacrifice your first born? Jim

If it makes the noise again, try make a recording please and post it up here as an MP3 or whatever. I may be able to diagnose the problem just by the noise it makes. Jim