kgallen

17mm diameter, 0.8mm square section, Sony part 4-227-025-01. We had quite a long chat about them here. Skip to later on, but I've given you a link from the top of the thread:

Good stuff. This is the first post I think I've read on this forum (in my short time here) where the interlocks are effectively defeated and expose the beam so I think our comments above are worth stating at this point.

IMPORTANT: May I add urgently here that you do not look anywhere near a laser where there is a chance it could be emitting. Looking into the INVISIBLE BEAM CAN DAMAGE YOUR EYES.

No, it's just I'm getting the hang of reading into Stephen's obscure comments and trying to piece together what he's getting at! Perfectly possible I got hold of the wrong end of the wrong stick. All we succeeded to do was disrupt the thread. My apologies! Nothing more to see here! Please continue!

Preamble and TOC is on the inside near the spindle. Disc reads inside to outside. (Below diagram not to scale on the "area" annotations.) But I would agree with your earlier assertion Stephen, that reading the TOC is very little movement of the sled, The TOC is relatively very little data so can reside on a small number of tracks even on the small circumference of the inner spirals of the disc. For the OP if technically minded, see this "technology primer": http://minidisc.org/manuals/minidisc_training.pdf

I think your videos got truncated to 7secs. But either way I'm a little stuck now (doesn't take much!). In Service Mode can you work the sled back a forth a few times to ensure it's running smoothly? Maybe you already did this after applying the oil (risky, I'm sure you were careful!). This must be a mechanical thing with the heat unless there is a bad contact that makes when heated up slightly (unlikely I guess!). Clutching at straws! My only other suggestion before @NGY saves the say is the 'ole ribbon cable trick, but you're not having the same issue as I had at the time. But I don't think you should be using that hairdryer any more!

OK, no problem. Good luck, let us know how you get on if you're confident of having a go!

There are a lot of unknowns here, you'll need to give more detail. With an SP/LP2/LP4 disc and an appropriate machine, it is possible in some circumstances to use "TOC Cloning" to allow you to regain access to the audio data. But there are a lot of "ifs"... http://www.minidisc.org/cloning_procedure.html

I think I'd be careful with the heat otherwise some of the components are going to distort! Note for read, this is a laser-only operation and this is on the underside of the disk (pointing up). The "head" you can see is the overwrite head and this will drop to the surface if a write operation is needed - writing audio data or updating the TOC. At this point a clean and careful regrease of the sled rail would be my starting position. See here:

I think this one is already long solved by @NGY but in general if we can find schematics for the machine we can usually work it out from there if we can find a datasheet for whatever regulator chip they’ve used.

I think 510 is an MDM5 series drive and they don’t have any belts.

Of course, go for it! MDM7 jig v2 has the I2C labels too... ! :-D

Here is my MDM-7 jig in action, as kindly provided by @NGY. Erm... what do you mean I'm not using it as intended?!!! :-D Here it is, perfectly repurposed to allow me to read the I2C EEPROM chip on an MDM-7SC drive (MDS-E10) :-D - in conjunction with an Arduino (sketch also attached). For the eagle-eyed, yes they are Nichicon Fine Gold caps in there on the analogue I/O. Factory fit. Not so in my other later E10 though... sketch_read_mdm7_eeprom.ino

Thanks for putting other info in from the manual. Not so much issues, as pretty much dead. It had been robbed of a few parts (prior to me), including the DC-DC converter for the display. I did manage to get this working - although not brightly as I couldn't quite generate the -30V needed, but at least I could demonstrate the machine had some life. I already bored everyone with that one here: I thought mine was a Mk1 but I could be wrong as it definitely has the BU-801 socket as can be seen on the photo in the above thread. Mine is also missing the PS/2 keyboard interface board. That's fine, we have the detail on the chip now in the additions to my post above. No need for you to pull your machine apart. I forgot I had the Service Manual which fortunately listed the chip number and I managed to interpret from your photo the part used on yours. So we're good for any retrospective build of this sub-module. :-) Astounding prices! One could probably build that BU-801 module today for around 20USD/GBP/EUR once the DRAM chip was sourced. Kevin

HOW MUCH? And it's knac*ered! Robbing g... grrr.

Welcome! ETA: Sorry my bad, you mean the charger from the previous post. Doh! Stephen knows this stuff, I'm sure he'll comment when he wakes up (any time now...) I'm not sure I understand this part of your statement/question. BCA-MZNH1 is the Sony charger/dock. https://www.sony.co.uk/electronics/support/portable-music-players-minidisc-portable/mz-nh1

@zedstarr - sure, go for it. No pride in that code!

My 801 is very poorly since it seems to be missing (at least) the laser lens, possibly the whole laser. Some photos of that BU-801 next to a 1/10” rule(r) would be useful. I’m guessing the PCB pins are 1/10” spacing - but what about the left/right pitch? Assuming a suitable DRAM can be found these days a PCB for that module would be straightforward to design. Can you capture here the part number of the DRAM? It’s not fully clear for me from the photo - the line starting M5 I think it might be M5M416400CTP, 4Mx4-bit (note: no speed grade is evident from the markings on your chip, e.g. -6 or -7): DSAFRAZ0013654.pdf The more clear info you can post the better as good data on all this kit is virtually impossible to find. Whilst the data is with someone interested and knowledgable we should get it captured in good quality. Still love that setup. Kevin ps An MD801R sold on eBay here the other day. Had a disk read issue otherwise smart. Went for around 50GBP plus postage. Also from the same seller went a working Tascam MD-CD1mk1 and a mk2 and an MD-350. They went for pretty good money too (145GBP for the MD-CD1mk1) so someone out there is still keen on minidisc! pps Note for the future, other 4Mx4 DRAMs of 80ns or better access time from other suppliers, other than the Mitsubishi used originally, might well work. A datasheet comparison would be required to check key timing specifications, but there is unlikely to be anything unique about the Mitsubishi part. ppps From the MD-801R-mk2 Service Manual: NEC UPD4216400G3-80-7JD NECCS00623-1.pdf pppps The socket is Toshiba/KEL ICC04-20-350T but cut down from 20-way to 11-way for each side.

@zedstarr Thanks for the py, I like it! There were a couple of comment errors - also "...4-byte fill..." should have been "8-byte fill" (it changed!). Should be fixed in the uploaded C (and Tcl) above. Any more, let me know, I'm a stickler for correctness! :-D

@zedstarr - looks like you could knock us up a Python version of same... we'll find a language that is portable enough for everyone to have a play, sooner or later! Thanks for the 'bump' on the Blog :-D

If you can make use of it, here is the same thing in the scripting language Tcl. It's interpreted rather than compiled like C. You can get a Tcl interpretter here, but you have to "register" with ActiveState these days: Tcl Download The script: it's just a rehash of the C code provided above. elektor_scms_rom.tcl If you're on Linux you can almost certainly use wish or tclsh.

Here is some C code to generate a hex and bin version of the ROM. I'm no C coder and this C code is awful. Someone, please rewrite! I compiled this with gcc on Linux. I've no idea how to compile C on Windows, sorry. So use this code as inspiration for your own more worthy efforts! elektor_scms_rom.c I used tkd iff to check the hex output from this code matches the hex dump I generated from the bin file uploaded above by @zedstarr .

Fixed a couple of the Comments on state47 COPY/PARITY and improved a couple of other Comments in the Table pdf above if you've already downloaded it and are scratching your head on some of my documentation errors...

You have to "fill in the blanks" for me on the 0x7? stages to make sure I didn't miss anything! :-D Just look at the technical insight in your other posts - you would have got there.

Right I'm being lazy now and jumping to the endgame from what I see in the 0x7? blocks. This is what I "promised" you right? I might finish the entries in my table later just for completeness, but I need food and to remind myself what the rest of the family look like... Here is my take on the state diagram. Not much of a surprise there, huh! Apologies for the brevity but with the above information I'm sure you can work out what I'm saying... (Sorry this is so large, using a thumbnail and expansion leaves the text unreadable.) Table: elektor_scms_rom_fsm.pdf Overall I think I'd comment that both the design of the SPDIF frame is smart and the ROM-based design of this "Copy-bit Killer" is also very neat and well implemented. I'll note also from the FSM state diagram above that the "illegal states" (0x0a-0x0f) are also handled. If the machine ended up by error in one of those blocks, if will self-recover back to the initialisation state where it will look for Z preamble again. Good robust design. Actually it's required since IC9, the register chip, doesn't have a reset, so in theory it could come up (from power-on) in any state (any binary value) and thus dump us unceremoniously into any state of the FSM, including the "illegal" ones. Hex dump of the bin file if anyone else wants a play. Open in a text editor. elektor_scms_rom.hex Please post your own homework below :-)