MSX "Junk" sale....

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By Manuel

Ascended (17678)

Аватар пользователя Manuel

15-02-2009, 21:37

Who bought the Sanyo MPC-25FD?
We'd like to see if the internals look anything like the Phiillps NMS 8250...

By jltursan

Prophet (2448)

Аватар пользователя jltursan

30-05-2009, 20:05

Sorry for the delay; but I've been out of bussiness for a long time...

I was the buyer of the Wavy25FD. Now, I've found enough spare time to open it and try to put it in working order. That's what I've found inside (beware, 2MB jpgs):

Upper plate:
img242.imagevenue.com/loc114/th_10034_Wavy25FDu_122_114lo.JPG

Bottom plate:
img7.imagevenue.com/loc782/th_10048_Wavy25FDb_122_782lo.JPG

After replacing the broken Mitsumi D357 drive (I'm starting to collect a pile of D357 faulty drives, they're shit) with a standard PC drive and some hard cleaning, the machine looks much better now.

Any suggestion about how to upgrade this machine (specially the 64KB RAM with some piggybacking ICs) is welcome.

By Jipe

Paragon (1443)

Аватар пользователя Jipe

30-05-2009, 21:04

Philips 8250 is very different
the design recalls that of Sony hb700 especially to the level of the bridge

By RetroTechie

Paragon (1563)

Аватар пользователя RetroTechie

30-05-2009, 21:50

Interesting machine! Case (frame) looks very much like the Philips NMS8250/55/80 models, it wouldn't surprise me if this came from the same factory. Keyboards compatible by any chance?

Singlesided board with lots of wire bridges (like in several popular Sony models). Several places that look like it's meant to take additional IC's, for ... built-in software? Superimpose / digitize function? Something else?

Memory looks like 128K VRAM (IC120~123) and 64K main RAM (IC109+110). Not a mapper, I think: that usually involves an engine with built-in mapper (not used here), or 1 or more 74LS670 IC's (or equivalent, none of those in sight).

And a switching power supply (taking 100~110V AC from the looks of it). A floppy drive, and (is this correct?) 1 cartridge slot?


Any suggestion about how to upgrade this machine (specially the 64KB RAM with some piggybacking ICs) is welcome.

Well, modifying or adding ROMs (for whatever purpose) should be a piece of cake in this machine. I suspect this machine would lend itself *relatively* well for an MSX2+ conversion. Would be a lot of work though...

As for main RAM: you could add circuitry for mapper registers, and make the 64K main RAM into a 64K mapper. Then piggyback a few 64Kx4 DRAMs to expand that into a 128K mapper (256K if you make stacks of 4 IC's). Or use that empty ROM soldering place (IC113) to put in 1 or more static RAMs (of 512K each). Do-able, but a big job to work out how to do it in this specific model. With design and/or circuitry ready, hooking it up should be easy (thx to the wire bridges), and you'd have plenty room for it. Don't think the power supply would complain either.

Other things like internal MSX-Music, MSX-DOS2, 7 MHz. upgrade etc. should be straightforward, that is: no more difficult than for other MSX machines.

So: a nice mod-able machine, but exactly how to build in your extension of choice, and who would do the work? (not me, I afraid). That's the question.

By Manuel

Ascended (17678)

Аватар пользователя Manuel

31-05-2009, 00:37

Whatever you do, first dump the ROMs and get an idea about the slot layout, please Smile I'd love to be able to emulate it.

By jltursan

Prophet (2448)

Аватар пользователя jltursan

02-06-2009, 23:46

Here we go...

As far as the tools I've used to collect data are giving the right info, here're the results:

From GetROM:

Slot 0-0 MSX2 BIOS (MSX2.ROM) - 32KB
Slot 2-3 Extended BIOS (MSX2EXT.ROM) - 16KB
Slot 3-1 BDOS 2.2 (DISK.ROM) - 16KB

From TestRAM:
Slot 3-2 64KB (no mapper)

If you need more info; please, let me know...

By Manuel

Ascended (17678)

Аватар пользователя Manuel

03-06-2009, 19:11

Thanks, great!

Can you make some detailed pics of the other board, below the one of the photo you posted, to see what other chips are in there? Or just tell us the exact PSG, Z80, MSX-ENGINE (S3527? S1985), ROM (kanji?) etc. chip Smile
On the current pic I mainly see the WD2793 FDC chip, the clock chip and a ROM near that battery.

Also, a picture of the keyboard is necessary to find out if it's ANSI or JIS. It has 128kB VRAM, right? Are there more texts on the machine which reveal other things?

Another question is which are the external slots. Could you check that out with GetROM, by putting some non-booting ROM in the external slots and see where it appears when getrom.bin does its scan?

Thanks again and also in advance.

By Manuel

Ascended (17678)

Аватар пользователя Manuel

03-06-2009, 23:52

Are you sure the Extended BIOS is in slot 2-3? That's very odd...

By jltursan

Prophet (2448)

Аватар пользователя jltursan

04-06-2009, 00:40

Yep, that's what GetROM reports. The dump created seems fine...

There're no more boards on the machine, only the upper and bottom ones. The bottom board has all the main ICs you mention, take a look at the hires picture.

The keyboard is a JIS one, there's a picture of it in the first message. Anyway I'll take a more detailed photo to show how the keys are arranged.

Having inserted Kun BASIC cart onto the only external slot this machine has, GetROM reports that there's a 32K ROM in slot 1-0; so definitely the external slot is 1-0 Smile

There're no more noticeable differences between this machine and others I own. Oddly that this machine has a SCART-like connector that (as far as the european cable doesn't work) must fit the Japanese 21-pin standard. I'll build a cable to check this.

By Manuel

Ascended (17678)

Аватар пользователя Manuel

04-06-2009, 22:00

Thanks for this info. The single external slot is quite peculiar!

ARGH! I completely missed the photo of the bottom board, I see now :S Sorry about that Smile Anyway, all clear, thanks.

Can you check the following things:
- VRAM size (I guses 128kB)
- is shift-graph-control keyboard ghosting protected (check what SHIFT-GRAPH-0 gives)
- does the kana/code key lock? (like CAPS)
- does the GRPH key lock? (like CAPS)

Does it have the usual other ports, like a printer port, cassette port?

I'll add a machine config to openMSX soon! Thanks!

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