FDD/service test cartridges?

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By judge_

Supporter (4)

judge_'s picture

06-10-2008, 21:29

I was reading through the service manuals for the nms8250 and nms8255 and they mention a service cartridge (code number 4822 397 30138) and an FDD test cartridge (code number 4822 397 30135).

I have never heard of the cartridges before and was wondering if anyone happens to have (a dump of) one of these cartridges?

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By Manuel

Ascended (19677)

Manuel's picture

06-10-2008, 21:50

I think Bas Kornalijnslijper has them, check his web site: http://bas-ditta.info

By judge_

Supporter (4)

judge_'s picture

06-10-2008, 22:58

Great. Thanks for the link.

By friguron

Master (188)

friguron's picture

13-04-2020, 16:13

Hi, epic refloat (almost 12 years! <3 )

I've come across the famous mirror of Hans Otten MSX stuff (served under TheFileHunter web page). Part of this stash of useful info and files is the dump of the (famous?) Philips MSX Service cartridges. Apparently it consists of these files:

1.- Floppy disk drive
2.- "MSX 1" test cartridge
3.- "MSX 2" test cartridge (8250 oriented? who knows)

The thing is I have my 8250, an EEPROM programer and I said: "why not experiencing the MSX2 test/service cartridge for myself"?

So I downloaded the MSX2 service cartridge alleged dump, which consists of a 16 KB binary file.
What's the problem with it? It's not an AB rom file, (As Hans Otten page claims), it's just RAW code. In fact it doesn't even say "what to do with it", or "how to make it work".

Studying its Z80 code, it seems to assume it will be run in rom page 0 (?), as all CALL opcodes seem to be done inside the 0000..3FFF space. All good. The thing is, "what should be the proper strategy to create the .rom file and then burning said file into my EEPROM IC"?

I have some ideas. Should I create some loader code inside my (still to be created) asm -> rom file? I might create some AB header starting from 0x4000, change pslot selecto into page 0 = ROM 1 (ignoring the BIOS code in this case), and jumping to PC=0x0000. Does it seem a good idea?

example for a 64 KB rom file:
[page 0] => service cartridge dump
[page 1] => easy AB rom code with some pslot selection for ROM page 0 and then a jump to PC=0000
[pages 2 and 3] => 0xFF

I don't like that in Hans Otten mirror page it claims something like: "the dumps are just plain AB rom files" (that's not true, at least for the MSX 2 service dump).

Any hint? Any other assumption I should make before starting to program my .rom file? (I'll do it and experiment a bit to see if my assumptions are right anyway).


EDIT: Maybe I shouldn't do anything but "pressing the 8250 MOBO switch", and then the 8250 will just boot the cartridge, even it's not an AB rom file?

Rom layout plan:
[page 0] = MSX2 service RAW bin dump file (16 KB's)
[pages 1, 2 and 3] = 0xFF

By dproldan

Resident (44)

dproldan's picture

21-06-2020, 08:38

Hi @friguron, Any progress with this ROM file? It would be a really good tool to have for adjusting these old drives.

By calderone

Resident (36)

calderone's picture

22-11-2020, 18:24

Great idea to revive this tread Wink

My interest was to make myself a Philips Service Test Cartridge (STC) for MSX1 from the same Hans Otten site.
Instructions are extremely minimal, no offence, better minimal than nothing. It just shows a drawing how to connect the components, nothing more, and a download for the 16k ROM image, which is great!

I soldered all components to a MSX generic PCB, soldered wires between the the 3 components, ROM, 74LS74 and 74LS32 and inserted this PCB in my Philips VG-8010 but nothing happened. The 'Repair Method' manual mentioned to put +5V onto pin 20-IC663, which is the onboard ROM. I imagine this is to disable the onboard ROM and boot from the external ROM. But still nothing happened.

I believe, there are some components missing on the drawing and more questions arise:


1) Has someone tried this before and made it to work ?
2) Do I need a 27C128 ROM, as I burned the 16k image 2x into a 27C256 ROM
3) Aren't there any Caps needed?
4) Is the drawing showing resistors between the data lines and ground ? Each line a resistor ?

By st1mpy

Paladin (947)

st1mpy's picture

22-11-2020, 21:50

If you post a photo of your board, may be someone can help?

By st1mpy

Paladin (947)

st1mpy's picture

23-11-2020, 20:21

This proto board doesn't have sw1 and sw2 connected together, that would make the cart do nothing?

By st1mpy

Paladin (947)

st1mpy's picture

23-11-2020, 20:40

And the rom appears to not have 5v and ground.
Are all the other rom pins connected up? If you sketch out again the schematic (that you built on the board) I think people can help you add the decoupling caps etc.

By ducasp

Paladin (712)

ducasp's picture

23-11-2020, 20:41

st1mpy wrote:

This proto board doesn't have sw1 and sw2 connected together, that would make the cart do nothing?

Not exactly, but some MSX won't detect what is in the slot if SW1 and SW2 aren't connected, but it seems that VG8000 and 8010 have no circuit connected to those pins, so this shouldn't be an issue for those computers if the service manual is correct....

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