The Strange case of a Victor HC-95(a) 512KB!

Page 2/5
1 | | 3 | 4 | 5

By retrocanada76

Hero (540)

retrocanada76's picture

04-06-2022, 19:34

the RGB is a db25 i don't know why they needed so many pins... is the external floppy toghether ?

By sdsnatcher73

Prophet (3809)

sdsnatcher73's picture

04-06-2022, 19:41

No the DB25 has same pinout as RGB21 connector (for pin 1 until 21, the rest is not connected). Possibly gdx mistook the keyboard connector to external floppy drive connector (they look similar). Or maybe some version exist that does have external floppy connector?

By gdx

Enlighted (5996)

gdx's picture

05-06-2022, 02:40

sdsnatcher73 wrote:

Mitsubishi ML-G30 (and as such so does the Hitachi MB-H70) has external floppy unit even if it already has 2 internal drives.

You are right. I confused with the keyboard connector. The Victor HC-90/95 does not have a floppy drive connector at back. Only the Mitsubishi ML-G30 have one despite there being two locations inside.

gdx wrote:

HC-90/HC-95 looks a little too dull but it's a great MSX2. The only thing I don't like much is the RAM not locating in a 3-x slot. If I had one I'd try to swap the RAM slot with the Disk-ROM slot.

It's probably complicated to do this because of the accesses to the FDD registers via the addresses 7FF8h~7FFFh.

By retrocanada76

Hero (540)

retrocanada76's picture

05-06-2022, 04:55

probably it would be easier to make a slot converter for the JVC extend slot and use can put a mapper sitting on slot 2 alone. I guess the connector is this one but I need to make some measurements:

https://www.digikey.ca/en/products/detail/molex/0850421079/2...

By gdx

Enlighted (5996)

gdx's picture

05-06-2022, 10:36

It's maybe possible just to build memory boards over 256kB. That would be a pretty effective solution although, in rare cases, the Bios mismanages slots when RAM less than 8000h is in a 0-x slot.

Alternatively, BMMS or the MSX-DOS2 also bypasses the problem that causes RAM in slot 0-x to prevent a RAM extension from being automatically selected as main RAM.

By sdsnatcher73

Prophet (3809)

sdsnatcher73's picture

05-06-2022, 11:20

retrocanada76 wrote:

probably it would be easier to make a slot converter for the JVC extend slot and use can put a mapper sitting on slot 2 alone. I guess the connector is this one but I need to make some measurements:

https://www.digikey.ca/en/products/detail/molex/0850421079/2421592

I think an angled connector will work better with a PCB:

https://www.digikey.ca/en/products/detail/harting/0903196692...

By retrocanada76

Hero (540)

retrocanada76's picture

06-06-2022, 00:52

I agree with the right angle but I couldn't find a female version :/

By retrocanada76

Hero (540)

retrocanada76's picture

06-06-2022, 00:54

By retrocanada76

Hero (540)

retrocanada76's picture

06-06-2022, 01:12

unfortunately Nextor fails with kernel error 6 when switching Z180.

Sofarun also does not run it exits instantly on z180. Does it really pay using undocumented instructions on these ?

By gdx

Enlighted (5996)

gdx's picture

06-06-2022, 02:14

I remember seeing an excerpt from the documentation for the HC-90/95. It said that the Z80/Z180 switching should be done when the computer is off only. Then several people say that most games that do direct accesses do not work in Z180 mode. Panasonic did much better with the Turbo R.

Page 2/5
1 | | 3 | 4 | 5