Another rare brazilian coco clone...

[zephyr]

I only know another person who has this machine and it have keyboard problems.

Is there any chance of getting a ROM dump from that machine (temporarily put the EPROM chip in your MX1600) so we can check to make sure that the ROM code from yours has not been hacked and rewritten to the EPROM by a third party?

I would be very surprised if that MEM function hack was done at the factory.

[sixxie]

Using PAL-M as you do, do you get the same sort of artifacted colours as NTSC? The colour subcarrier looks like it's *very* close...

I want to add a "-tv-type pal-m" option to XRoar, and wonder whether that should default to NTSC-style artifacting (ie be treated identically) or not (turn off artifacting by default, but run the VDG at 60Hz).

[Dantyr]

I only know another person who has this machine and it have keyboard problems.

Is there any chance of getting a ROM dump from that machine (temporarily put the EPROM chip in your MX1600) so we can check to make sure that the ROM code from yours has not been hacked and rewritten to the EPROM by a third party?

I would be very surprised if that MEM function hack was done at the factory.

Steve, very unlikelly to be rewriten, because the other machine has the same label with an "MX" marked on the EPROM. That is the one from Dablio (the other known owner of a MX-1600):




Note that the label is the same on my own MX-1600:



It most certain that this MEM hack was done on factory yes. Probably was a loose try to use as a marketing tool to show that the machine have more memory available to BASIC than the others (it's only a suposition, we have no information that sugests that whatsoever)
I raise that question on the brazilian coco list, but very little is know about this machine as it was launched too late on market and on the same year that the MSX "invaded" and "raised" the market for all others 8bit platforms in Brazil.

Daniel

[Dantyr]

Using PAL-M as you do, do you get the same sort of artifacted colours as NTSC? The colour subcarrier looks like it's *very* close...

I want to add a "-tv-type pal-m" option to XRoar, and wonder whether that should default to NTSC-style artifacting (ie be treated identically) or not (turn off artifacting by default, but run the VDG at 60Hz).

Oww, but both my Color64 and the MX-1600 were modified to have composite video output on NTSC. I changed the cristal oscilator for the NTSC one and removed all transcodification circuitry that existed on PAL-M.

Normally, PAL-M Cocos have artifacting yes but a combination of green and blue, instead of orange and cian, like an american Coco. See the zaxxon running bellow on a CP400 on PAL-M:





Now on my Color64, modified to NTSC:





Regards,
Daniel

[Dantyr]

Unfortunatelly, I don't have any of the CP-400 models to confirm that.

I confirmed with the friends of the brazilian coco list that CP 400 models I and II, both used two 2764 EPROMS.

Daniel

[Dantyr]

Besides that, the remaining brazilian clones to be dumped would be the following:

CP400 Color II (Brazil)
Varixx VC50 (Brazil)
Codimex CD6809 (Brazil)

Keep up the good work!

Edit:Sent the current Brazilian clones roms to MESS

Robcfg,

I think there is no difference on the CP400-I to CP400-II in terms of ROM modifications, but I will validate that for you.

Codimex is my next target for acquisition Very very hard to find too...

https://picasaweb.google.com/1035297112 ... directlink

I know another person who have one in working condition, and will try to convince him to bring to the next TRS meeting this year.

Varix VC-50 is a "myth" machine...nobody have seen one. We know just for the photos from his launching on the international computing fair of 1983:



Varix VC-50 and the fabled prototypes of TK-S800 from Microdigital (bellow) are the "holy grail" of our search here...



Daniel

[sixxie]

Oww, but both my Color64 and the MX-1600 were modified to have composite video output on NTSC. I changed the cristal oscilator for the NTSC one and removed all transcodification circuitry that existed on PAL-M.

Normally, PAL-M Cocos have artifacting yes but a combination of green and blue, instead of orange and cian, like an american Coco.

Interesting! It occurred to me on the train home today that the PALiness of it would affect one component of the colour anyway even if the artifacting was the same otherwise...

Out of interest, what crystal did you replace? Did it have a separate colour crystal, or did they just use a 14.302MHz to clock the SAM (which would give *near enough* 64µs scanlines and *near enough* 60Hz refresh... actually I have no idea if that would work well ).

[Dantyr]

Oww, but both my Color64 and the MX-1600 were modified to have composite video output on NTSC. I changed the cristal oscilator for the NTSC one and removed all transcodification circuitry that existed on PAL-M.

Normally, PAL-M Cocos have artifacting yes but a combination of green and blue, instead of orange and cian, like an american Coco.

Interesting! It occurred to me on the train home today that the PALiness of it would affect one component of the colour anyway even if the artifacting was the same otherwise...

Out of interest, what crystal did you replace? Did it have a separate colour crystal, or did they just use a 14.302MHz to clock the SAM (which would give *near enough* 64µs scanlines and *near enough* 60Hz refresh... actually I have no idea if that would work well ).

There is no separate crystal for video. it only uses one for everything. PAL-M is 14.302445Mhz and NTSC is 14.31818Mhz.

Daniel

[sixxie]

Cool, that sounds sensible.

[robcfg]

New version of MESS released:

Code: Select all

0.148u1
-------

New System Drivers Supported:
-----------------------------
- NEC TK85. [Robbbert, Nama]
- Chunichi ND-80Z. [Robbbert, Nama]
- BINBUG [Robbbert]
- DG680 [Robbbert]
- LZ Color64 [Dantyr]
- Dynacom MX-1600 [Dantyr]

Do you see a familiar name there?

Everybody keep up the good work!