Hey guys,

I've just today got my hands on a complete CX5MII/128, and I know there is a simple way to upgrade the CX5MII/128 to MSXII Standard, but EVERY page with the documents has gone under, even cached pages. I've scoured the web for these documents ever since I found out I was getting this computer, but no luck. Does someone happen to have a copy saved? I would appreciate it so much. Now that I actually own an MSX I'll be active on this page, and I'm going to post pics of my machine soon. I know I probably have the crappiest machine on this forum but dammit I'm still proud of it! Anyway, I would really appreciate help here. Thanks guys.

The site where the documents are stored has exceeded its bandwidth limits this month.
It will be back april 1 hopefully.

You lucky one.

I'm working on this too, but found that my cx5mII board is different (easier) to upgrade. It's a CX5M II C and the ic sockets are already powered so It's just a matter of plugging them in.

Seems the most difficult thing is to find a - working - HD floppy disk and write a MSDOS image with promprog because winXP doesn't support my eprom burner anymore... I have to image the original CX5MII bios and fit in the MSX2 ROMS....

grit, buy an old (486 < ) system/laptop from marktplaats and hook on you eprom burner.
They often come with hd floppy's also.
Most burners work great with a 486dx system.

WHy HD floppies?

Manuel: PCs in general use HD floppies. DD floppies are even hard to find!

Although... I recall RemcoZ having several kilograms of DD-disks - he told me on Bussum. Maybe you could contact him?

Well I found a few in the attic which could hold the extra 16KB(!) files for a while, so the Eprom part is now finished, but as you might have read in naother thread I now have a little problem in getting the MSX2 subrom mapped at address $0000 instead of $4000.

see info on hans otten web page

Thanks, I looked through that a bit, I haven't fixed the address part (A14/A15 lines both 0) on the extrom yet, but I found something in the SVI msx2 conversion which I should do on the CX5M too; disable the RTC clock routines because the CX5M-II doesn't have it either. All and all this conversion is completely different from the description you can find on the internet

try this link for CX5

http://www.msxarchive.nl/pub/msx/mirrors/hanso/hwmodsetc/yamahacx5m2msx2.pdf

the rom without clock exist but you can also reconstruct the RTC clock
on a PCB the place of clock chip are present but not IC and it's easy sold
on other PCB no place for clock chip but you can added a little board with IC

Yes, this is the link I mean, my mainboard s is nothing like the mainboard on my CX5M-II service manual or on this link. My board says xb300 and has all videoram on he mainboard itself. I can't see RTC space on that board either.

the schematic is the same only RTC miss
how many size as your video ram and how many IC
if is 16 ko you desold all IC and sold 2 x Ram 64k x 4 but is not same pinout
you can make a little board or sold on PCB with wire

I'm telling you I have a different mainboard... look here:
board:
http://www.rgp.nl/cx5m/DSC00014.JPG
vram section (topleft):
http://www.rgp.nl/cx5m/DSC00013.JPG (before)
http://www.rgp.nl/cx5m/DSC00015.JPG (After)

IC's have different numbers, no seperate 16kb vram stuff

my CX5MII is not the same but i have a friend with a CX5MII with this vram
i conctact for saturday and take many photos with the modification
i have added a clock on additional PCB and 4Mo memory
but i have no schematic and no photo
the clock of CX5MII is the same of VG8235