Hi fellas,

I'm trying to upgrade my Yamaha CM5XII/128 computer to MSX2 standard. I did search the board, as well as look up the information on www.hansotten.com/. While it's helpful, it's a bit confusing, so I'd like to find someone who performed the conversion and can help me out with advice.

First of all, I can see that motherboard has four DIP-18 sockets for VRAM, and only two have dram chips (2x416 = 16Kbytes). Noise filtering capacitors are already preinstalled next to empty DIP-18 sockets, so I guess that's all... If I am to desolder two 416 chips and solder four 464, is that all I need to do for VRAM upgrade?

Next thing: there are two ROM chips on motherboard, both socketed: one is 16Kbytes and the other is 32Kbytes. It's a bit of the overkill for MSX1 computer without internal disk drive, so I'm just curious, what is the content of this ROM ICs? I guess I have to build a programmer and burn MSX2 ROM images in them, but I need to know more in advance...

The third thing I'd like to do is RGB output. The video out board in this US model only supports RF and composite. It does have the place for RGB DIN socket and holes in PCB for extra components. I'd like to know if anyone can send me a picture of european videoout PCB, so I can see how the jumpers are soldered and transistors are placed.

The last thing I'd like to do is to mod the RAM board to support 512Kbytes (probably 4 x 44256 DIP-20 dram ICs) instead of standard (8 x 464 DIP-18 dram ICs). Anyone did this in past?

Maybe Erik Lie can help you, He has a homepage dedicated only to the Yamaha-CX5M
Here you have is adres.
home.online.no/~eiriklie/CX5MFAQ.html

Erik's page is more about using and programming CX5M computers.

This page is a bit more "technical", but still, it's just specs and links to service manuals on funet.fi from Hans Otten collection.

This is why I'm hoping to find someone with practical experience. If I won't find such a person, I'll just try my best and hope I won't destroy my CX5MII/128

Quote:

Erik's page is more about using and programming CX5M computers. This page is a bit more "technical", but still, it's just specs and links to service manuals on funet.fi from Hans Otten collection. This is why I'm hoping to find someone with practical experience. If I won't find such a person, I'll just try my best and hope I won't destroy my CX5MII/128

I received much of the published CX5M information about the Yamaha CX5m from Jipe, Jean-Pierre Dubois, a guy from France. He did visit the comp.sys.msx newsgroup, the last time in june 2004.