Titan QX-PC clone

[brijohn]

So some time back I as able to acquire a version 2 Titan QX-PC card for my Epson QX-10.

I have used that card to reverse engineer the schematics or this card as well as dump the firmware and decode the PAL chip used on the card. This has led me to create a clone of the card that has been updated slightly so that except for the actual 8088 chip as well as its clock generator, the 8284, all the chips are still being produced. One of he biggest changes has been that instead of using separate memory boards populated with DRAM modules I am simply using a single 512k SRAM chip. I've also removed the use of the 82S129 BPROM used for address decoding in favor of a 16v8 GAL.

One minor issue is that my card did not come with the software to boot the card and the only version online seems to be for the version 3 card. However a slight modification of the V3 software will allow it to boot a V2 card and things seem to work correctly.

If anyone has access the the V2 Titan software it would be helpful or if there is anyone with a V3 board I'd be interested in figuring out what the hardware differences are as well as getting a dump of the V3 BIOS EPROM from the board.

Board Design and Firmware: Titan QX-PC Clone
Disk Images: CP/M Boot Disk, MSDOS 2.11 Boot Disk

 

[Add-ERA]

Hello I recently got a QX-10 and was lucky enough to find a QX-PC card in it. I had disks made with the image for the QX-PC software on your GitHub page, but I haven't been able to get it working and was wondering if you had any tips for troubleshooting? When trying to boot the disk it will start loading CP/M, but then it errors out. When I boot into CP/M I can read the disk fine. I'm not sure what revision of the QX-PC card I have so I don't know if the software is for the wrong version. Thanks.

 

[brijohn]

Hello I recently got a QX-10 and was lucky enough to find a QX-PC card in it. I had disks made with the image for the QX-PC software on your GitHub page, but I haven't been able to get it working and was wondering if you had any tips for troubleshooting? When trying to boot the disk it will start loading CP/M, but then it errors out. When I boot into CP/M I can read the disk fine. I'm not sure what revision of the QX-PC card I have so I don't know if the software is for the wrong version. Thanks.

Hmm it seems that something is wrong with the boot tracks when you wrote that image to disk. I know the image will boot successfully in mame, and i also have booted it on my development QX-10 that uses a gotek as its boot drive. So i'm not sure why it fails after writing it to a disk.

Try making a copy of your working boot disk that will boot cp/m on your QX-10 using copydisk, then once you verify that can boot properly put the qxpc disk in drive B and copy its cpm2.sys file onto your boot disk copy in drive A (along with the qxpc.com file. Now try booting the system again and hopefully you will have a working boot disk with the correct CP/M version on it.

Its cool that you found a QX-PC card in your QX-10 though looks like it even comes with two memory boards. It looks like its version 2 judging from the chip layout i can see from the top down view but its interesting that only some chips on it seem to be socketed. On all of the version 2 boards I've seen all chips are socketed.

 

[Add-ERA]

I can't copy CPM2.sys over, getting an error saying there is a bad sector on the disk. I had the disk made by an eBay seller since I don't currently have a way to make any myself, but they didn't normally do CPM disks so I can't say I'm entirely surprised there are issues. I have a gotek, but I'm at college and it's back home so I'll probably just have to wait till I get back to fix this. Ordered the disk because I'm impatience and didn't want to wait. Thanks for your help.

 

[brijohn]

I can't copy CPM2.sys over, getting an error saying there is a bad sector on the disk. I had the disk made by an eBay seller since I don't currently have a way to make any myself, but they didn't normally do CPM disks so I can't say I'm entirely surprised there are issues. I have a gotek, but I'm at college and it's back home so I'll probably just have to wait till I get back to fix this. Ordered the disk because I'm impatience and didn't want to wait. Thanks for your help.

Ok it sounds like the disk may not have been made correctly, espeically if you are getting a sector error while trying to copy the cpm2.sys file. I'm not sure what was used to create the disk from my image file, but the disks for QX-10 are slightly odd. The first two tracks (the system tracks) are are 16 256 byte sectors, while the rest of the disk's tracks are 10 512 byte sectors. So depending on how the image was written back things might not end up working correctly. Its also possible the disk the image was written to just has some bad sectors on it it as well if there are actually bad sectors in part pf the cpm2.sys file that would explain why the copy fails as well as the boot fails. either way it does appear your disk image might be corrupted in some manor.