mio2repair

Hello. Note thaat there are a few odd 30 pin SIMs made for IBM PS/2 that had different parity pinout mostly. Could be used if possible pin swap or parity ignored check pinout lists for needed changes if any. Anybody have SpartaDos X cart schematic? Cy

Hello, I wonder what the MUX boards are for? Hope I don't sound dumb. Some kind of cartrige stacking or adding a 6522? ICD 1 meg MIO with case on Ebay or feebay etc. Cy

Hello, I found a rom binary mio11os.bin out there somewhere. Version 1.1 for the 1 meg MIO. Still looking for the 256 k version. It would be nice to test old 256k board with out having to upgrade to 1 meg before getting it to work otherwise. I will have to make a SIO2PC cable to make a utility disk I guess since I can not read the disk that came with my other MIO. I guess it is supposed to be regular 1050 format. My drive reads other disks well.

This is one of the cooler thing about the MIO. You can allocate part of the memory as a ramdisk, format it with SpartaDos and make it bootable. You then designate it as drive 1 in the firmware. When you shut off the computer, the MIO stays powered on (it has its own power supply). When you turn the computer back on, it boots instantly to the ramdisk. This is how I used to use mine until it stopped working. I also have the schematic in PDF form. It is posted in another topic but will attach it here when I get home. Hello, I looked and you mentioned it but I could not find the file attached.

Hello, If those are the ploters I am thinking of they are similar to Radio Shack and Commodore models. There are 1 or 2 little plastic gears that crack in two. I got some once from Radio Shack parts. They might even still have pens?

Hello, Here is a new topic for miscellaneous repair configuration or modification suggesions and questions. The other people do not want their thread filled full of stuff so here is some room. So to start out with is the rom different for the 256 k and 1 meg versions? If it is different what are the differences? Could one byte be changed or a small portion of code? Where is this byte or code address within the rom? Does anyone have the schematic diagram or source code available for aiding in repair or modification? Possible for allowing use of more reliable smaller lighter and more energy saving modern SCSI drives. Who cares if half of the 512 k sectors are not used as the drives available are way bigger and very plentifull and the circuitry would be more simple and reliable. If power is left on on the mio and computer turned off and restarted does the ram still contain valid ram disk data and is it accessable right away? You may post a link to any usefull information you may suggest to be helpfull. I know there are manuals and disk images out there already and maybe even more. Sorry but I am not limited to Atari but am interested in several old 8 bit machines but I see that as a plus as it allows ideas from different machines to be used on each other etc. Thank You That should get something started

Hello, Have you found some 6551 chips? Maybe trade some for a blank board? There is the clock speed of the CPU buss and the clock for the serial buss. The 6551 has its own bit rate generator and other chips like 6850 and 8250 needed external chip circuitry. there may be some newer chips with built in circuitry but may have different internal registers from the 6551 and may need software modified or io remapped to emulate. Could it be an option to leave it out and the rest still work? Thanks

Hello, Did anybody figure out the exact difference between the 1 meg and 256k mio roms if any. I need to figure out which one I have since my board was worked on before and it may be swapped from original. Thank You

Hello, I have some old MIo's to repair. I am unsure what rom I have and would like to know the difference between them what byte is changed to what and also what the schematic is to trace the problems as they have ben attempted to repair by someone else before. If I could get a blank board like you are making just in case there is too much wrong to figure one of these out what would you want? There may be a chance your board will not work with more than 256k. Is there refresh for the high addess lines or is there some reason you would not need to add it? Thank You