tep392

I've only run this on a real 800 so far. The drive is emulated with SIO2USB for the moment because I haven't had a chance to put it on real floppies. It looks like Larry has got this running on an XL machine HERE. It should be pretty easy to trace the boot process with an emulator. I'll take a look at it later. LOMEM is set to $0e04 with ROMDOS loaded. I took a brief look at the area from $700-$e04 and there are just a few bits of code with mostly empty space for the buffer I would guess.

I checked DOSINI and DOSVEC and they are $CD38 and $CCB0 respectively. Maybe that is what it get's from the boot sectors. I don't know much about the DOS boot process. So it seems an added benefit to ROMDOS is some extra space on a boot disk.

Here's something interesting I found. The disk from bob1200xl is a single density disk with DOS.SYS, DUP.SYS, DUPR.SYS and AUTORUN.SYS. I formatted a double density disk and wrote the DOS files to it and all it has on it is DUPR.SYS. When I boot the disk, it reads sectors 1-3 and 361 then goes to the READY prompt. When I type DOS, DUPR is loaded as expected from sectors 4-26. I'm not quite sure how that boot process is working.

I thought I would post my success on getting ROMDOS to run on my 800. I started with the 0.1 binary that Curt linked to in the first post, though I had to get it through the Wayback Machine. I burnt it to a 2732 EPROM and put it in the $C000 slot of my Ramrod. After a lot of searching I found the ROMDOS 0.1 disk posted by bob1200xl HERE. And the result is 36106 bytes of free memory with BASIC. This is compared to 32433 bytes with MyDOS 3.011 loaded. Seems like a lot of effort for an extra 4000 bytes. Finally, I'm posting the DOC that is on the MyDOS 3.011 disk because it does talk a bit about ROMDOS. MyDOS3.011_Manual.txt

I just picked this 800 up from Ebay. I paid more than I would have liked but I was really after the goodies inside of it. It came with an Axlon 128k RAMDisk card and a Newell Ramrod with OSN6, Omnimon 8K and a Fast Chip. I figured out the functions for all the switches too. This must have been owned by a serious hacker. The final surprise was the pre-sally CPU card with a 65C02. Switch functions: 1) select U and L banks of Omnimon 8K 2) CPU reset 3) bypass cartridge door switch 4) write protect left cart slot. Must have been used with a RAM cart.

I just ran across this topic as I was searching for information on these plungers. I bought an 800 from an AA member maybe six years ago that didn't include the keyboard. I was able to get a NOS keyboard from Best Electronics which is the yellow plunger Stackpole type. The keys all work smoothly and I haven't had any problems with it. Out of curiosity I pulled a few of the keys to look at the mechanism. Several of them do have small cracks but they are tight in the plungers. The plungers pull out with the keys when I remove them. Anybody try these? I decided to order a set, 75 pcs, to see how they work out. https://www.ebay.com/itm/155123593241

Mine is an 8K EPROM with pull-up resistor on A12 and a switch to ground. I put it in a 24 pin socket and then in my burner set for a 2732. I dumped each half separately then concatenated the files.

I dumped the 8K Omnimon EPROM from my Ramrod. I would be curious to know if it matches the one on reifsnyderb's board. I could not find any previous dumps so posted mine here.

I just dumped an 8K Omnimon L+U so will leave it here. OMNIMON8K.BIN OMNIMONL.BIN OMNIMONU.BIN

The Fastmath chip is interchangeable with the Atari chip, so you should be able to get the pinout from the Atari OS board schematic. The difference is probably chip enable is active high instead of low.

Just picked up this 800. It has numerous switches and there are a few mods visible through the vents that I’m looking forward to investigating. EDIT: switches are for 1) Omnimon U+L bank selection, 2) cart door switch bypass, 3) CPU reset, 4) left cart write protect The computer also had these in it, which I've tested and they work perfectly. Axlon 128K Ramdisk and Newell Ramrod.

I found it in the Omnimon 8K manual. Also, I was wrong about the switches. There is just one connected to the Ramrod and it's used to switch between the upper and lower banks of the 8k Omnimon.

Mystery solved. Ramdisk Hardware Modification A very useful modification can be made to your Ramdisk board to make it much better behaved. It will save you from having to •flip the switch on the Ramdisk in order to run software which loads into the $FC0—$FFF range. As it stands. writing to this address range will cause Ramdisk banks to be switched in in place of user memory. This usually causes the program to crash. This mod disables the $FC0—$FFF range and doubles the other select range from $CFC0-$CFFF to $CF80-$CFFF , which should cause no problem. If you do this mod carefully it will probably not affect the warranty but it is best to check with AXLON to be safe. In the past they have recommended it. 1) Locate pin 18 on the card edge of the RAM board in the front RAM slot (the slot just behind the OS board) . It does not matter what type of RAM board this is (16K or 32K) . Follow the etch back to a convenient place to solder (perhaps the pin of an IC) and solder one end of a 6" wire to this spot. On an ATARI 16K board this would be Z501 pin 1. 2) Locate the 74LS133 IC on the Ramdisk. Solder the other end of the wire to pin 1'5 of this IC. Referring to the diagram bel ow , make the indicated cut on the underside of the Ramdisk board and the mod is complete.

The wire goes from Z501, pin 1 on the 16k board to pin 15 of the 74LS133 chip on the Ramdisk. There is also a cut trace near the wire.

Claus, I just bought an 800 with a Ramrod OS board and the same Axlon 128k board with identical blue bodge wires, so they must have come from the factory that way. Mine also has a white wire connecting it to the 16k board in slot 1. I have no idea what the owner did that for. He also has four different switches installed in the 800 that I haven't investigated yet. Two switches go to the Ramrod, which has a large ROM in the C000 slot, so I assume they are to switch between four different versions of Omnimon and maybe Omniview. I'll be dumping them soon and then testing to figure out what they are.

Thanks! That would explain it.

I just discovered that the CPS disk tests don't work with my Super Archiver/Bitwriter or Mini-speedy drives either. I would have thought that the SA drive would work since it wasn't "opened". It doesn't even start the drive motor for the speed test. Almost like Atari made it intentionally not work with the modded drives.

Turns out the World Storage mechs use a different package for the sensor, so the OPB840 type wont fit. I discovered that it can be pulled apart, so I'm going to try replacing the bad LED and see if that fixes it. I was able to check the photo transistor works by shining my phone's light into it.

I'm glad I found this. Tonight I learned that accidentally swapping the J1 and J10 connectors will kill the track 0 sensor.

Thank you for the sales you have sent my way!

I added this update to the first post. 8/12/2022 Update: I have decided to stop selling the physical carts of this game. I'm out of the boards and don't have any interest in continuing to produce these in small quantities. I will continue to offer the serialized A78 file for $10 to use on emulators or multicarts. I have been working on Donkey Kong Remix (see my avatar) on/off for a few years and will hopefully finish it some day. It's a nice enhancement of the original game with more screen variations to keep it interesting.

I occasionally buy original 5.25" floppy software and I would say 95% of them are still fully readable. The NOS games I have bought worked 100%. I've purchased a bunch of blank NOS Athena disks produced back in the 90's and they all work very reliably. It depends on how well they were stored, but it's really amazing how reliable these old floppy's can be.

I just noticed this again when I booted a disk with the wrong driver. I now realize that I'm not seeing a line moving across the bottom of the screen. The cursor has moved into the status line and I'm just seeing the top edge of it due to overscan. The cursor seems to be stuck in the status line and can only be fixed with a reset.

Anyone here ever use the Atari Macro Assembler with Omnimon installed in their 800? I'm having a problem with it going into the monitor during assembly. I've tracked it down to an instruction located at 37CD, which is changed during assembly. I've seen the instruction change between CLD, NOP and BRK. I didn't do any further digging, to see why this happens and if it is some kind of bug. The vector for the BRK instruction points to the standard PLA/RTI in the OS, unless Omnimon is enabled, so I don't think the BRK was intentional. Of course this causes the monitor to be triggered. My work around is to switch off Omnimon during assembly, but it's a bit of a pain because I have to remove the cover and shut down the machine. I was just curious if anyone else has experienced this or knows anything about it. Thanks!

I did a little modification to my Axlon compatible 512k. I added a battery and a DS1210 non-volatile memory controller so that it will retain its contents after a power cycle. This screen shows the contents of DO: were intact even after I removed the board to photograph it. I can also boot other programs, and as long as they don't touch banked RAM, it will retain the files when I reboot SDX.