Retrochallenge – Day 1

Welcome to the start of what I hope will be a productive and fun Retrochallenge. Let me begin by stating my goals for this round of Retrochallenge:

  • Take inventory of my available Atari hardware and software
  • Refurbish or repair anything that needs to be brought up to working order
  • Go through each of the floppies I have for the system and catalog what software might be resident
  • Teach myself how someone would have used the system for general use back when the system was current and relevant
  • Evaluate any productivity software I find on the floppies for my other research projects

On the surface, these seems like relatively simple goals. Hopefully, they will prove to be.


Let me introduce you to the main components of my little project.


I’ll be working with an Atari 800XL, a 1050 Disk Drive, an Epyx 500XJ joystick, a few carts, and a box of floppies with unknown software. For backup, I have a 130XE that I can call upon in case the 800XL proves to be unusable for whatever reason.

All of the hardware was acquired in a lot from Craigslist. The floppies came from an IRC friend of mine in the classic gaming community.

Atari 800XL

I’ve messed around with the computer and disk drives before, but I never really gave them a deep look. The 800XL does have some modifications to the ROMs. The OS ROM seems to be a custom affair, and it’s missing the BASIC chip entirely. Here’s a not so perfect shot, but it shows the basics of what I’m working with.








The computer itself seems to work fine, though sometimes I’ll get a green screen instead of blue on my TV. Banging the machine around a little bit will usually shake it back to blue, but that is something I need to look into once I figure out what can be causing it. I can load most XL/XE compatible carts just fine, and I’ve got a few games that boot and play without issue.

I’ve previously gotten a little bit of help with figuring out the custom OS ROM at this AtariAge post. There was some useful information, but I think I remained more confused than I was before I asked my questions. I’ll be starting from scratch on it now so I’m ok with that. The main change I can see in the ROM is a custom character set. This quick clip of the In-Store demo cart shows it off nicely.

I’ve learned that peeking certain memory locations in BASIC will reveal clues as to what versions of BASIC or the OS are contained in memory. This photo shows the results of a few of these locations. This is also a pretty good look at the custom character set.


As to the character set itself, this is what has been suggested to me by Rybags at the AtariAge forums: “Looks like it’s got the character set as used by Adventure International games like Sea Dragon and Preppie.” I’ve looked up the games and it appears pretty close.

Until I get a chance to pick up a ROM programmer and dump the contents of this ROM chip, I think it would be in my best interest to find an original or replacement with the original OS on it, just to keep things stock. Same with the BASIC chip. Physically, the machine seems stock, it’s just those two pieces I need to get back to reliable working condition.

Atari 1050

The disk drive is one of three that came in the original Craigslist haul. The other two were a Happy modded 1050 that worked perfectly fine once I reseated a few of the chips, and a partial Happy mod that was never completed. I sold those off a while ago to other collectors as the third seemed to be close to stock. Or, that’s what I thought at the time. What can you fine people discern from this picture?


Please, tell me. I have no clue what I’m looking at. Again, the fine folks at AtariAge were able to guess that the previous owner was attempting to do a homebrew US Doubler mod to it. If so…nice!


Alright, now that we’ve identified the important hardware, it’s time to talk about what I’ve discovered so far. Basically, I’m kind of screwed. The drive powers on just fine, it does the initial head seek and tracking. The Track 0 sensor seems to be working fine. When I insert a disk, it does the normal ¼ inch track seek and returns to track 0, but then…nothing. It just spins forever until I reset the computer or pop the latch on the drive.

I’ve checked that all the chips are seated properly. All the cable headers are in the right place. I just get an infinite quick repeating BOOT ERROR message on the TV. I know the drive and the computer are communication though. When I insert a disk and flip the latch, the boot errors will pause for a second or so before continuing. The computer is getting word from the drive that there’s a disk, but the drive isn’t giving the computer anything to work with.

Here’s a short video I made showing what happens with the cover off to show the internals. I wasn’t thinking and filmed it vertically so it’s a bit…vertical.

Just for shits and giggles, I pulled out the 130XE that I know is in perfect working order and tried the drive with that machine. Same response. I’ve tried all 97 floppies I have and not one of them gives a different response. If anyone has any suggestions on what to do with the drive next, I’d love to hear it. Speaking of the floppies…


A friend from IRC heard that I was in need of some SSDD floppies and sent me a box full of them. In all, there are 97 total. The vast majority of them are either copied disks or without a label. Only a few of them are commercial disks. There’s a PQ Party Quiz Game set, and what looks like software that may have come with a Koala Pad. I’ll have to explore those later.

Overall, the disks look like they may have come from a school environment. There are lots of unlabeled disks, but some have handwritten labels that look like children’s handwriting. There are a bunch of quiz type games. Aside from that, there’s several copies of AtariWriter, or least the labels say that. I’ve also seen most of the Syn* series of productivity software. That may come in handy for my other research if I can get them to work.

Of the carts I own, most will work fine. I’ve got a few that are in blank cart cases, and some that are obvious custom chips on the boards. A couple of the carts require OS A/B so I haven’t been able to confirm that they work.  The one cart that made me wonder was Pac-Man. If I turn on the computer with the cart inserted, it goes straight to the self-test. However, if I hold down the Option key, it’ll boot the cart. Dunno, something I’ll have to look into.

Day_1-cart_3 Day_1-cart_2 Day_1-cart_1

Project Scope

So, with all that said, and this deeper look into the functionality of the hardware, I believe I can define the following action items to achieve my goals:

  • Replace the OS and BASIC ROMs inside the 800XL. This will bring me back to a stock configuration and I can work from there.
  • Figure out a final diagnosis for the floppy drive. Without this, the rest of the project is pretty much screwed. It’ll be awhile before I can find another one so getting this one working is paramount.
  • Pick up a ROM programmer. This will let me dump the current ones I have and replace any I need to replace on my own.
  • Find a 5 ¼” floppy box. This is kind of silly, but it’s better than keeping almost 100 floppies in a cardboard box.