ClausB

My friend had an early GN. The ECU used a standard EPROM for performance tables. We modified them to get better track times. Now he designs racing ECUs for a living.

To check the caps, remove all the chips and then use your multimeter to measure resistance between +5V and Gnd lines. It should read high resistance, > 10 kOhm.

Did you check the caps for shorts?

I held out until 1997! At work I had the latest PCs and fast internet so I would surf there after hours. My Ataris served me well enough at home. By '97 I had a toddler ready to play with preschool programs and another on the way so it was time to upgrade. That year my company downsized and dumped their '486s so I grabbed a low profile one with W95 and a dial-up modem. It made a good family PC for several years. I recall New Year's Eve '99 when I teased the kids to stay away from the PC at midnight in case it blows up. Really had them going!

In my senior year my high school bought two Altairs, each with 16K RAM, no ROM, and serial and cassette interfaces. To boot from cassette we had to toggle in a short boot loader program. Once BASIC loaded we typed on terminals and forgot about the switches and lights. There were two terminals, an ADM-3 CRT/keyboard, and an ASR-33 teletype with paper tape. Those were the days!

That's clever, just reading the high and low bits. How did you determine whether the POKEY counter behind K5-K0 is binary or polynomial?

There was no adult in charge that day, believe me.

In '92 a friend and I flew my plane over Monument Valley and circled one of the narrower buttes part way up for fun. Then we buzzed the top, and WHAM we hit the column of rising air pretty hard. Dumb kids!

Looks like another 1979 unit. Please verify with a photo of the numbers imprinted on the rear underside, like in post #187 above.

Thanks, it was happy. My daughter's graduation from veterinary school, and my wife's birthday!

Ad says it can display on a TV screen. What does that look like?

ACE80 uses 12.4K, because it's a resident E: device. 7.7K display, 1.9K character buffer, 1.0K character set, 1.8K code.

The original PRANTIC does Epson Graftrax in monochrome. I suppose the ESP code could be made to support other printers using GRANTIC.

The standard 800 has 56 kiloheptads of RAM while the 800XL has less than 44 kiloslabs, so I doubt it would help.

Nice work! You can avoid wiring to the motherboard by plugging into the second RAM slot. There you get all your signals except one, and that one you get from the OS ROM board in slot 0. Slot 2 has A0 - A13 and /S2 - /S5. Slot 0 has A15. So your /CE would be A15 AND /S4 AND /S5. Your A14 would be /S2 AND /S3. That gets you 48K. So you don't need /S0 or /S1, and the /S4 and /S5 you get from slot 2 are already disabled by inserted cartridges. Of course banking is more complicated (I recommend the Axlon scheme) but the point is you don't need anything beyond what's available in slots 0 and 2. Here's how to modify that Axlon-compatible SRAM board linked above so as not to need any 16K boards:

Looks like a variation on the David Byrd mod.

ACE-80 disk files, including original text for the manual above and for the tech notes mentioned in the manual:

@jcbstein When were you in CHAOS? I was there from founding through 1983, and occasionally after.

Certainly rare. Valuable? I don't know. Many 8K boards were converted to 16K in the day, a fairly simple mod. Every club had a guy who would do it for members. Some shops would do it for a price. One down side of those boards is they have tin contacts instead of gold, so they're prone to corrosion.

Another 1979 800, will be #4 in the list:

Awesome! Cover art by Karlis Adamsons.

Hope the music's good, cuz that drawing sucks on every level.

Wow, I read those old threads and see that my excuse was my robotics team coaching, which has been quite a time sink, though a rewarding one. Well I'm retiring from that after 12 seasons, so I should have more free time now. But is it too late for this project? How useful would this enhanced S-video thing be nowadays?

@jeffpiep PRANTIC could do that. PM sent.