Sinclair ZX80 / ZX81 / Z88 Forums

Love the $1.95 "phone order credit".

Looks fairly decent quality for what it is. I bought one that had stickers that you applied to each key, and the action wasn't much better than the membrane keyboard. Complete piece of junk. I eventually got a Memotech keyboard, which was great. Unfortunately I loaned it out to somebody 20 years ago...

"Factory sealed"?

Was that the A&J Microdrive? I think it was a re-branded Exatron.

Missing ROMs? Sorry about that. Like I said, I only used it for the ESF drive. Looking through the schematic, the I/O board has an 8250 UART and an 8255 PPI on it. I think these were fairly standard parts for the time. The parallel port was used for communicating with the ESF, but is not limited to ...

It was great to talk to different folks and reminisce about playing with ZX81s. The CAI/O board and ESF are on their way to a new home in Texas (ironically where dug them out of my parents house at Christmas after 30 years). Thanks to everyone who was interested.

Manuals and schematics for CAI/O board and ESF drive. CAI/O: https://c1.staticflickr.com/1/724/31999323813_5eed9ec002_o.jpg https://c1.staticflickr.com/3/2276/31970742034_33657c2bd0_o.jpg https://c1.staticflickr.com/3/2344/31999329163_cdf55631cf_o.jpg https://c1.staticflickr.com/3/2839/32813491295_a...

I'll try to scan the manuals and post them here in a few days. There are even schematics, though the one for the CAI/O board isn't very legible. To operate the Exatron drive, I had to open up the CAI/O and install an EPROM chip into a socket. At 13 years old I was terrified of breaking something, bu...

It's been fun to pull out my old ZX81 and see that it still works, but I've decided I don't have the time to devote to doing anything with it. I have a couple of pieces of hardware that might be of interest to those still working with Sinclairs. I have an Exatron "stringy floppy" drive and the CAI/O...

It's alive! When I got it first put back together, only 3/4 of the keyboard worked. I found this video, which shows how a tear can develop in the keyboard cable. Sure enough mine had that tear. I cut the cable back, re-attached it, and success! https://www.youtube.com/watch?v=LO-m4W95h74 I tried a c...