Follow

Who knew such a little computer could be such a big pain πŸ™„

Β· Web Β· 5 Β· 1 Β· 3

Well RAM is ruled out. I think I am dealing with a bad ROM. D3 off the ROM seems to have lots of 0's. Also I am told there are HALT instructions in the rom code but the /HALT pin never drops on the Z80. What ever code it is executing sure doesn't seem right. Sockets installed. Ordered a 2364 to 27c64 EPROM adapter from RETRO Innovations. Now to wait for the mailman 😴

Show thread

Well I got a EPROM burner and rigged it work on the 2364 rom I pulled. I see 8 bytes that don't match the ROM images I find on the internet. I put my read image in an emulator and it never boots. The live memory map shows it stuck in a bootloop at about the same rhythm I am seeing on the scope. I think I am on the right path 🀞

Show thread

@junkman All computers are a pain. That challenge is what makes them so fun. πŸ˜€

@publius Ya thats the plan. The ZX81/TS1000 boards are not the most study things so I want to minimize the amount of times the iron touches it.

@junkman
It verily appears to me that you're outputting with the horizontal & vertical transposed!

@junkman folks who had them in the early 80's? (:

(Still have mine, just, not here. Need to get it here.)

Seriously, though, getting a proper keyboard for this was ... pretty much impossible; yes Memotech made one, but it wasn't readily available and cost more than the machine, tv, and tape recorder (which is what I had money for.) My dad bought a keyboard for me - which came from some mainframe or something - and while it had keys, it had no... I couldn't solder and it just... yeah. He was rather upset that he'd not been able to help, as he knew I really wanted a proper keyboard -membranes are just crap...
But, well, I did do a lot with it despite it being such a pain (:

@Truck Ya I thought the CoCo1 "chiclet" keyboard was bad. The ZX81 one is next level πŸ˜†

You could always get/make one of these zx81keyboardadventure.com/2019

@junkman I could now; and likely will; but back in 1985 that wasn't an option (:

@junkman ❀️ I loved my old TS1K. So many hours spent loading programs from tape and arduously keying in new ones on that membrane keyboard. Dad thought I was nerding out too hard so he put a literal axe through mine. Good to see at least one has survived this long!

Sign in to participate in the conversation
Mastodon @ SDF

"I appreciate SDF but it's a general-purpose server and the name doesn't make it obvious that it's about art." - Eugen Rochko