Sinclair ZX80 / ZX81 / Z88 Forums

[Had posted this incorrectly under Lambda 8300] Hi all, I was finally able to recover an assembler I wrote back in the mid 80s as a kid on my US ZX81. Being a young whipper snapper, of course I didn't document it so I've been trying to recollect how it works by reading through the code. I'm doing a...

mrtinb wrote: ↑Tue Apr 23, 2024 7:04 am Great work, but I think you put it in the wrong section. This is the section for Lambda 8300 specific software, not ZX81.

Oops...thank you for pointing this out. Now I feel foolish...picked the wrong Software section. I corrected it and added the link above.

This message has been moved to appropriate section...sorry, posted it here thinking this was the ZX81 Software section.

https://www.sinclairzxworld.com/viewtop ... f=11&t=5477

I tried creating a Z88-to-Mac cable with those instructions and I get nothing. The Mac DIN-8 connector is a strange serial port but I did find this picture that helps turn it into a normal DB9 (or DE9). Still, that did not help. PC-Link is just waiting and the Mac software never finds the Z88. MacSe...

I'm up to 87K now. I had a second spare motor and that did even better. I'll need to check if it will now read/write files on a QL formatted cartridges when hooked to a QL. Before the second motor swap, it could get the directory listening hooked to a QL, but nothing else. I found the following feat...

Ok, I'm finally at 83K formatted, which is likely the best I can expect. I followed the Byte Delight refurbishment guide. https://www.bytedelight.com/?page_id=1623 So, I changed the two capacitors (0.22uf and 0.47uf) with new ones (two 1uf's). I need to locate a couple of 100pf ceramic capacitors to...

On the motor sits a rubber roller. This can need cleaning and if heavily used in the past it's a good idea to remount it upside down so the tape is moved by the "fresh" part of the rubber. Thank you. I have used two different rubber rollers and cleaned and rotated each. There doesn't seem to be any...

I don’t know. But has the head been cleaned? Does it look worn? If the ULA was faulty, I would not expect it to work at all. Mark I don't think the head is worn and I have cleaned it thoroughly with isopropyl alcohol and a cotton swab. The center part still looks shiny and you can still see the dis...

Does anyone know best way to debug a microdrive. I seem to have a faulty one. When hooked to my Spectrum via ZX Interface 1, it formats a microdrive cartridge anywhere from 2K to about 35K. I can even save and load a program. It's never consistent and mostly settles on between 15 and 20K. The same m...

I got a reply from Charlie: The vLA82 analogue circuitry is fairly close to the later Sinclair ULAs but ended up slightly more sensitive. I'll send you the schematic... Speaking of sensitivity, I also tried my 4th generation ULA (out of 5) with different volume levels (between 70% and 100% at 5% inc...