Sinclair ZX80 / ZX81 / Z88 Forums

Glad that you are now all sorted

Mark

The ZX81 uses mode 1 (IM 1) so does not care about what is on the data bus. Hence you don’t need to worry about /M1.

Mark

Lots get caught out by the UK700 producing 12V to 16V when off load, and 10V to 12V when on load.

Good that you are making progress.

Mark

Hello and welcome to our forum reanimate!



I hope you enjoy this forum

Nice set of 1980s computers and extra hardware

You are welcome to ask questions!

Mark

Hello and welcome to our forum Staffan!



I hope you enjoy this forum

You are welcome to ask questions!

Mark

The cursor is not likely to be off-screen, more likely is that the video contrast (voltage) is wrong. Hence the K cursor may be there, just not visible. If the picture size was incorrect, I would expect a rolling image, due to incorrect sync. Keep in mind that the transistor type composite modificat...

Ahh, I was going to reply the other day, must have forgotten

As the Opus also uses it's own ROM, has the previous owner fitted or modified the MF1 board with a switch or some other method to disable/prevent it's ROM and RAM from being paged in?

Mark

Hello and welcome to our forum Luke!



I hope you enjoy this forum

You are welcome to ask questions!

Mark

voorsk wrote: ↑Tue Apr 02, 2024 3:34 pm I tried before, and it didn't complain, altho the message is still in my outbox. I can think of a couple more things to post, just in case.

As Moggy says, a PM/DM will sit in your outbox until the recipient reads it. Only then will it move to your sent box.

Mark

You can't force a NMI. A NMI is a non-maskable interrupt which is a hardware signal. Machine code can jump to the address where the NMI routine is, but it's not quite the same. Machine code can HALT the processor, just execute the HALT instruction. But this will not do what you want on a ZX81. I pre...