Sinclair ZX80 / ZX81 / Z88 Forums

Good Afternoon,

I have posted the following in the German forum.tlienhard.com, but not had any feedback as yet.

I wonder if anyone else has come across a similar issue to mine.

I have an ZX81 Issue 3, the ULA failed so it has been replaced with a vLA81

I have also fitted the ZX-WESPI ready ZX81 composite mod from the following:
https://www.youmakerobots.com/sinclair/ ... it-without

The ROM is ZC M38818P 82 43
CPU is NEC 8234XD D780C -1
RAM is MOSTEK MK14118AP-72

This works and provides a nice solid screen output.

I have an ESP-WROOM-32 ESP32-S Nodemcu ESP32 Development Board which is programmed with zx-iot-mi
https://github.com/holmatic/zx-iot-mi, this is connected to the ZX-WESPI ready board mentioned above using the connections in the instructions.

When I type LOAD "" on the ZX81, I get lines on screen and the ESP32 blinks rapidly a few times, but I can't see the ZX-WESPI display on screen.

I have tried different combinations of MOD on the vLA81 and the option switches on the ZX81 Composite mod to enable disable capabilities.

Just wondering if anyone has come across this issue.

I have spoken to the Charlie, the creator of the vLA81 and he has said that the vLA81 has been tested with a ZX-WESPI and does work.

Any thoughts appreciated, happy to provide pictures of the setup and the screens shown if it would assist.

Kind regards,

Peter.

Probably an obvious one but are you connected to a cassette player while doing this? They don’t work well with the tape player plugged in.

Less likely given the age of your zeddy but Issue One ROMs don’t work with these.

Lardo Boffin wrote: ↑Thu Oct 17, 2024 6:47 pm Probably an obvious one but are you connected to a cassette player while doing this? They don’t work well with the tape player plugged in.

Less likely given the age of your zeddy but Issue One ROMs don’t work with these.

Thanks, I tried it with the ear and mic cable connected to nothing initially, then I connected the ear and mic alternately to a TXDuino which was set to play.

The only difference is the screen seem to wobble a lot more then a lose the display and the ZX81 seems to reset but goes to a blank screen.

I ran the ZX81 ROM TEST program, result was 855106, 0.5 so it seems to be an 2nd ROM issue 622

When you power up the system, is it with a regular ZX81 power supply?

Does it supply enough power to the ZX-Wespi, so you can connect to the web-interface in a browser?

It is a regular ZX81 power supply.

I will test the power supply voltages and the regulator in the ZX81, the ZX-Wespi is getting it's power from the Composite Mod board which it is wired too.

And the 2nd question is whether you are able to access the webpage, that the Wespi is running?

I can't see the ZX-Wespi screen on the ZX81 to connect it to my Wifi SSID, so I can't get to the webpage.

Unless you can configure the wifi SSID and password manually in a config file for the ZX-Wespi?

You're right.
I was just curious as to whether the firmware was actually working, but it's difficult to see.
Maybe you can record your screen and wespi with your phone while trying to load, so we can compare it with videos of working hardware.
I could upload a hidden video to YouTube for comparison.

The difficult part here is if you have a modern TV, that does not show the black/white lines on the TV while loading a program. Then it wont help much. :'(

Thank you for helping

I'll get a video of the screen and the ZX-Wespi when I initiate the load "" on the ZX81.

Just need to get the power readings as well