Sinclair ZX80 / ZX81 / Z88 Forums

Well, if you take away the cooling pad and desolder the modulator you might be able to put the ZX81 PCB upside down into the top right corner the connections could be in the correct order for power and tape. If you resolder the modulator to the bottom side of the PCB it might nearly line up with the...

Moggy wrote: ↑Wed Feb 21, 2024 10:44 pm Just thought it might be of interest.

Hi Moggy,
I think it is of interest and as it's still fresh, could you please add some links for interested people to those pdf in the forum and also to the four resistor add-on.
Oldies like you and I know, but there are newbies out there as well

I can't work those CAD programs but a 3D printed ZX81 top case with the added ZX80 hood would be a funny thing to own

I wish you success with the AV conversion.
Please make sure which Modulator and video circuit you have.
There are UK US and French models as well.
Please compare with the circuit diagram.

(Pseudo)static RAM chips can easily be tested with a retro chip tester.
I don't know who in the UK owns one and would offer to test your chips.
I have one but living in Germany postage would be ridiculous.

I haven't checked the poke. But you have to execute NEW instead of clear. There is a way to reduce it without retyping: Reduce RAMTOP to 2K and new. Now you can load from wespi. After this execute CLS, then save again. The ZX81 collapses the screen if less than (not exactly shure) 3K of RAM is avail...

If you want to make files for the 1k ZX81 its a good idea to lower RAMTOP before programming.
This way you get a collapsed DFile

No need to worry.
Zxpand disables romcs which ist used with a ROM mod.

On the other side deactivated listings during absence are a sign of good sellers

https://www.ebay.de/itm/176099977330
Is the product.
I have no experience with this seller.
I normally buy at the seller
gc_supermarket (247002) which is on holidays until 16th of February