Sinclair ZX80 / ZX81 / Z88 Forums

That does work for open spaces, however, if there is an object in the space it will stop.

For example add

: CIRCLE 90,85,20

after the other circle command and you will see what I mean.

Looking for a graphic fill routine in 100% BASIC, saw this which is clever as it uses the GOSUB stack. It works well but gives 4: Out of memory errors as it uses a lot of memory for big or complex fills. 5000 PLOT x,y: 5010 IF NOT POINT (x+1,y) THEN LET x=x+1: GO SUB 1000: LET x=x-1 5020 IF NOT POIN...

The AM9016 and 4116 (and MM5290) chips tends to be unreliable due to the 3 voltage set up. the old Williams arcade games (like Defender) used these chips and most repair guides they replace the 4116 chips with 4164s mainly as 4116s fail to often. By getting rid of the 9V input and desoldering all th...

As i don't have the budget to buy another ZXpand and I was thinking of dedicating a unit to ZX81 / Spectrum homebrew games. I was thinking of looking at ways to load games onto a ZX81. On other machines like the Spectrum, it is possible to turn a .tap file into a .wav, copy this to a decent MP3 play...

Because emulators are a cop out. If you go to a museum you want to see original items not faux copies of items. LCDs TVs and emulators are horrible. In the exhibition I help run, 98% of the 150 odd games (and soon to be 180!) we have run on original hardware with the screens they originally came wit...

Thanks for the suggestions. The unit will be mounted to a shelf in a unit and a wooden front will cover everything behind the ZX81 logo will be hidden out of sight. The only add on I will be using is a ZXpand. The power I would probably route via the back of the machine so I can mount it like this w...

I will have a ZX81 (with a ZXpand) in an exhibition, it will be running 8 hours a day, 7 days a week for 6 months. So I want to do everything I can to make it run cooler so it will last that long. So any suggestions on what I can do to bulletproof it? Would adding a larger heatsink to the 7805 help?...

Me personally, am based all over the world, depending on where this exhibition is. However the units will be sent to London. If you could test one then that would be great. I only really need the loose unit as I have lots of PSUs and RF cables. The other ZX81 if it works then it is a bonus, but othe...

I am after 2 ZX81s for a museum exhibition, I plan to use one with a ZXpand and use the other one (which should be in reasonable condition) with a ZX Printer for a display.

Hopefully I can get two reasonablely cheaply...