Chroma 81 and vLA81

[Lardo Boffin]

Does anyone have a Chroma 81 attached to a zeddy using a vLA81 ULA?

My rebuilt zeddy (https://www.sinclairzxworld.com/viewtop ... 533#p27533) has a vLA81 and when I connect the Chroma 81 I don’t get a screen output. The Chroma works fine on other zeddies.

I wonder if it is the fact that it is rebuilt that is causing issues or maybe being incompatible with the vLA81? I don’t think I had tried the Chroma with it before as it produces a very nice composite output anyway. This zeddy also has a switchable ROM.

Having seen 3D Monster Maze in colour I fancied a go at it but can’t on this zeddy. Ok, I have ‘one or two’ others but this is my main zeddy.

[Lardo Boffin]

Bump.

[Fruitcake]

Have you tried swapping the vLA81 for a real ULA in that ZX81? That would prove whether it is the computer itself or the vLA81.

[Lardo Boffin]

Have you tried swapping the vLA81 for a real ULA in that ZX81? That would prove whether it is the computer itself or the vLA81.

I tried another ULA and it still didn’t work so I guess its the computer. To be fair it is the one I rebuilt from scratch!

[1024MAK]

Test the connections between the edge connector contacts and the destination of each circuit (e.g. to the Z80)...

Mark