Sinclair ZX80 / ZX81 / Z88 Forums

Erm wrote: ↑Tue Apr 20, 2021 4:52 pm You don't by any chance have a very early ULA spare? I have an issue 1 board with a later ULA and would like to revert it to original (with the Spider mod).

Sorry I don’t have one. I bought this mainly in the hope it would have one being a fairly low serial number!

Is the broken trace / gap intentional?

Looks like it lead an interesting life - pretty sure that isn’t the original ULA (the serial number is 001-057303) and also an interesting daughter board near the Z80. Part of the 48K glue logic?

I just got an issue two Spectrum which doesn’t boot, as below. The two lower RAM chips marked with splodges get very hot quite quickly so I’m assuming are faulty? I have a couple of 4116s somewhere but is there anything I should check / change first to avoid them also becoming broken? 7EF8AFF1-9FCC-...

Thanks for the kind offer Chris!

I am banished to the garage to solder so with no heating and temps not getting above 8 deg C today it was probably not the best time to try precision operations. I will wait until it warms up a bit and try again.

Blimey! You have a very large switch sir! I want a switch that will do the same job as the existing one but is physically larger so I can actually solder it. It will be living in my rebuilt zeddy case so it would be cool if it could be mounted somehow to make it accessible without dismantling the ca...

I went to fit another ROMel with multi-ROMs to my zeddy and came to the conclusion the current switch is just too fiddly! I managed to do one a year or two ago but frankly have no idea how I managed it last time. The switch: 4E3CC8A6-FD59-4CA7-B1F9-44FDD30C9CC0.jpeg Zeddy for scale: B0962080-B9EC-45...

Only anecdotal not technical but I have sold a lot of zeddies with ZX8-CCBs fitted and once tuned (to nearly always the same settings) I don’t need to further adjust them. I always soak test the ones I sell for two lots of 8 hours so would notice any warm up effects. The only thing I have seen once ...

Its a hard lesson we all learn at some point I think.

The problem with zeddies is that unlike say a Tatung Einstein, it is easy to lose track of how many you have as they are so small (they slip into drawers and lurk in cupboards) and generally quite cheap to buy. For years I have been trying to maintain my innocence as to the quantity of them I have. ...