Sinclair ZX80 / ZX81 / Z88 Forums

All things considered I think I am lucky to have a working ULA out of it!

Are the battery connectors soldered to the correct places does anyone know?

Yes, the wires look like they are connected to the correct points on the ZX81 circuit board. See picture: I do however recommend that a 1N4001 (or a 1N4002, 1N4003 ... 1N4007) diode is wired in series with the +V positive wire. See diagram: This will prevent damage if the input plugs are incorrectly connected

Or you can use any reasonable sized cable with a 3.5mm mono jack plug like this: Mark

Zeddies wired for 5V use are incompatible with an unmodified ZXpand. And some rampacks.

Not important, but noteworthy.

sirmorris wrote: ↑Fri Jun 16, 2017 5:44 pm Zeddies wired for 5V use are incompatible with an unmodified ZXpand. And some rampacks.

Not important, but noteworthy.

If I do get round to making a zeddy laptop I am not carrrying a cassette player around so very pertinent information thanks.

This then leads to two questions:-

1) If 9 volts were used would that be ok?
2) What changes would be required to the ZXPand otherwise?

Thanks

Lardo

1024MAK wrote: ↑Fri Jun 16, 2017 5:06 pm Yes, the wires look like they are connected to the correct points on the ZX81 circuit board....
Mark

Thanks Mark!

Lardo Boffin wrote: ↑Fri Jun 16, 2017 7:15 pmIf I do get round to making a zeddy laptop

1) If 9 volts were used would that be ok?
2) What changes would be required to the ZXPand otherwise?

A1: Yes.
A2: I build 5V 'spands by leaving off the regulator and jumpering the 5v line on the edge connector to the regulator output pad. For a pre-existing 'spand you can either remove the regulator (quite hard) or cut its tracks/jumper the 5v.

A decent 5v supply should be able to supply both computer and xpansion.

I have not posted one of these for a while so here is the latest purchase. I think I may have missed one or two...


Another nice clean shiny issue one. This one came in a postal box rather than the usual printed box.

I'm not sure who CM is or why they chose to decorate the motherboard but I have seen a few with similar now.

At some point I may get one with the 4 major components with the same date stamp - I may have to keep that if I do!

Lardo

And an issue 3. Not had one of those for a while!

In a nice sleeve type box.


Lardo

And it appears the kludge fix bus is in town -


That's number three now!

It's working but needs a new keyboard or someone with smaller fingers than mine. I tried the trimming back the ribbon but the smaller connector is so stiff it keeps bending. I tried another keyboard that is not attached to a case and that went in fine as I could get a better grip on it.

This is up for 'adoption' on viewtopic.php?f=8&t=2482 if anyone is interested.

Now the obvious question is will you make a custom unit that has a switch for choosing the power supply circuit...?

sirmorris wrote: ↑Fri Jun 16, 2017 11:44 pm

Lardo Boffin wrote: ↑Fri Jun 16, 2017 7:15 pmIf I do get round to making a zeddy laptop

1) If 9 volts were used would that be ok?
2) What changes would be required to the ZXPand otherwise?

A1: Yes.
A2: I build 5V 'spands by leaving off the regulator and jumpering the 5v line on the edge connector to the regulator output pad. For a pre-existing 'spand you can either remove the regulator (quite hard) or cut its tracks/jumper the 5v.

A decent 5v supply should be able to supply both computer and xpansion.