Sinclair ZX80 / ZX81 / Z88 Forums

Retronaut wrote: ↑Thu Jan 25, 2024 12:11 pm Don't get me wrong, the ZX80/81 were vital stepping stones, but they were certainly NOT mass market.

This may be true for the ZX80 but ZX81 sold about 2 Million at what number do you think mass market starts?

That's not what /wait is intended for. I don't know what happens to all the other z80 control lines. If you try a /busreq and wait for busack then z80 goes into tristate and you can acces the ram in any way you like for as long as you like. Of course the screen will not be updated by the zeddy. That...

The ZX81 capacitor are not known to leak but they dry out.
They are unimportant so nothing breaks if they fail.

The 1uF only needs replacing if you have a zeddy that needs more than a single try to start properly.

I have something like the first link you provided. But I never needed it. I also have the zd915 and use the following steps: First I apply flux gel Next I desolder every pin. Not from the top but horizontal. This way I can see what I'm doing and it's not necessary to work against gravity. After ever...

1980 is the copyright, not he building date

There is nothing preventing the ribbon to break if it's original. It's brittle and can't be rescued. A replacement is the best you can do. Warm up the old membrane with a hair dryer then fiddle it of beginning at one edge of the left side. Most probably there will be glue sticking on the case, it ca...

The trick on desoldering is to apply fresh tin before desoldering. Normal metal pliers are what we use because plastic will melt.
I have pliers that are like needles at the tip. The smaller the tip the less heat is transferred.

I have a birthday.p as Autorun program on my zeddy.
So every time I start up my zeddy it tells me who's Birthday is next.
That happens a few times a day

SMB for SirMorrisBig and 17 for a year or a version number