Zx81 composite mod with backporch-Advice

[Lardo Boffin]

It kind of looks like it is trying to produce a K at the bottom of the screen so may just be down to the adjustments?

[rmbrowngr]

I should learn to count!

I it works how attached to the correct pin on the ULA. The strange things is I count the pins, checked with the multi-meter it was the right pin, and then solder to the next pin down!

[Lardo Boffin]

Oh yes! Pin 17 not 16. Easily done.

[rmbrowngr]

A working ZX81!!!

Thought I had a problem with the keyboard, but I hadn't push one connector in far enough.

And the modern equipement:

[1024MAK]

I’ve got a very similar analogue multimeter:

My analogue multimeter

Mark

[Moggy]

Me too as a reminder of the AVO units I used as an apprentice many years ago!

[rmbrowngr]

Me too as a reminder of the AVO units I used as an apprentice many years ago!

I remember this one (or similar) from college.

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[rmbrowngr]

I would also get a KDLX keyboard at the same time. Much better than a standard flat membrane.

After spending half an hour trying out the ZXpand+ I got recently, and playing games like 3D Monster Maze, I will invest in one. I was a bit unnerved when the screen blanks to build the maze, and saw the message no signal. I had fogotten about FAST mode. When this happened back in the 80's with my little B&W TV it didn't bother me at all, e.g. no on screen message about no signal.