Search found 1416 matches

by mrtinb
Fri Sep 17, 2021 9:42 am
Forum: Sinclair Misc
Topic: R.I.P Sir Clive.
Replies: 17
Views: 526

Re: R.I.P Sir Clive.

The most amazing (and occasionally throw it out of the window frustrating) things! If you are frustrated at a computer you are either asking it to do something it can't do, or you (or someone else) is not explaining the task correctly to the computer. Remember computers do what they are told to do,...
by mrtinb
Mon Sep 06, 2021 8:44 pm
Forum: SALES
Topic: Memotech keyboard for the ZX81 in box
Replies: 7
Views: 665

Re: Memotech keyboard for the ZX81 in box

Are you selling - when it's listed in Sales section?
by mrtinb
Wed Sep 01, 2021 8:42 pm
Forum: Welcome Area
Topic: Hello! New first time owner of zx81
Replies: 5
Views: 377

Re: Hello! New first time owner of zx81

The save signal that comes from the ZX81 is VERY WEAK. I don't know which equipment you are saving to, but some newer equipment might just ignore the signal.
by mrtinb
Wed Sep 01, 2021 7:30 pm
Forum: Welcome Area
Topic: Hello from Ukraine
Replies: 2
Views: 182

Re: Hello from Ukraine

If you are new to machine code, I recommend this book Machine Code for Beginners.

After that you can get the ZX81 specifics with Mastering Machine Code on your ZX81 or ZX80
by mrtinb
Wed Sep 01, 2021 10:45 am
Forum: Development
Topic: Working on my displayroutine for MAKE A SHIT
Replies: 7
Views: 495

Re: Working on my displayroutine for MAKE A SHIT

UDG requires special hardware on the ZX81, except when no RAM is attached and the internal 1k/2k is used.
by mrtinb
Wed Sep 01, 2021 10:33 am
Forum: Hardware
Topic: another rampack with problems
Replies: 9
Views: 444

Re: another rampack with problems

Great job, and great reference for future fixes.
by mrtinb
Sat Aug 28, 2021 9:25 pm
Forum: Hardware
Topic: Oscilloscopes
Replies: 7
Views: 572

Re: Oscilloscopes

I bought a Hantek 2C72 for $130. It has 70 MHz. My first oscilloscope.
https://a.aliexpress.com/_msSyV3l
by mrtinb
Sun Aug 22, 2021 8:20 pm
Forum: Hardware
Topic: 32k Internal ram with m/c above 32k
Replies: 10
Views: 658

Re: 32k Internal ram with m/c above 32k

There is a trick, if you are not a beginner in Z80 assembly. All instructions that start with 0,1,2,3,8,9,A and B will be overridden with a NOP instruction, but all instructions that starts with a 4,5,6,7,C,D,E and F are not modified, so these can be used to programs on any address. Since you'll be ...
by mrtinb
Sat Aug 21, 2021 9:46 am
Forum: ZX BASIC
Topic: How do i get a movement on screen using the ZX80
Replies: 23
Views: 1626

Re: How do i get a movement on screen using the ZX80

Just remember. Saving in EigthyOne is a two step process. Having the file shown in the tape window is not enough. It just means it’s in EightyOne’s memory. You have to save it to a Windows file from here. When you add another file to the tape, it is still in RAM, so you need to save to a new file ag...
by mrtinb
Wed Aug 18, 2021 10:23 am
Forum: Hardware
Topic: TS1000 Video Issue
Replies: 5
Views: 388

Re: TS1000 Video Issue

You could try to measure the pins of the ICs like described in this thread

Getting your logic probe to work, and compare how the pulsing should be, would be a good start.