Search found 3003 matches

by 1024MAK
Wed Jul 15, 2020 8:15 am
Forum: ZX BASIC
Topic: ZX80 Character position
Replies: 2
Views: 43

Re: ZX80 Character position

One other thing, the display file has to be fully expanded.

Mark
by 1024MAK
Wed Jul 15, 2020 8:12 am
Forum: Hardware
Topic: ISSUE 2 - memory problem
Replies: 7
Views: 147

Re: ISSUE 2 - memory problem

Well done! :D 👍

Mark
by 1024MAK
Mon Jul 13, 2020 11:50 pm
Forum: Welcome Area
Topic: Hi Sinclair fans
Replies: 4
Views: 116

Re: Hi Sinclair fans

Hello and welcome to our forum rcmolina!

:D :D :D

I hope you enjoy the forum :D

Mark
by 1024MAK
Mon Jul 13, 2020 6:43 pm
Forum: Hardware
Topic: A tale of 2 Spectrums...
Replies: 9
Views: 229

Re: A tale of 2 Spectrums...

Is it possible that one of the traces is damaged? Yep, that’s what I was getting at! It is possible to test for that by using the continuity range or the 200 ohm (or equivalent) resistance range on your multimeter. Do the tests with the power disconnected from the computer. Put the negative (black)...
by 1024MAK
Sat Jul 11, 2020 10:10 pm
Forum: Hardware
Topic: ZX81 ROM burning
Replies: 6
Views: 167

Re: ZX81 ROM burning

For the ZX81 ROM content, you need a 64K bit (8K bytes) EPROM such as a 2764. But these have been obsolete for many years. You can also use a 128K bit (16K bytes) EPROM such as a 27128 or 27C128. Alas these are also now obsolete. You can however have the ZX81 ROM code in the first 8K bytes and your ...
by 1024MAK
Sat Jul 11, 2020 9:47 pm
Forum: Hardware
Topic: Memotech 16K Ram pack failure
Replies: 14
Views: 472

Re: Memotech 16K Ram pack failure

Well done 👍 :D The 74LS157 are multiplexer chips to switch between the 14 bit address from the Z80 to the two lots of 7 bit addresses used by the DRAM chips. I don’t know why there are extra resistors fitted to the Memotech 16K RAM pack in that photo. They were not present on the unit that I took ap...
by 1024MAK
Fri Jul 10, 2020 11:18 pm
Forum: Hardware
Topic: A tale of 2 Spectrums...
Replies: 9
Views: 229

Re: A tale of 2 Spectrums...

I THEN decided to check at IC6 and got 8v at ground ! Measured again and got 0v, measured again and got 7.6 and rising, then 0v again Now I just need to figure out WHY ! I suspect a faulty ram module leaking volts to ground ? Hmm, what point are you using for the negative lead (black probe) for you...
by 1024MAK
Fri Jul 10, 2020 6:09 pm
Forum: Development
Topic: ZX81 Assembly on OSX
Replies: 15
Views: 327

Re: ZX81 Assembly on OSX

wietze wrote:
Fri Jul 10, 2020 4:39 pm
Would you be able to point me to some more in depth resources regarding this?
Read Wilf Rigter’s Video Tutorial first ;)

Note: by default the pages at the linked to web site may not display correctly, so switch your character set to "western" for correct display.

Mark
by 1024MAK
Fri Jul 10, 2020 3:06 pm
Forum: Development
Topic: ZX81 Assembly on OSX
Replies: 15
Views: 327

Re: ZX81 Assembly on OSX

It maybe worthwhile mentioning that a user program (BASIC or machine code) will only run at the maximum MPU speed if the machine is not generating a display, this is known as FAST mode. This is the same as the system used by the ZX80. The normal ZX81 mode is SLOW mode, also known as compute and disp...
by 1024MAK
Thu Jul 09, 2020 10:47 pm
Forum: Hardware
Topic: ISSUE 2 - memory problem
Replies: 7
Views: 147

Re: ISSUE 2 - memory problem

Oh, since I forgot to welcome you, let me do that now...

Welcome on board Rob!

:D :D :D

Welcome to Sinclair ZX World :D

Mark