The TMS chip has its own set of RAM which is totally separate from the rest of the system. One of those chips did have a fault, which showed up as display corruption. I replaced that.
Someone wrote a diag ROM which I used to test the main RAM, which passed. It thinks that it tested the high page and that passed, but of the address decoding part of the circuit isn’t paging correctly it could actually be testing one of the lower 16K of the 64Kx1 chips.
I could do with an independent 4164 chip tester to verify this.
As for testing the memory paging. I’ll have to learn Z80 assembler as the BASIC ROM will get paged out when this memory is paged in so it can’t be accessed from BASIC. Z80 assembler seems not as easy as 68000 though.
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BOOKMARK THIS PAGE !
https://www.exxosforum.co.uk:8085/IP_CHECK/
You can unban yourself if needed. It also sends me reports to investigate the ban.
https://www.exxosforum.co.uk:8085/IP_CHECK/
You can unban yourself if needed. It also sends me reports to investigate the ban.
DO NOT USE MOBILE / CGNAT DEVICES WHERE THE IP CHANGES CONSTANTLY!
At this time, it is unfortunately not possible to whitelist users when your IP changes constantly.
You may inadvertently get banned because a previous attack may have used the IP you are now on.
So I suggest people only use fixed IP address devices until I can think of a solution for this problem!
At this time, it is unfortunately not possible to whitelist users when your IP changes constantly.
You may inadvertently get banned because a previous attack may have used the IP you are now on.
So I suggest people only use fixed IP address devices until I can think of a solution for this problem!
My next challenge: Memotech MTX500.
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stephen_usher
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- Posts: 7367
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- Location: Oxford, UK.
Re: My next challenge: Memotech MTX500.
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
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exxos
- Site Admin
- Posts: 28224
- Joined: 16 Aug 2017 23:19
- Location: UK
Re: My next challenge: Memotech MTX500.
Could it simply be a bad trace on one of the more upper address lines which separates the upper and lower ram banks ?
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stephen_usher
- Site sponsor
- Posts: 7367
- Joined: 13 Nov 2017 19:19
- Location: Oxford, UK.
Re: My next challenge: Memotech MTX500.
After the weekend, when I can turn my spare bedroom back into a hobby room, I can pull all the chips and do another continuity check.
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
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