Search found 1304 matches

by Chr$
Mon Jan 22, 2024 6:24 pm
Forum: Compatibles Corner
Topic: ICL OPD 3 vertical white stripes fault
Replies: 24
Views: 1244

Re: ICL OPD 3 vertical white stripes fault

The ROMS are I think it 3 parts - the first 64K are a combined OS ROM - so that's ROM A and B ROM C has a header like other application ROM's - so I wonder if this OS Extension is handled as an application ROM - ROM D seems to be the one that may have different code in it and seems to be mostly pro...
by Chr$
Mon Jan 22, 2024 5:22 pm
Forum: Compatibles Corner
Topic: ICL OPD 3 vertical white stripes fault
Replies: 24
Views: 1244

Re: ICL OPD 3 vertical white stripes fault

SRAM issue I found on my machine was the lack of the POWER-GOOD from the power supply, listed as "shutdown" on the pinout. Check VCC (from the 3V battery) and /CE (from PSU via MOSFET on the left of the board) on the SRAM chip. The SRAM chip has battery 3v on pin 24. There are 2 /CE pins....
by Chr$
Sun Jan 21, 2024 9:24 pm
Forum: Compatibles Corner
Topic: ICL OPD 3 vertical white stripes fault
Replies: 24
Views: 1244

Re: ICL OPD 3 vertical white stripes fault

Back to the one with the bootloop... I discovered that the bootloop is the same whether the ROM pack is plugged in or not, so does that mean it's somehow not communicating with it? i.e. that it's died. I've re-touched all the solder joints and short of removing and testing all the 4 LS244/LS245 I'm ...
by Chr$
Sun Jan 21, 2024 7:53 pm
Forum: Compatibles Corner
Topic: ICL OPD 3 vertical white stripes fault
Replies: 24
Views: 1244

Re: ICL OPD 3 vertical white stripes fault

SRAM issue I found on my machine was the lack of the POWER-GOOD from the power supply, listed as "shutdown" on the pinout. Check VCC (from the 3V battery) and /CE (from PSU via MOSFET on the left of the board) on the SRAM chip. Thanks. I'm not sure if my NOS board 3v battery is properly c...
by Chr$
Sun Jan 21, 2024 6:53 pm
Forum: Compatibles Corner
Topic: ICL OPD 3 vertical white stripes fault
Replies: 24
Views: 1244

Re: ICL OPD 3 vertical white stripes fault

Thanks for the suggestions. After much re-seating, cleaning etc, I do sometimes get a different message: INITIALISATION (c) ICL 1984 SYSTEM RESET AHPk (at the bottom) AA CTRL - FAIL Then that message goes away but the bottom AA CTRL - FAIL remains and it says 'Loading saved store', then it resets it...
by Chr$
Sun Jan 21, 2024 1:01 pm
Forum: Compatibles Corner
Topic: ICL OPD 3 vertical white stripes fault
Replies: 24
Views: 1244

Re: ICL OPD 3 vertical white stripes fault

Some progress... I had a spare NOS daughter/CPU board but that was just giving me a black screen. I tried various combinations of ROM chips (ICs 4-7) and with one combination it gets much further but goes into a boot loop, thus: Chequer pattern Black screen/white screen a couple of times Vertical st...
by Chr$
Sat Jan 20, 2024 10:26 pm
Forum: Compatibles Corner
Topic: ICL OPD 3 vertical white stripes fault
Replies: 24
Views: 1244

Re: ICL OPD 3 vertical white stripes fault

Thanks. I did try unsuccessfully to find that info... Hmmm, data registers. I happen to have a spare NOS main board, so swapped them over (using the same daughter board) and the 3 stripes are still there exactly the same, so that's either a coincidence and both main board have the same issue or it p...
by Chr$
Sat Jan 20, 2024 7:25 pm
Forum: Compatibles Corner
Topic: ICL OPD
Replies: 180
Views: 166856

Re: ICL OPD

I made my interface card today, here it is: 20240120_201159.jpg Before I even had a chance to test it I found that my working Merlin Tonto has quietly died in storage and now shows 3 vertical white stripes. Instead of cluttering this thread, here is a new one on that: https://qlforum.co.uk/viewtopic...
by Chr$
Sat Jan 20, 2024 7:22 pm
Forum: Compatibles Corner
Topic: ICL OPD 3 vertical white stripes fault
Replies: 24
Views: 1244

ICL OPD 3 vertical white stripes fault

Just got my Merlin Tonto out to try out Stephens' C1 disk interface clone. I didn't get as far as plugging that in though, as I get a chequered pattern and then this screen with 3 vertical lines on boot: 20240120_201219.jpg It was working a few months ago when I packed it away. Likely RAM issue? I c...
by Chr$
Fri Jan 19, 2024 10:47 am
Forum: Compatibles Corner
Topic: ICL OPD
Replies: 180
Views: 166856

Re: ICL OPD

I read that too on the WD1770/WD1772 re the stepping. I suppose I could just try a WD1770 when I've built the adapter.

Thanks Stephen and Pr0f.