Minerva ROM hangs on start up

[issue5]

Hi there, could someone give some advice pls - on starting my original QL with Minerva 1.98 ROM fitted it checks the memory, gets to the start screen (see photo) and then won't go any further - just hangs and is unresponsive. I've tried a different Minerva ROM and JS ROMs with the same result - pressing F1 or F2 at this stage does nothing. Any advice would be much appreciated.
Thanks Keith

[XorA]

Sounds like keyboard membrane is knackered!

[Pr0f]

Possibly nothing to do with the issue, but there is no red in your picture - which seems a little odd.

As XorA says - keyboard membrane, or possibly IPC chip or the Zx8302 chip not communicating - so the keypress isn't getting detected.

[issue5]

I'll check the chips you mentioned - it's definitely not a membrane issue as that is working fine, and even if the membrane was broken after a short time the Minerva ROM goes to the TV screen anyway, regardless of whether a key is pressed or not - the Minerva screen is the oen that always comes up on start up - it's a Minerva ROM I got from Chris Perkins and I replaced that with a spare so I knwo that isn't the problem. But I'll definitely check out the chips you mentioned.
And I'll let you know what the outcome is, thanks guys

[Ruptor]

Possibly nothing to do with the issue, but there is no red in your picture - which seems a little odd.

Yes and looking at the picture there are white pixel columns so doesn't that suggest a ram issue that would affect processor operation & screen?

[Pr0f]

The only thing is - to get to that screen it must have done the memory check and passed it and reported 128K

[XorA]

so in my experience writing emulators what makes minerva lock up at that point is missing irq or the irq register not being read properly.

[Pr0f]

Are there any other upgrades to this machine or is it just the Minerva ROM ?

[issue5]

Well I have solved the problem - I have replaced the co-processor next to the microdrive 1 with a hermes 8049 co-processor I had laying around, and now the QL starts up as per normal and doesn't hang on the start on screen, so it must have been the co-processor. Anyway it was a nice easy fix without any outlay as I already had the Hermes, so happy days . Thanks for all the suggestions.

[Pr0f]

Glad you got it fixed