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Weird QL Faults

Posted: Sun Nov 23, 2014 9:02 pm
by RWAP
Hmm - I have a couple of 'interesting' QLs in my small pile of non-working QLs.....

One gives a white screen as soon as I switch it on - great, I thought, a memory problem.... Plug in Minerva to get the error code, and would you believe it - it goes straight to the F1/F2 screen, even on reset...

Put back a different set of ROMs (JM or JS) and there's the white screen back. Try Minerva in the other socket, and still it boots up fine....

The other one may be down to my Trump Card issue (Derek has fixed that for me but not returned it)... The QL works fine on its own, but plug in a Trump Card, and the screen is just black.... All the pins look fine on the expansion connector

Re: Weird QL Faults

Posted: Mon Nov 24, 2014 10:38 am
by Derek_Stewart
Hi Rich,

Minerva can go down to 32K of memory and still boot. The error code can be put into the RAMFAIL_BAS programme and it will tell you which internal ram chip is faulty.

I was always going to try and expand the programme to handle external memory expansions, but never got it finished.

Sorry about the delay in the Trump Card, I have cleaned all the ram chips and it works fine now. I am in the process of house decorating, this is the reason for the delay. I will return the Trump Card this week.

Re: Weird QL Faults

Posted: Mon Nov 24, 2014 11:21 am
by RWAP
Ah but Minerva does not report any error code to look up which suggests all of the RAM is passing the RAM test... odd...

Re: Weird QL Faults

Posted: Mon Nov 24, 2014 12:44 pm
by tofro
What does "Minerva" in this case exactly mean? It could well be it puts a bit of a different (less) load on the CPU bus drivers than the original ROMs. I would guess you should try and change the CPU as well.

Tobias

Re: Weird QL Faults

Posted: Mon Nov 24, 2014 9:11 pm
by Dave
When it boots with Minerva, how much free memory does it report? All may appear normal, but memory could be reduced.