The Sinclair QL Forum

Hi there, just wondering why when I switch on my QL with tetroid sgc fitted it doesn’t start up and the screen looks like the photos attached? It’s an issue 5 with Minerva Rom and Hermes co-processor. I’ve also tried it on issue 7 with JS ROMs which gives a red and white chequerboard screen. Any help would be greatly appreciated.

Is the Tetroid card plugged directly into the QL, or in a backplane?

And also - is the QL's original 68008 processor still in it's socket, or has it been removed - this was an issue for the Miracle cards sometimes - and the processor on board the QL is just disabled by the Gold card - but sometimes this doesn't seem to happen properly - removal of the processor takes that issue away..

It's worth a try as they say...

The other thing to check is whether any of the pins in the expansion connector are bent - quite often this is the cause of issues!

But was it OK originally, but then later failed when switching on recently ?

Also check
viewtopic.php?p=3918#p3918

Solved the issue for me

So just to check if it was the scart lead, then if I tune it in to my tv and use an RF lead and disconnect the scart/RGB lead should the SGC then work ok, as I’m not using a scart lead?

issue5 wrote: Thu Feb 09, 2023 8:45 am So just to check if it was the scart lead, then if I tune it in to my tv and use an RF lead and disconnect the scart/RGB lead should the SGC then work ok, as I’m not using a scart lead?

Yes. But disconnect the scart lead with power off.