Problematic QL

[RWAP]

I was testing yet another QL last night - it has a Minerva ROM in it.

However, when I connected the Trump Card, there is a flash of a white screen with two red vertical bars on the right hand side, just before the memory test starts.

Minerva reports no errors, but the Trump Card is not initialised.

Remove Minerva and insert JS ROMs and the machine starts up and initialises the Trump Card.

Minerva and Trump Card work fine together in another QL.

However, one thing I did notice, was that after using the original QL, with JS ROMs for a while (with or without the Trump Card) the QL freezes with some flashing bits on the screen.

Any ideas what could cause these symptoms?