I did the stupid mistake of connecting my sd2iec powerlead to the userport upside down. The connector I am using isn't keyed.
When I turned the power on the screen got all garbled. After disconnecting the powerlead from the userport the screen remains garbled - the effect is kind of like a fried PLA.
I have connected the mk2 to my pc and this works fine. No error is reported. The led on the motherboard is blinking though.
I have tried different CIA chips, VicII chips and another cpu but it does not make any difference. When running a diagnostic cartridge the system actually gets thru the SID test before hanging up and you can see stuff is happening on the screen but it remains garbled.
I guess I'll have to order another mk2 but please let me know if anything can be done to save this one