I picked up an A600 from the carboot sale today for only 5 euros. Came with PSU and mouse too

It had the floppy cable installed the wrong way and the keyboard ribbon cable loose. Fine fixed them in 10 mins and it works, loads and plays games and all.
The problem is when it is switched off or reset.
After reset it just refuses to boot, just giving a black screen and the caps lock switched on. Refuses to accept the 3 finger salute and all.
After a million times switching it on and off it finally manages to go to the kickstart screen. Could take one on and off or else 10.
I have no idea why as it does not crash or anything.. Spent an hour playing Midnight Resistence with no problems at all.
What could be causing this issue ?
Any ideas?