All the signs pointed to a bad solder, but I have already done all of the usual suspects, and it doesn't seem to have helped.

One thing is a bit weird - immediately after I did the soldering, the picture was perfect. A couple of days later, it was flickering again.

Of course it is possible that my soldering was not good enough, but I am also wondering whether the culprit may be the power plug on the motherboard, rather than on the analogue board, or whether it might be a grounding problem. Has anyone ever seen this happen?

Thanks,

Daniel