Shaky picture when warm

[Minwah]

I've just got an old Microvitec Cub low resolution monitor...

I've altered the internal jumpers to get it to work with analog RGB (TTL as standard) and it works pretty well. Problem is that as it warms up the picture starts to move/wobble/shake/shimmer. Would I be on the right lines to think it might need the capacitors replacing?

[mgb]

Maybe the power filter cap

[Minwah]

Maybe the power filter cap

Thanks, can you give me an idea how to identify that cap?

[mgb]

It's the largest cap on the board and should be in the area around where the power feeds in.
 I would think a full cap kit would also help

[Minwah]

Great thanks, will give it a try!