Strange Video Issue

[ajamsandwich]

Hi, I've dug my Atari ST and started to clean refurb it by adding a GOTEK cleaning up the case etc, getting a RGB SCART cable.

However I've come to a problem. When using the ST going in to GEM or on the GOTEK boot loader menu when moving the cursor or selected menu item the item that gets highlighted kind of wobbles like a mini bounce for a few hundreds of a second. So in reality it appears that when you select and item it appears out of focus then in focus this happens with the menus in GEM and around the mouse cursor (less noticeable).

I've tried this through both RGB SCART and RF and on 2 different LCD TVs with no difference.

Any ideas on why this may be happening? Should I replace all capacitors around the video circuit or is there something else I should look for? I've changed the PSU and that had no affect.

Any help greatly appreciated.

 

Andy