I would start from the video output board (PCB3) at the cathode end of the tube. Of course the fault could be upstream from there (or even internal to the CRT)  but resoldering that board is an easy first step.

Usual caveats about lethal voltages potentially remaining even if the set has been off for some time, etc

Is it a '4000 or a '4002 ?They are quite different beasts!

If it's a '4000,then yes indeed,there may well be a dry joint on  the crt module.If it only occurs when the set is cold though,it suggests a lazy component,praps one of the video output transistors.

Also there could be dry joints around the video processor chip TDA3505 (IC4)on pcb 41 to the left hand side of the chassis.

Take care in there!

Nick

Going open it up this week and start by stading back when on and looking for intermittent sparks on all the boards. If that fails I’ll have to test for continuity across boards but board order helps :) 

This one is a MX4000. I replaced it due to the problem with a MX4002 that’s perfect apart from the screen internally being 1cm offcentre which I’ll also be trying to fix (made a different thread for that). 

I will open it up and look for sparks and if that fails discharge it all and update you guys with pictures and questions. 

Cheers. 

link

Just to let you guys know. I’ve opened this up and not dry solder points I have however figured out that it’s a scart connection issue. It doesn’t like RGB scarts? If you connect via scart to rca it’s fine but actual RGB scarts bring along the green hue. If you pull it out slightly it’s fine. 

Good to hear it was that easy! SCART is handy, but mechanically a very bad connector (or maybe just most implementations are bad). I have met many devices that only work reliably with certain cables, and in my MX2000 I had to carve some of the back cover plastic off to get a SCART plug seat deep enough.