My LX is not as sharp as it could be and varies a little as the TV warms up. I have adjusted the focus control on the tube neck thanks to the excellent thread by Die Bogener but this control is now at its maximum level. Does this mean the tube is on its way out? I also have an orange mark showing up at the bottom right of the screen when there is red in the TV picture.

Thanks for any help.

David

Its possible that the focus unit is not in its prime ... you could try scaveging another and see how it performs.

Neil

This happens when the highvoltage begins to change due to wear and tear...

The tube is probably not the problem, this type of philips tube is one of the very best tubes ever produced. It's very resistent and durable.

You should begin to replace the caps of the mainboard. Since the mainboard is still working, it's really not a big deal to replace around 20 caps. Then most of the parameters of the tube are in spec again.

Thankyou very much both. I am pleased to hear that it is probably not the tube! A question of repair or replacement of the boards? There will no doubt be plenty of parts available from salvaged sets.  The video board has been replaced. 

I have a 4500 that is much sharper and I would like the 5500 to be as good