Hi,

my trustee old Sony monitor occasionally turns yellow. This happens
periodically and it remains yellow for a few second or up to several
minutes.

I suppose the yellow is caused by a missing "blue", and I'm pretty
sure that the problem isn't located in the cable.

I've read somewhere that older Sony products suffer from poor
soldering - could this be the case here? If yes - where on the circuit
board should I focus?

TIA
Ryan