I took the motherboard out and had a good look over the topside. Nothing out of the ordinary but I think that it definitely needs to be re-capped. In any case, there's nothing obviously wrong on the top.
Turn it over and look at the back. My attention is immediately drawn to this:
Anyway, as it happens, I have a few of these value SMD caps in my box so I just replaced it:
Now, I may not be an expert electronics engineer but this does not look like an improvement.
I dug the board out again and got the USB microscope on it for another survey, this time I was looking for ANYTHING that might look out of the ordinary. It didn't take long...
These two resistors have been replaced by someone:
|361? 360 ohms? Are you sure?|
R217 is very badly soldered and looks like it has been messed with:
|Bad Solder Joints|
R345 has been replaced:
|681? 680 ohms? Are you sure?|
This one (and another nearby - close to the op-amps for the audio) have also been replaced:
|Correct - but REALLY badly soldered..|
Fortunately, these are all 22nF which just so happen to be the only value of SMD caps that I have (and was also the same as the one I replaced at the top of page!). So, out came the soldering iron again. And now we have this:
|More new shiny...|
And that completely cured the video problem. Rock solid. I left Frontier playing its demo for nearly six hours and no problems. Another great result.
Just waiting for the 'real' caps to arrive so I can do a complete job on this A1200 now. :)