I've been hunting down several problems with a Sharp Image 429-DS-SY monitor
(Dual-scan 15k/25k monitor with Sony Trinitron tube used in video games, mfg
1998). I've totally recapped (the lytics) and replaced a diode in the power
supply that had opened up. I'm so close to wrapping it up, yet keep running
up against a wall with the last few issues.

Schematic: http://www.sharpimage.net/images/schematicD.pdf

In my latest saga, I've got a compressed right edge of the picture. From
everything that I know, this indicates that there's not enough current. I
would guess that perhaps it's a snubber cap issue, but I'm at a loss looking
at the schematic which caps to suspect (I don't have values onhand to
substitute each one). Further confusing to me is the E/W correction
components (most of the stuff I work on are much simpler devices).

Next, there's a twitching of the image. Maybe 1 or 2 twitches (horizontal
size appears to increase for a fraction of a second) every couple of
seconds, sometimes a longer interval of a steady image. For this, I would
suspect cold solder, but I've touched up just about every solder joint and
still haven't found it. Could this be a component issue?

And finally, sometimes on cold start, the pincushion is really bad--as if
it's non-existant, and there's a really bad hourglass effect (looking at a
convergence grid pattern). Pulling out the freeze spray doesn't allow me to
locate the fault once the monitor warms up and the pattern returns to
normal. Again, I'm suspecting cold solder could be the culprit.

Any tips or pointers for identifying cold solder joints? I've tried tapping
and using a toothbrush, but no luck.