On 10/21/2015 9:31 AM, Percival P. Cassidy wrote:
This is a SyncMaster 2233SW that worked fine for years, but then the
image disappeared. Further investigation showed that the image would
display for just a second or so after power-up or after switching
inputs. So: looks like classic defective-power-supply problem, probably
resulting from crappy electrolytic capacitors.

When I took it apart I found that there were bulging caps and a
partially discolored PC board.

Since the PC board itself showed signs of overheating, I thought it
better to look for a replacement power-supply module than to simply
replace the electrolytics on the old one. I bought one on eBay that was
described as having come from a monitor with a cracked screen. It had no
sign of bulging capacitors or overheating, but it did not solve the
problem. The seller refunded my money and did not want the apparently
defective unit returned, so I got a set of replacement capacitors for
that one. BUT that has still not solved the problem: with two different
computers, whether I use the analog or the digital input, there is an
image for just one second or so. AND I do not see any trace of an image
when I shine a light onto the screen either.

I cannot find a service manual for this monitor -- at least not without
sending money to a person or business of unknown integrity.

Where do I go from here?

Perce
There's typically a sensor that shuts down the backlight if it senses
a problem with the backlight.
I fixed one of those with a new transformer, but the first one of
those shipped to me with an open secondary. Second one worked.

I "fixed" a second monitor by disabling the protection chip.
I wouldn't recommend that to anyone else tho...

If the backlight is on a different board, you may find something
there.
It's possible that the new board had the same failure mode.

Normally, you'd expect the image to stay up even if the backlight
turns off, but who knows what the designer decided on that model.

Had one monitor that had a bad cap in the 5V. Supply.
The spikes on the 5V caused the controller chip to malfunction
and lock up.

Probe around with a digital storage scope to see what happens
on power up.