Samsung Sync Master 943bw monitor shuts down after a few minutes, behaves as though it is overheating, will only flash briefly if attempted to open immediately. starts again after standing for some minutes, but then closes after about five minutes

The back light tubes are probably exhausted. They can be replaced, or you could try a CCFL to LED back light conversion. eBay.com has some kits for doing that.

Is this happening while your are playing games or you are doing a specific task? If not try to change your connectivity cable (HDMI or DVI)

Run a monitor self test: http://skp.samsungcsportal.com/integrated/popup/FaqDetailPopup3.jsp?cdsite=ae&seq=240423

If pass follow steps on what to do when screen remains Blank/No Image even though I turn on the monitor?: http://skp.samsungcsportal.com/integrated/popup/FaqDetailPopup3.jsp?cdsite=ae&seq=240496

Ref: http://www.samsung.com/ae/consumer/computers-peripherals/monitors/lcd-monitor/LS17MYAKF/XSG-support

Samsung sync master monitors were well known for bad capacitors, if you have a esr capacitor meter you can check in circuit, if not look for dome shape at the top of the capacitor, a dead give away it is open, also check for poor solder connections in the power supply inverter board area.

No! there is no second hand available.

Hello
Not much to do by web, this message mean you most likely need a new fan, tv shuts down due to overheating. Contact service.

Generally an overheating issue.
When it shuts down, what are the LED indications if any?
http://www.fixya.com/support/r4282412-find_no_post_diagnostic_information_dell

I would check the caps with ohm meter. Make sure they all show increasing resistance. Caps can be bad without looking bad. Check output voltage on the power board, should be around 12V. If all that checks out then I'd look next at the backlight bulb. I'v repaired many monitors and the problem was almost always overheated caps on the power board. Post back and let me know.

Sounds like overheating of something inside. Open the monitor, get access to PCBs and observe for darkened areas especially over the power supply and inverter. Also that long working before shut down may tell about bad solder junction, also caused by constant local overheating - look for those with tiny cracks, especially over darkened areas on PCBs.
Most likely - that's the source of problem with your monitor. And, as far as you open the monitor, check for any popped electrolytic capacitor - never bad to replace them too.

Change the audio amplifier IC are in shortcircuit