Samsung 740NW

[almamater]

Hello

Do you think it still has a solution?

A normal 17 "monitor from Samsung (SyncMaster 740nw) decided to do this:




When starting there are 'ghosts' of any old image that was (that has stayed there for some time), but then it disappears and gets darker:


I replaced one capacitor at the power supply. The others don't look too bad and I didn't take them off.



However, and due to the symptom of the burned image that appears, I deduce that the problem is in the board that send the signal to the LCD, the processor crashed or so..!?

[Chalcogenide]

First rule: check the voltages. If you see any voltage which seems suspect check capacitors and voltage regulators associated.

[PKTKS]

These monitors are above the mid level service tech.

They are uPs based and several "versions" evolved
in time  in which some are  SYNCH with SMPS
some are not and some use a crappy PFC front end.

Overall results is that you need the service manual
the proper bench setup to do simultaneous checking
of the uP regenerated synch signals..

Yes they are re-synched and regenerated by uP
which in turn drives the SMPS properly

Very complex and VERY ACCURATE HIGH QUALITY images

Last need you may have a proper program to drive the
 screen with usable data.

Paul

[Manul]

Check all voltages on a connector and on the capacitors of the main board. If it is all good, reseat and check LCD flat flex cable on both ends and inspect LCD panel vertical and horizontal drivers. If still no good, you can try some stressing techniques. Lightly flexing the main board while observing LCD image, slightly heating with hot air and freezing with upsidedown air duster can to see if you get any response. If there is some response to thermal or machanical stressing it may be a cracked solder joint. If nothing gives result, then most probably there will be no quick or economical repair.

[PKTKS]

Check all voltages on a connector and on the capacitors of the main board. If it is all good, reseat and check LCD flat flex(.)

I must have been mistakenly assumed a CRT ?

If so disconsider my previous comment.
LCDs are not even close the hassle of a multi-synch CRT

LCDs are kinda kid stuff next to those CRTs.


Paul

[almamater]

Thanks for the replies!  I will test the voltages, the cable and  temperature stressing.