Re: Samsung SyncMaster 940BW no backlights

Gambling that it was the board I ordered one from China for a little over 20 bucks. It must have come on a slow boat, but it finally arrived. Now I have my second monitor once again! It was like wallpapering with one arm in a sling there for a while.

Re: Samsung SyncMaster 940BW no backlights

I appreciate all the help, but I must say at this point I am a bit stumped. I read elsewhere on this forum that a mosfet requires some sophisticated equipment, that I don't have, to test in circuit.

I could order a new board from an OEM source for 20 bucks, which would solve the possible mosfet and/or transformer issues, but I can't be sure it is not the ccfl's.

I started to take the screen apart to access the ccfl's and realized it would be pretty easy to ruin it in the process. The bulbs have been in use regularly...

Re: Samsung SyncMaster 940BW no backlights

The vcc voltage is 14.72 V.

Re: Samsung SyncMaster 940BW no backlights

I checked the caps and continuity from all their leads. They all seem to be OK, no cold solders. They are snipped short enough not to be shorting.

The fuse at F201 checks out OK also.

The leads from the transformers have continuity. If the inverter transistors are the ones in the heat sinks, as I expect they are, they too have continuity. So, it appears those components are soldered in good contact with the PCB.

There are also no visible signs of anything gone awry.

PWI1704SV LCD backlights don't come on LED does

Same symptoms appeared about 1 year ago, detected 2 bulging capacitors and replaced for successful operation.

Although no visible problem with caps, at Badcaps' suggestion I replaced all but the big one with quality caps.

Symptoms remain with video detectable with front light, LED on, but no backlights.

I assume either the inverter is not working or the bulbs are bad. How can I determine which one is the case?...