NEC LCD3000 20" monitor (problems and repair)

[ChaoZ]

Hello folks,

I have managed to land my hands on this 30" LCD monitor, it does not have high resolution but it provides very comfortable reading.

Monitor displays graphics well, in resolution 1280x768. However, there are 3 problems which I have noted :-

Problem 01
- The main problem is that the monitor is displaying the picture but it had shifted the display to the southwest, leaving a 1-inch row on top, and a 1-inch column on the right.

I had tried to configure the monitor via the menu button, picture positioning but I am unable to - the display gets shadowed behind the above-mentioned area. Nvidia display driver didnt work either.

There is another 'reset picture configuration' from the monitor menu, but i am unable to execute the reset even though i clicked repeatly.

Problem 02
There is a mild fading pale white 3-inch-column on the left of the screen. I reckon this could be a faulty inverter or CCFL.

Problem 03
I can sense some electrical leakage via the metal casing when I am running my hands over the monitor. And the monitor has a higher than usual temperature, especially on the left top corner(HOT).

FINDINGS :-
I only managed to get to the top-layer boards (system_board and power_supply board). My findings upon inspection are :

Power Supply Board
No bad caps on the power supply unit, actually it is very strong with double serving of everything. Tested with cap meter, esr and capacitance within good tolerence.

Systemboard
I have yet to finish inspecting the board, this is huge The only complains are the smaller caps(47uf/100uf 50v/100v) suffering heat stress - they are shrinking their label-sleeves. Capacitance dropped to 20% border line for electrolytics.

I have yet to get to the inverter board/s, this monitor has too many screws .

I have attached a look-alike 'inverter' (Mitsubishi LT3050, # KLS-300W3) which I had goggled.

If someone has a service manual for this monitor, I would be very grateful.

Help and reference to previous similar case is certainly welcome.

Meanwhile, keeping my fingers crossed.

[ChaoZ]

Re: NEC LCD3000 30" monitor (problems and repair)



When I started to dismantle the cables and connectors, i found this metal connector on the system board. There are some melted solder traces, might be due to heat-stress.



bare board with connectors.

is there a way to test the ccfl using a multimeter?



Seems to be clean, other than some minor brown marks on the soldering of the transformers.

please ignore the 1st disconnected cable. I was getting the resistance, but there was no reading.

Out of ideas, LCD is just way too warm for normal operation.

This monitor board uses Rubycon capacitors mainly.

PS: I will continue to troubleshoot the system_board, too many components. Will post a better picture soon.