Thread: Urgent! Need Help! Flashing monitor

I am not sure, but the source of the problem can be a backlight problem.
The system enables backlight, but it consumes too much current.

Set the backlight off. Make a picture with good contrast. Enlight the display with a strong lamp. Can you see anything on the screen (of course very faded)? If the picture stands and does not flash, I won and backlight unit is guilty
If the pale picture also flashes, I am afraid you have to search problem around the voltages on the PCB.


Methods to set backlight off:

If the backlight unit is separated, de-connect it at the low-voltage connector. If it is not separated, solder the backlight fuse out.
The backlight unit is, where that small transformer is located and those teflone-insulated cables (usually pink and white) are connected.

thanks for the help! Somehow I got it working. Not sure what I did but it works.

I kinda wondered if something such as the material you used to construct monitor case - was causing abnormality on circuit board. In other words, maybe acted like capacitance or even resistance...

Or, one of the connectors loose. Those nasty little ribbon connectors to lcd or boards can be demonically troublesome. Hopefully it doesn't recur.

happy carpc'ing

I have an 8" shark screen myself, it has the same problem. When i turn it on all i see is a flash and thats it. The touchscreen part works, i hear it through the computer. Please help and thanks

Originally Posted by brucedog

I kinda wondered if something such as the material you used to construct monitor case - was causing abnormality on circuit board. In other words, maybe acted like capacitance or even resistance...

Or, one of the connectors loose. Those nasty little ribbon connectors to lcd or boards can be demonically troublesome. Hopefully it doesn't recur.

happy carpc'ing

well the monitor case is plywood covered with fiberglass - not sure that would cause any electrical interferrance. I used the padding to prevent the boards from doing exactly what you said on the back on the actual panel.

Anyways... I got in the car yesterday morning and fired up the pc. The screen continued to flash for a good 5 minutes then it settled down. Then on the way home from work, same thing, except it was for maybe 2-3 minutes.

I wonder what it's going to do today?

sure enough, screen was blinking the whole way into work this morning (my commute is maybe 10 mins). It slowed down to almost nothing by the time I got to the office. I'm wondering if the cold has something to do with it or maybe the screen needs to 'warm up'? Yesterday temp in the AM was in the high teens, this morning temp is in the mid 20s.

A bit of a shot in the dark here, but I'm thinking foam + plexiglass = static electricity? If so, that might explain your problems, and would lead me to concerns about frying your LCD.

Originally Posted by bugmenots

A bit of a shot in the dark here, but I'm thinking foam + plexiglass = static electricity? If so, that might explain your problems, and would lead me to concerns about frying your LCD.

I hadn't thought of that. But, one question - what part of the screen is plexiglass? The foam is lining the back of the panel - I think it's an aluminum - and then the boards are placed on top.

Once I repaired a small TFT, where the two main GND parts on the PCB was totally separated and connected via the aluminium backplane by screws. And because the customer removed that, there was no picture.