flatron lcd 575lm monitor blinking white screen

[jean luc ferre]

Hello,
removing the original controler board by the contoler kit suited for screen; then this last one works perfectly. The problem is due to the controler board breakdown. i will soon change the 10µF 16v cpacitors and we will see.
Thank you for all.
Jean Luc Ferre

[jean luc ferre]

Hello,
After the holidays i come back to you for more informations about this issue.
i noticed that with anothers pc with others graphic boards (nvdia, intel hd graphics, instead of amd ati) the blinking phenomenon disapeared. i also put a small radiator on the Gmzan1 chip which improved things. With all that, now i no longer experienced disconnections of the screen with the switch to amber of the power indicater.
Nevertheless i haven't the correct informations displayed on the screen...it might be a problem with the graphics panel?
i haven't yet used the hitachi graphics controler i mentioned to you previously.
Waiting for your answers.
jean luc ferré

[jean luc ferre]

Hello,
Thank you a t Harp for his answer.
i examined severa times the main controler board; and nothing strange appeared...all the signals and power rails are ok...
Perhaps it's a matter with the inverter board because tle coils l1 l2 of the filters are very hot.
waiting for new ideas.
Jean Luc Ferré

[harp]

Changing resolution to lower one, it cause less generated heat in processor, but also less current consumption, or involving less running signals to operate, so your conclusion to do a better cooling is maybe a unclear step. I have one monitor that work in bios / boot time / dos, but blinking in graphics. The fault is a small caps on controler board which control some signal, not even power rail... I found faulty one also by changeing temperature while measuring point which fluctating. You can see in video https://m.youtube.com/watch?v=aPAeZWeJ-nw

[jean luc ferre]

hello,
thank you for your answer...
the vga cable works fine with other display and pc...
i am waiting for a cooling radiator that i could stuck on the gnzan1 chip...and we will see.
i have also ordered the controler kit in order to dispel any doubt about the quality of working of the screen itself. (a new screen that's relatively expensive!!!).
thank you for all.
Jean Luc Ferré

[tom66]

If the input signal is VGA, try changing the VGA cable.

It could be such an old monitor got upset by bad video signal.

[jean luc ferre]

hello,
as i said yesterday i can confirm that if i adjust the parameters of the graphic board for this flatron monitor to : resolution 800x600, frequency :56hz there are almost no cut off of the light on the screen; and the gmzan1 processor warms very less.
i also noticed that changing of pc with this time an nvdia graphic board rather than an amd/ati now i haven't no more cutt off of the display and no amber color of the power indicator led. Probably that was a matter of power options of the pc.
Now i will look why i am not displaying the desktop of the pc on this screen.
Once more thank you for all.
Jean Luc Ferré

[jean luc ferre]

hello,
thank you for your help and all your contributions.
i made some new tests...
lowering the resolution of the screen from 1024x780 to 800x600 suppressed all the instability; the screen remains lighted and didn't blint...
putting a coin on the gnzan1 chip for acting like a radiator made the saving energy process (color amber of the power indicator led) is happening less frequently....
so i supposed that all the difficulties came fom the operating conditions.
but i have allways a default ; i don't see the osd screen and the error message when the vga cable is disconnected...
thank you for all
jean luc ferré

[tom66]

Might be possible but that LVDS connector is rare due to the age of the monitor so you'd have to find a kit that supported it.

[jean luc ferre]

Hello,
thank you for your answer...
the price of a new board is very expensive.
Searching on the net for the lcd ht15x13-200 i found informations relatives to controler kits (i put below the links). Can i replace the main board nd so on by such controler?
https://www.google.com/search?q=ht15...client=gws-wiz
here is also a capture picture of this page.

[tom66]

Well, I think the problem originates from the MICOM.

Either the MICOM is detecting something wrong and resetting the system, or the MICOM has bad/corrupted firmware.

There are a couple of communication signals between MICOM and scaler chip (GMZAN1), it is possible that scaler has a problem and MICOM detects this.

I don't have any more suggestions at this time. The problem is likely on the main board (with GMZAN1 and MICOM) but could be difficult to repair without sourcing a new board. For such an old monitor, it would only be worth it for sentimental reasons.

[jean luc ferre]

hello,
i have just removed the j4 connector (inverter) but apart that the screen doesn't light i have allways the same thing on the previous signals...
now i think that the screen sometimes is entering in power saving mode...
jean luc ferre

[jean luc ferre]

hello,
that's allways the same thing that i had previously; on u12 pin4 is effectively at 5v, but all the other pins particularly pin5 are oscillating...
i will do the same thing but this time trying to disconnect the inverter j4 connector...
waiting for new manipulation.
jean luc ferré

[tom66]

Is the VIN voltage on pin 4 of the U12 also changing or is it steady, I think should be 5V?

[jean luc ferre]

Hello,
thank you for your answer and suggestion.
i disconnected the J5 cable and that's allways the same thing...when the vga cable is plugged the screen is blinking and the modpwr3v3 voltage is not steady. what happens is not resulting from this j5 connector; the only thing that stays powering the screen are the connectors of tne inverter...
sometimes i noticed that the screen was coming to saving energy mode (amber color of the power indicator)...with a bip signal of disconnecting on my pc.
waiting for your suggestions and thank you for all.
jean luc ferré

[tom66]

Try disconnecting the cable with MODPWR3V3 on it, and see if the voltages are steady. The screen will still be white but we will be able to determine if a regulator is overloaded.

[jean luc ferre]

hello,
here is the link for the entire document to download :https://elektrotanya.com/lg_flatron_.../download.html
i hope this will help you...presently i am examining the signals coming from and to the microprocessor...but i have not a very clear answer.
Waiting for more ideas...
Jean Luc Ferré

[tom66]

Can you link to the full schematic so I can get a better understanding of what is going on.

[jean luc ferre]

Hello,
thank you for your suggestions...
apart the u30 allthe regulators are ok with correct voltages...
The u30 chip drives the signal modpwr3,3v which is blinking (oscillating) and is connected with the c301 that you recommend me to examine previously.
The u30 chip is driven by the u12 chip where the output signal is oscillating also because the input signal modon is itself corrupted...
this modon signal is coming from the microprocessor.
Below you will find two pictures of image captures relatives to the schématics of these previous signals.
Waiting for more suggestions.
Jean Luc Ferré

[tom66]

I think you should test all regulators on the main board, you may find a defective one.