Help me fixing my Fujitsu LCD Monitor

[cyberbro]

I have Fujitsu Siemens Color Monitor 3816 FA-M Model TFT1560A+, the problem is it goes black after a few seconds ( 6 seconds ), one thing i've noticed is i can see the screen ( whatever i have on the screen) but it is very dim. What could be the problem... please help me...

[stevo1210]

Re: Help me fixing my Fujitsu LCD Monitor

It sounds like an issue with the inverter. what you are seeing is the backlight turn on and then turning off after a few seconds which is why you can still see but very dim. I think there maybe a short somewhere on the inverter or backlight circuit which is why you are experiencing these issues.

[KeriJane]

Re: Help me fixing my Fujitsu LCD Monitor

Hi Cyberbo

I've fixed some LCD monitors over here.

Yours sounds like the LCD backlights aren't working, but the display itself is OK. The fact that the backlights go on for a few seconds then turn off may indicate that the backlight controller thinks something is wrong.

The backlights themselves are high-voltage florescent tubes at the top and bottom of the screen. There are usually either 2 or 4 total. They run off of 500 volts suppled by the Inverter. The Inverter takes 24v from the Power Supply and boosts it up to the 500v that the tubes need to run.

Stuff I've seen go wrong:

Bad capacitors in the Power Supply. These are usually very obviously bad with swollen tops and sometimes electrolyte venting. Most often, the whole thing shuts down and the power light blinks or goes off. Sometimes just the Inverter for the backlight goes off though.

If you lose any one florescent tube, usually the inverter shuts off after a few seconds. A likely cause of this is "drowned" florescent tube(s), usually at the bottom of the screen. This often happens when someone sprays glass cleaner right on the screen and it runs down and contacts the tube itself. This usually ruins the tube.
If you look very carefully at the screen during the short time it is lit and it is unevenly lit (slightly brighter at the top) this could be the culprit.

The easiest way to test a dead tube is to temporarily connect the suspect tube to the opposite wiring (top to bottom or vice-versa) and see if it lights up. Replacement tubes are available on eBay but be warned: Disassembling the actual panel to get at the tubes is very delicate, exacting and tricky. The tubes themselves are incredibly fragile, usually being only 2mm thick and over a foot long.

If you are handy at taking things apart, it wouldn't hurt to look over the capacitors..... they're an easy fix if you find bad ones.

Have Fun!
Keri

[EGuevarae]

Re: Help me fixing my Fujitsu LCD Monitor

I needed a Dell monitor to complete a system I was assembling and stumped on a 15" Dell that i ended up buying in $15.50 Shipping included. The reported problem was exactly the one in this thread. When I inspected it, the backlight turned on and off quickly, and you were able to actually see the picture, but very dim because the lamps did not light fully. I inspected the power supply ( and replaced some CapXons that were OK but have bad reputation) and when I arrived at the inverter, I noticed a small Sanyo 100uf 25v that seemed to be OK. I changed it for a Stone 100uf 25v from a dead board, and that was it. It is working ever since (like 3 weeks ago). I was suspecting a lamp, and ended up being a small cap. You can check that also.

[cyberbro]

Re: Help me fixing my Fujitsu LCD Monitor

Thanks for the reply, I already replaced most if not all the capacitor i will check the tube today and let you know the result. Aside from tube what else can be the problem?

Hi Cyberbo

I've fixed some LCD monitors over here.

Yours sounds like the LCD backlights aren't working, but the display itself is OK. The fact that the backlights go on for a few seconds then turn off may indicate that the backlight controller thinks something is wrong.

The backlights themselves are high-voltage florescent tubes at the top and bottom of the screen. There are usually either 2 or 4 total. They run off of 500 volts suppled by the Inverter. The Inverter takes 24v from the Power Supply and boosts it up to the 500v that the tubes need to run.

Stuff I've seen go wrong:

Bad capacitors in the Power Supply. These are usually very obviously bad with swollen tops and sometimes electrolyte venting. Most often, the whole thing shuts down and the power light blinks or goes off. Sometimes just the Inverter for the backlight goes off though.

If you lose any one florescent tube, usually the inverter shuts off after a few seconds. A likely cause of this is "drowned" florescent tube(s), usually at the bottom of the screen. This often happens when someone sprays glass cleaner right on the screen and it runs down and contacts the tube itself. This usually ruins the tube.
If you look very carefully at the screen during the short time it is lit and it is unevenly lit (slightly brighter at the top) this could be the culprit.

The easiest way to test a dead tube is to temporarily connect the suspect tube to the opposite wiring (top to bottom or vice-versa) and see if it lights up. Replacement tubes are available on eBay but be warned: Disassembling the actual panel to get at the tubes is very delicate, exacting and tricky. The tubes themselves are incredibly fragile, usually being only 2mm thick and over a foot long.

If you are handy at taking things apart, it wouldn't hurt to look over the capacitors..... they're an easy fix if you find bad ones.

Have Fun!
Keri

[cyberbro]

Re: Help me fixing my Fujitsu LCD Monitor

I dont know what else could be wrong, b4 removing the tube I tried something else, i removed the inverter board and put it in a working monitor (same model and brand) and it does the same problem, the moment you turn it on it work for at least 6 seconds and it goes black so I thought the problem is with the inverter board but when I used the inverter board from the working monitor to the one i was trying to fix, it is the same problem.

Any idea what could be the problem? thanks in advance.

By the way, the power source is an external adapter (12v) and the monitor itself has 2 boards, inverter board and another board where you connect the vga cable.

[EGuevarae]

Re: Help me fixing my Fujitsu LCD Monitor

Tubes in bad LCD failing and need more power than the inverter provides, and an inverter dying because of over work?

[PCBONEZ]

Re: Help me fixing my Fujitsu LCD Monitor

Yes, or some kind of short at the ends of tubes (connections).

[cyberbro]

Re: Help me fixing my Fujitsu LCD Monitor

UPDATE:

First of all thanks to all of you, its really a great help reading all your replies.

Seems the problem is the tubes in the lower part of the LCD plus the inverter board. After replacing these two parts it become ok (LCD monitor) so far it was working for more than 1 hour now.

On the inverter board, what could be the problem, i've almost replaced all the capacitor.

Thanks again.

Tubes in bad LCD failing and need more power than the inverter provides, and an inverter dying because of over work?

[Bobdee]

Re: Help me fixing my Fujitsu LCD Monitor

hello
Just on the off chance, I have not got a clue what your inverter looks like,but check if there is one of those dreaded tiny minute fuses, by the connector, it may be open, if you have one,
Then check the 4 transistor that havent to my knowledge been mentioned upon as yet
bob

[EGuevarae]

Re: Help me fixing my Fujitsu LCD Monitor

Post a picture, and give more data on the inverter itself.

[cyberbro]

Re: Help me fixing my Fujitsu LCD Monitor

Here are the details of the Monitor:

Fujitsu Color Monitor 3816 FA-M
Model TFT1560A+
Power: 12V / 2.5A

715L983-1A-2 AU INVERTER BRD (Written on board)

Done: Replaced 9 capacitor with exact value

Any help will be appreciated, thanks

[EGuevarae]

Re: Help me fixing my Fujitsu LCD Monitor

Maybe it's just me, but I can't figure out anything from the picture (too small). In the meantime while you manage to upload a bigger/better one, why don't you put the known good inverter in the failing monitor (with your old top lamp and your replaced bottom one) and test it? I've just finished fixing a Proview LT716s with a similar problem, and ended up swapping both upper and lower lamps. It it fails, maybe the problem resides in your lamps rather that in the inverter itself (caps changed already, you said)