Black Screen Dell E1910Hc 19" LCD

[dig29089]

Can you please help me on how to troubleshoot this monitor?

When I connected the power, there's a blue power led indicator but the screen is black only and there is no display or shadow picture.

I tried to open and I did not see any busted electrolytic capacitor, I tried to search first on the internet and what I found as the same model with my monitor to replace the electrolytic capacitor.

I replaced all the capacitor but I don't have the same voltage rating, what I do is, I used 680uF 35V as replacement for 680uF 25V and 470uF 25V as replacement for 470uF 16V, the voltage rating become higher but the capacitance are all the same.

When I tried to power on again it is still the same symptoms, blue led indicator and black screen.

See the attached actual pictures...

Thanks

[Rtech]

Re: Black Screen Dell E1910Hc 19" LCD

Check D902 and D907,would be my first option.If they are Ok then I would piut the whole thing together,apply a Pc Signal and ensure that you can measure approx 3volts DC on C902 Blue (-) and Black (+).OR>>you can Power up the Power Board ONLY, being very careful,and put a 1k resistor betwen the 5v and Gnd on C902,and with the Backlights ONLY connected see if they illuminate.

[dig29089]

Re: Black Screen Dell E1910Hc 19" LCD

Rtech,

D902 = 0.435
I cannot find D907 on the board, I measure these two diodes:
D901 = 0.422
D905 = 0.435

CN902 = Blue/Black = 3.2Volt

[Rtech]

Re: Black Screen Dell E1910Hc 19" LCD

The diode on the heatsink next to C904..probably a Schottky diode ??.If that is ok measuring from the centre pin to the outside legs, then it looks to be probably the Inverter transformer and/or a Backlight fault ...You need some test backlights ??

[dig29089]

Re: Black Screen Dell E1910Hc 19" LCD

I saw it, D907 = SRF1060 Schottky Rectifier, I tried to test using digital multimeter set to diode, from center-right (2-3) = 0.143V; from center-left (1-2) = 0.144V

thanks

[dig29089]

Re: Black Screen Dell E1910Hc 19" LCD

how can i test the inverter transformer using digital or analog tester?

thanks

[Agent24]

Re: Black Screen Dell E1910Hc 19" LCD

how can i test the inverter transformer using digital or analog tester?

thanks

Normally you could compare winding resistance but if your board only has one transformer there is nothing you can compare it to, unless you find the model number of the transformer online and find what the resistance is supposed to be.

[Rtech]

Re: Black Screen Dell E1910Hc 19" LCD

As Agent 24 noted,that is the only way.But as I suggested spare baxklights for test would certainly confirm or not if they are the problem...which I think it probably is.

[dig29089]

Re: Black Screen Dell E1910Hc 19" LCD

You means guy we cannot conclude if the transformer is bad or good on testing it using multimeter?

@rtech
how can I test the backlight? this backlight is the one inside the LCD?

thanks guys

[Agent24]

Re: Black Screen Dell E1910Hc 19" LCD

You could try this: https://www.badcaps.net/forum/showthread.php?t=19987

If you don't have a spare CCFL lead you can cut up, you could probably just solder some wires to the underside of the connector's pins on the board.


PS: Anyone else notice the weird white IC901? I have never seen an IC like that before!

[rtstorm]

Re: Black Screen Dell E1910Hc 19" LCD

did you try to turn off the lights in room and light the LCD display to see if there is a picture? Maybe monitor works but you dont have a backlight only

[dig29089]

Re: Black Screen Dell E1910Hc 19" LCD

@rtstorm,

there is no picture or shadow on the screen when I used a flash light or turn off the light in the room.