Benq E2200 HD inverter failure

[cheebster]

Hello ! I have this Benq E2200HD here i got for free. It powers on, goes to black after showing the benq logo and saying no signal. With a flashlight, image is displayed with a pc input so it's backlight failure.

Here's a picture of the power supply with included inverter. Caps LOOK fine, however they are JAMICON in the inverter section (270UF, 50V)

The smaller one at the other end, there are 3 25V 680UF Su'scon (wth), 5 220UF Su'scon, 1 black 25V 47UF Su'scon near the big cap, and a smaller 10uf 50V near the audio output.

I've reflowed most of the pins on the bottom of the board in the inverter section to start. I'm not so sure what i should do next, i'm able to power on the screen's CCFL with an external inverter. thanks !!!!

Oh, here's the actual picture of it attached. thanks for any help !!!

[budm]

Re: Benq E2200 HD inverter failure

Did you check the resistance of High voltage windings of the inverter transformer?

[selldoor]

Re: Benq E2200 HD inverter failure

It powers on, goes to black after showing the benq logo and saying no signal.With a flashlight, image is displayed with a pc input so it's backlight failure. !!!!

Oh, here's the actual picture of it attached. thanks for any help !!!

\That sounds a bit odd shows a picture but reports no signal?

[Davi.p]

Re: Benq E2200 HD inverter failure

check smd mosfets on bottom, blue high voltage capacitors for short or leakage also to be sure..

[Rtech]

Re: Benq E2200 HD inverter failure

Is that a pico fuse F8802 on the Inverter side, ?? and have you checked that ??? also do as Budm asks ref the transformer.

[cheebster]

Re: Benq E2200 HD inverter failure

Sorry for the lack of input on this one, been a bit busy here.

budm: don't know exactly if im looking right here, but i see 780ohms on each side

selldoor, i did a few tests.. i mean i know it's the inverter that's in trouble. When a pc signal is connected, i see the faint image using a flashlight. works for 2-3 seconds

davi.p : well, they don't look to have any shorts (the mosfets), they seem to tests ok. i'm not sure how to properly test the blue hv caps though ! i only have a fluke 115 to poke around.

rtech; fb802 is a pico fuse yes and it tests ok !

[selldoor]

Re: Benq E2200 HD inverter failure

I would have thought FB802 the black one in the middle is a ferrite bead however there looks to be a small yellow fuse at F802 near the connector
Have you tested that also?

[cheebster]

Re: Benq E2200 HD inverter failure

Yes, tests good as well !

[selldoor]

Re: Benq E2200 HD inverter failure

Have you any spare bulbs or anything you can plug the bulb leads into?

[budm]

Re: Benq E2200 HD inverter failure

You need test lamps at this point to save time troubleshooting.

[Davi.p]

Re: Benq E2200 HD inverter failure

If you don't want to go crazy finding a spare test lamp, disassemble the screen and see if the lamps have darkened ends, if yes them are to change.

[cheebster]

Re: Benq E2200 HD inverter failure

AH ! fixed this one. I just reflowed everything with fresh solder in the inverter section, re-assembled, and voila !! as new. tested for hours, it seems it's the only thing it needed, sounds odd no ? visually all looked fine...

[Davi.p]

Re: Benq E2200 HD inverter failure

Some earlier Benq are known for bad solder quality..

[selldoor]

Re: Benq E2200 HD inverter failure

I would have suggested that earlier but you said you had done it in the original post? anyway - well done

[cheebster]

Re: Benq E2200 HD inverter failure

Yeah, i did reflow them but never tought it would have fixed it so easy, so i didn't bother to re-assmemble to test... but i should have, it fixed it