Benq ET-005-N No backlight

[b19_george]

Hello,

I have an Benq ET-005-N with backlight problems, the CCFL lamps are not starting at all but i test them and are fine, I know the monitor works because I used another board to fire up the CCFL lamps and once the lamps are on you can see the image on the screen, the caps are replaced are not bulging and tested for capacitance, the transformers have the same resistence both of them (0.63K) so either are both damaged or is the right reading. Any advice will be more than helpfull!
Thank you very much!

[boyebaran]

Re: Benq ET-005-N No backlight

hi
how about dc voltage on d803 d805?
check F802
if all voltage is ok so read SMD ic part number(ccfl controller under inverter board)and inform.
tnx

[budm]

Re: Benq ET-005-N No backlight

https://www.badcaps.net/forum/attach...8&d=1474979853
What DCV do you have on pin 5 (ON/OFF = BL-ON) and pin 6 (Brightness = DIM) with ref. to the chassis GND?

[b19_george]

Re: Benq ET-005-N No backlight

hi
how about dc voltage on d803 d805?
check F802
if all voltage is ok so read SMD ic part number(ccfl controller under inverter board)and inform.
tnx

on d08 with red probe on the middle pin and black on the other 2 pins is 14.9 V
on d805 same probe arrangement is 5.1

part no: OZ9938GN

[b19_george]

Re: Benq ET-005-N No backlight

https://www.badcaps.net/forum/attach...8&d=1474979853
What DCV do you have on pin 5 (ON/OFF = BL-ON) and pin 6 (Brightness = DIM) with ref. to the chassis GND?

there are 6 pin notations and 8 wires so looking at the back of the board starting with the upper pin (blue wire) that is near the hole with the ground of the board the voltages are as follows:
- 3.27
- 0.03
- 0.88
- 3.3
- 0
- 0
- 5.1
- 5.1

Thank you very much for your help. another thing that i should say that the monitor when stooped working i replaced the caps, they were bulged, i don't know if they are any good brand and they were not tested with an ESR meter.

[b19_george]

Re: Benq ET-005-N No backlight

https://www.badcaps.net/forum/attach...8&d=1474979853
What DCV do you have on pin 5 (ON/OFF = BL-ON) and pin 6 (Brightness = DIM) with ref. to the chassis GND?

thanks a lot for your help!

[boyebaran]

Re: Benq ET-005-N No backlight

do you check F802?if yes so:

As picture put 10k ohm resistance and inform me what happen after turning on the monitor.if did not work please jump this point together .

[boyebaran]

Re: Benq ET-005-N No backlight

for more information .this inverter board like as LG :w 1934sI.

[b19_george]

Re: Benq ET-005-N No backlight

for more information .this invertor board like as LG :w 1934sI.

hello, the fuse you mentioned is fine, if i will try that test with the 10k resistor and if is still not working there is nothing else to try?

i will try to put the resistor and see if i managed anything