Acer AL2216W Backlight Problem

[kmoonen]

Hey guys i have a Acer AL2216W which when powered on the backlight comes on for about 3-4 seconds, and then goes off, all caps are new

Ken

[budm]

Re: Acer AL2216W Backlight Problem

Please read this for a starter:
https://www.badcaps.net/forum/showthread.php?t=10419

Good clear pictures will help, use GO ADVANCED, ATTACHMENT function.

More info here:

Inverter tester using old CFL: https://www.badcaps.net/forum/showthread.php?t=19987
Bad CFL: http://s807.photobucket.com/albums/y...klight%20lamp/

[kmoonen]

Re: Acer AL2216W Backlight Problem

Here are the pics







ALL CFL bulbs have been tested and work 100%

[budm]

Re: Acer AL2216W Backlight Problem

On the bottom side of the board, there are 4 MOSFETS (8-PIN) on the right side by the transformer, please get the numbers on them. you should also check the transformer resistance of the inverter transformers (pin 5 and 6) as suggested in the link.

[kmoonen]

Re: Acer AL2216W Backlight Problem

Numbers for MOSFETS are

4910N
AA7EAL

[budm]

Re: Acer AL2216W Backlight Problem

Please use attachment function to post the pictures, do not post in line. Lamps are tested with another board? Transformer reading next.

[kmoonen]

Re: Acer AL2216W Backlight Problem

sorry i will use attachment function from now on

yes the bulbs were tested with another power supply, the worked 100%

Not 100% sure on what i am doing with the transformer reading.?.

Ken

[budm]

Re: Acer AL2216W Backlight Problem

Check Source and Drain pins resistance. All 4 have the same P/N?
AF4910 is Dual N-CH MOSFET's. I expect to see Dual P-CH MOSFET's also.

[budm]

Re: Acer AL2216W Backlight Problem

We are looking for resistance reading as explain in the link. Pin 5 and 6 is the secondary side (high voltage winding), the should be within 3% of each others.

[kmoonen]

Re: Acer AL2216W Backlight Problem

sorry im lost. just in my first year of electroncis ..

[budm]

Re: Acer AL2216W Backlight Problem

9? What is that? It should show xxx Ohms. Over Range more likely.
What are the number as printed on the transformers? I may have to look up the pin outs.
I looked at the bottom side (pictures are not well focused) of the board and looks like pin 5 is not used.
There are 6 pins on each transformer, so you will have to put one probe on pin 6 and probe the other 4 pins to see which one is connected.
6&1 = xxxOhms
6&2 = xxxOhms
6&3 = xxxOhms
6&4 = xxxOhms

[kmoonen]

Re: Acer AL2216W Backlight Problem

339.7 is the reading

[budm]

Re: Acer AL2216W Backlight Problem

Between pin 6 and pin? All 4 transformers has exact same reading?

[kmoonen]

Re: Acer AL2216W Backlight Problem

Ok .. i got it now.. wow.. sorry. long day.. give me a couple of minutes

[budm]

Re: Acer AL2216W Backlight Problem

That's OK, long distance troubleshooting is not easy. it is getting close to my bed time here for me.
Also report the reading of the MOSFET's

[kmoonen]

Re: Acer AL2216W Backlight Problem

Transformers

1 - 173.8
2 - 352.3
3 - 352.4
4 - 352.4

1 - 174.0
2 - 352.6
3 - 352.7
4 - 352.6

1 - 175.1
2 - 0
3 - .68
4 - 0

1 - .467
2 - .469
3 - .469
4 - .469

[budm]

Re: Acer AL2216W Backlight Problem

Two of them look almost the same, but the last two look bad. Are you able to get the numbers printed on the side of the transformers so we can look up the spec?

[kmoonen]

Re: Acer AL2216W Backlight Problem

80GL20T-23-DN
Darfon 6501F 725062Z

[budm]

Re: Acer AL2216W Backlight Problem

DARFON! they are bad news! Let me see if I can find the spec.

[budm]

Re: Acer AL2216W Backlight Problem

Well, it looks like this transformer will be hard to get, 80GL20T-23-DN Darfon 6501F 725062Z. A lot of people are trying to locate this thing.