Acer AL718: It Goes On And Off

[nick2012]

Re: Acer AL718: It Goes On And Off

It go's true its old cycle LED and Lamps on off,this time I could hear some hissing noise
frome the Inverter side ?

[nick2012]

Re: Acer AL718: It Goes On And Off

edit double post.

[budm]

Re: Acer AL718: It Goes On And Off

OK, something in the inverter circuit is the cause of the problem. Try it again in the real dark room to see if you can see any arching/sparking around the inverter section, also check the pin of the lamp sockets on the board to make sure it does not have bent pins.
BTW. can you also smell Ozone?

[nick2012]

Re: Acer AL718: It Goes On And Off

No ozone smel,and no sparklins ,no bend pins in the lamp sockets also.

[nick2012]

Re: Acer AL718: It Goes On And Off

the hising noise is gone .

[budm]

Re: Acer AL718: It Goes On And Off

But the LED is blinking still, some thing in the inverter circuit for sure is bad. BACKLIGHTS come on?
I need to know if the backlights even flash on or not, I am suspecting either bad inverter transformer or bad dual MOSFET's (8-pin device next to the inverter transformer).

[nick2012]

Re: Acer AL718: It Goes On And Off

yeah stil blinking his orange/bleu cycle ,and backlichts come on as the Led is bleu and
go off when Led is Orange.

[nick2012]

Re: Acer AL718: It Goes On And Off

can you point out the inverter transformer or bad dual MOSFET's on the picture,and how
to check then for error,i'm a' eletronics specialst just a' low grade basic Eletricity paper for
home,however I, can measure with the multimeter and have a'solder iron,And now the
basic components to identefy like the Caps and resistors,I have also checkt the inverter
IC's for shortings but they where fine.

Regards

Nick

[selldoor]

Re: Acer AL718: It Goes On And Off

Your pics are not really big/clear enough for trouble shooting.
Inverter transformers are the large black rectangular components
with the white label on top. and the mosfets are the 8 legged components
close by.

For testing I suggest you read the 2 seconds to black sticky at the beginning of this forum - click on trouble shooting computer displays (above centre) almost all are power off tests. start at post19

Also try and get the part numbers off the mosfets and look up the data sheets.

[nick2012]

Re: Acer AL718: It Goes On And Off

okay will try the transformers and the Mosfets(the IC's are the 8 legged) ,
I will the 2seconds sticky ,and post19,I'also will look at the part nunbers.

thanks

[nick2012]

Re: Acer AL718: It Goes On And Off

its way to dificult for me,
As alternite I'found that it may be beter to buy a' replacment board at:

http://nl.aliexpress.com/item/ViewSo...944393283.html

[Davi.p]

Re: Acer AL718: It Goes On And Off

Don't do this i say, almost before exctracting the light tubes from the lcd panel and check for burning on the terminals or darkened ends..
"i'm a' eletronics specialst just a' low grade basic Eletricity paper for home"
What do you say?

[nick2012]

Re: Acer AL718: It Goes On And Off

Okay i'l wont order yet then,I'will inspect the tube's for burnings,
I'have yesterday resolder all the major joints and have swiths the black inverter blocks
to see if that would make a'diference ,but it wouldent did so.

[selldoor]

Re: Acer AL718: It Goes On And Off

OK I see that with the language problem the 2 sec to black may be hard to follow.

To test the inverter transformers see the picture.

No Power to boards. Set Meter on ohms 2000.
Test S1 to S2 and S3 to S4 and post results

[nick2012]

Re: Acer AL718: It Goes On And Off

I'have disassembled the display and made pictures off the tubes,they are as I'can see so
far good exept for the ends they are litle black at the ends.













what do you think are they good ?

[nick2012]

Re: Acer AL718: It Goes On And Off

OK I see that with the language problem the 2 sec to black may be hard to follow.

To test the inverter transformers see the picture.

No Power to boards. Set Meter on ohms 2000.
Test S1 to S2 and S3 to S4 and post results

Thankz will try that later on,my head needs some relaxing for now

Reagards

[selldoor]

Re: Acer AL718: It Goes On And Off

They look good to me - need to be careful putting them back

Some Acers did have a problem with the wires detaching from the bulbs
but yours look ok.

Just read your post - yes its a hard job taking lights out. If you can
keep them safe you can test them again out of the frame to listen or look for
any arcing.

[nick2012]

Re: Acer AL718: It Goes On And Off

Oeps I'have putting all all back in place
But will first measure the voltages on the powerboard,after that i'l disamble the display
again for furter inspecktion then.

[selldoor]

Re: Acer AL718: It Goes On And Off

I would leave it if its back together - too much chance of breaking glass

[nick2012]

Re: Acer AL718: It Goes On And Off

At S1 & S2 I' get .471 .
At S3 & S$ I' get .473 .
Meter on 2K