Acer AL718: It Goes On And Off

[selldoor]

Re: Acer AL718: It Goes On And Off

But will first measure the voltages on the powerboard,

If that is to test the inverter transformers DO NOT power the Boards

[selldoor]

Re: Acer AL718: It Goes On And Off

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

Whew - thought you were going to test the voltage on them!!!!
could be 1800 vac - dont try it.

If that is 471 ohms and 473 ohms then they are good.

[selldoor]

Re: Acer AL718: It Goes On And Off

Something else to try : In the brief period it flashes on turn the brightness right down and see if it stays on any longer.

[nick2012]

Re: Acer AL718: It Goes On And Off

Dear god 1800vac the meter go's only to 600V,you stated measer "cold" so i did exacly that
I will try the brightnes test,but it must done in the onscreen menu ,that would be dificult
in a'very short time.

[nick2012]

Re: Acer AL718: It Goes On And Off

I found a' Dutch Electronics forum,and hope that they can help also,so options from 2 site's.

Did not maneged to get the brightnes to set lower,simply there's no time to get there
picture is gone before entering the Menu.

[Davi.p]

Re: Acer AL718: It Goes On And Off

nick i know pulling the light bulbs out is an hard work but from your picture 4 - post #35 i see a little darkened end that seems outside the glass, if you read well i have told to leave the little white rubber to see the terminals, them can be burnt / desoldered.

[nick2012]

Re: Acer AL718: It Goes On And Off

Okay its a'major job again but will do so ,and inspect then extra.

[nick2012]

Re: Acer AL718: It Goes On And Off

Ii'have put a'movie on youtube of the the tubes.

http://www.youtube.com/watch?v=UJrk1...ature=youtu.be

[nick2012]

Re: Acer AL718: It Goes On And Off

While measering the voltages,I have made a' shorting and now is the board dead,the main
fuse is still okay but the others i' dont know where they are located,while measering
the 5V I did see that It wash 5.2V and verry unstable ,so maybe badcaps then.
But first I'll have to get it back to live.

[nick2012]

Re: Acer AL718: It Goes On And Off

I'Have manege to get 1 of the bulps out of the metal strip,but how to undo the rubber
end aps for inspection ?

[Davi.p]

Re: Acer AL718: It Goes On And Off

"While measering the voltages,I have made a' shorting"
Hi nick, these sort of things happens quite a lot of times and i do them too :-(
so keep in mind that if you are unsure of the touch of the probes and them slides away don't do the measurement or try a different method like masking with tape all possible near obstacles (pins). Now it's useful if you post a picture with a mark where did you make the short; for the lamp i have handled them only 1 time in life and i've found impossible to slide the rubber along the wires 'cause them are siliconic or "matted skin", the only way is to slide it on the lamps themselves very slowly taking the lamp with 2 fingers near the end where the rubber to move is..

[nick2012]

Re: Acer AL718: It Goes On And Off

I'have put the a' picture off the measure area where the power markings text stands,Its
the band wirecable that conect the two boards.
Is it realy nesesary to remove the rubber endcaps,they are so very fragiel ?

[Davi.p]

Re: Acer AL718: It Goes On And Off

Nick i'm not so an expert, i think that if you want to eliminate possible causes you have to check the integrity of the soldering of the tube terminals, i don't have your lamps in hand and i can't feel how much fragile them are, i have done this on mine very carefully and nothing crash has happened; about the testing area, were you testing that with band wirecable connected to the each board? If so i think the damage is now on the main logic card. Test the power supply board detached from the rest and see if there are the output voltages.

[nick2012]

Re: Acer AL718: It Goes On And Off

The tubes are about 2mm diam,so they are very fragiel,but will atempt to get closser in
to solders.
At the time off shorting the Logic bord was not connected,so fault must still in the power
board,I'll suspect there must be some fuse around that area.

[selldoor]

Re: Acer AL718: It Goes On And Off

Ok - You need to start again- forget the lamps for now. I can show you later a thread on how to make a test lamp.

Power off
1 Test the the main fuse - near the mains input socket - meter on ohms200
probe each end of fuse - should be same as holding the probes together.

2. If fuse is good
POWER ON - High voltage test so very careful.
Meter on 600vDC put one probe on each end of BIG cap.

[Davi.p]

Re: Acer AL718: It Goes On And Off

Nick i'm sorry for you but there isn't clearly any fuse on the secondary from your pictures.
after the selldoor's test, test newly all outputs in the same connector you circled but now put your elbows on a steady plane and if you want mask other solderings with tape or measure on the connector not on solderings, by putting a short piece of wire (not cable, like a resister terminal) in each hole of it... i think you won't find any V. If so test the main switching mosfet , from your first picture is the lowest chip with 3 legs on the smaller heatsink, test in diode mode, it must not read approx 0,00 in any combination. BYE!

[nick2012]

Re: Acer AL718: It Goes On And Off

okay will try all that, I have a spare test lamp/tube from another defective display the
tube works fine for testing,I have also a'spare Mainboard from where i can use spare parts,
like the big Cap enz.

[Davi.p]

Re: Acer AL718: It Goes On And Off

mainboard is intended as the one with digital signals connected between panel and PSU board (or IP board, other name).

[nick2012]

Re: Acer AL718: It Goes On And Off

I meant powerboard/PSU instead of mainboard,there are maby usable parts on it?
last days not must testing done, A' bit busy with outher things.

[nick2012]

Re: Acer AL718: It Goes On And Off

Nick i'm sorry for you but there isn't clearly any fuse on the secondary from your pictures.
after the selldoor's test, test newly all outputs in the same connector you circled but now put your elbows on a steady plane and if you want mask other solderings with tape or measure on the connector not on solderings, by putting a short piece of wire (not cable, like a resister terminal) in each hole of it... i think you won't find any V. If so test the main switching mosfet , from your first picture is the lowest chip with 3 legs on the smaller heatsink, test in diode mode, it must not read approx 0,00 in any combination. BYE!

The Mosfet 27G11 gives (Cold)fluctuating readings on one the right leg .625 on the left
leg noting at all .

Will fabricate some small wire's on the testing area,so i'wont short it again
while testing.