A1278 "Stagelighting" on screen + high freq whine

[850csi]

Hey all,

Picked this up cheap intending to use it as a desktop (mid 2009 mb991ll/a) It works perfectly for that purpose, but I'm tempted to try to fix its lcd anyways. It is remarkable how fast these old things feel with El Capitan.

The display has the so-called "stagelight" effect at bottom:



Obviously far more noticeable with lighter colors.

In addition, the lcd will sometimes "freeze" and get washed out with lines and other gibberish:



The screen becomes unresponsive when this happens. When this occurs, some strong pressure to the lower right portion of the bezel and/or moving the display restores the image.

In addition, at anything less than full brightness there's a quiet high-pitched [incredibly annoying!] "whine" that gets quieter as brightness is lowered.

If I had to guess, two independent issues, one perhaps with the power board and the other with the LVDS cable or hinges? Thoughts welcome.

[stj]

Re: A1278 "Stagelighting" on screen + high freq whine

led strip needs replacing.
some are dead, the working ones are stressed by overcurrent.
that may be causing the whine too.

it may even have a damaged driver chip.

[850csi]

Re: A1278 "Stagelighting" on screen + high freq whine

led strip needs replacing.
some are dead, the working ones are stressed by overcurrent.
that may be causing the whine too.

it may even have a damaged driver chip.

Thanks! So it needs a new display, then, and should be fine?

With regard to the bolded, any way to check on this? Isn't the fact that physical manipulation of the screen resolves/affects the situation suggestive of there being nothing wrong on the logic board itself? Or are you referring to the [constant] "stagelighting" rather than the other issue? Sorry, n00b here.

[stj]

Re: A1278 "Stagelighting" on screen + high freq whine

i was refering to the led driver,
when they blow they usually have a hole in them!
take the panel out and examine the small square chip near the led strip cable.

[850csi]

Re: A1278 "Stagelighting" on screen + high freq whine

i was refering to the led driver,
when they blow they usually have a hole in them!
take the panel out and examine the small square chip near the led strip cable.

You're referring to it as shown in this picture, correct?



Mine looks fine as far as I can tell...



(really appreciate your help & patience)

[stj]

Re: A1278 "Stagelighting" on screen + high freq whine

that looks o.k.

i'm surprised it's there though,
on most laptops it's on the display panel itself, not the mainboard.

[dellxps15]

Re: A1278 "Stagelighting" on screen + high freq whine

first picture looks like a bad led , while second picture looks more like bad panel or bad lcd cable. if u can try another lcd cable and lcd.

[850csi]

Re: A1278 "Stagelighting" on screen + high freq whine

that looks o.k.

i'm surprised it's there though,
on most laptops it's on the display panel itself, not the mainboard.

Yeah I figured there was something being lost in translation - I only knew this because of extensive googling, got that image from ifixit. Can't verify the accuracy myself.

first picture looks like a bad led , while second picture looks more like bad panel or bad lcd cable. if u can try another lcd cable and lcd.

Thank you both for your help. We'll see... I'm tempted to try getting a replacement cable and see what happens but taking the screen apart to get at it is quite an ordeal. Was mostly trying to figure out if it's worth the effort - can I be reasonably confident my logic board is ok?

[dellxps15]

Re: A1278 "Stagelighting" on screen + high freq whine

try with a dvi adapter and see if image is ok.

try also a pram reset and smc reset before change lvds cable as u have to unglue the glass (very noisy part)

also when u have that king of lines, try open close the lcd and see if problem still present or disappear. if disapper probably a bad lvds cable, if still present probably bad lcd.

check also temperature of component with hardware temperature monitor if they re ok (max 100°)

[850csi]

Re: A1278 "Stagelighting" on screen + high freq whine

Have been using it as a desktop and it works like a champ

PRAM/SMC didn't resolve anything

When I have the screen cut out like in the 2nd image, some pressure to the bezel or moving the display sometimes resolves it. The spotlights are there ever-presently, though.

Will check on temps.

[850csi]

Re: A1278 "Stagelighting" on screen + high freq whine



Temps look good. This was taken with the screen fading in and out. Sorry forgot to switch to Celsius first.