Anything I Can Do To Prevent Screen Blooming?

Syze · Jun 21, 2012

I have had a 21.5" 2009 model iMac for two years and have just had the LCD replaced for the second time due to screen blooming. Is there any steps I can take to prevent it from happening again? Would a new power supply help?

chscag · Jun 21, 2012

That is very unusual. I have never, repeat, never seen screen blooming on an LCD screen. Describe to us what you mean by blooming. Perhaps we have a different interpretation of that term.

Screen blooming was and still is prevalent with CRT type screens. It's almost always caused by poor high voltage regulation to the CRT. Since LCDs do not use high voltage to light the screen, screen blooming would be very rare.

Syze · Jun 21, 2012

Brownish dirty looking streaks running down the screen...

Syze · Jun 21, 2012

Also maybe it's LED not LCD...

dtravis7 · Jun 22, 2012

It is LED but I have never seen an LED screen bloom either. Blooming happened a lot on old Oscilloscopes with CRT's and the trace instead of looking clean and thin got distorted and fat at higher brightness levels. Like Charlie said a lot of times that was caused by the High Voltage power supply.

What you are describing sounds more like issues with the LCD. Remember it's still an LCD but with LED backlighting, Normal LCD's had fluorescent lighting that would go bad over time and needed an inverter. LED's get rid of that issue and are much more vivid and bright.

Is your new display doing this blooming as you call it? I would ask you to take a shot of the screen and post it so we can see what is going on.

Syze · Jun 22, 2012

The screen is fine at the minute because I only got it back a few days ago from it's second replacement. I've had the machine 2 years 1 month. It was fine for about a year and then the dirty brown streaks showed up in the corners, not too bad but annoying. I figured since I have AppleCare I might as well get it fixed and so I did last October, they replaced the LED. It was fine for a couple of months but then it happened again, quicker and worse than before, all over the screen not just the corners and darker. So I got it replaced again last week and obviously don't want it to happen again.

EDIT: It never showed up in screen shots anyway. And it was definitely inside the LCD and not just the glass panel.

chscag · Jun 22, 2012

OK that's not blooming, at least in the sense of the word. What you're describing sounds more like defective backlighting. Backlighting as Dennis pointed out is supplied by LEDs. It's possible that one or more of the LED panels were defective, however, Apple does not replace backlighting. They always opt to replace the entire display which includes the backlighting.

I don't know how you could prevent it from happening again. It may be that you were just unlucky having it go bad twice. Or, it could be something to do with the power source that supplies the low voltage current to light the LEDs.

mrplow · Jun 22, 2012

I had my 27" panel changed a few months after I got it. It looked like dirty marks inside the sealed screen unit (not on the removable glass/polycarbonate magnetic front panel)

I suspected at the time it was a manufacturing error - a substance on the rear side of the glass panel that 'cooked' over time and got darker and darker.

The genius bar suggested it was condensation - in a sealed unit in a temperature controlled room .... doubtful. But they changed it anyway.

The long and short of it is that I don't think you can do anything to prevent it. I just got extended Applecare to cover myself. The repair will billed out at £650!

dtravis7 · Jun 22, 2012

What I meant and said was a SHOT of the screen, not screenshot! Using a Camera to take a shot of the screen!

Just a note, now that it's clear what you are seeing, my Acer Aspire Netbook did that on the screen 1/2 a year after I bought it and Acer refused to cover it. It looks bad with those marks all over the INSIDE of the screen. The Acer is a LED backlit display BTW.

chscag · Jun 22, 2012

What member mrplow stated above could in fact be what has happened to your display as well. Without looking at the screen myself it's hard to determine but I think mrplow probably has it right. Although it could also be bad backlighting.

pendlewitch · Jun 22, 2012

Syze said:
The screen is fine at the minute because I only got it back a few days ago from it's second replacement. I've had the machine 2 years 1 month. It was fine for about a year and then the dirty brown streaks showed up in the corners, not too bad but annoying. I figured since I have AppleCare I might as well get it fixed and so I did last October, they replaced the LED. It was fine for a couple of months but then it happened again, quicker and worse than before, all over the screen not just the corners and darker. So I got it replaced again last week and obviously don't want it to happen again.

EDIT: It never showed up in screen shots anyway. And it was definitely inside the LCD and not just the glass panel.

I think this could be the infamous ventilation intake issue. They are underneath the bottom of the panel and air is drawn in 'bottom up' streaking the display. I have it and it is very annoying. Tilt your screen as far backwards as you can and you will see fluff collecting on the vents underneath.

http://www.mac-forums.com/forums/apple-desktops/257120-air-intakes-my-imac.html

Syze · Jun 22, 2012

Thanks very much pendlewitch, I have a small vacuum would vaccing out these vents regularly help do you think?

pendlewitch · Jun 23, 2012

Syze said:
Thanks very much pendlewitch, I have a small vacuum would vaccing out these vents regularly help do you think?

It's got to help.I read somewhere that dust is a combination of all sorts of things dead skin cells, desiccated dust mites and clothing fibres etc, cotton being the worst. My theory is because some of the components are organic with some containing oils and moisture they are being baked onto the front of the sealed screen unit.

I've been gently picking the dust off with my fingertips so a vac is going to do a better job I think.

Syze · Jun 23, 2012

pendlewitch said:
It's got to help.I read somewhere that dust is a combination of all sorts of things dead skin cells, desiccated dust mites and clothing fibres etc, cotton being the worst. My theory is because some of the components are organic with some containing oils and moisture they are being baked onto the front of the sealed screen unit.

I've been gently picking the dust off with my fingertips so a vac is going to do a better job I think.

I'll give it a go, thanks!

Anything I Can Do To Prevent Screen Blooming?

Syze

chscag

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Syze

Syze

dtravis7

Syze

chscag

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mrplow

dtravis7

chscag

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pendlewitch

Syze

pendlewitch

Syze

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