I bought LED light checker , test result is each stripe 54V shown.

I found one of boost schottky diode ( STR0+ ) exploded. also mosfet has burned.

according to A1267's service manual I can find 24.5v and 15V from PSU into MLB.

I need to clarify "Power Source voltage firstly". please tell me some data if you have a exprience.

Question:

1. PSU Connector's Pin voltages: Can you tell me correct voltage each connect pin on MLB ?
   • now I measured pin#1 : 24.5 V , pin#2 : 24.5 v ( tied up pin#1 ) , pin#3: GND , pint#4 : GND ( tied up pin#3 ) , pin#5 : ? , pint#6 : ? , pint#7 : ?
2. Back Light LED test result
   • I can read about 54v each stripe by Back light Test. I guess back light well.

**

I am going to exchange 540N Boost MOSFET and B2100 schottky diode and HV9982 controller.

firstly I have to check power source of back light , locally I guess PSU provide 24.5V.

order to check TP11 --> TP12 --> TP81 and STR0+

anyone who know proper parts?

1. Mosfet part : Rds value ?
2. Schottky Diode part : Vd value ?

⟐ Edited July 07, 2024 at 7:58 MST

(which includes, late 2009 poly MacBook, early 2009 20inch iMac and a late 2009 27inch iMac ) someone please have a fix for this as I’ve been dealing with it for a long time now

⟐ Commented July 12, 2022 at 13:22 MST

When I connect my Apple Cinema Display 24" ... the flickering goes mental ...

Tried every configuration. still no luck

⟐ Commented May 30, 2022 at 20:40 MST

Thanks for your attention.

Cheers

Mauro

⟐ Commented January 13, 2022 at 16:28 MST

The screen goes black on reboot or start up. The Mac knows its there (I have dual displays) the hard drives etc plugged into it are seen by the Mac and the Mac thinks its on but the screen is black.

If I unplug the power leave it 10 seconds and then replug it back in it usually starts back up again. Sometimes it might take 2 goes of doing that for it to come back to life.

I am not sure if this is connected but the screen is slightly more dull than the other screen. ie not a bright and crisp. Image quality is still great. Its just slightly duller.

Any thoughts, before I plow in and pull it apart? LED, Backlight or Logic board?

Thanks much appreciated.

⟐ Commented September 07, 2020 at 4:45 MST

I hope someone can help me.

My Apple Cinema Display won't turn on.

When Mag Safe is connected the fan turns on and the USB works for about 10-15sec. The USB turns off and then it turns on for 10-15sec. Keeps looping.

It won't be recognized by iMac or powerbook. It still can charge the powerbook.

I removed the LCD and disconnected all cables except the power cables from the logic board. The boards looks like new, no heat damage to see.

I measured the voltages on the Logic Board an they are all ok (i use the Apple Technicians Guide for help).

I then connected the USB and plugged in an memory stick and it works fine from the iMac. One by one I started to connect cables to the logic board. This to locate where the problem occur.

The fan runs full speed even with sensor 1+2 connected.

When connecting the Cinema Display LVDS LCD Cable MB382LL (LCD Function Interface cable) it went fine until it was connected to the Display. Then the problem reoccur. I tested the LCD Function Interface cable and it seems ok. The backlight cable was not connected to the logic board during test.

The miniDP cable was not connected to the LCD during test. So I don’t think the problem is the all in one cable.

Could it be a short circuit in the logic board or in the LCD?

How to test the LCD for short circuit?

Any suggestions?

In advance thanks.

Dan

⟐ Edited by author April 29, 2020 at 10:56 MST

can’t find cable online except shady sites BBB says report of not receiving 922-8679. power and usb good shows system report cam speakers etc no display connector busted.

Please help

Microsoft PowerPoint - K23_LM270WQ1-SDA2 CAS Ver1.0_090916 this is the display specs for 24 apple cinema

⟐ Edited by author August 18, 2018 at 20:18 MST

A day after the screen stoped working I noticed the backlight had dimmed a little bit. Also about ten minutes before it stopped working it smelled a bit to "burnt chip".

Probably a new board will solve the problem but the source of the problem is elsewhere. Could it be the fan stopped working and I didn't notice it?

Is there any fuse in the main board I could replace so that I don't have to buy all the mainboard?

⟐ Commented February 11, 2018 at 19:25 MST

The biggest problem in the voltage readout (testing point diagram can be found on Page 16 on the guide):

LCD and LED part:

TP81: 0V (should be 24.5V),

DC in part:

TP11: 12.7V (should be 24.5V),

TP12: 0V (should be 24.5V),

TP13: 0V (should be 12.0V)

I read through the forum, there may be some problems with the fuse on the logic board or the power board is broken? I am sure which is more likely to happen. I don't know where is the fuse located neither the data sheet of the fuse.

Any suggestions?

Thanks!

⟐ Commented October 16, 2017 at 19:12 MST

After some time (more than 6years of almost everyday usage that's not bad) my display got some difficulties to stay "awake", and then goes definitely black.

First I though, after some deep reseach on internet that it was the PWM module on the main board. (I could see a perfect image on the dark with a flash light.) So I cut some wire and short circuit the "power balun" as they said that energize the back panel. You find a lot of info on google. But.... this was not this. ( this is not for everyone)

Too bad I did it for nothing.

They come the idea, to do another try with a probabilist failure approach : change as much as possible capacitor in the power supply ( you can still find this power supply for sale on Internet type PA-2201-02A 661-4821 or A1267 on Ali express even mother board for 80-150$ each)

Then I ordered, same parts characteristics mostly, a couple of 1uF 450v, a combination of 400-450v 39-120uF and 10uF/50v + 22uF 50v.

Did it on Ali Express to test the approach fix a chinese pb with chinese supply. Intellectually, this was an interesting idea ?

Found some componant that was reasonably priced. ( 30 - 40 days of shipping but arrived )

typically : I bought this lot and une one of the capacitor to repair.

https://fr.aliexpress.com/item/10pcs-120...

It is just a little to large but the power supply still fit in place. ( I just did not put on the screw )

Then for about a budget of $11 + about approx $15 for the other capa the display when on again.

You have then a lot of spare for other device.

Basically the power supply is well design, very few capacitors, the only difficulties is the board is RHOS

so tin takes more time to be unsolder.

My tips to helps I add a traditional lead solder to lower the fusion point of the mix.

I hope this helps other.

And for once, thank Apple for a reparable design.

⟐ Commented October 09, 2017 at 16:59 MST

I am new to these forums.

I just purchased one of these units and the sound is very distorted. Is it a common fault? Likely to be hardware (perhaps run too loud by previous owner), or firmware?

Thanks

See You photos

https://discussions.apple.com/message/31...

thank you very much

Anyone can Help ?

Thanks

Anyone can Help?

Thanks

⟐ Edited by author January 16, 2017 at 15:44 MST

Thank you so much in advance anyone who can help with my question.

I've just received a LED Cinema Display 24 inch which I have plugged into my 2011 Macbook Pro 15 inch with Yosemite and the latest OS installed.

When I turn the Macbook on with all wires plugged in the laptop the screen flickers uncontrollably which also causes lag to mouse movement as if the display is constantly connecting and disconnecting.

I've scoured the internet and found that there was a common problem which occurred to all LED Cinema Displays when Thunderbolt was introduced which caused them all to bug out with the same problem that i've described.

I've looked around for the fix which apple no longer supply and have found what I believe was the fix but it didn't work.

Currently the only way I get it to work is to put the whole monitor on its back and after a few minutes it powers into life and works perfectly fine for hours and hours until the computer is restarted then the problem occurs again.

Does anyone out there have a solution or a suggestion? is it a problem with the wires or a software problem? I've tried jiggling the wires to no avail and before I open it up to have a more in-depth look at the soldering on the board where the wires are connected I thought I'd ask the wonderful community to see if anyone else had the same or similar problem and whether they fixed it or someone who might have an educated guess as to why this is occurring.

Sorry for the long essay and again for anyone prepared to help thank you so much in advance.

Peter

⟐ Commented October 13, 2015 at 20:04 MST

⟐ Edited May 24, 2015 at 10:34 MST