LED Display Driver board broken - why?

Question

iMac Intel 21.5" Mitte 2010

Modell A1311 / Mitte 2010 / 3,06 & 3,2 GHz Core i3 oder 3,6 GHz Core i5 Prozessor

342 Fragen Alle anzeigen

frickj @frickj

Rep: 11

1

Veröffentlicht: 7. Aug 2016

Einstellungen

LED Display Driver board broken - why?

So I replaced the harddrive to a 1 TB SSD, using OWC Thermometer. Cleaned the interior, especially the vents that were very dusty.

Reassembled it. Turned on the iMac, everything worked fine. Formatted the drive, let it install Mavericks. Came back after 20 Minutes and see that LCD backlight is not working. I can see that the LCD works though. IMac was hot, but it had a good work to do (installing Mavericks), so nothing special.

Disassembled iMac again, all cables were properly installed, not broken.

But my nose smelled something broken. PSU is okay, no damages visible.

But LED driver board seems not okay. One of the three cubic things on it (SuperCaps? - DN680 1016 written on it) is just hanging, might have had a hot time, the tin melted obviously.

Picture: https://drive.google.com/open?id=0B6PdYO...

So my questions is: why did it melt? I don't want to spend 100 Bucks to buy a new one just to destroy it once again. Do you think it's possible just to replace the broken part? What is it exacly? I couldn't find one on the web using the written description on it.

Thank you very much for any help.

Beantwortet! Antwort anzeigen Ich habe das gleiche Problem

Ist dies eine gute Frage?

Ja Nein

Bewertung 0

Einen Kommentar hinzufügen

1 Antwort

Gewählte Lösung

oldturkey03 @oldturkey03

Rep: 781,5 Tsd.

1,1 Tsd.

893

2,3 Tsd.

Veröffentlicht: 7. Aug 2016

Einstellungen

frickj no "supercaps" just regular wire wound 68uH,20% inductors. Measure the size of the case so we can get you that information as well. For the reason why it happened, no answer yet. Still contemplating that one.

War diese Antwort hilfreich?

Ja Nein

Bewertung 3

5 Kommentare:

Thank you very much! With your information, it's easy to find one similar. But when I measured it, I saw, that behind the inductor, the "SD2" seems burnt too. Don't think that I can replace that one.

So I'll oder a new LED board. Just hope, that it will survive then :-)

7. Aug 2016 von frickj

@oldturkey03 & @frickj - Added image of backside of bd so you can see the power transistor which likely blew. Check your backlight cable for damage (possible short).

8. Aug 2016 von Dan

"SD2" would be a diode. Schematics for this a re a bit hard to come by and I think you are going the right way about repalcing the board. Best of luck.

8. Aug 2016 von oldturkey03

I got a used V267-707 LED board, which the seller said is compatible to my defective V267-702. It looked very used though.

Before mounting it, I checked all cables and discovered that one wire of the led power cable was punctured! I remembered that this part was behind a handle when I removed it. But I forgot to put it there when I remounted it. So maybe at this puncturisation where very little isolation was missing, came in contact with the metal back of the screen...

So I mounted the 707-board and isolated the wire better. Now the iMac light is working since one week - so far so good. Thank you all for your help finding the problems!

The only thing that bothers me now: the backlight flickers some time. Maybe all 10 minutes it's making like a horizontal flash in the middle of the screen. Too much energy?

Next step will be replacing the used 707 board to a brand new 702 board... hope that this is it.

14. Aug 2016 von frickj

I'm so stupid. Now everything works. Flickering came from a not plugged in backlight sync cable :D My dear. Ok, now all is fine, thanks everyone.

17. Aug 2016 von frickj

Einen Kommentar hinzufügen

Thank you very much! With your information, it's easy to find one similar. But when I measured it, I saw, that behind the inductor, the "SD2" seems burnt too. Don't think that I can replace that one.

So I'll oder a new LED board. Just hope, that it will survive then :-) — frickj
@oldturkey03 & @frickj - Added image of backside of bd so you can see the power transistor which likely blew. Check your backlight cable for damage (possible short). — Dan
"SD2" would be a diode. Schematics for this a re a bit hard to come by and I think you are going the right way about repalcing the board. Best of luck. — oldturkey03
I got a used V267-707 LED board, which the seller said is compatible to my defective V267-702. It looked very used though.

Before mounting it, I checked all cables and discovered that one wire of the led power cable was punctured! I remembered that this part was behind a handle when I removed it. But I forgot to put it there when I remounted it. So maybe at this puncturisation where very little isolation was missing, came in contact with the metal back of the screen...

So I mounted the 707-board and isolated the wire better. Now the iMac light is working since one week - so far so good. Thank you all for your help finding the problems!

The only thing that bothers me now: the backlight flickers some time. Maybe all 10 minutes it's making like a horizontal flash in the middle of the screen. Too much energy?

Next step will be replacing the used 707 board to a brand new 702 board... hope that this is it. — frickj
I'm so stupid. Now everything works. Flickering came from a not plugged in backlight sync cable :D My dear. Ok, now all is fine, thanks everyone. — frickj

iMac Intel 21.5" Mitte 2010

LED Display Driver board broken - why?

1 Antwort

Antwort hinzufügen