Apple 27" Cinema Display (A1316) has trouble turning backlight on

[iuliantv]

Re: Apple 27" Cinema Display (A1316) has trouble turning backlight on

in the link above he also says in that post that, to connect only to 2 ends of some 3v resistors, that the third channel is not used, which is a mistake, because the inverter has 3 channels, 3 bars that go up to about 80v when pwm is forced to a maximum of 3 volts, why do I say that? today I struggled again and I managed to turn on the monitor only if I connected the third contact, I think it had a faulty channel or part of the LEDs to say that it was in error, finally I solved the problem without leaving that change, I had imperfect contacts inside the display, at the connectors of the led strips, I had to undo my eyes, working until about 30 minutes ago

what he was saying

,, The led driver is a three channel pwm controller and the board contains all components for three channels and the connector is prepared for three channel but channel three is not used! So don't put 3.3 on R1133! In this case the led driver detects an error and switch off. The led cinema display has only two led stripes! Therefore connect only R1135 and R1132 with 3.3 volts.
thank you
https://i.postimg.cc/J7NYnvdY/P-2020...4-v-HDR-On.jpg
https://i.postimg.cc/bNL60bPQ/P-2020...4-v-HDR-On.jpg
https://i.postimg.cc/CxQmXgz5/P-2020...5-v-HDR-On.jpg
https://i.postimg.cc/0yQVVQ5h/P-2020...7-v-HDR-On.jpg
https://i.postimg.cc/HsTZ7zqY/s-l1600.jpg

[avneeshshrotria]

Re: Apple 27" Cinema Display (A1316) has trouble turning backlight on

Guys I'm still unable to source a picture for the thunderbolt power supply. Would really appreciate if someone could help with images . Thanks

[Misterkeeks]

Re: Apple 27" Cinema Display (A1316) has trouble turning backlight on

See attached.

[avneeshshrotria]

Re: Apple 27" Cinema Display (A1316) has trouble turning backlight on

Hey misterkeeks, amazing picture dude... thanks a lot for it ! Exactly what I needed . Now I need to order all of the resistors and figure out the Oscillator pin caps the two white ones in your picture either-side of resistor 93b. If you have any ideas do let me know. But anyway thanks again for the image

[howardc64]

Re: Apple 27" Cinema Display (A1316) has trouble turning backlight on

I've fixed about 5-6 of these (27 iMac, Thunderbolt/Cinema Displays) by just resoldering the LED bar connectors. Old lead free solder joint probably weakened from thermal cycling. Here is the write up. See the last few pages for the actual LED bar connector that need solder touch up.

https://drive.google.com/file/d/13Gq...ew?usp=sharing

[slimmy182]

Re: Apple 27" Cinema Display (A1316) has trouble turning backlight on

Do you still want this info? Let me know and I will look. Send me a PM or I will likely not see your post.

Can you please help me figure out this cap value? C308