Apple Cinema Display 27" No TBolt - Buzzing and then dead

[bammbammfran]

Re: Apple Cinema Display 27" No TBolt - Buzzing and then dead

Now you might have an idea as to why they only produced this model for 1 year !!

I had a Samsung board doing this when hot and I tried changing all kinds of caps, resistors and diodes before I found that it was the actual transformer causing the issue.
Maybe the one transformer on these is a POS

[BeginnerEnthusiast]

Re: Apple Cinema Display 27" No TBolt - Buzzing and then dead

Damn it!!

Did you get a new PSU for the screen or do you mean you got a new screen? I am thinking about getting a new PSU and see if it works.

[typturbo]

Re: Apple Cinema Display 27" No TBolt - Buzzing and then dead

So, I managed to connect the Psu outside the display and took 5x12V (80mAH)motors to strain the PSU.
after couple of hours the orange film caps begann to buzz, louder and louder.

If u touch the orange with an isolated screw driver the buzz gets different.

I i decided to replaced those orange film Caps 2x 1uF 450V and 1x 470nF 450v.
hard to get those here in Germany. had to order those.

Psu for around 2 hours in Use. Let's see.
I give u an update

######
UPDATE:

it's there again...
got a new PSU on my desk.

I'm done with that

[bammbammfran]

Re: Apple Cinema Display 27" No TBolt - Buzzing and then dead

Have you tried unplugging the power and letting it overnight to see if that made a difference ?
I ask because basically this is what you unintentionally did when you took it apart to glue the parts.

I looked at your old pictures--On the orange plastic coated capacitors that are against each other: Are they the same numbers ? I ask this because one is a bit fatter than the other and I have seen these get fat on other boards when they fail

[BeginnerEnthusiast]

Re: Apple Cinema Display 27" No TBolt - Buzzing and then dead

Hello again!

I have tried and failed again. Last week I opened up the screen took the PSU out and glued the copper transformers hoping this would end the buzzing. I put the glue over and around the transformers and let it set. I then put the screen back together and started it up. It was silent. For three days. Now it has started again and it is as bad as before.

Now I and stuck again and I would really appreciate further advice. Should I have the transformers replaced with new ones? Should I just replace the whole PSU? Any other tips/thoughts?

Thank you!

[typturbo]

Re: Apple Cinema Display 27" No TBolt - Buzzing and then dead

exactly the same with mine. i could buy i new psu for around 150€, but there have to be the possibility to fix the old one.

no idea so far. pls let me know if something works.

[BeginnerEnthusiast]

Re: Apple Cinema Display 27" No TBolt - Buzzing and then dead

Could it be the coils that are making the buzz? Or the Polyester film caps, 0.47uF 450V? Those were making the buzz when I listened the last time. Would it help to replace them? Does anyone have a clue why the buzzing stopped for a week after replacing the capacitors and then returned slowly? I really don't know what to do here. Thanks!

[BeginnerEnthusiast]

Re: Apple Cinema Display 27" No TBolt - Buzzing and then dead

Well the buzzing IS back. Today it started again. I unplugged the magsafe connection to the mackbookpro and it got quieter but it is there. This kills me. So annoying. Well I do not know what I should do now. Maybe replace more of the components. I only replaced the green taicon capacitors so maybe I have to replace them all. Any ideas? How is it going for you typturbo?

[typturbo]

Re: Apple Cinema Display 27" No TBolt - Buzzing and then dead

.. And? everything fine?

i got mine in the ofen and glued every cap to the board.
this worked for me for 2 weeks.

But now. the same its buzzing all the time and loud, very loud.

again. i put this in the often and resolder some parts.
let's see

[BeginnerEnthusiast]

Re: Apple Cinema Display 27" No TBolt - Buzzing and then dead

Hey! I have FINALLY gotten around to getting the caps changed and I put the screen back together tonight. So far everything is perfect. No buzzing. But I got a little worried now that I read your post, typturbo. I am just gonna cross my fingers and hope for the best.

Thank you so much for all the help, Th3_uN1Qu3, budm and Khadgar!

[typturbo]

Re: Apple Cinema Display 27" No TBolt - Buzzing and then dead

HI. i Got every Got damn Cap replaced. (twice)
the first 10-15 hours i hear nothing. then it starts to buzz really quit and gets louder.

it gets louder with brightness and macbook plugged. I run this with a mac mini and my macbook gets charged over the display.


anyone knows wich component also needs to replaced?

[BeginnerEnthusiast]

Re: Apple Cinema Display 27" No TBolt - Buzzing and then dead

Ahh, again I am not very into how everything is connected and wired so that's why I asked. I will get to it but I am also curious about what this friend of Kahdgar might say about the photos.

Thanks!!

[Th3_uN1Qu3]

Re: Apple Cinema Display 27" No TBolt - Buzzing and then dead

By replacing those capacitors.

[BeginnerEnthusiast]

Re: Apple Cinema Display 27" No TBolt - Buzzing and then dead

Hey! Thanks for the tip.

Any thoughts on how I could fix that maybe?

[budm]

Re: Apple Cinema Display 27" No TBolt - Buzzing and then dead

They Polyester film caps, 0.47uF 450V. The circuit may be running at the wrong frequency, you may be hearing the harmonics of the running frequency.

[BeginnerEnthusiast]

Re: Apple Cinema Display 27" No TBolt - Buzzing and then dead

I have found some more clues. I managed to turn the PSU around and listen to it with an little tube when it was powered on. I found that most of the buzz was coming from these two orange components:

http://imgur.com/a/2zxdJ#18

http://imgur.com/a/2zxdJ#19

The buzz is not at all as loud when I turn on the power without the LED screen plugged in but the buzzing is there.

Hope this helps in some way!

[BeginnerEnthusiast]

Re: Apple Cinema Display 27" No TBolt - Buzzing and then dead

Oh thank you so much! Greatly appreciated!

[Khadgar]

Re: Apple Cinema Display 27" No TBolt - Buzzing and then dead

All I replaced were the caps and once all of the Taicon, you seem to have some variation on your board, all of my were Taicon.

My replacements were all Rubycon due to the generally good feedback from users here.

One of my current coworkers spent many years repairing electronics, I'll run the photos by him tomorrow if not one has responded and let you know if he thinks any look noticeably bloated.

[BeginnerEnthusiast]

Re: Apple Cinema Display 27" No TBolt - Buzzing and then dead

Hello!

Thank you for your reply. I have looked at the back of the circuit board and the solders but I can not see anything that looks broken or damaged. I did see some kind of yellowish gue/silicon on one part of the board. I am guessing it does not affect the electronics but I thought it was best to let you know. I have photographed the back side and added the pics to the album:

http://imgur.com/a/2zxdJ#14

Could the sound come from any of the other components like the copper coils (is that the name?) or something else? I guess I will just have to replace it all if it is to hard to tell which one is the guilty one.

Thank you for your help!

[Th3_uN1Qu3]

Re: Apple Cinema Display 27" No TBolt - Buzzing and then dead

That does not look, erm, sound, like a capacitor issue to me. In any case, if the caps are to be replaced, the Rubycon and Chemicon (black and brown) caps can stay. Replace the Taicon only, with equivalents from Rubycon, Chemicon or Panasonic. I don't have time to look at the pictures right now, but i think Chemicon KY will be adequate replacements.

I would look at the board for cold/cracked solder joints around the inverter area (the area where the backlights plug in). Resolder and see if it still makes the noise.