iMac 820-3478-A

[Justrepairs Ltd]

Happy new year to all

i have iMac 27? no back light I can see the Apple logo when powered on. On u8200 chip there is voltage coming in on pin but no led driver en on pin 10

any advise please

many thanks

 

[2informaticos]

Did you try another screen?
Check voltage and resistance to ground at BLC_VOUT1/2, with screen connected of course.

 

[Justrepairs Ltd]

Cheers man got it all sorted

 

[2informaticos]

Glad to hear that.
Please, let a feedback about the issue, it can help someone else...

 

[Justrepairs Ltd]

Hi the problem was at u4402 and R4404 input on that chip was there but no output changed them and the backlight came on.

 

[2informaticos]

Thanks for feedback...

 

[Justrepairs Ltd]

hi i need a diagram for A1418 IMAC 21" 2017 EMC 3068 820-00597-a
ITS DEAD BUT IV CHECKED POWER SUPPLY IV GOT 12V 3.3V BUT NO POWER

 

[2informaticos]

No schematic available (yet).
You can follow similar schematic using same chips.
But will not be easy to locate test points without boardview

 

[Justrepairs Ltd]

I was thinking the same to much work without board view just going give it back get on with the next cheers anyway

 

[Justrepairs Ltd]

Hi iv got a 820-2530 board it?s I know but customer is happy to pay
I?m not getting green light
iv got
pp3v42_g3h present
ppus_g3 12.58 present
charger acin
charger acok
checked r7060 r7061 all ok all are present
any advise please

 

[JohnB8812]

Start a new post do not put new posts in old threads......