GT-I9505 blank display, how to debug board?

[lfelipem]

Hello all,
I'm new here, I have some technical problem, I think here is the best forum to get appropriated help.
I have a I9505 with a blank display, the rest of the phone seems to work well, I can get to download or recovery mode.
Since I thought my display was the problem, I bought a new one and change it, but the problem continues.
Now I'm starting to wonder if it's not a board issue.
I could find some orientation here in the forum, regarding checking some components on the board and changing it:
/f258/i9505-schematics-1840305/
/f258/i9505-black-display-1728331/

Could someone tell me how to debug my board so I can know that the problem is really on the board.
How do I check if my emi filters are ok? Where should I measure?


Thanks,

[d-Artigo]

Originally Posted by lfelipem

Hello all,
I'm new here, I have some technical problem, I think here is the best forum to get appropriated help.
I have a I9505 with a blank display, the rest of the phone seems to work well, I can get to download or recovery mode.
Since I thought my display was the problem, I bought a new one and change it, but the problem continues.
Now I'm starting to wonder if it's not a board issue.
I could find some orientation here in the forum, regarding checking some components on the board and changing it:
/f258/i9505-schematics-1840305/
/f258/i9505-black-display-1728331/
Could someone tell me how to debug my board so I can know that the problem is really on the board.
How do I check if my emi filters are ok? Where should I measure?
Thanks,

samsung gt-i9505 blank display
your problem is no screen display but no lights ... not explained
first try to check both its working voltage at pin lcd 20 and 24 if the capacitor is faulty replace or jumpers
if good and still as before rehot or change its fifth emi filter
(or jumper) ..... see picture below :







only press thank

[lfelipem]

Hello, thanks for the replay.
I tried to measurer the resistance of the capacitor C829 and C1109 with a meter.
Both show small ohms and increase to open circuit. Is that a faulty capacitor?
What is the best way to check the working voltage of pin 20 and 24. Through C829 and C1109?

Thanks