820-3332 ...again....

[Patricia]

Hi 2informaticos and the rest of you nice people

Well here I am again with my favorite nightmare board , the 3332 ....
This time i have a board with some oxidation and no green light at all ....
No liquid damage noticed (the sensors still white) , while checking it out on the microscope i noticed that the R6920 and R6905 are blown , so I thought this will be one easy one (optimistic ha )
replaced those two and connected the charger to see if all is ok now , and as you might guess it was NOT
The R6920 tried to communicate with me the old indian way , sending me smokesignals just before it died , puffff
The R6905 didnt but that is probably because the battery wasnt connected ....
Removed the D6905 and replaced it thinking that might solve the problem , it didnt . Checked the U6990 for short and it seems ok , only the pin 5 goes to ground ....
On pin 1 of the R6920 i do get 18.5 V so that side seems ok so my problem must be on the other side unfortunately .
On the D6905 pin 3 in diode mode i get 0.213 and on pin 2 on L6995 in diode mode i get 0.315 V ....
And there I am stuck .... any help is highly apreciated
Thanks in advance

 

[2informaticos]

"replaced it thinking"
NO, you must change in base of some reason; justfied by measurments, of curse.
Thiking and praying will not solve problems; apart of sentimental ones .

"replaced those two and connected the charger"
When you replace components, ALWAYS check for short, or low/incorrect values, BEFORE applying power on the board.

"D6905 pin 3 in diode mode i get 0.213"
Not short, nor even "too" low, but really INCORRECT; in fact much lower than normal.

Remove C6990/91/93 (one by one) and check again.
If still incorrect, change U6990...

 

[Patricia]

Thank you 2informaticos for your answer , if you are not here we can close the forum
I did apply a prayor before but as you said it did not help ?
I did heck for short but couldnt find one , the value on pin 3 of the D6905 is very low , I wish a had another working board to see what the value should actually be .
I will remove the C6990 /91/ 93 and see if the value changes .
Thanks again for your answer !

 

[Patricia]

Well what can I say , as usual you are the champ !!!!!
It was the C6993 , mark this thread as SOLVED (thanks to 2 informaticos )

THANK YOU SOOOOO MUCH
Fixing a board after 2 days can feel better than sex sometimes

 

[acowan]

I wouldn't know I've never fixed a board ?