820-3662-a chime loop

shlom

Member
hi

working on a liquid damaged 820-3662-a

the board powers on and chime sounds again and again
also, after smc reset or pram reset back to chime in loop...

liquid damaged around d2920 c8300 looks also burned..

also around c8051 and r8052

haven't replaced anything yet..

anything worth to measure or check before starting to work on this one?
those chimes could be RAM related? the RAM looks very clean though..

thanks..
 

shlom

Member
i will take out the heasink and look

the RAM looks very clean on both sides.. one burned capacitor on the back near the RAM..

i will check the cpu area and update...

btw, those chime loop is what called "beeps" that are related to RAM?
 

shlom

Member
ok thanks, just never ran into a beep in a macbook...

so i've done this diagnosing..
the cpu and ram area looks very clean, no visible corrosion..
i replaced the next parts that was corroded around the board..
c8300
d2920

c8030
c2350
c8051

all of those was corroded or burned and were replaced..

i noticed that the board only chimes echo when the lcd is connected..
when it's disconnected it only chimes once.. BUT when connecting HDMI monitor
i get horizontal an vertical lines, and no image...

i noticed when the lcd connected i get 44v on c8300
not sure if suppose to be so high...

the LCD itself is good, checked it on another machine...
 

dukefawks

Administrator
44v would indicate an open circuit so if the LCD works on another machine the connector is probably bad.
The lines and garbage on external would still indicate a RAM or CPU issue.
 

shlom

Member
hi

the lcd is good with another board

the lines and garbage on hdmi screen, with the lcd disconnected meaning the board is toast?
 
Top