820-3115 board slight water damage , no green light

[turbo]

3115-b board, ppbug3h is good 12.59v, PP3V42_G3H_REG= 3.4v

PP3V3_S5_REG=3.3v

no green light


SYS_ONEWIRE=3.4v on u6900


pls chk attach pic where was the water damage


pic 1 u5400 fixed...

 

[turbo]

pic 1, u5400 fixed

 

[Alan.L]

i bet u3890 is shorted. remove that thunderbolt shit..it create chaos. check caps near the smc to see if the smc is shorted as well,

 

[dukefawks]

Clean off all the crap first.

 

[turbo]

cleaned everything . i put the pic for reference perpose..... no green light

 

[2informaticos]

Do you have continuity between U6900 and central pin of MagSafe board?
Pins 4 and 5 of U6900 have the same voltage?

 

[turbo]

yes same voltage . took out u3890.... still n no luck ... no green light....

 

[turbo]

No Title

update !!! i change the magsafe now turn on!!!!!!!!! but no post, the white led is on ... does not boot or chime, is this because of i took out u3890..... or something else??? pls chk attach pic

 

[larossmann]

U3890 will have nothing to do with this. What do you measure on CPU vcore? Check R7403 and R7402.

 

[turbo]

U3890 will have nothing to do with this. What do you measure on CPU vcore? Check R7403 and R7402.

ton r7403 and r7402 is good L7520 and l7510 both haS = 1.12v


BUT L7550 NO VOLTAGE...


also is u5400 is related to turn on l7550?!

 

[2informaticos]

If VCORE doesn't drop from 1.12V to aprox 0.8V, no AXG voltage.
Check SPI chip area; traces, resistors.
Do you have 25MHz oscillation?

 

[turbo]

If VCORE doesn't drop from 1.12V to aprox 0.8V, no AXG voltage.
Check SPI chip area; traces, resistors.
Do you have 25MHz oscillation?

which one is spi chip