820-2936 sometimes green light no power

[lincev]

hello I need help with this board, no antecedent damages, only sometimes green light no fan spin

neither turn on with smc bypass mode

some values:

ppbus is 1.0v
pp3v42 is 3.3v

 

[2informaticos]

First remove F7040 and check C7040 voltage.
If still 1V, then post U7000 basic voltages: 1, 2, 3, 9, 12, 13, 14, 15, 17, 19, 20, 27.
Also check resistance (ohm scale) between pins 17/18 and 27/28.

 

[lincev]

U7000 mode diode to ground I have continuity pin 17, 18 and 23,

 

[2informaticos]

Not sure what you've meant.
I asked about resistance between some pins, not to ground.

Why don't you post the "continuity" values you've got?

 

[lincev]

ok sorry

C7040= 1v

U7000

Pin1=0,35v
Pin2=0v
Pin3=0v
Pin9=0v
Pin12=0v
Pin13=0v
Pin14=0v
Pin15=0v
Pin17=0,53v
Pin19=0v
Pin20=0v
Pin27=1,3v

R - Pin17/18= 0,32ohms
R - Pin27/28= 20,1ohms

 

[2informaticos]

"Pin2=0v"
No need to check anything else then; fix that problem!
Start checking diode mode to ground there.
Bad R/D7005?

 

[lincev]

nice my problem is with D7005

now I have Pin2=16,5v but don't turn on and don't have led green

now I detect continuity in pin 21 and Q7035, maybe I could have reballed the U7000 wrong and this pin21 is playing dough?

 

[2informaticos]

Now is time to post voltage on U7000's above mentioned pins.

 

[lincev]

C7040= 1v

U7000

Pin1=15,5v
Pin2=16,5v
Pin3=3,95v
Pin9=0v
Pin12=3,44v
Pin13=3,4v
Pin14=0v
Pin15=0,03v
Pin17=0,58v
Pin19=5v
Pin20=5v(but count down to 0v)
Pin27=15v(but count down to 0v)

R - Pin17/18= 0,28ohms
R - Pin27/28= 20,1ohms

 

[2informaticos]

Check R/C7025.
Replace Q7030/35.
Keep F7040 out.

 

[lincev]

im replace Q7030/35 of other board with problem gpu

check C7025 value 556 and R7025 I check with 2 boards (once is work) 0,01 value scale ohms 200 and check for example R7022= 09,9

F7040 out a pin1 0.9v

 

[2informaticos]

"check C7025 value 556"
If you don't know how to check capacitor, replace it.
Be sure to get good solders...

 

[lincev]

hi again, I replace C7025 but continuous with 1v at F7040 Maybe it doesn't replace Q7030735 correctly?

U7000

Pin1=15,5v
Pin2=15,9v
Pin3=0v
Pin9=0v
Pin12=3,44v
Pin13=3,4v
Pin14=0v
Pin15=0,03v
Pin17=0,58v
Pin19=5v
Pin20=5v (pero cuenta atrás hasta 0v)
Pin27=15v (pero cuenta atrás hasta 0v)

 

[2informaticos]

"Pin3=0v"
Check in diode mode first.
Next, remove C7011 and check again.
If still the same, check R7010.

 

[lincev]

ok i have shot in R7011 and C7011(remove two items)

R7010 is good value 29,3 (scale 200k ohms)

now I have 0,67v in pin3 without fuse, R7011 and C7011

 

[2informaticos]

R7011 MUST be soldered.
Change U7000.
ACIN should be around 3.9V...

 

[lincev]

ok R7011 and C7011 soldered ! no short

change U7000

U7000

Pin1 CHGR_AGATE=15,5v
Pin2 CHGR_DCIN=15,9v
Pin3 CHGR_ACIN=0v
Pin9 CHGR_AMON=0v
Pin12 PP3V42_G3H=3,44v
Pin13 CHGR_RST_L=3,4v
Pin14 SMC_BC_ACOCK=0v
Pin15 CHGR_BMON=0,03v
Pin17 CHGR_CSO_N=0,58v
Pin19 PP5V1_CHGR_VDD=5v
Pin20 PP5V1_CHGR_VDDP=5v (now permanent)
Pin27 CHGR_CSI_N=0v (now 0v)

 

[2informaticos]

"Pin3 CHGR_ACIN=0v"
Still???
Did you change R7010 too?

 

[lincev]

R7010= 29,5 ohm scale 200k is good im compare with other board..

maybe this U7000 is bad too... I try with other IC

Edit: sorry I try again and now I have 0,64v... CHGR_ACIN

 

[2informaticos]

Still not good.
Calculate R7010/11 voltage divider, to know how much you expect there.