820-3209-a power on only without u7000

[dellxps15]

Re: 820-3209-a power on only without u7000

fan at maximum speed could be because of no touchpad connected. check all s0 voltages if present or not. do also a smc reset and a pram reset.

[opethfan]

Re: 820-3209-a power on only without u7000

pbus_s0-vsense is not present for example. I going to replace smc, right?

[dellxps15]

Re: 820-3209-a power on only without u7000

no smc should be ok. let me check schematics for that pbus_s0-vsense

edit: u7000 pin 13 voltage?

8volts on fuse present?

PBUSVSENS_EN voltage?

[opethfan]

Re: 820-3209-a power on only without u7000

u7000 pin 13 is 3.4v

which fuse do you mean?

i checked pbusvsens_en on q5300 pin 2 and the is 3.4

[dellxps15]

Re: 820-3209-a power on only without u7000

q5300 voltage pin 3, 4 , 5 , 6 ?

[opethfan]

Re: 820-3209-a power on only without u7000

3 7.6v
4 7.6v
5 3.8v
6 0v
r5302 is 30k and not 100k like schematics

[dellxps15]

Re: 820-3209-a power on only without u7000

try change it

[opethfan]

Re: 820-3209-a power on only without u7000

replaced with 100k size 402 not 201 but same 0v on pin 6 of q5300

[dellxps15]

Re: 820-3209-a power on only without u7000

R5303 voltages both side?

replace old r5302

[opethfan]

Re: 820-3209-a power on only without u7000

r5303 voltages: 7.27 v and 1.1 v

[dellxps15]

Re: 820-3209-a power on only without u7000

check r5303 r5304 values.

[opethfan]

Re: 820-3209-a power on only without u7000

r5303 27k
r5304 5.4k

[dellxps15]

Re: 820-3209-a power on only without u7000

output should be 3.3 volt no 1.1

[opethfan]

Re: 820-3209-a power on only without u7000

the resistance value are right, could be the capacitor c5304 ?
or maybe is low because 7.27 should be higher?

[dellxps15]

Re: 820-3209-a power on only without u7000

remove capacitor and see. input is ok as it is a macbook air. if after capacitor remove that 1.1 voltage goes to smc.... so could be bad balls or bad smc.

check u9701 vin and enable voltages for backlight if present when macbook is turned on.

[opethfan]

Re: 820-3209-a power on only without u7000

u9701 Vin present, enable voltage aren't present

removed capacitor, same 1.1 v

do you think i need to reball/replace smc?

remember that now when i plug battery, the fan starts to spin...

[anandkv123]

thanks schematics helped me ,thamks a lot

[mcplslg123]

Re: 820-3209-a power on only without u7000

r5303 voltages: 7.27 v and 1.1 v

I have the exact same problem on this very mb. Someone tried to repair it but was perhaps not skilled enough to handle macbook and thereby damaging a lot of stuff. I have carefully put evrything in order. Now have the same problem.

When magsafe connected, there is no light on adapter but it turns on automatically with max fan. R5303 8.2v and 1.39v. No corrosion around smc. I beleive SMC Reset L is the issue.

Any advice friends.

[piernov]

Re: 820-3209-a power on only without u7000

R5303 is fine, 5.49*8.2/(5.49+27.4) = 1.37V on pin 2, close enough.
However, you should have 8.6V on pin 1 and not 8.2V. 8.2V means SMC not turning on or not communicating with U7000.
What's the voltage on SML_RESET_L? It should be 3.3V for the SMC to turn on.

[mcplslg123]

Re: 820-3209-a power on only without u7000

R5303 is fine, 5.49*8.2/(5.49+27.4) = 1.37V on pin 2, close enough.
However, you should have 8.6V on pin 1 and not 8.2V. 8.2V means SMC not turning on or not communicating with U7000.
What's the voltage on SML_RESET_L? It should be 3.3V for the SMC to turn on.

SMC_RESET_L measured at R7000(3.10v on both sides). R5303 mepeat measurement- 8.40v and 1.39v