820-00034 imac 21" 1#led

[yair37]

just first led is on-STABLE.
PM_PWRBTN_L is 3.3v and stay stable when i trigger SMC_ONOFF_L. i was replaced SMC but the same.
PP3V3_S4 pulsing 3.3v-0v when i trigger SMC_ONOFF_L.
PP3V3_S5 on L7610 3.3V stable.

 

[2informaticos]

"PP3V3_S4 pulsing 3.3v-0v when i trigger SMC_ONOFF_L."
Do you mean that 3V3_S4 is present BEFORE pressing power button?

Check S5_PWRGD and PM_DSW_PWRGD.

 

[yair37]

Do you mean that 3V3_S4 is present BEFORE pressing power button? yes, its 3.3v stable. but no 2# led.
PM_DSW_PWRGD 0v
can find S5_PWRGD on boardview there is just NC_SMC_S5_PWRGD and its under SMC chip.

 

[yair37]

PP3V3_S4, PM_PWRBTN_L, PM_PGOOD_REG_P3V3_S5 all 3 look like they acting the same, all 3 a 3.3V and pulsing when i trigger SMC but not always.
3V3_S4 0V

 

[2informaticos]

"3V3_S4 0V"
You've said to get 3V before.

Also I don't see any mention about PM_SLP_S4, as I asked.

S5_PWRGD shouldn't drop when you trigger SMC_ONOFF_L.
Change Q6970, if note it drops.

 

[yair37]

sorry PM_SLP_S4 is0v 3v3_s4 is 3.3V

 

[yair37]

i dont find S5_PWRGD! where is it on board?
i dont have where to get from new Q6970 but i was take it out and connect D to S (PP12V_G3H to PP12V_S5)

 

[yair37]

PM_PGOOD_REG_P3V3_S5 3.3v stable

 

[2informaticos]

Looks like SMC issue.
Once S5_PWRGD is high, SMC must release PM_DSW_PWRGD.
Did you solder SMC pulled from same model board?

 

[yair37]

Not from the same model board, but it’s look the same chip, is it different?

 

[2informaticos]

After two years on the forum still have doubts about SMC replacement?
Get the correct SMC for this board...

 

[yair37]

Really didn’t know about it
I will get one..

 

[yair37]

some update,
i was get "new" board, install it and it was work great for 2 days...suddenly it was not turn on, i was open it and now just one led on, when i press power button the #2 led turn on for half second and off(like is short or something) pp3v3_s4 0v when i press power button it jump to 0.8v and back to 0v.
very weird!

 

[2informaticos]

Try changing Q8450.
Check for short on any S3, or S0 power rail.

 

[yair37]

replaced Q8450
no short on S3 and S0 rails..
still the same..

 

[2informaticos]

If LE032 flashes, means ALL_SYS_PWRGD is pulsing.
So all voltages controlled by PM_SLP_S4L and PM_SLP_S3L should pulse too.
Check them all.

 

[yair37]

PM_SLP_S4L and PM_SLP_S3L and of course also ALL_SYS_PWRGD pulse when i trigger on/off. 0v-0.5v
PM_PWRBTN_L is 3.4v when i trigger on/off is down to 0v and up again(normal)

 

[2informaticos]

Then you should get pulse on all S3 and S0 voltages (at same time).
Same behavior without RAM?