820-00165-A No Power/Fan, draws 0.027A on PS, all S0 state rails 0V

[karoliens]

I hit a wall with this one. As per title No power/fan spin when connected to PS.

And to make things even more difficult it looks that the board was run through ultrasonic cleaner so I can not find any suspects.

I went through all power rails and all the S0 state rails are not present.

V
PPBUS_G3H 8.58
PPBUS_S5_HS_COMPUTING_ISNS 8.59
PPBUS_S5_HS_OTHER_ISNS 8.59
PPDCIN_G3H_ISOL 18.50
PPDCIN_G3H 18.50
PP3V42_G3H 3.417
PPVRTC_G3H 3.320
PP5V_S5 5.022
PP5V_S4RS3 0
PP5V_S0 0.048
PP3V3_S5 3.320
PP3V3_S4 0.311
PP3V3_SUS 3.319
PP3V3_S3 0.068
PP3V3_S0 0.055
PP3V3_S4SW_SNS 0.041
PP3V3_S0SW_SSD 0
PP3V3_S4_TBTAPWR 0
PP1V8_S3 0
PP1V2_S3 0
PP1V05_SUS 1.060
PP1V5_S0 0
PP0V6_S0_DDRVTT 0
PP1V05_S0 0
PP1V05_S0SW_PCH_HSIO 0
PPVCC_S0_CPU 0

Any suggestions?

[piernov]

Re: 820-00165-A No Power/Fan, draws 0.027A on PS, all S0 state rails 0V

Green light? Known good genuine Magsafe2? Any pulse on PM_SLP_S5_L (use oscilloscope if you don't know if your multimeter is fast enough)?

Look closely for corrosion around SMC, SPI ROM, J6100, U1950…

[karoliens]

Re: 820-00165-A No Power/Fan, draws 0.027A on PS, all S0 state rails 0V

Green light? Known good genuine Magsafe2? Any pulse on PM_SLP_S5_L (use oscilloscope if you don't know if your multimeter is fast enough)?

Look closely for corrosion around SMC, SPI ROM, J6100, U1950…

Thank you for a quick reply.

I am using Power Supply for troubleshooting with genuine cut MagSafe2 cable and the light is amber. When connected inside the housing the light is green.

As I mentioned the board looks as it was run through ultrasonic cleaner so it makes difficult to see any corrosion as the board looks clean.

Areas around SMC, SPI ROM, J6100, U1950 seem to be clean, but as I mentioned it is most likely had ultrasonic cleaning before so if the crap is under the chip I will not notice it.

PM_SLP_S5_L is 0.006V once I start measuring but after couple of seconds drops to 0V. Unfortunately I do not have oscilloscope, but my multimeter is branded Brymen. I do not know how well it could capture though.

[piernov]

Re: 820-00165-A No Power/Fan, draws 0.027A on PS, all S0 state rails 0V

What model of Brymen is it? Also check for a pulse on PM_SLP_S5_L when plugging in Magsafe.
If there is no pulse at all, check voltage on PM_BATLOW_L, PM_RSMRST_L, PM_PWRBTN_L.

[karoliens]

Re: 820-00165-A No Power/Fan, draws 0.027A on PS, all S0 state rails 0V

What model of Brymen is it? Also check for a pulse on PM_SLP_S5_L when plugging in Magsafe.
If there is no pulse at all, check voltage on PM_BATLOW_L, PM_RSMRST_L, PM_PWRBTN_L.

When I plug in MagSafe PM_SLP_S5_L jumps to 3.318V and then goes to 0V.

I am using Brymen BM257s.

[piernov]

Re: 820-00165-A No Power/Fan, draws 0.027A on PS, all S0 state rails 0V

Ok, try SMC bypass mode with fan connected and see if the fan starts spinning (and for how long).
→ Short power on pads (SMC_ONOFF_L to ground), plug in Magsafe, wait 5 to 10 seconds, remove the short. Magsafe should turn directly to orange (no green → orange).

Also check charging circuit current sensing.
→ Measure resistance between pins 17/18 and between pins 27/28 of U7100. Should be around 2.2 ohms and 20 ohms (sum of the resistors).

And check if you also get a pulse on PPVCC_S0_CPU when plugging in Magsafe as well.

[karoliens]

Re: 820-00165-A No Power/Fan, draws 0.027A on PS, all S0 state rails 0V

Ok, try SMC bypass mode with fan connected and see if the fan starts spinning (and for how long).
→ Short power on pads (SMC_ONOFF_L to ground), plug in Magsafe, wait 5 to 10 seconds, remove the short. Magsafe should turn directly to orange (no green → orange).

Also check charging circuit current sensing.
→ Measure resistance between pins 17/18 and between pins 27/28 of U7100. Should be around 2.2 ohms and 20 ohms (sum of the resistors).

And check if you also get a pulse on PPVCC_S0_CPU when plugging in Magsafe as well.

First of all thank you for your effort helping me. I mostly fixing iPhone logic boards so MacBooks are still fresh for me.

PPVCC_S0_CPU jumps to 1.8V and goes to 0V.

Resistance between pins 17/18 3.2 Ohm 27/28 20.1 Ohm.

SMC_ONOFF_L is shorted and I plug in MagSafe there's no light at all. And when I remove short there's still no light but fan spins two times and stops.

[luckydip]

Re: 820-00165-A No Power/Fan, draws 0.027A on PS, all S0 state rails 0V

Is PP3V3_S4 0.311? check for shorts on S4 and S3 rails.

[karoliens]

Re: 820-00165-A No Power/Fan, draws 0.027A on PS, all S0 state rails 0V

Is PP3V3_S4 0.311? check for shorts on S4 and S3 rails.

I'm pretty sure that I've checked that before, but here are the results.

Resistance to ground:

PP3V3_S4 57.25 kOhm
PP5V_S4RS3 2 MOhm
PP3V3_S3 1.2 MOhm
PP3V3_S4SW_SNS 1.6 MOhm
PP1V8_S3 53 kOhm
PP1V2_S3 413 Ohm

[luckydip]

Re: 820-00165-A No Power/Fan, draws 0.027A on PS, all S0 state rails 0V

I know you don't have a scope but can your meter check the clock signal on u1900?

[karoliens]

Re: 820-00165-A No Power/Fan, draws 0.027A on PS, all S0 state rails 0V

I know you don't have a scope but can your meter check the clock signal on u1900?

PCH_CLK32K_RTCX1 is 32 kHz

Other lines are 25 MHz and I don't think my multimeter is capable of measuring that. In the manual it says 5.00 - 500 kHz (3Vpeak).

[luckydip]

Re: 820-00165-A No Power/Fan, draws 0.027A on PS, all S0 state rails 0V

This sounds like a rabbit hole - could be anything. As Piernov suggested, did you check voltage on PM_BATLOW_L, PM_RSMRST_L, PM_PWRBTN_L and SMC_RESET_L?

Using a Magsafe adaptor does the light go from green to amber or stay green?

[piernov]

Re: 820-00165-A No Power/Fan, draws 0.027A on PS, all S0 state rails 0V

CPU VCore pulses when plugging Magsafe in. So there's no issue with BATLOW#/RSMRST#/PWRBTN# themselves (and no issue with SLP_S5#/SLP_S4# either). SMC_RESET_L is present since there's orange light, S5 rails are present and CPU VCore comes up anyway. 32kHz RTC clock is good as well since SLP_SUS# is present.
As I said originally there can still be an issue with something around SMC, SPI ROM, J6100… or something random somewhere, maybe pulling too much current. Those pulsing issues are always a waste of time to troubleshoot when they're not obvious since we still do not exactly know what can cause them (and there are different patterns). We try to collect some info over here https://logi.wiki/index.php/820-00165_Pulsing

[karoliens]

Re: 820-00165-A No Power/Fan, draws 0.027A on PS, all S0 state rails 0V

It's definitely a rabbit hole this one. It's quite difficult to troubleshoot when there's no hints whatsoever and board is clean. Nonetheless thank you for the effort guys.

P.S. I've attached photos of the SMC (I removed underfill intentionally to check underneath), SPI ROM, J6100 areas.