820-00164 Only provides a 1/4 fan spin

I have a 11" Macbook Air, with no visible signs of liquid damage but it's only providing a 1/4 fan spin on DC power.

PPBUS_G3H - 8.57v
PP5V_S5 = 5V
SMC_RESET_L = 3.4 V
PP3V3_SUS = 3.3v
PPVRTC_G3H = 3.34V
PP3V3_S4 - Pulsing
PP5V_S4RS3 = 0V
PCH_CLK32K_RTCX1 = 36Khz (Read from my scope)

I'm guessing that the 36 Khz frequency is an issue here but would like some advice. At the moment, I have removed the SMC chip to reball it and I'm waiting for a stencil to put it back on the board.
 

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"PP3V3_S4 - Pulsing "
L7520 must pulse at same time.

R7551 is OK?
Do you get pulse at EN1/U7501?
Post diode mode to ground at L7520.
 
SMC is off the board at the moment as I wait to get 0.3mm Stencil.
So can't validate pulsing

R7551 = 0.1ohms
Diode Mode at L7520 to Gnd is showing 423
 
SMC is back on the board now

L7520 is pulsing....
R7551 is 1 ohm
EN1/U7501 is pulsing 1.4v to .1mv
Diode Mode at L7520 is 417

Power Supply to LIO board is switching between 2 mA to 154 mA with Voltage set to 18.10V
 
So checked all the big coils...here is what I found

L7320, L7310, L7430, L7630 & L7520 are pulsing
L7130 - 8.58 V
L7560 - 3.35 V
L3095 & L7701 - Not showing any reading

Also ALL_SYS_PWRGD is pulsing
 

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Surely no pulse at all at PLT_RESET_L?

Check CPU_VCCST_PWRGD and all voltages from pages 55/56.
Any drop pulse at pins 5/6 of U6100?
 
Double checked PLT_RESET_L and no pulse.

CPU_VCCST_PWRGD pulses very low voltage.
Pins 5&6 of U6100 are 3.34V and drop pulse.

PP1V8_S3 - Pulses
PP1V05_SUS - 1.057V
PP1V5_S0 - Pulses
PP3v3_S4SW_SNS - Pulses
PP5V_S0 - Pulses
PP3v3_SUS - 3.348V
PP3v3_S4 - Pulses
PP3v3_S3 - Pulses
PP3V3_S0_FET_R - Pulses
PP3v3_S0SW_SSD_FET_R - Pulses
PP1V05_S0 - Pulses
OO1V05_S0SW_PCH_HSIO - Pulses
 

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Check all SPI Bus Series Termination resistors and their traces.
Try known good BIOS file, clean ME.

Did you correctly try SMC bypass method?
 
Since I'm a Noob.....can you explain or point me to...the following...

1. What is involved in trying a 'good BIOS file'? and what does clean ME mean and entail?

2. What is involved in performing the SMC bypass method correctly? Upon searching the forum it looks like you just touch the last pin on the keyboard connector that is 'SMC_ONOFF_L' to a ground point on the board for a brief second? Please correct me if I'm wrong.

Thx
 

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"What is involved in performing the SMC bypass method correctly?"
Keep SMC_ONOFF_L to ground (use R5115/16 pads), connect charger and maintain 5-10s; fan should start at max speed.

"What is involved in trying a 'good BIOS file'?"
Reflash U6100 with known good working BIOS file.
 
So Upon connecting R5115 pads together for 10s, supplying power and upon letting go....I got full fan spin for 2 secs then go off and back on for approx 2 secs, almost in sync with the PSU using more current.

Haven't checked SPI_BUS resistors and traces yet and haven't looked at BIOS also as I don't know how this is done yet. BTW, do you have a URL or link on how the process to reflash U6100?

Will check resistors and traces sometime this weekend.
 
Are you suggesting that I look to reflash BIOS prior to validating all SPI Bus Series Termination resistors and their traces?

Curious as to why you think the BIOS needs to be reflashed?
 

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"haven't looked at BIOS also as I don't know how this is done yet"
I just replied to your question about "how to"; didn't say to reflash prior checking the resistors...

You cannot imagine how many weird issues can generate corrupted BIOS.
This can only be discarded with known good working BIOS file.
 
I've checked all the SP BIOS termination resistors and they seem fine, and I don't find any issues with the traces.

I've ordered a Medusa programmer (it will take several weeks), in the meantime I'm guessing I can use a CH341A USB programmer? What software do you recommend to use with it 'AsProgrammer' or the 'CH341A' utility.

Also I can't seem to find a link to a 820-00164 BIOS, appreciate if you can assist with this.
 
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