820-01041 No Video

[prodigy83]

My reference only: TT10011

Issue: Screen is not producing picture, no external video either.

History: Very small amount of corrosion found at TP: GPU_CLKREQ_L_R (just below C1951), I did not at first think the corrosion was touching anything except the metal casing on the board. I ended up replacing U7701 because I was not getting 1.2v where I should have been. The higher voltages at first were present. After looking back at TP GPU_CLKREQ_L__R, I cleaned it up and the center pad was gone, I tried to scrape the board with a diamond tipped pen but I could not get the solder to adhere. There was however part of the trace from this TP still there. I scraped that area and routed a jumper wire from there to R1945 pin 2. Continuity to those areas checked out. I am however not getting any S5. I keep coming back to U1200 being a possible issue?

USB-C meter shows 20v but pulls almost no amps other then when first plugging in it shoots up to .27 amps but drops to about .02 amps thereafter but maintains 20v.
What should I be testing or looking for next?

 

[2informaticos]

Do you get expected SLPS2R and AWAKE voltages?
Is the machine recognized into DFU mode?

 

[prodigy83]

Do you get expected SLPS2R and AWAKE voltages?
Is the machine recognized into DFU mode?

I get PP1V8_SLPS2R, which AWAKE are you referring to?
I have not tried DFU, let me give that a shot now.

 

[prodigy83]

I have not tried DFU, let me give that a shot now.

I forced it in to DFU mode, had no problem in doing so, but getting to step 4 of 4, the progress bar stops at the last word, then it gave me this exact same error both times while trying to do the revive (see image). The customer has files that are not backed up so cannot try the restore. Which AWAKE were you asking me to check out?

Just tried again after updating my Mac to Sonoma, was reading this was supposed to fix this error but still the revive did not work.
Update: Finally convinced the customer to let me try the restore. That did not work either. Same thing with same error.

 

[2informaticos]

If machine enters DFU, all necessary SLPS2R and AWAKE voltages should be present.
You should reflash SoC ROM and try again DFU.

 

[prodigy83]

I am using the CH341A programmer but I do not have the circuit board to solder the chip on to. You had me once before go to PCBway.com to order the WSON-8 setup. Where can I find or order this so this chip can be read? Also, I know this is a 1.8v chip, anything I need to do to make sure the CH441A is not going to fry this chip?

Nevermind! I guess the USON-8 worked. The two extra pins in the middle were throwing me off. I found the board bin files but it comes with two files. One ends in U2890 and the other ends in UB090. Not sure which one I am supposed to use. I guess I will try them both.

 

[2informaticos]

The above mentioned files are for left/right TBT ROM.
You need to flash U4770.

A1990 T2 Unlock Data.BIN

drive.google.com

Sometime helps just erasing it.

 

[prodigy83]

Thanks, I did erase it first and then programmed the file you provided. At first it did not work, then I plugged in the trackpad and battery, this worked doing a Restore. What I am seeing though is when I plug the motherboard in to power, it ramps up to about .27amps, then drops to about .10amps. No video still. Still getting a good constant 20v.

I am getting PP5V_S0_ALSCAM_F but it seems like the lower voltage like PP1V8_S5 I do not get. This is confusing, how can I get S0 for the camera, but no S5 for the lower voltage?
I get no PP2V5_S3.
I have P5V_3V3G3H_EN
No PPVCC_S0_CPU.
No PP3V3_S5.
C7020 is giving12.59v.
P3V3MAIN_PGOOD is good.
I get 1.8v at R7670 so this looks good.
What am I missing? S5 seems to be an issue here?

 

[2informaticos]

"This is confusing, how can I get S0 for the camera"
Check schematic, before making wrong assumption!
It comes from 5V_G3S (L8504).

Did you try original 87/96W charger?
Also test with battery connected.

 

[prodigy83]

It comes from 5V_G3S (L8504)

Okay, I assumed you are not supposed to get S0 without first getting S5, S4, S3, and so on. Thanks for correcting me.
I am using a 140v Apple USB-C charger, I have nothing less.
When I connect the battery and battery sense cable:
PP1V8_S5
PP2V5_S3
Both have 0v.
PPVBAT_G3H_CONN has 12.59v.
I am however getting U8250 voltage at PP3V3_G3H_T, but no voltage out at PP3V3_G3SSW_SNS.
Sensor issue?

 

[2informaticos]

Do you get any other G3S voltage?
Apart of 5V_G3S.
SSD gets any voltage?

S0 is the last state in power on sequence.
God knows why Apple used 5V_S0SW_ALSCAM name: it is directly derived from 5V_G3S.

 

[prodigy83]

Do you get any other G3S voltage?

Yes, I have PP1V8_G3S, PP3V3_G3S_T, PP3V3_G3S_X all are present.
Yes! PP1V8_SSD0. PP3V3_G3H_SSD0_SNS, PP2V5_NAND_SSD0, PP0V9_SSD0 are all present and stable.

 

[2informaticos]

Then you should get L7600 voltage; check diode mode to ground there.

 

[prodigy83]

Then you should get L7600 voltage; check diode mode to ground there.

I sure do, .398. Openboard data shows this is pretty close.

 

[prodigy83]

PP1V2_S3 in diode mode shows .166. It is supposed to be .182. Is that too far off?
PPVDDCPUSRAM_AWAKE is .398 which also looks off, I do however get .8 volts here.
Still no PP1V8_S5.

 

[2informaticos]

There must be something more affected by corrosion.
Possibly accumulated crap underneath BGA chips.

 

[prodigy83]

This pad in the pink circle was completley gone because of corrosion. I ran a jumper wire from a trace it was once conncted to which has continuity to U1950 pin 2 after I ran that jumper wire to R1945 pin 2. All continuity is present. I ran some flux under U1200 just in case any corrosion but still no PP1V8_S5. I noticed I get voltage to RK022 pin 1 but nothing to pin 2. This is a debug resistor so I am not sure if voltage should be going here.
I do also get 1.8v at RK018 pin 1.
No voltage at PPVCCPRIMCORE_PRIM_REG.
I get PPVDDCPU_AWAKE .539v which seems slightly low? I turned it off (the power) and back on and it did jump to .900v then dropped back down to the .539v.

 

[2informaticos]

You don't get pulse on any S5 power rail?
Just in case, reflow/reball U7800.
May need to reball PCH too.

 

[prodigy83]

You don't get pulse on any S5 power rail?
Just in case, reflow/reball U7800.
May need to reball PCH too.

On PP3V3_S5 I get .102v ONLY when I first turn it on very briefly, but it drops to .002v right after. No Pulsing.
I reflowed U7800, still nothing.
Diode mode measures .325 on PP3V3_S5.
The USB-C meter still shows 20v and at first the amps draw .28, but then drops to .17, then to .0 amps and stays there.

 

[2informaticos]

"I get voltage to RK022 pin 1 but nothing to pin 2."
RK018 is also 0 ohm.
If resistors are placed there, replace them.

Please, do not quote an entire post, visible few centimeters above...