A1534 820-00244-A Not turning on

[Hatwatt]

Hi, this is my first post and I am a total noob so bear with me.

History: Was working and someone removed the LVDS cable before pushing the battery disconnect button and after that it was dead. (This is atleast how the story goes
No signs of liquid damage.

Charger voltage 15v and it is not taking any current. (Don?t know if the battery is full).
Don?t know what should I measure for you, so just tell me what values you want and I will gladly get them.

Here are some measurements from the board:

Q3100 Pin-8 = 14.7V
PPVIN_G3H_P3V3G3H = 14.7V
PPBUS_G3H is 8.7V

PPBUS_S5_HS_COMPUTING_ISNS = 8.7V
PP5V_G3H = 5V
PP5V_S5 = 5V
PP5V_S4 = 0 V

PP3V3R3V0_AON = 3.3V
PP3V3_G3H = 3.3V
PP3V3_S5 = 3.3V
PP3V3_SUS = 0V
pp1v8_SUS= 0V (pulsing?)
P1V8SUS_PGOOD= 0V

Any help or suggestions would be much appreciated. Thanks in advance!

 

[2informaticos]

LCD connector has NO voltage when board is off.
But working on that machine with battery enabled can result in really dead board.
PP3V3_G3H is present and also PPBUS_G3H is high.

Disconnect battery and check if board tries to start when connect charger.
Also try disconecting LCD screen.

"pp1v8_SUS= 0V (pulsing?)"
If really pulses, all S4/3 voltages and signals should pulse too; check that.
Start checking if you get at least one pulse at PM_SLP_S4_L.
Better to see that when trigger SMC_ON_OFF_L to ground; use R5225/26 pads.

BTW, there is no LVDS cable; panel is eDP type.
However, we understood what LVDS cable means in your post.

 

[Hatwatt]

Thanks for the quick response.

Aah, ok. Nice to know, that there is no voltage on the display connector. And the panel type.

All measurements are done with just the board and PSU. I took the board out before doing anything.

I might have wrong word for pulsing, sorry. My multimeter has a line that makes pulses and that what I have tried to describe. Other S3/4 voltages are not "pulsing" when I measured them.

PM_SLP_S4_L rises to 0.06V when SMC_ON_OFF_L is shorted to ground.

 

[JohnB8812]

Do NOT use a PSU for these USBC is not the same as magsafe....use a known good OEM 87 watt brick and cable and see what happens.

 

[Hatwatt]

Do NOT use a PSU for these USBC is not the same as magsafe....use a known good OEM 87 watt brick and cable and see what happens.

Yeah, of course not. Sorry for the confusion. I am using the 29W Apple original USB-C power supply.

I had another customers 87W for a while and otherwise same results, but got 20V on Q3100 Pin-8.

 

[2informaticos]

Do not short SMC_ONOFF_L to ground.
You must simulate power button, only make temporary contact.

 

[Hatwatt]

Do not short SMC_ONOFF_L to ground.
You must simulate power button, only make temporary contact.

Yes, I did that and the PM_SLP_S4_L rises to 0.06V the moment it is shorted (as simulated the power button would be pressed down) and goes to 0V after releasing the "button".

I consider myself a total newbie, but not that much that I would leave it shorted. I used tweezers. But I totally understand that it is good to make these clear. Thanks for that and sorry if my English is not that precise. Not my native language.

What does the rise in the PM_SLP_S4_L mean or could you please tell what should I check next?
This board should start up when the power (USB) is connected or do I remember wrong from Louis videos?

I saw voltage fluctuation on CPUCORE_PHASE1 from 0.2-1.2V but went back to 0V soon. This happened when I just measured after leaving it on the table with the charger connected, before shorting the SMC_ONOFF.

Any tips or suggestion would be great as the customer is coming to pick up the device tomorrow, repaired or not. Don?t get me wrong, I really appreciate all the help and I don?t want to sound ungrateful.

Thanks!

 

[2informaticos]

Board should start automatically, like all MacBook iCore platforms.

"I saw voltage fluctuation on CPUCORE_PHASE1 from 0.2-1.2V"
Then all secondary voltages should pulse too; less iGPU (GT) probably.
Do you note pulsing every 5s, or only 1-2 times when connect charger?

 

[Hatwatt]

Thanks for the reply.

I will check the pulsing as soon as I am back at the shop.
Just to be clear, do you mean the S4/S3 lines with secondary voltages or what should I check? Also do you mean fluctuating voltage with pulsing?

Sorry, just want to be clear as I am still very new with these.

 

[2informaticos]

PM_SLP_S4_L enables S3 voltages.
PM_SLP_S3_L enables S0 voltages.
CPU VCORE voltage is S0 type; if that pulses, all other should too.
iGPU voltage maybe not...
An o-scope can help you to check if pulses reach nominal voltage on the coils.

 

[Hatwatt]

Thanks for that. Nice to know about the enables.
Should there be voltage on those or are they just datalines that would need an o-scope to see something?

Well I don?t detect "pulsing" on PM_SLP_S4_L and S3 lines at any point, but I don?t have a o-scope and my multimeter testing is probably wrong to say pulsing in the first place.

Never could see the voltage again in CPUCORE_PHASE1.

Is there anything else that I could measure for you?

 

[Hatwatt]

Customer picked up the device. You can close the thread.

Thanks for 2informaticos for all your help!
PS. If you want to throw your wild guess what have might been the issue it would be nice so I can learn more from this.

 

[2informaticos]

There are several signals need to check.
We usually ask for few of them and see which one else to verify.
Is better to assist directly on the board.