MacBook pro A1502 - No power Need help

[Dallas90]

I have a MacBook Pro A1502 with no power.

180-200mA without battery, 1500mA with battery, and orange light on the charger.




Short facts:

*USB with LED lights up.

*No fan spin.

*Adapter sense and sys_onewire is ”only” 2.861V.




I checked the DC board as well and the adapter sense is 2.861 V, I'm not sure if it's too low

That's why I'm asking you guys for help.

[dellxps15]

on some a1502 fan spin after getting hot. usb light is better to check with pendrive (not mouse) if it blink. also check if cpu vcore is present. generally 2,8 volt on adapter sense is bad dcin board. if u can try another one. had one a1502 with no post and i fixed it by replacing dcin board.

[Dallas90]

Thanks for answering, The SSD warms up, the USB lights up, and all readings except those in the photo are normal.
I'm just curious why the sysone wire and adapter sense are the same reading, are adapter sense generating sysone wire to SMC?

I guess I will try to order a dcin board, that was my next idea; I just wanted someone's confirmation.

[reformatt]

Doubting this is the cause of your trouble. The fact the battery appears to be charging eliminates the one wire circuit. If you have Vcore present, this also indicate that BATLOW is fine and rules out the charger. Often static 200ma is bad RAM on Air boards, which are fundamentally similar.

[Dallas90]

Hi and thanks for you reply!

How can i check if there is a ram or vcore issues ?

[reformatt]

Follow these sequences:

https://logi.wiki/index.php/G3_to_S3..._and_Broadwell
https://logi.wiki/index.php/Bootup_Signal_Order

[Dallas90]

I found out that PP3V3_S4_TBT was shorted after checking a few caps (C2950, C2951, C2952, C2953, C2954) it turned out that it was related to the thunderbolt chip and my thermal camera confirmed that the chip heats up.
Now to another problem... I cannot find a replacement chip, so does anyone know where to order a new chip?

A1502 - 820-3476A
Part: 338S1247 - U2800

[reformatt]

So does the board boot without it fitted? Thunderbolt shouldn't prevent it booting.

Most people will take these chips off a donor board. You can get some on Aliexpress if you don't have one. They have the CPU/RAM removed, and often have areas drilled through.

BTW, this board is from 2013/14 models and often go quite cheap if the screen is broken. 2013~15 Macbook Pro's aren't considered economical to repair once the screen is busted so they often go quite cheap on eBay. So that is another option.

[Dallas90]

It still doesn't power on after the removal of the shorted chip I will hopefully get my new DC IN board tomorrow so I can test with a working one, if that does not solve the problem I don't know where to look else...

[reformatt]

What voltages do you get in the power sequence? At the very least, you should have PP3V42_G3H, PPBUS_G3H, and PP3V3_S5. For it to go any further, you have to get PM_SLP_S4 to go high. Follow the power sequence I gave you above, that's how you troubleshoot these boards.

Look for any corrosion on the board, especially around the SMC and the edges of any QFN IC's.