Macbook 820-3115-B help (repair U1800)

[audiomodder]

Hey all,
First I want to say I am so grateful for this community. All the info and boardview stuff has helped me fix quite a few things already!

I have one project I'm super stuck on. A very water damaged Macbook 2012 i5 that I am repairing. I got it to boot up and chime with LCD and all (yay! see that repair here: https://vimeo.com/251045518) but now I am stuck because:

1) It does not see internal SATA HDD (though drive spins up, as does DVD player)

2) USB seems to work for a second, but then external drive starts making clicking sounds

3) External FW boot crashes with Kernal Panic

This is with many different cables, drives, etc.

Firewire port works and it will boot a drive off there, but usually hangs and goes into kernal panic:
https://www.flickr.com/photos/158377...posted-public/

(I can upload a better pic later today).

It looks like USB / SATA are obviously not working...I think the culprit is going to be a connection to U1800. I don't know where to start though, that chip is massive. I examined the board carefully and things look OK, voltage seems good and I did RAM changes (both slot and card). The only really dubious point is a the PEGCLKRQA_L_GPIO47 signal to U1800. It's a BGA connection to internal trace so I can't do much to check it though :/ It says it's for PCIE though I kind of doubt that is the issue.

Anyone know where to start? Which clock signals I should check ? Kernal panic seems to indicate USB error...

Thanks!!

-Audiomodder

[ibrahim03]

Re: Macbook 820-3115-B help (repair U1800)

start measured

PP1V05_S0_PCH_VCCIO_USB

PP3V3_SUS_PCH_VCCSUS_USB

PP1V05_S0_PCH_VCCIO_PLLUSB

PP5V_SUS_PCH_V5REFSUS

PP3V3_SUS_PCH_VCCSUS

and check port usb vcc 5v .

look around pch no liquid damaged or missing components

and Make sure , no liquid damage anywhere

after all this

1- reballing pch

2- change pch

[audiomodder]

Re: Macbook 820-3115-B help (repair U1800)

Thanks for the reply!! So cool to get help all the way from Cairo

All the points you mention test OK:

PP1V05_S0_PCH_VCCIO_USB - 1.04V
PP3V3_SUS_PCH_VCCSUS_USB - 3.3V
PP1V05_S0_PCH_VCCIO_PLLUSB - 1.046V
PP5V_SUS_PCH_V5REFSUS - 5V
PP3V3_SUS_PCH_VCCSUS - 3.3V
and check port usb vcc 5v . yep, 5V

These all seem to be for USB port stuff, though. Since the issue is both SATA and USB, don't you think maybe it is a clock signal?
I have examined the board very closely with a microscope and see no other missing parts. Water damage is cleaned up very well now too.

Does anyone know what PEGCLKRQA_L_GPIO47 signal is for? it just goes to a pull-up to 3V3_SUS..

[audiomodder]

Re: Macbook 820-3115-B help (repair U1800)

UPDATE: WOW, I actually got this thing to boot into the OS using a USB HDD !!! It seems too good to be true....

Internal SATA is still not recognized, I don't know why. I'm going to see if it will see HDD on the ODD slot, although I think that is SATA II instead of SATA III :/ Tried 4x HDD cables so I kinda doubt that is the problem...though you never know?

I was thinking of probing the SATA I/O maybe. Chipset on that side of the board is super clean tho (nowhere near the water damage) so I'm still thinking it is a U1800 issue.

for anyone wondering, I fixed this by:
1) inspecting and cleaning (flux + reflow) U4650 (USB debugger chip), U9410, U6201, R4650
2) Cleaning and soldering wire *into* the water damaged vias (including PEGCLKRQA_L_GPIO47), hoping to make internal connections to U1800

Seems to boot OK now. WOW this is exciting, thank you!! now to just get SATA working (if possible).

-Audiomodder
2)

[audiomodder]

Re: Macbook 820-3115-B help (repair U1800)

FIXED IT!!!
Turns out all FOUR of my HDD cables were bad...wow. 5th time pulled one from another machine and SATA0 works great! Put everything back together with new RAM and battery and everything boots and runs great. Wow, I can't believe this one got brought back from the dead.

Thanks for your help ibrahim03!

[audiomodder]

Re: Macbook 820-3115-B help (repair U1800)

OK, so I jumped the gun a little with all my excitement. Still not perfect.
After I power up and am running for a few minutes I get the
"USB Devices Disabled" and it says its shutting off USB ports - when nothing is plugged in! That can't be good.. Does anyone know how / what manages this message for the logic?

[audiomodder]

Re: Macbook 820-3115-B help (repair U1800)

OK, now I think I got it all going.
The issue was with U4650 (PI3USB102ZLE) - USB debugger chip. It connects to the SMC and looks for errors on the ports. It's a "critical" part which will keep the system from working if it is missing connections.

There was the smallest freaking corrosion on pin 4 (SMC_DEBUGPRT_TX_L) which is the output to the SMC. That is why it booted fine but then after looking for a signal for a while, determined there was a fault.

Ran for a couple hours and plugged / unplugged USB plenty of times. No issue as of yet.