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Hi, I have an 820-00840 that had liquid damage around the USB C port It works perfectly, other than it wont boot to a USB OSX instal. It loads most of the way and then shows the prohibited icon. I have tried many drives, OSX versions and USB C adapters. It can boot to its internal SSD, and an...

I have an 820-00045 that has no power, It has no liquid damage, and the chasis is in good condition so i doubt its impact damaged. started poking around and noticed i have 3v3_S5 but no PP3v3_SUS pinpointed this fault to a break between Pin 6 of u8020 and R1464. ran a jumper wire and got...

I know that, I was just stating that it can cause similar issues. Anyway, I was using the wifi card to test wifi on another unit and it started doing the same thing. Its the wifi card surprisingly. Close thread.

Backlight with no image. J6100 is okay, so are the termination resistors. The rest of the time, it Posts with the apple chime noise, And then chimes again but slightly more distorted, and then again, and again. Repeated chimes can be due to Display or GPU initialisation in my experience.

I have an 820-3437 doing some bizarre things. Backlight no display, pulled all peripherals without change, Tested with a known good display. It sometimes shows backlight no display, and other times, it Chimes over and over again, Each time it chimes, the chime becomes more and more distorted...

Im not sure how correct you are, as part of diagnosis i lifted the USB lines from the trackpad connector. I did this to try and disable USB, to see if the black screening was resolved, but even without the USB lines it still black screened. If memory serves correctly it was corrosion on a pad...

No that wont work (as far as im aware), You need to read up about USB-C type power delivery and learn about Chanel configuration pins and understand it before injecting voltage to a USB C based laptop.

Holy thread revival. I figured it out a while ago, there was a resistor for SPI (maybe a pullup) that looked okay, but the pad underneath was half missing. I cannot remember which resistor, i only figured it out by deciding to replace all components related to trackpad SPI Thanks though

Nope, none in that area at all, guess it coulda got into the TCON board somehow. Probably CPU, i would really like a good source of reasonable CPU's. Pulling U series chips of a scrap board is a waste of time as they always warp under rework (no matter what you do!)

Tried USB High Sierra and Mohave. It is definitely a hardware issue. I have also tried the machine in a known good chasis with all known good parts. It is a board fault.

I have an 820-00840, with very minute signs of liquid damage around the SSD (logic board is perfectly clean) It gets all power rails, yet never posts, and V-core remains high at 0.9V (these boards go a little lower when the post, maybe to around 0.75V) I have tried a new EFI with clean ME (known...

I have a 13" touchbar here, it came in with liquid damage, and a blown J4402. The liquid damage was only seemingly to the touchbar connector J4402. Replaced J4402, and patched up and ran a jumper wire to pin 22 of the connector due to a blown out trace. Tried booting the laptop to High sierra...

Replaced all 4 CD3215's with no improvement. I am confused because something is causing the CD3215's to not communicate with the charger during its failed state. Because PP3V3_G3H is not pulsing it leads me to believe a GPIO pin is causing the DCIN Rail to pulse. Does anyone know of all the...

R7021/22 and R7061/62 All measure perfectly (1ohm) each I have been able to get it into its failure mode. When this happens all power rails other than CPU-Vcore pulse. I belive it is caused by some USB C charging issue maybe. This is because in its failure state DCIN seems to be wrong (pulsing...

Holly thread revival, if not for anyone interested i revisited what seemed to be the same issue recently. I had an 820-3476 that would freeze as soon as you got to OSX, however if plugged into an external display would run fine. This was due to corrosion under 8340 and a rusted pad. I think...

Failing direct compatibility you can change for different model ram as long as it falls in with the boards BOMs. There are RAMCFG (ram config) strapping resistors, and a corresponding BOM table with the required for certain ram brands and capacities

When it is running it is recognising and charging the battery. It does starts normally (not in SMC bypass). Since the original repair i have removed my wire from debug power button and replaced r4911 wiring it to the correct net, so this board can now be treated as unmodified. I will check...

Nope, liquid was very localised to R4911 and the surrounding area, and extremely minor. You can only tell its ever been damaged if you really look hard for it.

820-00281 i fixed around 18 months ago for minor liquid damage has come back to me. I originally fixed the board by running pin 2 R4911 to Debug power button, at the time of doing this no schematics were available and pin 1 of R4911 was completely destroyed, so running to the debug power pads...

I changed U4810 and redid u4820 again just to be sure. No in normal condition you cannot access boot menue, Just a blank black display, No USB activity, Wont read internal SSD.ect