[SOLVED]820-00923 5V on PPDCIN_G3H_CHGR

[bjf]

Any thoughts on what might be causing this? I've seen the lowered DC-In voltage happen on these boards with standard component failures and shorts but I'm wondering what else might cause it. Any idea where to look next on this? I'm not finding anything off. C3100 and C3108 were damaged and barely hanging on so I replaced those. I included pictures before I cleaned it but I received this board after it was already mostly cleaned so the clues aren't obvious.

 

[dukefawks]

SMC needs to be running for it to enable 20V. 3v3_g3h present?

 

[bjf]

I do have PP3V3_G3H

 

[dukefawks]

How did you replace those caps? If you used hot air near that undefilled CD3215 you probably screwed that.

 

[bjf]

I've replaced those caps before on this board without issue but it definitely could have been damaged something on this board. Not sure really. What is CD3215? I'm going off of the 820-00239 board view and schematic and don't see that.

Also, if it was damaged, any next steps?

 

[dukefawks]

The USB-C controller chips CD3215C00 on this board next to those caps. It is that chip that is between the charger and SMC. So check resistors/traces/caps around that chip.

 

[bjf]

Thanks, I'll check. And do they only control the USB-C ports on their side? Meaning, would the ports on one side work even if there was an issue with the circuit on the other side?

 

[dukefawks]

If 1 of the CD3215 is not working none of the ports will works. All chips must talk to the SMC for this shit to work. It is just a nightmare....

 

[bjf]

No Title

All I can find is that USB3_EXTA_R2D_C_N and USB3_EXTA_R2D_C_P are slightly higher than a good board at .430 on both versus .330 on a good board. I can't find anything else off on this. I've compared every component in the CD3215 areas to a functional board and there's nothing else that's measuring incorrectly. The only thing I can find is that the pad for PP3V3_UPC_XA_LDO is disconnected and not measuring anything but all the other points on PP3V3_UPC_XA_LDO are measuring fine. I attached a picture of the pad I'm talking about. That's it.

 

[dukefawks]

You cannot verify the balls under the chip actually are connected. There could be a via under that corroded probe point. You kind of need a donor board and go dig it up to see what is going on. I would not mess with this board or pull the CD3215 just yet. Can you source a donor for science?

 

[bjf]

I ordered some CD3215 chips from Louis. I have some donor boards coming from China too but that's going to be a while. I only have 820-00875 boards which appear to have a slightly different versions of the CD3215 chip.

If I did try to switch the chip, once I clean out the underfill, is there anything different about it compared to any other BGA? Also, I forgot to mention that R3110 was blown and I switched it before my last post. No change after replacing it, but that line obviously got hit pretty hard. I have a feeling my problems all reside with this chip and the damaged caused by PP3V3_UPC_XA_LDO getting burnt.

 

[dukefawks]

Only the older CD3215 is available, if you have CD3215C00 you are screwed, which I'm pretty sure is on your board.

 

[bjf]

I believe the 2016 15" model might have the CD3215C00 chip. Not sure, but I'm going to order some of those from China too.

 

[dukefawks]

I have not found those chips besides on donor boards....

 

[bjf]

I just realized I have an 820-00840 I had to write off recently so I actually have the chip. Is there anything special I need to do when replacing an underfill chip?

 

[dukefawks]

Not really, it is just really annoying. Practice on the donor first, you can also dig out that test point and see if it affects continuity to under the chip.

 

[bjf]

I reballed that chip off of the 00840 board and it's back up and running. Thanks a lot for the help.

 

[bjf]

Actually, there's one weird issue after putting it all back together. It won't turn back on after closing the lid. No auto-turn with lid-opening either. I need to do an SMC reset to get it to turn on. If I leave it open, I can turn it on and off normally - on battery and adapter. It also won't come back on after closing the lid while it's on. Screen is black. Touch Bar is non-existent. Caps lock works. Keyboard backlight is on. Power button will NOT force quit the computer. Need to do SMC reset to shut it down.

 

[dukefawks]

Was there any liquid near the SMC? Could also be keyboard issue as that has the hall sensor in it I believe,

 

[bjf]

SMC area wasn't hit and was clean. SMC_LID_LEFT was at around 1V vs 3.4V that it should be. R5256 is good but there was a break on line leading to R5251 on HALL_SENSOR_LEFT. Ran wire. All good. Thanks.