820-00165-A missing P5VS4RS3_EN_R

[macattack600]

820-00165 No start

No water damage ,BUT! The Shield on U2800 come off and was rattling around inside the board -JOY! (Thunderbolt Host Ic). The customer said it was working while it rattled but then it stopped , I noticed the battery was low charge icon from a working motherboard. I tried with fully charged battery no change.



All rails were good until I got to PPVRTC_G3H it was very low I replaced u1900 and it came to 3.3V

U7501 gives 5V at PP5V_S5 C7505 and I get 3.3v at PP3V3_S5_REG_R

P5VS4RS3_EN_R is very low like 0.18v when I trigger SMC_ONOFF_L at pad it drops to 0v
Replacing U7501 with known good ic result no change.

SMC_PM_G2_EN is 2v.

[reformatt]

Re: 820-00165-A missing P5VS4RS3_EN_R

Refer to the power sequence for these boards, it will save you wasting time. A base condition for troubleshooting is for PP3V42_G3H @ 3.4V, PPBUS_G3H @ 8.6V and PP3V3_S5 @ 3.3V.

You won't get the latter unless you have a high on SMC_PM_G2_EN from the SMC. Any S4 rail won't be enabled till you get PM_SLP_S4. 2V sounds a bit low, so check SMC supplies and whether PPBUS_G3H = 8.6V (with no battery).

[macattack600]

Re: 820-00165-A missing P5VS4RS3_EN_R

Ok I now have 2.93v for some reason on SMC_PM_G2_EN

PPBUS_G3H is infact 8.6v no battery.

Is the SMC in some sort of reset mode because the battery went dead or was bad? (SMC_RESET_L) is one side of r5100 3.4v other side 3.10v
SMC supplies would be 3.3v at L5501 and 1.2v at c5010?

I may just end up swapping smc and see what happens

[reformatt]

Re: 820-00165-A missing P5VS4RS3_EN_R

PPBUS_G3H is 8.6V, so the SMC is clearly communicating with the ISL chip (hence is not in reset). If it was, the SMC_RESET_L would be 0V (active low) and PPBUS_G3H would be ~8.2V.

Assuming you do have PP3V3_S5 (since you did not mention it), your issue will be PM_SLP_S4 related. Refer to the pre-requisites:

https://logi.wiki/index.php/PM_SLP_S...roubleshooting

[macattack600]

Re: 820-00165-A missing P5VS4RS3_EN_R

I got most all those voltage except
P3V3SUS_EN is missing for PP3v3_SUS I suppose I have dead PCH?

I get 0V on PM_RSMRST_L PM_PWRBTN_L PM_BATLOW_L and of course PP3v3_SUS.


I don't have scope to check clock chip but I did change that.



Also If I check 5v coil L7520 In diode mode it is complete short to ground L7560 has diode reading of 040 but thats irrelevant with missing PM_SLP_S4 ?

I have this hunch for some reason and i'm prob wrong but I really think the battery had something to do with this , maybe SMC is fault ?

[reformatt]

Re: 820-00165-A missing P5VS4RS3_EN_R

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

Review this flowchart. Your problem is before PM_SLP_SUS_L (P3V3_SUS generation is after this). PM_BATLOW_L is 0V so you won't get anything beyond that without this being high. Troubleshoot this with the board on the bench with no battery, known good LIO board and flex, and genuine Magsafe 2 charger. 820-00165 boards can be super picky about chargers.

[macattack600]

Re: 820-00165-A missing P5VS4RS3_EN_R

I think this one is done I get all voltage on flowchart till PM_SLP_SUS_L . I am using original 85w magsafe 2 charger.
My last attempt would be to replace SMC.

Thank you for the first 2 guides they both will help alot in the future.

I saw your post on here where you once had "open circuit inner layer track for PP3V3_SUS"
Do you remember what was repaired where fault was? Did you mean there was short in "VIA"?

[reformatt]

Re: 820-00165-A missing P5VS4RS3_EN_R

If I recall, it was no PP3V3_SUS present on R1583, but it was present on R8020 pin 2. I had to run a jumper to fix, as there were no spots visible that were corroded. Could've been a via I suppose, but sometimes these multilayer connections are under component pads in MAC's.

This would seem moot though as it's after PM_SLP_SUS_L this is generated. So you are saying you do have all the pre-requisites, including the clock and PM_BATLOW_L? Are you sure that your work previously is ok? It's easy to put in a faulty IC or not solder it down correctly. Review what you have done before binning the board.

[macattack600]

Re: 820-00165-A missing P5VS4RS3_EN_R

I decided to check r1450 PCH_DSWVRMEN resistor is good measured off board but I get 0 in diode mode leading to PCH good board gives around 450 .
I'm getting 2.2v with it back on pin 2 .
I wonder is this way to confirm I may have bad PCH?

[mon2]

Re: 820-00165-A missing P5VS4RS3_EN_R

What is the voltage reading of PPVRTC_G3H ?

Then remove all power,

what is the measured resistance of R1450 ? Is it ~330k ?

what is the resistance to ground of R1450, pin # 2 ?

[macattack600]

Re: 820-00165-A missing P5VS4RS3_EN_R

PPVRTC_G3H is 3.3
R1450 removed is 330k
In diode mode? Red probe ground I get 0 with the resistor on board and off

On good board I get 850 on pin 2 with it on

[mon2]

Re: 820-00165-A missing P5VS4RS3_EN_R

Oh...that is likely a dead PCH with such a low reading.

With the resistor in place @ R1450, the same pin # 2 is pulled down to 2v2 ?

Wait on others to comment but does appear to be a defective PCH.

[macattack600]

Re: 820-00165-A missing P5VS4RS3_EN_R

I feel totally dumb LOL.

I just removed the heatsink and the smaller part of CPU is shattered .

On the positive side i've gained so much in this post on diagnosing a PM_SLP_S4_L timing with hands on experience-- extremely valuable , so not total loss.

[macattack600]

Re: 820-00165-A missing P5VS4RS3_EN_R

Sort of makes me think about getting another BGA machine LOL

Awhile back I used to do a ton of GPU BGA replacements.

Just need replacement board and stencil, flash bios with clean ME and I bet this would start right up.

[reformatt]

Re: 820-00165-A missing P5VS4RS3_EN_R

I always check L7630 impedance to ground before working on any Air board these days. It should measure 150 ohms or more. Anything less, especially < 100 ohms it goes to the donor pile. Usual cause is disruption to the feedback for the 3.3V or 1.05 converters from liquid/bug shit etc.

The problem with replacing CPU's on these is that any replacements will be ones ripped off another board. Intel discontinue older chips pretty quick. This is why you can't get motherboards for older generation CPU's as the motherboard manufacturers can't get the chipsets from Intel.