820-2915-B - Green light no boot (no 5V)

[Allstartek]

This board looked very clean. There was corrosion on J3500 pin 16 but no where else. I used the USC anyway but I couldn't see any other issues.

I'm not sure where to find the course of the PP5V_S0 but after looking and looking It seems to come from U9500.

There is no 5v coming from here.

No PP5V_S0 from u9500

Pin 19 VSS is 0v
Pin 3 VCC is 3.6v not 5v
Pin 5 Vref3 is 3.2v not 5v

How do I identify the switch to turn on pin 19?

Any other ideas as to what my issue might be? I have looked at many videos but they all seem to end in finding a corroded area and replacing the component. I don't have any obvious bad components.

Thank you

 

[dukefawks]

U9500 has nothing to do with 5V. You are measuring 5V_S0 but is 5V_S3 even there. Are you using a known good REAL ORIGINAL 85W charger? PPBUS voltage?

 

[Allstartek]

Yes to the know good 85W OEM charger.

PPBUS_G3H at R5400 and R5410 is 12.59V
F7040 and F7041 12.59v

 

[dukefawks]

I asked about 5V_S3 and is 3V3_S5 present. SMC_ADPATER_EN present?

 

[Allstartek]

5V_S3 at l3408 0v R4532 0v U4600 pin 5 0v
3V3_S5 C4605 0v
C9841 pin 1 Fluctuates from 1.01-.0046
U9480 Pin 5 Fluctuates from 1.01-.0046

SMC_ADAPTER_EN u4900 pin 64 3.3v R5074 3.4v

 

[dukefawks]

Is PPBUS even present?

 

[Allstartek]

PPBUS_G3H at R5400 and R5410 is 12.59V

 

[Allstartek]

Interesting
R4260 and C4260 have 12.59v so does Q4262 pin 4
4260 in 1,2,5,6 have .03v each. F4260 is also .034 both sides.

 

[Allstartek]

Q4260 pin 4 is 12.57v and pin 3 is 12.24v

 

[dukefawks]

G2_EN present?

 

[Allstartek]

Checking it at u4500 pin 3 It reads .088 which I guess is nothing.
c4501 the same .087
u4350 the same .087
c4350 also only .087

 

[Allstartek]

So following G2_EN.
At R7940 the voltage fluctuates from 3.4v to .003v rapidly.

 

[dukefawks]

If G2_EN is pulsing PP3V3_S5 should also be pulsing at the same rate. If not then something wrong around the TPS51980.

 

[Allstartek]

PP3V3_S5 is pulsing but much less voltage:
r7940 1.002v - .002v
R7812 .998v - .003v

BTW thank you for your help. I'm sure that much of this is a pain in the *ss for you but the assistance you offer is very much appreciated.

 

[dukefawks]

S5_PWRGD pulsing too?

 

[Allstartek]

yes at R7941 3.3v - .007v
at R7940 3.3v-,014v
at U4900 pin 119 3.3v-,014v

 

[Allstartek]

Yes. at u4900 pin 119 3.3v-.099
R7941 3.2v-.007

 

[dukefawks]

Make sure there are no pulses at PP5V_S3. If there is 100% nothing there then check all rails for short. Is PPBUS stable at 12.6V?

 

[Allstartek]

PPBUS_G3H "was" stable at 12.6v until I shorted r5301 pin 1 and R5312 pin 1,, now the 12.6v is dropping slowly... no green light any more... $##%!^&#@^....

Previous to my shorting the to resistors.. I had 0v at PP5V_S3.

 

[dukefawks]

I see no reason to even measure at those resistors.....
Probably killed the ISL or SMC now.