A1534 820-00687-A no power on

[hgoncalves]

Hi,

I have an A1534 820-00687-A that doesn't power on. On the ampmeter it puls 20.5V, but 0A. Already tried a new flex cable, but no success.

I'm using one boardview and schematics of a 244 (not sure if this is OK, but don't have a 687)

PPBUS_G3H = 8.68V
PPBUS_S5_HS_COMPUTING_ISNS = 8.68V
PPVBUS_LIO = 20.54V
PP3V3R3V0_AON = 3.3V
PPVRTC_G3H = 3.0V
PP5V_G3H = 5.1V
PP5V_S0 = 5.1V
PP3V3_S5 = 3.3V
PP3V3_S0 = 0V
PP3V3_SUS = 0V

On PP3V3_S4, mesuaring on R7801 I only get 1.6V; On L4802, I only get 1.6V, and on pin 12 of U1900 I get 0V.

Can you help?

 

[2informaticos]

I'n wondering how do you get 5V_S0 without 3V3_S0, nor even 3V3_SUS.
Re-check your measurments...

 

[hgoncalves]

Sorry, you're right.
PP5V_S0 = 0V

PP5V_S5 = 5.1V
PP5V_S4 = 5.1V

The other mesuarements are correct.

 

[2informaticos]

To enter S4 state, board must pass through SUS first.
Still unclear ho do you get S4 voltage, but no 3V3_SUS.
PM_SLP_SUS_L missing for sure?

 

[hgoncalves]

Hi,

Unless my schematics is wrong (I'm using a 244 board schematics), I think that I'm reading it corectly.

I'm measuring 3V3_SUS on C6100, and C6101, and I get 0V on both.

PM_SLP_SUS_L on R1554 has 0V also.

PP5V_S4 on R7100 has 5.1V

PP3V3_S4 on L4802 has 1.7V

 

[2informaticos]

From schematic looks this board has different behavior for SUS state.

If you get 5V_S4, then 3V3_S4 must be present too; same enable signal is used for both rails.
Check diode mode to ground at 3V3_S4.
If good, then change U8200.
Be sure to get 3V at its ON pin.

 

[hgoncalves]

Hi,
Diode reading on 3V3_S4 is ok (0.491).
I've replaced U8200 but no sucess. However, now on 3V3_S4 I have 2.83V.

Voltages on U8200: I have PP3V3_S5 (3.3V), but on PM_SLP_S5_L (pin 6) I have 0.055V. Can it be U5000 or a bad U8200?

 

[2informaticos]

The same PM_SLP_S5_L is present at pin 4 of U7650.
Check for continuity.

 

[hgoncalves]

I don't have continuity from U8200 to U7650, but i have from U8200 to R8305 (pin 1), and I have from U7650 to R8305 (Pin 2).

On R8305 I read 9.96 kohm, but my schematic doesn't have R8305 (and I don't have other board to compare), and so I'm not sure if the value is the correct one. Do you think that it can be it?

 

[2informaticos]

Are you using 00244 schematic?
I can't find R8305 there.

You must check continuity for PM_SLP_S5_L...

 

[hgoncalves]

Hi, yes, I'm using 00244 schematic and boardview.

I've checked continuity of PM_SLP_S5_L from U8200 to U7650, but it doesn't have continuity.

The schematic doesn't have it, but the boardview shows it (R8305).

 

[2informaticos]

What is the voltage on both pins of R/D8305?

 

[hgoncalves]

D8305 is a no stuf. However, on pads I have:
1 = 0V
2 = 0.034V

R8305:
1 = 0.034V
2 = 0.053V

 

[2informaticos]

Then you don't have PM_SLP_S5_L.
How then do you get 5V_S4?

Possible there are more differences between board and schematic.
If PM_SLP_S5_L is really present at U7650, then wire it to U8200.

 

[hgoncalves]

After replacing (twice) U8200, because I broked it, now I don't have PP5V_S4 (0V), neither PM_SLP_S5_L (0V), and only have 0.650V on 3V3_S4.

I have PP3V3_S5 (3.3V), and PP5V_S5 (5.0V)

PP5VS4_EN pin 4 of U7650 has 0.054V

3V3_SUS = 0.003V

Possiblly, the heat damage something else?

 

[2informaticos]

Did you get PM_SLP_S5_L present at U7650 for sure before?
I suppose PCH problem; possibly affected by the heat now.

 

[hgoncalves]

I never had PM_SLP_S5_L on U7650. I had 5.1V on PP5V_S4, but I didn't measured it on U7650; I've used R7100 to measured PP5V_S4 , and I'm sure that there I had 5.1V.

Shall I try to replace U7650?

 

[2informaticos]

Why, if is not enabled?

Really strange to got 5V_S4 before; U7650 requires high level at pin 4 for that.

 

[hgoncalves]

I understood your point, but I'm not sure if I had it there before, because I didn't cheked. I suppose I had it.

Can't it be U5000? R1553 should be 100k ohm (i think) but I'm reading a lot of oscilating values on it. Do you think that this can be related?

 

[2informaticos]

PCH is the one in charge to release PM_SLP_Sx_L signals.
Of course, it requires some other previous signals; like RTC and S5 power.