820-00840-A no power only 5V on PP20

modesto1993

New member
hi everyone, logic board with no sign of liquid, no ignition, I receive 5 V on the PP20V_USBC line but nothing on the PP3V3_G3H line
 

2informaticos

Administrator
Staff member
What the client said about how the problem appeared?
Check if he uses original, or fake charger.

Check LDOs of both CD3215 chips.
Compare diode mode readings with good board.
 

modesto1993

New member
The problem occurred suddenly while the computer was on, it shut down and from there no sign of life. Original charger. Tomorrow I'll try to take other measurements, I don't have a good board for the values...
 

modesto1993

New member
Pp1v8_upc_xb_ldod 0.48 website 0.48
Pp1v8_upc_xb_ldoa 0.53 website 0.52
Pp1v8_upc_xa_ldod 0.48 website 0.48
Pp1v8_upc_xa_ldoa 0.52 website 0.52
Pp3v3_upc_xa_ldo 0.51 website 0.50
Pp3v3_upc_xb_ldo 0.51 website 0.50
 

modesto1993

New member
V3V3 G3 H- boost 0V
PPVIN-G3H-P3V3G3H 1,75 V
V3V3G3H-SW 0V
Agi ND-P3V3G3H 0V
V3V3G3H-BIAS 0.04V
V3V3G3H-FB 0V
PM-EN-P3V3-G3H 2.67 V
 
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modesto1993

New member
PPVIN-G3H-P3V3G3H" Diode mode 0
R6906 Diode mode 0 resistance 0.28ohm
D6905 ppbus_g3h 0.424
D6905 PPDCIN-G3H-CHGR 0
D6905 PPVIN-G3H-P3V3G3H 0

I realized that I performed the measurements with the power supply connected, without it all the values are completely different and therefore I rewrite them below:
PPVIN-G3H-P3V3G3H" 0.26
R6906 Diode mode 0 resistance 0.33ohm
D6905 ppbus_g3h 0.424
D6905 PPDCIN-G3H-CHGR 0.570
D6905 PPVIN-G3H-P3V3G3H 0.265
 
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2informaticos

Administrator
Staff member
Seems that you didn't understand what I asked about R6906 and D6905.
I didn't say anything about checking them in respect with ground!
Do you know how to check a resistor, or diode?
Remove them from board, if you don't know other way.
I hope you will not give diode mode to ground readings, once components are not soldered on the board.

About the short to ground, remove C6990/1 and see if gone from PPVIN_G3H_P3V3G3H.
 

modesto1993

New member
I corrected my previous post, I had done the measurements with the power supply connected.
If there is a need to remove them from the board I will do it, it's not very clear to me, sorry
 
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2informaticos

Administrator
Staff member
No need to remove them from board; just check ohm scale BETWEEN their pins.
Where diode mode to ground is specified, do it as normal.
But keep in mind, ALWAYS remove power (charger AND battery) when check in diode mode, or ohm scale!!!
 

modesto1993

New member
R6906 0.28
Do I measure the D6905 with black to ground? If these are the values:
Pin 1 3.7 M ohm (it is worth very unstable)
Pin 2 118k ohm
Pin 3 0.427k ohm
 

2informaticos

Administrator
Staff member
"Do I measure the D6905 with black to ground?"
NO!
Don't really know how to check a diode?
How will you check it out of board (no ground available)???
Is a DIODE; check it in diode mode between their pins.
You should get indication one way; and OL in reverse way.

At least post voltage on their pins (to ground), before removing it; charger connected.
 

modesto1993

New member
black pointer on pin 2
pin 1 1.24
pin 3 0.23

black pointer on pin 1
Pin 2 0
Pin 3 0.94

black pointer on pin 3
Pin 1 0.23
Pin 3 0

This is without power supply
 

2informaticos

Administrator
Staff member
Strange way to check it.
You had to check pins 1-3 and 2-3.
Anyway, diode looks good.

"At least post voltage on their pins (to ground)"
?
 
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