820-3437 No green light

[arghhh]

Is pp3v42 g3h present or not?

 

[Japtastic]

Nope not present.

 

[larossmann]

PP3V42_G3H is the first supply needed for anything to work. What is the resistance to ground on PP3V42_G3H? What voltage do you get on pins 6 & 8 of U7090?

 

[Japtastic]

U7100 is still off the board but...

Resistance to ground on PP3V42_G3H on 2MΩ mode = .445

I don't want to second guess anything so I shall now put back U7100 to test U7090 voltages of pin 6 and 8? Even when DCIN is all over the place with U7100 back on?

 

[2informaticos]

You don't need U7100 to check U7090 voltages...
Do you get PPDCIN_G3H_ISOL?
Check R7005, D7005 and resistance to ground after it.
Seems that charger detects leakage and gets in protection mode.

 

[Japtastic]

PPDCIN_G3H_ISOL is present at a solid 14.4v

R7005 tests fine at 10ohm
D7005 Pin 1 = 0.08v Pin 2 = 14.4v Pin 3 = 14.4v

Resistance to ground after these components is around 150k ohm tested at all points they connect to.

 

[2informaticos]

Check voltages at U7090.
Be aware at corroded traces.
Change it, if no other components are damaged around...

 

[Japtastic]

Didn't see your message until this morning.

U7090
Pin1 = 1.23v
Pin2 = 3.4v
Pin3 = 6.7v
Pin4 = 3.2v
Pin5 = GND
Pin6 = 14.4v
Pin7 = N/A
Pin8 = 14.4v

All tested from the pins of U7090

Can't see any broken or corroded traces around there.

Looks ok, right?

Edit: Realising that PP3V42 is back without U7100 on the board.

 

[2informaticos]

Now solder good U7100 and check PPBUS_G3H.

 

[2informaticos]

Check resistance to ground at R7120/50...

 

[Japtastic]

R7120 is 35ohm to ground
R7150 is 34ohm to ground

 

[2informaticos]

Pull Q7130 and check again...

 

[Japtastic]

Thanks for all your help. Removed Q7130

R7120 now OL

R7150 now 30 ohm to ground.

DCIN now 14.4v Solid.

PPBUS_G3H 0.1V Solid.

PP3V42_G3H 3.4v Solid.

 

[Japtastic]

Yes you are correct.

Pin1 is 3.3/3.5v
Pin 2 is 0.08v

L3095: Pin1+2 = 0.08v

Both L3095 and Pin 2 of F7140 are 144 Ohm to ground.

 

[2informaticos]

144 should be good on PPBUS_G3H, when F7140 is closed.
You told us something about 30ohms before...
I expected diode scale measurement after remove F7140, not voltages.
However, check if Q3080 is shorted.

 

[Japtastic]

Apologies for the misunderstanding. Q3080 is not shorted to ground.

 

[2informaticos]

And me never asked you to check short to gorund...
It is shorted D-S???