[SOLVED]820-00281 no power

[rex1986]

Hello,

i have a 820-00281 Board which won't turn on. I inspected the board and it doesn't have any corrosion or burned components. All fuses are ok! I mesured pp20v_usbc_xb_vbus. It has instead of 20V, only 5,2V. ppdcin_g3h also has 5,2v

ppvin_g3h_p3v3g3h 5,2v
ppdcin_g3h_chgr_r 5,2v
ppbus_g3h_r 0v

If you need any other values, please let me know.
Can anybody tell me how to find the faulty component ?

 

[dukefawks]

3V3_S5_SMC present and if not is it shorted to GND, diode mode measurement?

 

[rex1986]

Hi and thanks for your reply.

3v3_s5_smc 0v and not shorted to ground.

All coils on the board have 0v.

 

[dukefawks]

Voltages on all pins of D6902? Charger connected of course.

 

[rex1986]

Pin 3 ppvin_g3h_p3v3g3h 5,2v
Pin 1 ppdcin_g3h_chgr_r 5,2v
Pin 2 ppbus_g3h_r 0v

Charger is Brand new from apple store and plugged in.?

 

[dukefawks]

Check again for 3V on L6900 as the input to U6903 seems fine. Check voltage on R6921.

 

[rex1986]

l6900 0v and r6921 5,2v

for one moment it had the right values but after that, always the values i wrote bevore

 

[dukefawks]

So enable is present to U6903 and it is receiving power from D6902. I would actually expect 3V on R6921 so make sure you are measuring the correct thing.

 

[rex1986]

i mesured the wrong resistor, the value of r6921 is 0v

 

[dukefawks]

Check around U7000. Is there voltage on L7030? TBA_AUX_DET present?

 

[rex1986]

l7030 0V and TBA_AUX_DET 0,9V

Do you have any messenger? Otherwise we maybe need a few weeks to find the faulty component or IC

thx a lot!

 

[dukefawks]

What is the voltage on R7075? I'm starting to suspect a bad U7000.

My direct messenger is available for $100 an hour if you really insist.

 

[rex1986]

I Changed u7000 and it works now.

thank you very much!

 

[dukefawks]

Awesome! Another chip I need to get in stock then. It was probably killed by a shit Chinese charger or cable.