A1534 820-00244 no power

[hgoncalves]

HI,
I have an A1534 820-00244 that has no power.

At first it pulled 19.9V from ampmetter, but no amp.
I notice that PPBUS_G3H was low and so I replaced U7000 = ISL95530HIZ-TR5664 for an U7100 = ISL95530HIZ-TR5655 (not sure if compatible but I got none ISL95530HIZ-TR5664). For a while I geted the 8.7V on PPBUS_G3H but after a while it failed, and now only get 4.9V from ampmeter, and already replaced CD3215 but with the same result (4.9V).

Can you help?

 

[2informaticos]

Maybe bad solders under U7000.
Do you get 1V1 LDO for the CD3215 chips?
3V3_G3H comes on?

 

[hgoncalves]

HI,
I get 1.1V on PP1V1_UPC_XA_LDO_BMC, but PP3V3_G3H only gets 2.8V
PPVIN_G3H_P3V3G3H has 5.2V on C6900. Is this ok?

 

[2informaticos]

1V1 LDO appears only on the powered port.
If you can't get it on the other CD3215 chip (when powered), there is a problem.

 

[hgoncalves]

But the 1534 only has one port...

 

[2informaticos]

Yeah, sorry...

Seems to have overload at 3V3_G3H.
Can you check the board with thermal cam?

 

[hgoncalves]

Yes, I can. shall I look for a shorted component on PPVIN_G3H_P3V3G3H?

 

[2informaticos]

Why?
You can't get there more than the voltage provided by charger.
Be sure R6990 and R/C6994 are good.
Compare diode mode to ground at 3V3_G3H with good board.

You should try another CD3215 chip.

 

[hgoncalves]

R6990 has 9.9 ohm and R6994 has 0.06 ohm. C6994 seams to be ok, and the traces arte fine too.
I don't have other 820-00244 to compare, and I already replaced 3 cd3215 just to be sure, but the same result.
Can you give me a diode reference value of PP3V3_G3H? On my board I get 0.383V