820-00850 - PP1V8_UPC_TA_LDOA reading 3v

[Palhano]

While it had battery power, the mac would turn on, but it wouldn't recognize the charger. I have 20v, the board starts to boot, pulls it down to 0.6v and restarts.

I discovered PP1V8_UPC_XA_LDOD reading 3v on the UB300. I changed it, but the problem remains. But only when the charger is in its USB-C, in the other inputs it has 1.8v. The other CD3215 have normal measurements

It does not have direct contact with the 3.3v line close to the CD3215

Any light?

 

[2informaticos]

"PP1V8_UPC_XA_LDOD reading 3v on the UB300"
Are you sure?
Didn't want to say U3100?

 

[Palhano]

Sorry!

I was searching in another topic about the problem and I was mistaken with the line: PP1V8_UPC_TA_LDOA

 

[2informaticos]

You may have bad solders, or chip.
Check for short between C3100/5.

 

[Palhano]

I tested with two CD3215 chips, same problem.
There is no short between C3100/5.

Could it be a short inside the board?

 

[2informaticos]

Check C3105 voltage with U3100 removed.
You should have 0V.
If not, then you have lekage inside the board.

 

[Palhano]

Without the chip, the C3105 is zero. In OL diode mode. Good sign, right?

My CD3215 chip is over, I'm going to order it and try to change it again.

 

[2informaticos]

I asked about voltage...

 

[Palhano]

yes I understood! without the u3100 the voltage at C3105 is 0v.

 

[2informaticos]

So 3V can only come through U3100; no leakage inside the board.