820-02016 5v 0a

Outofwhack

Member
ppbus_aon 12.3v
3v8_aon 3.8v

When charger connected to top USBC port [nearest screen]
pp3v3_upc0_ldo [which powers the ROM] only gets 3.3 volt when
pp3v3_upc1_ldo sits at 0.4v

when charger connected to lower USBC port
pp3v3_upc0_ldo [which powers the ROM] gets 0.4 volts
pp3v3_upc1_ldo sits at 3.3v

What's going on?
 

2informaticos

Administrator
Staff member
LDOs must be checked on the same channel where the charger is connected.

Instead of top/low ports, isn't better to specify corresponding 0/1 channels?
If you click (boardview) on a port connector, will show you corresponding channel is...
 

Outofwhack

Member
The point I am making is that ROM chip is only getting the correct voltage on one channel. Something seems wrong and Im wondering if this is what stopping it shift to 20v. Ive replaced both CD3217 with new and now Im wondering if I have overtemped one.
 

2informaticos

Administrator
Staff member
New CD3217 chips?
Where did you get them?
These chips have firmware; must get them from same donor board model!
 

Outofwhack

Member
Ah thought left hand side CD3217 were replaceable with purchasable ones. Good job I kept originals. Im going to put them back and post status again!
 

Outofwhack

Member
OK the original CD3217 back in their places.

ppbus_aon 12.3v
3v8_aon 3.8v

When charger connected to channel 0
pp3v3_upc0_ldo [which powers the ROM] only gets 3.3 volt when
pp3v3_upc1_ldo sits at 0.4v

when charger connected to channel 1
pp3v3_upc0_ldo [which powers the ROM] gets 0.4 volts
pp3v3_upc1_ldo sits at 3.3v

Shouldn't they both be at 3.3v independent of which channel is receiving power?
Can you suggest what to do from here?
 

Outofwhack

Member
Ive just taken delivery of a locked identical board that gets to 20v. Ive just taken its CD3217s and I still get that asymmetry described in my post #6.
So the rom only gets 3.3volts when charger on channel0 and 0.5v when on channel1.
There are no voltages on inductors around U8100.
 

2informaticos

Administrator
Staff member
Don't expect same behavior as old T2 boards.
The powered port delivers 3V2_LDO from VBUS.
Second one requires 3V3_S2 as input.
 

Outofwhack

Member
But the asymmetry described in my post #6 is not present on the working board. The rom gets 3.3v no matter which channel is powered.

Anyway do you suggest I replace U8100?
 

Outofwhack

Member
I understand you are saying 3V3_S2 comes from the U8100 and there may be problems with that chip and that chip has a healthy power supply in PP3V8_AON_VDDMAIN.
But is it being told to turn on? In FlexBV notes there is a list of things that come before "step 11 (Many rails appear now)". Is that list supposed to be chronological? Anyway do you suggest I replace U8100?
 
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