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820-00281 - Not charging, shows sign of battery flat

overshoot

overshoot

Member
820-00281 Not charging, 5V 0.02A on charger only (battery unplugged), 20V 0A with battery plugged, shows sign of battery flat.
Should be a simple problem to fix but...

Each USB-C port shows 5V with 0.02-3A consumption. No port power cycles.
When checking rails around the USB-C chip, I'm getting my 1.1V, 1.8V, 3.3V and 5V as expected.
PPBus does not have a short, .4V drop in diode mode.
I am getting 0.04V on PPBUS, floating.

I went ahead and replaced the SMC from a donor thinking there might be communication issue on those BI lines. No cigar.
I also went ahead and replaced the ISL. No cigar.
However I got that ISL 9239C0 from Aliexpress (original being 9239HI) but read that the 9239C0 should work just fine.

Though, noob question here...
Shall I be getting 20V before getting PPBus?

I assume yes and that's why I believe I went on the wrong road chasing no PPBus when I should be chasing why I am not getting 20V first.
Any good read on the Wiki or idea where to look at please?

Also I assume a short on some rail down the road is not on the list since I am getting the battery sign showing up with the battery plugged in.
 
T

tcampbell34

Member
Make sure you using a 87w charger and USB-C cable that is rated for 5 amps. You need to get 20v before worrying about no PPBUS on this board.
 
overshoot

overshoot

Member
I went ahead and replaced one more time the ISL from a donor this time. No change.

The resistor connecting SMC_USBC_INT_L to 3.3V is measuring fine. (I've checked other thread talking about a blown resistor)
 
2informaticos

2informaticos

Administrator
Staff member
Post U7000 basic voltages (charger alone): P_IN, AUX_DET, SMC_RST_IN, VDDA/P, SMC_RST*, IRQ*, AUX_OK, A/BMON.
 
overshoot

overshoot

Member
P_IN 5.14V
AUX_DET 1.27V
SMC_RST_IN 3.4V
TBA_VDDA 5V
TBA_ VDDP 5V
SMC_RST 3.4V
IRQ 3.4V
AUX_OK 3.4V
AMON 0V
BMON 0V
 
2informaticos

2informaticos

Administrator
Staff member
SMC_USBC_INT_L is still a problem.
It keeps bloqued the SMC, which doesn't allow U7000 to work.

Does it start in SMC bypass (charger alone)?
 
overshoot

overshoot

Member
Unfortunately it didn't make any difference doing the SMC bypass

I've checked with the thermal cam and nothing seems to be warming up.
The only area on this board that looks pretty corroded is the right wing (underneath) where the T1 controller is.
I've removed every corroded capacitor and reflowed the area, no luck.
Indeed that was to be expected since it will work on battery so no short I assume.

I've measured the surrounding components around U7000 and all seem to measure fine.
I'm tempted to replace the SMC one more time since it's coming from one of these Chinese donors.

Anything else that I could be looking at knowing that SMC_USBC_INT_L signal is low?
 
overshoot

overshoot

Member
I went ahead and replaced one more time the SMC with a good known SMC and same behavior.
So my guess is that it is CD3215C00 related now since that signal only from the SMC to those ICs?!
 
2informaticos

2informaticos

Administrator
Staff member
Test R3038 with 1K, instead of 10K.
Check R3041/42 and R5320/21.
Also check diode mode to ground and voltage on that SMBUS "4".
 
overshoot

overshoot

Member
I did replace the resistor and the signal is still pulled down. It did not make any difference in terms of voltage on the SMC_USBC_INT_L side.
Those 4 resistors are measuring as they should.
I am getting around .53V drop on both SMBUS_SMC_4 SCL and SDA signals.
Measuring .63V on known good board.

What are the odds that a CD3215 is the culprit?
 
2informaticos

2informaticos

Administrator
Staff member
The CD3215 chips must release this signal.
There must be a reason, into USB-C areas, that doesn't allow that.
 
2informaticos

2informaticos

Administrator
Staff member
Until SMC_USBC_INT_L doesn't go high, I don't think to get it working with charger alone.
You can compare the behavior of this signal with similar boards.
 
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