(347) 552-2258 [email protected]

820 01521 140/150mA no power

R

Roan

Member
Been looking at an A1932 board and I am a bit stuck.

No short on PPBUS_G3H
one usb c port shows 0.14A 5.2V
other 0.15A 5.2V

pulled the ISL off, no shorts found on the pads underneath
placed a new ISL, exact same issue so I guess the old one was fine

PP20V_USBC_XA/B_VBUS reads 5.13V
PP1V8_SLPS2R reads 0.06V

PPDCIN_G3H reads
0.02V for 0.14A port
0.00V for 0.15A port

Could this be as simple as a charging flex that is defective? 140/150mA gets past the meter so there is a connection, is the fault all the way upstream? No shorts found. CD3215 fault feels unlikely since the behaviour is so identical. Trying to learn this stuff but don't know where to go from here. Thanks
 
R

Roan

Member
PPDCIN_G3H not shorted

chip A
LDO_BMC is 0V
LDOD is 1.1V
LDOA is 0V
LDO is 0V

chipB
LDO_BMC is 0V
LDOD is 1.1V
LDOA is 1.8V
LDO is 3.3V

PP3V3_G3H_RTC is 0V, not shorted
 
R

Roan

Member
Oh sorry

A port values are
LDOD = 40
LDO_BMC = 600
LDO = 10
LDOA = 530

B port
LDOD = 40
LDO_BMC = 600
LDO = 20
LDOA = 530
 
R

Roan

Member
Yes sorry, 0.040 voltage drop.

Then again the values of both cd3215 look very similar so since both are probably not bad at the same time is it probable to be a problem upstream?
 
R

Roan

Member
Checked them mutliple times, black probe on nearby screwhole and red probe on the caps around the CD3215s. LDO of both ports hovers around 0.012, LDOD around 0.042/43 for both ports.
 
2informaticos

2informaticos

Administrator
Staff member
"black probe on nearby screwhole and red probe on the caps"
In diode mode, ALWAYS red probe on ground!

HOW TO collection

I hope this "How to" collection will help our members. I will possibly modify this post in time, if updates available. Trigger SMC_ONOFF_L (PMU_ONOFF_L): It reffers to simulate power button function, when the keyboard is not connected. We need to do this when we work with the board...
boards.rossmanngroup.com boards.rossmanngroup.com

However, such low readings are bad, even in reverse way.
I hope you've disconnected charger first.
 
R

Roan

Member
Thank you for correcting! Is this because of passing through otherwise closed mosfets which are not turned on if the board is not getting the normal power rails?

Values of 0.020 and 0.040 are still unchanged when measuring the correct way with red probe on ground :(.

Yes charger always disconnected when doing diode mode measurements.
 
2informaticos

2informaticos

Administrator
Staff member
In such case, both CD3215 chips should be bad; if your measurments are correct.
Just in case, can you specify at wich capacitors found these readings?

I hope battery was also disconnected.
 
R

Roan

Member
In same order as measurements above:

C3105
C3104
C3108
C3106

C3205
C3204
C3208
C3206

Batterij also disconnected
Ill order 2 CD3215s and before putting the new ones on I will check for shorts on the pads underneath
 
You must log in or register to reply here.
Top