820-01598 5v loop without battery, but turn on with battery.

Yoel Ren

Member
this device got liquid damaged, shorted ppvin_p3v3hrtc_r, replacing u6903 relieve the short.
both port is 5v loop but mac turn on withbattery.

but usb c cannot be used to charge or detect usb drive.
i notice, if battery is connected. one port will have 5v 0amp, while the other port wont even turn on the ahm meter.
 
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Yoel Ren

Member
i have replaced both cd, one by one and test the symptom, but still same.
i have ruled out charging port aswell.
 
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2informaticos

Administrator
Staff member
Your problem should be on USB-C area, if machine works with battery connected.
Compare diode mode readings between both ports; especially CC1/2 lines.
 

Yoel Ren

Member
i compare the diode mode reading between port fpc, both port measure the same ( i compare the counterpart of the same line ).
i notice a chipped dz3302. but the line itself isnt shorted.
any chance its from u2800 ?
 

2informaticos

Administrator
Staff member
On the port where USB meter stays black, should be a problem with CC1/2 lines.
These lines are used for hardware detection of charger.
 

Yoel Ren

Member
when i test again, the top port that correspond to u3200 doesnt respond to ahmeter, even without battery.
the bottom port still loop.
pp20v_usbc_xb_vbus 0.93
usbc_xb_cc1 0.498
usbc_xb_cc2 0.496
usbc_xa_cc2 0.530
usbc_xa_cc1 0.530
 

2informaticos

Administrator
Staff member
Check the input fuses and compare diode mode readings around input MOSFETs too.
Also check continuity from XB_VBUS USB-C terminal and corresponding fuse.
 

Yoel Ren

Member
r7020 got continuity to both cd3217 fuse.
about pp20v_usbc_xb_vbus, i dont see any fuse there.
but it does have continuity from the port to u3200 and its nearby component
 

2informaticos

Administrator
Staff member
Hmm, on this model the fuses are placed after CD3217 chips; not a real input protection.

You should find something wrong on the port corresponding to U3200.
Maybe the chip is bad...
 

Yoel Ren

Member
yeah, im ordering new chip to make sure, im not sure mines known good..
will update after replacing both chip again, thanks for the guidance!
 

Yoel Ren

Member
both cd3217 has been replaced with new one, but still exact symtomps..
to sum up, macbook still alive with battery.
without battery, top port doesnt respond to magsafe at all.
bottom port is 5v from 0-0.26amp then loop..
any pointeR ?
 

2informaticos

Administrator
Staff member
5V from charger is enabled by CC1/2 pins configuration.
Check all components related.
Compare readings between both ports.
 

Yoel Ren

Member
pp20v_usbc_xb_vbus diode mode is 0.140
pp20v_usbc_xa_vbus 0.140
usbc_xa_cc1 0.580
usbc_xb_cc 0.585
usbc_xa_cc2 0.580
usbc_xb_cc2 0.586
doesnt see any component on these cc line, its directly connected to cd3217 which i have replaced..
continuity is good at every probe point to another.. any pointer where to go next ?
 
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