820-01949 - no power / changed CD3217

[quasimodo]

Hey guys,

history:

3 ports were showing 5V/0.45A
1 port was dead / burn mark on chip / nothing on amp-meter

changed the chip. now the 3 working ports showing 5V/0.25 -> dead port showing now 5V/0A

ppbus_g3h / 3v3 are there, when i connect to the working ports. strange voltages when i connect to the "faulty" port...

bad chip or what to do?

 

[quasimodo]

ppbus_g3h is 12.3v on working ports -> t2 crap?

 

[2informaticos]

You should get same behavior on all ports.
Compare diode mode readings and voltages around CD3217 chips.

 

[quasimodo]

everything looks okay. just read about the board on repair.wiki.

i put a new cd3217 on it - i really need to pull the cd3217 from a donor board?

 

[2informaticos]

Only 01700 is known for weird issues with CD3217 chips.
01949 should accept new chip (if good).

 

[quasimodo]

okay, whats going on here...

put another chip on it. on this chip the amp meter shuts off and on in a loop. on the same side the cd3217 gives me 5v 0.26a

on the other side i get on both chips 20.4v - jumping to 0.3a and then to 0.02a...whats happening here?

 

[2informaticos]

You still have problems on that side; CD3217 chip, bad solders, or surrounding components.
You may try reflashing corresponding TBT ROM chip.

 

[quasimodo]

okay, i think its like bad soldering.

put another new one on it. on the good side its booting up now, got an apple and login screen.

on the bad side same behaviour...

i thought every cd3217 should be good to boot up?

 

[2informaticos]

Good enough if T2 can talk with all CD3217 chips.
If a problem exists on the "front side" of CD3217 chips, that can cause this symptom.