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820-00239 only 5V
- Thread starter hascanio
- Start date
Usually CD3215 issue, as these chips connect directly with the charger.
Check first if R6915 is still 0 ohm.
Check first if R6915 is still 0 ohm.
Compare diode mode readings on LDO rails between all CD3215 chips.
I tried to pull out all the four CD3215 but still not 3.4V on PP3V3_G3H, only 2.2V.
Tried to pull also SMC, U5256 y U5165, nothing change. Tried to manually introduce 3.4V in the circuit but voltage not lower. So i think is something not related to resistance or capacitors, but i dont know where to search for.
Tried to pull also SMC, U5256 y U5165, nothing change. Tried to manually introduce 3.4V in the circuit but voltage not lower. So i think is something not related to resistance or capacitors, but i dont know where to search for.
I leave only one new CD315 to do this....
Diode mode on PP3V3_G3H circuit is 370, the same of a working board.
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Actually, do you get 3.3V at C6912, if R6915 is removed?
If you had short before on 3V3_G3H, R6915 should be damaged somehow; change it, just in case.
If R6915 value increases, 3V3_G3H will drop; even no short there now (or low value).
"with a terrible short on PP3V3_G3H."
What component was shorted?
If you had short before on 3V3_G3H, R6915 should be damaged somehow; change it, just in case.
If R6915 value increases, 3V3_G3H will drop; even no short there now (or low value).
"with a terrible short on PP3V3_G3H."
What component was shorted?
Yes, if i pull R6915 i have 3.4V at C6912. R6915 changed 2 times.
I changed D6902, U6903, C6905, C7081, C6905, all shorted. I changed also U7000 but it was good (put in place the old one, PP3V3_GH3 still remain).
I tried also to change R6915 with a wire, but nothing change, it lowers to 2.2V anyway.
I changed D6902, U6903, C6905, C7081, C6905, all shorted. I changed also U7000 but it was good (put in place the old one, PP3V3_GH3 still remain).
I tried also to change R6915 with a wire, but nothing change, it lowers to 2.2V anyway.
Replace C6907 and R6908.
You may need to play with FB resistor divider.
Shorting R6913, will increase probably not too much 3V3_G3H.
Better to try 10k in place of R6912; may need to try higher value, 22-33K.
You may need to play with FB resistor divider.
Shorting R6913, will increase probably not too much 3V3_G3H.
Better to try 10k in place of R6912; may need to try higher value, 22-33K.
You've changed C6905 too many times, don't you think?
I suppose to be a typo...
U6903 is the only one who could generate short on 3V3_G3H.
Unless one of the "C6905" mentioned caps is not C6915 instead.
If you (correctly) play with the resistor divider (R6910-13), 3V3_G3H must change accordingly.
If not there can be a problem with U6903; just in case, try another one.
Older MacBook schematics have a formula writen near the 3V42_G3H power supply; try to understand it.
Is still valid here, just reference voltage may change a bit.
I suppose to be a typo...
U6903 is the only one who could generate short on 3V3_G3H.
Unless one of the "C6905" mentioned caps is not C6915 instead.
If you (correctly) play with the resistor divider (R6910-13), 3V3_G3H must change accordingly.
If not there can be a problem with U6903; just in case, try another one.
Older MacBook schematics have a formula writen near the 3V42_G3H power supply; try to understand it.
Is still valid here, just reference voltage may change a bit.
Yep, one of the C6905 i wrote was C6906 instead.
The only thing i don't understand is why 3.4V is correct if i pull R6915. If there is a short with U6903, the voltage should be bad also without pulling out that res, no ?
And, as i told you in the prevoius post, i "played" correctly with the resistors but only with R6912-R6913.
Should be something after R6915 than lowers voltage ?
The only thing i don't understand is why 3.4V is correct if i pull R6915. If there is a short with U6903, the voltage should be bad also without pulling out that res, no ?
And, as i told you in the prevoius post, i "played" correctly with the resistors but only with R6912-R6913.
Should be something after R6915 than lowers voltage ?
Should be something there, but strange that you can't detect a low diode mode reading; check again, in both directions (red/black at ground).
So, i pull out R6915 and measure diode mode as you told me, in both directions. At Pin1 are the same comparing with a working board in both modes (red/black to ground); at pin 2 red to ground are the same (0.370) , but black to ground no (working 1.400, faulty 0,755). So, now, how can i find the component that is causing this on the pin2 part of the circuit ?? I have not a 6 digit tester.....
As i already told you in a previos post i tried to enter 3.4V manually at pin 2 but in this case it doesn't lowers and no shorts.
As i already told you in a previos post i tried to enter 3.4V manually at pin 2 but in this case it doesn't lowers and no shorts.
You don't need 6 digit multimeter.
You should start removing chips connected to 3V3_G3H, starting with the ones more easy to remove.
Also think which one is more suspect, to remove first (one by one).
Let the board cool down and check diode mode each time.
You should start removing chips connected to 3V3_G3H, starting with the ones more easy to remove.
Also think which one is more suspect, to remove first (one by one).
Let the board cool down and check diode mode each time.