-
For $29/mo, we provide access to advanced level technicians who will answer your questions on any Macbook board related matter to the best of their knowledge promptly & walk you through how to solve your problem so you can deliver a working board to your customer.Subscribe Now
820-3302-a dead imac
- Thread starter Yoel Ren
- Start date
We need to know some voltages on the board.
Do you get any diagnostic LED on at least?
Do you get any diagnostic LED on at least?
You must check some voltages.
First LED is for S5 state.
You must check U7600 area, it fails a lot...
First LED is for S5 state.
You must check U7600 area, it fails a lot...
so I change c9450 because of pp3v3_s5 short, now imac is up and running normally.
i have 2 imac screen which i forget is working or not, then I plugged the bad one, and L9100 blowed up, the question, can I just use solder blob there / wire ?
any shipping is very long in my third world country
(
i have 2 imac screen which i forget is working or not, then I plugged the bad one, and L9100 blowed up, the question, can I just use solder blob there / wire ?
any shipping is very long in my third world country
(
How can you power up a machine, testing unknown LCD, without checking diode mode first???
If there is still short, what do you think will happen if you solder direct wire (or blob)?
If no short, use some tiny magnet wire; 0.05-0.1mm should be good enough.
If there is still short, what do you think will happen if you solder direct wire (or blob)?
If no short, use some tiny magnet wire; 0.05-0.1mm should be good enough.
Bad cable.. So i change L9000 and use another cable and screen turn on fine
. But i notice that, when i plug power cable, fan start ramping to max speed, but if i turn it on, the fan goes.normal ( not maximum speed), if I shut it down, the fan goes maximum speed again
I use 220 ohm ferrite bead from 820-3476 L8300..
. But i notice that, when i plug power cable, fan start ramping to max speed, but if i turn it on, the fan goes.normal ( not maximum speed), if I shut it down, the fan goes maximum speed again
I use 220 ohm ferrite bead from 820-3476 L8300..
Which is the exact ohm value for the coil soldered in place of L9100?
I mean real value, measured onboard.
Do you mean fan spins at max when machine off?
Power fan is not available in S5 state; you have a shorted MOSFET (Q7950) between S5 and S0 rails.
I mean real value, measured onboard.
Do you mean fan spins at max when machine off?
Power fan is not available in S5 state; you have a shorted MOSFET (Q7950) between S5 and S0 rails.
2 ohm is OK.
Check first if that MOSFET is shorted.
Post Q/U7950 voltages.
Check first if that MOSFET is shorted.
Post Q/U7950 voltages.
voltage is 11.75v on pin 1 2 7 8 of Q7950
U7950 pin 1 : 11.75v
pin 2 : 0v, because in s5 state ? ( im not turning it on yet )
pin 5 :11.75v
pin 6 : 11.45v ( pc is not turned on yet, but there's voltage there, so do I change both or only U7950 ?
pin 7 :10v
pin 8 : 0v
U7950 pin 1 : 11.75v
pin 2 : 0v, because in s5 state ? ( im not turning it on yet )
pin 5 :11.75v
pin 6 : 11.45v ( pc is not turned on yet, but there's voltage there, so do I change both or only U7950 ?
pin 7 :10v
pin 8 : 0v
Last edited:
"Check first if that MOSFET is shorted."
Looks like yes, but why don't you do that???
Replacing it should solve the problem...
Looks like yes, but why don't you do that???
Replacing it should solve the problem...