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Got the clock issue fixed but then suddenly now I have a short on PPBUS_G3H. It was measuring 2v at F7140. I was looking around for something that was getting hot but couldn't identify anything. I injected voltage to the PPBUS_G3H line and slowly added voltage up to 1v. The CPU was heating up...
Changed clock chip out and now I have 3.41v on U1900 pin 1. Now have .04v on U7501 PP5V_S5. I've already changed out the chip. Do you think that something else cooked it while I was messing around with U1900? Ugh
PP5V_S5 diode mode measured at C7505=.479Ohms
PPVRTC_G3H diode mode measured at C1910=.472Ohms
Looking for a replacement clock chip in my donor boards to replace this one with
Do you think that if I inject 5v on the PP5V_S5 line at maybe C7505 I'd have a better chance of finding the short? I also tried with the battery but there is no change.
Looking for the short:
Removed 4820-.75v
Removed C4810-.82v
Removed C7505-.81
Removed C7400-.81
I have an 820-00165 MacBook Air 2015 board liquid damaged with green light/no power/no fan. Damage was centralized on U7501. Via to C7500 to pin 23 on U7501 burned.
Replaced U7501. Voltage at pin 14 on U7501 .75v before chip changed. No change in voltage after chip changed, still .75v
Replaced...
I've also checked out R5110, R5111, R5112, etc. R5121-R5128 and they all check out with correct readings. Steady 3.3v at R6101 even during power cycling.
On R7086 I get a steady 6.81v on pin 1. On pin 2 I get 0v. Resistor checks out as 330k with meter. Not sure what I should be getting at pin 2 for voltage.
Diode mode measurement PPVCORE_S0_CPU=.46 ohms
PPVRTV_G3H=3.3V
Nothing that I can see on JTAG. I put it in the ultrasonic tank and cleaned it thoroughly with alcohol and a toothbrush as well.
I have an 820-3023 with liquid damage that will not start up. Corrosion was found at U6100 and cleaned. Voltage at Y2705 is 1.14v when power cycles up.
Green light on charger, PPBUS_G3H 8.6v
When power is plugged in the fan spins for 1 second then stops then starts again 5 seconds later...
I'm in need of an 820-2915 for parts or specifically Q7080 for a repair that I have pending. I have donor boards in my shop and I have some on order but none have this specific component.
Anyone have a faulty board or component that I can buy? PM me if so. Thanks.
Thanks all! I found a replacement battery and it started right up! Interesting how the battery is inline with the rest of the power circuitry. Makes things harder to troubleshoot if you don't have all of the necessary parts on hand. On the bench now running overnight to see if all is good...
I have an 820-2915 that was liquid damaged. Will not start up. Green light on the charger. Replaced C4691 due to it being burned. Cleaned in ultransonic tank and reassembled. Still a green light on the charger but will not power on.
U7000
Pin 14 2.33v
Pin 19 0v
Pin 20 0v
Pin 12 3.42v...
Right ok. I'll source another battery and give that shot. Some measurements for the record:
PPBUS_G3H AT D7005 12.6V
PPVIN_S5_HS_OTHER3V3_ISNS AT C7581 12.6V
PPDCIN_G3H AT C7130 18.7V
PP3V42_G3H AT U7090 3.42V
PPVRTC_G3H AT R1100 3.3V
PP5V_S5 AT C7505 5V
PP5V_S4 AT R8165 5V FOR 10 SEC...