820-3437 Liquid Damage Pulsing S0
Hello!
I have always interested in component level repair, so when the opportunity to get a liquid damaged Mac Book Air arrived, I was delighted. So bear with me, as this is my first attempt at this.
I get Green/Orange on the Mag Safe, but no fan spin.
Below are my voltages.
PPBUS G3H = 8.58
PPBUS_S5_HS_COMPUTING_ISN = 8.58
PPBUS_S5_HS_OTHER_ISNS = 8.58
PPDCIN_G3H_ISOL = 15.13
PPDCIN_G3 = 15.13
PP3V42_G3H = 3.44
PPVRTC_G3H = 3.33
PP5V_S5 = 5.2
PP5V_S4RS = 3.34 Pulse
PP5V_S0 = 3.14 pulse
PP3V3_S5 = 3.33
PP3V3_S4 = 0.33
PP3V3_SUS = 3
PP3V3_S3 = Pulse 2
PP3v3_S0 = Pulse 1
PP3V3_S4SW_SNS = Pulse 3
PP3V3_S0SW_SSD = 2.3
PP3V3_S4_TBTAPWR = Pulse 3
PP1V8_S3 = 1.7
PP1V2_S3 = Pulse .70
PP1V05_SUS = 1.06
PP1V5_S0 = 1.5
PP0V6_S0_DDRVTT = Pulse .34
PP1V05_S0SW_PCH_HSIO = 1.05
PP5V_S4RS3 = Pulse 3.34
The little corrosion I found was near U6100. I cleaned with with isopropyl alcohol. I measured all 16 terminator resistors and they are fine. The only issue I can find (besides the voltages) is Pin 2 on U6100 (SPI_MLB_MISO), does not have continuity with R6114, R6123 or it’s VIA (824). My questions are…
- Should I be getting continuity from those locations? If so, is re-soldering the chip/replacing is my next step? I know it’s a BIOS chip, so it’s not a simple rip and replace.
- Is 15.13 too far out of tolerance for PPDCIN_G3H_ISOL/PPDCIN_G3 which should be 18.5?
- Any other suggestions as to what I should look into.
Is dit een goede vraag?
Have you reviewed Louis Rossmann’s vids? Louis’s YouTube stuff He gets into board level repairs.
door Dan
Yep, he is the only reason why I made it this far, starting with no knowledge. :)
door bill