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No change with known good BIOS and cleaning ME region.
try flux and heat to CPU as last resort or USC first?
Or any chance to being a lid closed error related issue? NOt sure if CPU should boot at all regardless of lid closed as I've believe these tend to go to 20V an 0A when installed...
Testing with board on bench and SSD removed:
Board boots to 19.9V pulling 0.55-0.6A for about 10 seconds then goes to 20V and 0A for about 3 seconds and repeats the power cycle. Gettting readings from all big coils including VCORE but VCORE is not dropping, it's steady at 0.97V when board is...
Was some stuff on and near u1950 that I didn't notice prior so I'm glad you had me check that. Now I'm missing SMC_DELAYED_PWRGD. SMC bypass still won't start the board either.
J6100 originally had stuff on it, that was one of the first things I addressed thinking that was going to solve it...
Won’t start in smc bypass. Plt reset not present. No history but there was some corrosion near u6100. Issue related to rom could prevent board starting? Correct?
NOt sure why I have no fan spin on this 5V and 3v3 at the fan connector but Fan Rt PWm is 0V. Tried a different fan to make sure I wasn't getting trolled as I was thinking if I have VCORE there should be fan spin. 0V at L3095 DOes that rail need to be present for board to start?
Wondering if...
Originally this board came in with what I believed to be U8900 issue but I think was malfunctioning GPU regardless as resoldering with lead solder U8900 multiple times. Something happened while working on board that caused PPBUS G3H to drop to 1.4V. I discovered that appeared to be a short but...
This board had multiple small spots of liquid contact in these areas, most were minor and just noticeable liquid but looks not significant corrosion to solder joint/pad: U7210/20/30 (minor), CB701 (corroded and replaced), R4922 Corroded and replaced, TPB206 pad is gone, U8110 (minor) , above...
Logic and DCIN flex are out of the Mac on bench. THis board starts and boots upon initial attachment of proper magsafe charger. However if you unplug the charger and plug it back in, it can take up to 45 seconds for it to come back on. Measuring PPDCIN_G3H when this occurs it hangs around .3-.4V...
NOt sure if this is appropriate to post on someone else's post, but I thought important for people to see my soltuion:
I had this exact same issue on 3023 board that would intermittently have this issue. WHen it did boot, the camera didn't work. I tried with different camera and camera worked...
THanks for your help on this. I didn't think it would be related to SMC_LID being that image was always there and only backlight was unstable but it is apparent that SMC LID hall sensor was the issue. On closer inspection there was corrosion under pin of the IC and the cap on the hall sensor...
That appears to be the problem. Voltage is not stable at LCD_BKLT_PWM and is sometimes 3.3V but then drops and coordinates with the loss of actual backlight in the display.
I see that line comes from PCH so guessing if not a poor trace then it is a PCH problem? How does the LCD_BKLT_PWM line...
Tested on separate display/cable and same issue. Seems to get worse after power up. Liquid damage to board mostly near DCIN connector. I have steady 12.65 at pin 1 of D9701 but voltage at pin 2 is sometimes 40V and usually shortly after power up unstable so backlight flickers sometimes is out...
Board never starts.
Removed F7040 and both PPBUS and PPDCIN rise and drop. At first I thought was related to TPS chip being PPBUS is sometimes 12.65V and drops but if the DCIN is rolling from 16V and dropping, different issue I'm guessing?
No shorts on any of the coils and made sure to check...
This one got the last laugh as it turned out it was not fixed after all. I ended up swapping the SMC. I would really like to kick this thing into the parking lot. :)
This board can kiss my ass. Issue was related to U6901 apparently was pulling down SMC BC ACOK? once powered? Anyway after pulling it and putting it back I got intermittent SMC_BC_ACOK signal. Replaced it and signal was solid 3.3V but then pPBUS GH was no longer 12.3V and flaking around 5V. I...