(347) 552-2258 [email protected]

820-4924 a1502 intermitent power

Jeffotskie26

Jeffotskie26

Member
hello got this a1502 now sign of corrosion.
it was randomly very hard to turn it on
once can on it hangs after you enter the password cannot move the
cursor and keyboard. (notice that the fan is not spinning.)
btw battery detects and charging

the board does not start also without keyboard. triggering onoff (c4810 is removed)

smc bypass it boots. SMC_ONOFF_L is steady high at 3.4V

ppbus_g3h 12.57V

u7100
17/18 4.1Ω
27/28 20.6Ω

SMC_DCIN_VSENSE 2.4v
SMC_PBUS_VSENSE 2.1v
SMC_DCIN_ISENSE 0.2v
SMC_BMON_ISENSE 0.06v

PLT_RESET_L, = 3.3v
CPU_VCCST_PWRGD = 1.01v
CPU_VR_READY = 0.01v

P3V3_S5_AVREF_SMC 3.3v

once charger is connected cpu warm. (no fan spin)
 
Last edited:
2informaticos

2informaticos

Administrator
Staff member
Fan doesn't spin on this board model until CPU gets really hot; is normal behaviour.

If KB/TP only works before typing the password, there is a problem with SPI mode connection between TP and PCH.
Check all traces and resistors TPAD_SPI_ related.
Also check U4910 and its adjacent components.
Try known good TP board/flex.

Be sure SMC_TPAD_RST_L is steady high, w/ and w/o TP/KB connected.
Does the board always turn on in SMC bypass mode?

"CPU_VR_READY = 0.01v"
Are you sure about this?
CPU core voltage should be present, if you get even PLT_RESET_L.
 
Jeffotskie26

Jeffotskie26

Member
SMC_TPAD_RST_L is steady high, w/ and w/o TP/KB connected. -yes it is
Does the board always turn on in SMC bypass mode? yes it is
tried new tp/kb still having issues to turn on.
i just notice if the battery is connected the macbook hangs on apple loading logo
tried change new battery still same. i can see the battery is charging like normal but macbook hangs
 
2informaticos

2informaticos

Administrator
Staff member
Does it turn on using R5115/16 pads, instead of power button?

Without battery, just charger, can you turn it on normal way (not SMC byapss)?
 
Jeffotskie26

Jeffotskie26

Member
yes i put back everything except the battery i boots normally. not smc bypass.
but when i put the battery even new battery it hangs apple logo only. but i can see battery is charging on my psu.
 
2informaticos

2informaticos

Administrator
Staff member
Start in diagnostic mode; let see if any error pops up.
Also disconnect internall SSD and start with USB macOS.
 
Jeffotskie26

Jeffotskie26

Member
can boot into safemode with battery once but when i
tried to do for the second time still same it hangs.
if still need good bios can u share it to me. thanks.
 
You must log in or register to reply here.
Top