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.
There is an initial blink on the 2 snow edition drives in the USB ports at start of fanspin but no further flashing
Fans do ramp up to full after a short while.
I used my CH341a programmer to write each of the two provided binaries to the Flash chip.
APPLE A1286 MLB 820-2850-A OK resulted in no fan spin.
PCT25VF032B_20160916_185643 still got fanspin but still no chime.
Should I be expecting a chime to occur when board is devoid of all peripherals...
I took off all the feedback components U7000 and C7020/21/22 and R7021/22 and found one trace had 2.7kohm to ground. All reassembled, test tomorrow, need sleep. Thanks for your help.
Yes double checked the 0.3v on pin 27
I changed R7021/22 yesterday as 7021 looked ugly before (lumpy) so if they have gone wrong there is something else causing it.
Current situation is I get fanspin with LAB PSU only. On connection initially get green light but quickly changes to orange.
ppbus_g3h has an 800mV ripple but does average 12.6v
U7000 voltages when fanspin with Lab PSU.
PIn voltage
1 0
2 15.8
3 3.8
9 0
12 3.4
13 3.4
14 3.4
15 0
17 12.5
19 5.5...
Right away but just found ... I put a new R7085 in and Im now getting fanspin but only with lab PSU. 2 genuine charger 60W/85W wont start it.
Shall I get those voltage when on genuine charger without fanspin?
I was using genuine chargers but good idea to try lab psu.
Lab PSU at 16.6v gets orange light and fans did spin but not for long. Now dead again.
Orange light stays on when plug charger
pp3v42 3.4v
ppdcin_s5_chgr 16.42v
chgr_agate_div 15.68 so left side of Q7080 should be conducting yet...
Customers board not turning on. No corrosion evident.
Replaced U7000 and Q7080 and seemed to fix but trackpad cursor had jerkiness.
Very quickly went bad again.
The 68k ohm sparkitecture resistor was not 68kohm so I replaced it with 68kohm and some changes occurred.
Green light would come on...
Oh does that "1V8R1V55" mean 1.8v or 1.55v is ok?
History: owner said it was bought refurbished from Apple. Had a loose hinge screw that just needed tightening. No corrosion evident.
Im a BIOS virgin Im afraid. I do have a CH341A programmer bought in anticipation. Hope it will do. I don't have a...
I was using a 60W charger! I didn't know about the 85W requirement :)
I switched to using an 85W charger and I am getting the same symptoms but now not needing the battery connected to get some activity.
So still no chime or video or USB activity.
Wondering where to go from here
With board in case and fully connected I get green light, fan spin, no chime or video
With board removed, battery disconnected and charger attached I get no fan spin.
ppbus_g3h and pp3v42 good.
S0 and S3 rails 0 volts.
pm_slp_s4_l = 0v
pm_batlow_l = 0v. (wont this always be low with no battery...