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Ive tried the BIOS above but still no usb activity, video or spinning of the fans via the keyboard ribbon cable in the case. Could it be lack of a clock signal or is that ruled out somehow? I have an oscilloscope

Client said simply stopped working. I haven't collected a BIOS for an 820-00923 A1706 as yet and can't find one on this forum. Is there anywhere else I can go?

No external video. CPU 55centigrade

PPVCC_S0_CPU 0.72v PPVCCSA_S0_CPU 0.78v PPVCCGT_S0_CPU 0v

I must have made a mistake in measuring originally as R1401 pin 1 is 3.0v, pin2 is 2.8v Diode mode to ground at pin 2 is 0.75v

No corrosion evident on board. pp3v3_g3h 3.4v ppbus_g3h 13.07v pp5v5_s5 5.12v pp3v3_s5 3.35v pm_slp_s4_l 3.3v smc_reset_l 3.4 all_sys_pwrgd 3.2v pp5v_s0_fan_conn 5.1v pp5v_s0_vcore1 5.1v pp5v_s0_vcore2 5.1v pm_slp_s5_l 3.3v rtc_reset_l 3.1v pch_srtcrst_l 3.1 pch_intruder 0v pm_slp_sus_l 3.3v...

I think customer would welcome disabled gpu if there are onboard graphics available. Would you have a pointer to disabling GPU?

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...

Resistance between pins 27/28 is now 20.6ohms and I have fanspin. Happy man.

Well I seem to have Q7080 and its current sensing working reliably now and pin 27 is at 14.3v

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...

C9560 changed just now but still no USB activity visible on snow edition memory stick. PP1V8R1V55_S0GPU_ISNS_R only achieving 1.56v No video

ppvcore_s0_cpu is 0.82v ppvcore_s0_gfx is 0.88v gpu_vcore_vid0 is 3.3v fans at full speed, no usb activity