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I did see a .5v DM measurement on the track to the cpu whilst R7704 was removed indicated an intact ESD diode and thus ok track. Ive tried a different charger and Im getting a green light now. So Im left wondering what else can cause bklt_pwm to remain at 0v.

Backlight came on bright after jumping. I replaced resistor and cap but I am unable to verify continuity of track to cpu as there is no accessible test point at cpu end. bkl_pwm remains at 0v and image very dim = same as before. I have to admit also I am currently not getting a light on the...

I have a known good screen connected to the board. On boot I am getting such a dim display I need to view it perpendicular to the screen to see the faintest image. pp5v_s0 5v pp3v3_s0 3.3v pphv_s0sw_lcdbklt is approx 16v Current sense starts around 3v and ramps down after a few seconds but...

is there anything else I can try to get it to respond?

Just tried a switch with leads - still no luck getting into DFU mode. Verified SOC_FORCE_DFU goes from low to high. Tried with battery and trackpad connected too.

Ive tried for hours to get it into DFU mode with keyboard commands both inside case and with external keyboards and with battery connected with no luck. Ive tried jumping SOC_FORCE_DFU (pin 1 R8010) line to PP1V8_SLPS2R (pin 1 C7840) with no luck

Ive replaced one visibly blown CD3217 and reloaded the TBT rom and have both USB C ports now achieving 20volts but thats it - still no boot. 20volts 90mA with battery disconnected. ppbus_g3h 12.3v ppvin_g3h_p5vg3s 12.3v pp3v3_g3h_rtc 3.3v pp5v_s5_ldo 0v pp5v_g3s 0v p5vg3s_en_dly 0v p5vg3s_en 0v...

Yes Im just after the TBT ROM. Ive looked and looked on the forum having to read every thread after a search on 820-01958. The search function really lacks the ability to find it.

I need a binary for board 820-01958 Thanks in advance

Safe mode -> chime, usb activity and video! Fan shuts off before can fully boot. (although I cant seem to repeat it) Then performed a reflow on U8900 - no change.

Loose screw inside case No liquid damage visible no usb activity all_sys_pwrgd. 3.3v pm_slp_s4_l 3.3v ppvrtc_g3h 3.3v pp3v3_sus 3.3v for 30 seconds until fn stops then 0v ppvcore_s0 0.8v pp1v05_s0 1.05v Thermal: CPU quick to get very hot (3seconds). PCH slow to get hot...

Can the graphics chip be disabled to leave a workable system using onboard graphics?

Is this problem a result of manufacturing like the older iMac graphics daughter boards that could be fixed by baking to remake solder joints? Is there any way to make a repair. I have already had the experience of purchasing a board that exhibited the exact same problem and had to be sent back...

In safe mode: progress increases to 50% point then sits for a minute or two then finally shows the login screen when I login I see a 30 seconds of beach ball, black background then says its rebooting because of a fault. instead of rebooting shows a black screen with moveable cursor. when I hold...

This iMac exhibits strange effects when transitioning from login screen to the desktop. Its a bit like a horizontal Venetian blinds being opened to view the fresh desktop. i.e. it paints the new screen in horizontal bars from the bottom up. Customer says it is also tediously slow. Is this...

Thank you! That will teach me never to purchase second hand trackpads. I just took out a corroded one to replace with a faulty one.

Liquid damage declared but logic board is immaculate. Trackpad circuitboard badly corroded. Trackpad replaced, trackpad flex cable replaced. Some keys dont work, some keys return the wrong character. A replacement A1932 keyboard produces exact same result although an external keyboard works...

If the CPU is dead what displayed the apple logo and increased the time bar? Surely that is driven by the CPU isn't it?

Aren't those ruled out? Ive got the logic board connected to the screen only for the most of this. However the results are the same with trackpad and flex connected. But I will find alternative trackpad and flex if you think so.

Ha! Ive been trying to install Linux on another Mac all week! Ive tried creating a bootable USB stick via a ew different utilities off an ISO and it is never seen when I hold ALT. How can a bootable usb be made? Im using an ISO of opensuse. I dont have a windows distribution but I do have a...