Re: MacBook Pro A1286 Mid 2012 no power, no LED on the charger
JTAG programmer ordered.
@mon2 can you help me with finding the file I need to flash?
JTAG programmer ordered.
@mon2 can you help me with finding the file I need to flash?
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Re: MacBook Pro A1286 Mid 2012 no power, no LED on the charger
Hi mon2,
Are we sure issue is not somewhere else?
Looking at DDC circuit, LVDS_DDC_CLK at pin 2 of R9011, is reading 0.72 on 20V scale.
Suggests monitor not detected?Comment
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Re: MacBook Pro A1286 Mid 2012 no power, no LED on the charger
Ok. This clk is an output from the logic board -> to the LCD screen.
Trace this signal back to the mux @ U9270.
What is the voltage @ R9272, pin # 2 ?Attached FilesComment
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Re: MacBook Pro A1286 Mid 2012 no power, no LED on the charger
Will check. Sorry mon2 not trying to say I know anything as you are the expert
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Re: MacBook Pro A1286 Mid 2012 no power, no LED on the charger
Mon2, pin 2 showing 3.3V.
But LVDS_DDC_CLK (OUT) showing 0.72V, so is there issue inside this chip U9720 then?Comment
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Re: MacBook Pro A1286 Mid 2012 no power, no LED on the charger
Can you confirm if you are measuring pin # 2 reading at the chip U9270 ?
If yes, that is a good reading, yet pin # 3 = LVDS_DDC_CLK is 0v72 ??
Pin # 2 and pin # 3 should be at the same voltage level.
Measure to confirm directly at U9270 and then again at another site on the logic board. Perhaps a trace break ?
While measuring, what is the voltage on pin # 1 of U9270 ?Comment
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Re: MacBook Pro A1286 Mid 2012 no power, no LED on the charger
Sorry mon2, pin 2 with TP LVDS_DDC_CLK! 0.72V confirmed. 0.72V also on pin 3 so looks ok.Comment
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Re: MacBook Pro A1286 Mid 2012 no power, no LED on the charger
U9270 on pin 1 is 0.72V!Comment
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Re: MacBook Pro A1286 Mid 2012 no power, no LED on the charger
Mon2, think then LVDS_EG_DDC_CLK coming from U8000 is low? 0.72V should be higher?
This is the cause of the problem?Comment
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Re: MacBook Pro A1286 Mid 2012 no power, no LED on the charger
Measure & post the voltage readings of the following:
PP3V3_S0_LVDSDDCMUX
LVDS_DDC_SEL_EG
LVDS_DDC_SEL_IG
PP3V3_GPU_LVDS_DDC
also adding:
PP3V3_S0_DDC_LCD
Next, remove all power.
With the LCD attached - meter in resistance mode - check the resistance between pins 17 & 18 on the LCD connector. This is the resistance check between:
LVDS_CONN_A_CLK_F_N
and
LVDS_CONN_A_CLK_F_PLast edited by mon2; 05-02-2022, 04:19 PM.Comment
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Re: MacBook Pro A1286 Mid 2012 no power, no LED on the charger
Hi mon2,
I spoke with dosdude2, he is ok to send me dump of 2012 demux chip so I can reflash but he does not think this will resolve the issue
I will measure the readings of the above shortly. Thank you once again for your kindness and patience
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Re: MacBook Pro A1286 Mid 2012 no power, no LED on the charger
Hmm. What are his thoughts on this case?
Forgot to ask, is your JTAG tool compatible for reflashing the target Lattice FPGA / CPLD ? Is it based on the FTDI chip set. From our experience, the JTAG tool should have the FTDI MPSSE feature to remain compatible with the Lattice or the many open source toolchains.
Is this lcd the compatible lcd for the logic board?
I lost an eBay auction yesterday - believe it was the same as yours. Want to have one here for some measurements. Will continue to search for another A1286 2012.
A key concern is that your logic board will boot (POST) only if the LCD is removed.
Interested in the last batch of readings. You should have boot chime with or without the LCD. So do the measurements with and without the LCD for the resistance check on the lcd connector.Comment
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Re: MacBook Pro A1286 Mid 2012 no power, no LED on the charger
Yes mon2, have boot chime with or without the LCD.Comment
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Re: MacBook Pro A1286 Mid 2012 no power, no LED on the charger
PP3V3_S0_LVDSDDCMUX at C9270, 3.3 on 20V mode
LVDS_DDC_SEL_EG at TP[1] LVDS_DDC_SEL_EG, 3.3 on 20V mode
LVDS_DDC_SEL_IG at TP[1] LVDS_DDC_SEL_IG, 00.2 on 200m mode, going to 00.0 to 00.1 back to 00.2
PP3V3_GPU_LVDS_DDC at R9270 pin 1, 3.3 on 20V mode
PP3V3_S0_DDC_LCD at R9010 pin 1, 3.3 on 20V mode
LVDS_CONN_A_CLK_F_N and LVDS_CONN_A_CLK_F_P shows 1 on all modes up to 2mComment
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Re: MacBook Pro A1286 Mid 2012 no power, no LED on the charger
Is this lcd the compatible lcd for the logic board?
Yes, as you will recall it initially did work then went black during usageComment
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Re: MacBook Pro A1286 Mid 2012 no power, no LED on the charger
LVDS_CONN_A_CLK_F_N and LVDS_CONN_A_CLK_F_P shows 00.7 on 200 mode after re-test, with display connected
LVDS_CONN_A_CLK_F_N and LVDS_CONN_A_CLK_F_P shows 00.7 on 200 mode after re-test, without display connectedComment
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Re: MacBook Pro A1286 Mid 2012 no power, no LED on the charger
These are not good readings. There are 2 select signals for the 4066 mux switch, IG and EG.LVDS_DDC_SEL_IG at TP[1] LVDS_DDC_SEL_IG, 00.2 on 200m mode, going to 00.0 to 00.1 back to 00.2
Be sure to measure both.
One of these must be 3v3 to enable the lcd signals to flow through this analog switch.
Remove the lcd and check again the voltage of the 4066 enables.
If low, the 4066 switch will remain open. If 3v3, the switch will close and the signal will appear at the lcd connector.
Also, when does the logic board work? After you remove only the lcd LVDS cable ?Comment
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Re: MacBook Pro A1286 Mid 2012 no power, no LED on the charger
Hi mon2,
Logic board shows fan spin and chimes with or without display connected.
But no video on internal display when internal display connected, NOR on external.
When I remove internal display, external display works via HDMI.Comment
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Re: MacBook Pro A1286 Mid 2012 no power, no LED on the charger
Mon2, if I have cable connected but no LCD at the other end, works fine on external monitor.
But if I connect display, still chimes but no display on internal or external monitor!Comment
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I am looking at an A2337 and found this for the order of power rails and what they do. Can this be confirmed before I dive into hunting down power rails that do not exist or are not neccisary?
- PPBUS_G3H (12.6V-12.8V)
- This is the main power rail that supplies power to the entire system. Check this rail first, as it must be present for other power rails to work.
- PP3V42_G3H (3.42V)
- This power rail is derived from PPBUS_G3H and is used to power the SMC (System Management Controller) and other essential circuits. It should be present if PPBUS_G3H is working correctly.
- PPVRTC_G3H (3.3V)
- This
- PPBUS_G3H (12.6V-12.8V)
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The screen seems to blackout and stay black, but with a flashlight I can see the display.
With my Playstation 4 connected via HDMI, and running a game I can hear sound.
Assuming... -
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