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Thanks for the feedback. I have never replaced a BGA chip this large before. Even if I could perform the work, where can the chip be sourced from? Does it need to come from a donor board or can it be ordered online? In your experience is specialised equipment needed or can it be done with a...

Hi, PMU_VDDHI R8170 pin 1: 12.340V, pin 2: 2.580V R8171 pin 1: 2.580V, pin 2: 0.0V U8100 diode mode readings PP0V8_S2_CLVR_VDDDIG - 0.313 PP3V3_AON - 0.423 PP1V8_S2SW_CLVR_VDDC1_LDO - 0.517 PP3V3_S2 - 0.413 PP1V2_S2 - 0.294

Thanks for the explanation! Here are the voltages I think I have them all covered. U7700: PP1V8_S2 - 0.3-0.4V fluctuating PP1V2_S2 - 0.3-0.4V fluctuating PP3V8_AON_SPMU_ISNS - 3.8V PP1V5_AON_VCORE_SPMU - 1.5V PP1V2_AON_SPMU - 1.2V PP1V8_AON_SPMU - 1.8V PP1V2_AWAKESW_BLC - 0.0V PP0V72_S2_VDDLOW...

I originally replaced the screen. Since replaced, sold on eBay. The customer returned it after 1 month, when I got it back it is in this state. There were no known issues with the board. 3V8_AON - 3.8V I'm not sure what to probe around U8100. What is an LDO? If you can tell me what to test I...

Hi there, I have a faulty board. The meter is reading anywhere between 5.020 - 5.040V and 0.000 - 0.030A. The amp reading seems to suggest it is power cycling somewhat... I tested U5700 and I'm getting the correct voltages. In fact I am getting PPBUS_AON. Around U5200 PPDCIN_AON_CHGR_R I am...

Okay so it appears as if the problem may be the display assembly... DFU restore still did not work with the LCD disconnected, however I was able to boot with an external monitor connected. I've since found the device is activation locked! Now I will have to contact the eBay seller as they said...

Nope, no reaction.

Tried both. They both fail approx 30% into the final step.

Thanks, DFU blaster worked great for getting it seen by Configurator. I'll use that again for sure. It gets to the last step of the restore, at which point it reboots and then says "unable to complete restore" or something along those lines. The boot looping is not happening any more. Now, the...

Thanks for the info. I haven't attempted a DFU mode restore before. I just installed Apple Configurator on a host A2485. I have the Thunderbolt cable in the uppermost USB-C slot closest to the MagSafe connector for both host and target. I can't get the A2779 into DFU mode. It just continues...

Happy New Year! You were right, U5700 was bad. Replaced and now I have the following status: Boot looping every 15 seconds. Image is present, but no backlight. I will look to troubleshoot the backlight circuit. Any ideas on the boot looping, maybe related to backlight? Thanks

You're asking me to check and if it's low, and to remove the cap if it is. How can I know what qualifies as a low reading?? Diode mode to ground is 0.481. I have not removed the cap. Let you know if you think I should remove the cap and test again. Thanks

What do you consider low? I don't have access to any reference values. Thanks

PP3V8_AON diode mode - 0.369 U5700 8 - PPVIN_P3V8AON - 12.3 7 - PP5V_AON_P3V8AON - 5V 5 - P3V8AON_PVVC - 0.87V 12 - P3V8AON_PWR_EN_R - 4.5V Is the enable signal too high? I can't find a datasheet for RAA225501C.

Thanks for the explaination. I removed both fuses and the reading is the same. 12.3V on C5250. Thanks

Hola Vali, I have been away and so haven't been spending too much time on this. Just back at it now. Sorry no I don't understand that circuit, can you explain what the discharge function does there?? Regardless, I replaced the UP701 and there is since an image, but still with no backlight...

Hi, I replaced UP701 as advised, but still no voltage. All readings remain as prior to swap. Pretty sure QP700 is an en N-channel, so it wants voltage on the gate to turn on. Because pin 10 (EDP_PANEL_DISCHARGE) of UP710 is 0V, it is not switching... What are your thoughts? Thanks

UP701 tested at RP700 and CP718 LCD connected: 0.425 LCD disconnected: 0.849

I think the readings I gave above the LCD connector must have been misalgined. I tested again and got the following: UP710 PIN 1 PP1V8_AON - 1.79V PIN 2 LCD_PWR_EN - 1.79V PIN 3 PMU_SYS_ALIVE - 1.79V PIN 4 EDP_PANEL_PWR_EN - 1.79V PIN 11 EDP_PANEL_1V8_EN - 1.79V PIN 13 EDP_BKLT_1V29_EN - 1.79V...

Yes I don't know everything, that's why I pay the forum membership ;). JP600 has no power going to it. Power in via pins 37 & 38 "PP3V8_AWAKESW_TCON" from what I can tell this power is coming from UP710. All readings taken with LCD connected. PPDCIN_AON - 19.8V PPBUS_AON - 12.3V PP3V8_AON -...