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Hello again I've got a question - do I always need P13 programmer or can I do a straight swap from same exact donor board, with same exact configuration without programming the nands? Thank you, I really appreciate the help

Thank you, I will report with results later

Sounds about right, thank you for the help. Would you advise a NAND swap? This is definitely an option, I have a couple dead boards with same exact NAND configuration. I am also familiar with the whole procedure.

Forgot to add: NAND voltages present, correct and stable. Measure only left side, only this side is populated

I have A1990 that died randomly during use, customer says image on the screen dissapeared when the device was on. Board is in pristine condition, never dropped, no dust, zero signs of corrosion anywhere. Trackpad clicks, its powering on and battery is charging. Both cpu and gpu getting warm...

Hello Thank you for the help, that's an okay news for me. To be honest I am glad I can stop working on it. A bit off topic - would you be so kind and point me in the right direction? I want to have better understanding of how laptop/consumer electronics work, and to be able to understand...

Forgot to mention - U5200 and UP800 were seriously corroded all around, I replaced UP800 with one from donor, but U5200 I just reballed, because I did not have anything to pull from. Didn't want to touch working motherboard just yet at that point.

Thank you for your reply. Yes - resistors measured when completely pulled from motherboard, removed from motherboard that was 100% working during daily use past 6-7 months. I tested them with two different multi meters. Oh, I see now - it is clearly mentioned on the same page in the schematics...

A2442 02098 Liquid damage, data recovery is a priority Lots of damage everywhere, I replaced and reworked 70-80% of stuff that I thought is critical When I start diagnostics - 5V 0amp on cable, out of the chasis After PMIC U8100 replacement I'm getting 5V 0.25-0.3 amp Nothing is getting warm...

I will do that. Sorry for not being informed, thank you for the link

Also I’m waiting for the usb chipmunk to arrive, I don’t know any other way to check for usb activity

Hello Thanks you for your reply, I have tried dfu in every possible configuration and option, error messages stating that there’s a problem with communicating with the chip - which is T2 from what I understand and if the voltage powering T2 doesn’t go to values specified in the schematics the...

820-00850 board, zero signs of corrosion or any damage Without the battery: 20V 0.135A - slowly rising to 225-230mA as the fans spin faster Nothing heating up, CPU not even warm T2 doesnt warm up PPBUS_G3H 12.58V PPVDDCPU_AWAKE goes as follows when plugging in power: 0.75V --> 0.51V -->...

Aight, thanks. It was unexpected for me that those trouble could be caused by wrong cable. But of course the pin outs vary from one model to another, what can be data pin on one can be ground or unconnected on another

Solved: I used and original cable from A1706, will order proper lvds cables. 3$ cables from China aren’t very reliable after all, who could have known {facepalm}

Hey guys Sorry but I have to ask for help, I’m stuck. A1990 01041 liquid damage 55V on backlight - PPVOUT_S0_LCDBKLT I have image and backlight on a screen from A2141. Two known working A1990 screens give no backlight and no image with 55V on backlight Touchbar works, keyboard backlight...

Alright, I understand now. Thank for explaining this to me. Thank you for the the help and your time.

Well I have only managed to see a proper boot then it has all connectors plugged in, but it still required some acrobatics to even try to measure anything. I assume working board doesn’t turn on the backlight when it’s not booting properly, am I correct?

Yes that’s correct, but that backlight was switching on when using external display. The way I understand this: - even without good or properly soldered mux chip I had display on external - mux chip has connections to the backlight controller and U9801 - I have assumed it might be one of those...

I'm afraid that's out of the question. I can't really spend 600-700$ on a screen then have it lying around without any use. What I'd like to know - is there any way I can check these two IC's if theyre damaged? U9801 has connection to the mux chip, so if the mux got burned so could the U9801?