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Thank you for that. Just to clarify what i am trying to achieve since i did not actually mention it.
I do not have a failed one here to measure, but i am trying to get the resistance values of one that has failed in the common way these are now failing. That is the 2.5v supply on L9081...
Would anyone that has one of the boards with an irreparably failed SSD (a1990) (820-01814) be willing to take a few resistor measurements for me?
I am looking for
R9080
R9083
R9081
and if C9085 happens to be open or closed.
Ideally this would be on a failed board that is outputting 7.4V on...
yeah, the little scope i was using is indeed hopeless for the measurement task i was giving it. I used a better one and the 24mhz is present at the crystal. 100mhz is beyond this scope's ability but im going to order a 200mhz model. That said, i have a strong feeling the elevated DC at the...
this clock situation may not be relevant. I just looked it up and the scope im using maxes out below 1MHZ, so there is a very good chance my measurements are irrelevant.
I just swapped y8600 with a donor board. No change. r8600, and r8602 measure correctly. I assume that this should be a simple crystal oscillator at 24mhz?
Booting Linux with y8600 removed from the board yields no change positive or negative
i get elevated steady voltages, but no discernible clock signal. Solid 1.8v on XTALi and solid 0.9V on XTALO
I also noticed that SSD_BOOT_L is at a constant 1.8V. _L suggests to me it should be logic low, but you never know with these things.
Tested every pin on u9300 just to be sure. Everything checks out as normal. i think I can almost certainly rule out a power issue with the SSD at this point
I dont have a known good board to test with at this time. What else is critical to the SSD that i can point my efforts to? U8600 looks...
Ok, can confirm there is no clock signal on either of those test points near u9100. PCIE_CLK100M_SSD_LBp/n
Also my boot after the OS install on an external USB drive failed with the message of not being able to install a needed firmware update. This happened both on Sierra (OEM OS) and...
Ok, i found the test points. Kind of hidden under one of the NAND shields. Running a USB install presently, but when that finishes im going to check for clock there.
My thought on the clock request needing to be low is that it should normally be held high through r2080 (from 3v3_S0) until it...
Working on a 820-00923. Works perfectly other than not seeing the internal SSD. Ive verified every power and enable signal related to SSD i can think of, and everything seems normal. Seem to be getting PWRGOODs on everything SSD related as well. That said, happy to provide specific...
i am waiting on an adapter for my SPI chip programmer for this footprint before i can read and write to it. It does seem like the board is interfacing with the chip at least. If i remove the chip the board will not really even attempt to boot. I replaced the chip with one from a 820-00244...
PLT_RESET_L is 3.3v
For what it's worth, it responds to the power button on the keyboard. Holding "t" for target disk mode does not seem to work, as it does not show as connected to another MacBook pro. As well Caps Lock light does not respond. So i think it is safe to say it is not booting...
So it gets even stranger. It seems like VR_Ready may actually be present, but goes away and shuts down the board when i try to measure it. If i measure with a multimeter i never get anything, if i leave a scope on it while its booting VR_READY will go high for maybe 3 seconds, then go low...
is 1.7v, then 1.5v correct for CPU core voltage (measured at c1032)? I believe it is, but you know better than me. Am i correct that u7200 is responsible for that voltage change after the initial 1.7v?
r0850 measures 10K which matches schematic.
Thank you for the info. I agree, it must have been the heat. At this point the only real suspect thing ive determined is CPU_VR_READY is missing. u7200 has power via PPVIN_S0_CPUVR_VIN. CPU_VR_EN is present (CPU creates this, i believe) . VR_Ready is the PGood output from U7200 and is...
P1v05s4SW and it's good are missing. If i force the e85HSMUX_USB_EN high on q4530, those are present.
Randomly e85HSMUX_USB_EN now remains high after multiple power on/off/unplug
I have one of the awful 12" MacBooks that came in for repair. Customer puled the bottom off for a battery replacement and damaged the KB/Trackpad connector and cable. Everything besides KB and trackpad worked fine. I used it for a few days through a USB dock with USB KB/Mouse and HDMI monitor...
I think it was q5660, i just pulled one from a donor board it seems promising so far. running ASD again to see what happens.
:Edit: Yep, all good. passes ASD now. thanks.
I have a 17" 2011 that is blasting the fans all the time. ASD shows all the temp sensors in working order. No obvious signs of liquid damage, but prior shop did ultrasonic it before i got to see it. I assumed this was going to be a bad temp sensor/trace/etc but it seems like that is not the...