Recent content by realmacmods

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...

giving up. now randomly has a short through u8600 that was not there before. probably a bad u8600 all along

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.