Re: 820-00875 SSD only boots sometimes
My bad, you did point me to the correct resistor, I was just a bit too quick assuming it was the other one.
Alright, so here we go again:
- replaced R8645 with a 10k resistor
- powered up, SSD not detected
- removed C8676
- removed C8675
- removed C8677
- powered up, SSD not detected
- replaced R8645 with a 4k7 resistor
- powered up, SSD not detected
- replaced U8640 again (this time from a donor board, last time it was a new chip)
- powered up, SSD not detected...
duxzero
Member
Last Activity: 11-09-2023, 07:31 AM
Joined: 11-21-2018
Location: Oslo
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Re: 820-00875 SSD only boots sometimes
Alright, so I got around to do some work on this one today. These are the steps performed:
- removed C8676
- powered up, SSD not detected
- removed C8675
- powered up, SSD not detected
- removed C8677
- powered up, SSD not detected
- at this point soldered the caps back (but new ones that has the same tolerance)
- wanted to change R8637 as you suggested, but this is marked nostuff on schematic and is not present on board
- looked more at schematic and saw the notes for C8671 for SSD_PWR_EN_CONN_L...Leave a comment:
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Re: 820-00875 SSD only boots sometimes
Will do, thanks again for the in-depth explanation. It makes sense. I think at one point I hooked up some of these lines to a logic analyser and logged timings with the Saleae software, but can't remember the results, may have it stored somewhere. Is this something you'd recommend me do again, like before and after removing caps to get a better understanding what's going on here?...Leave a comment:
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Re: 820-00875 SSD only boots sometimes
I think you may be on to something. I actually bought all these caps from Farnell a year back or so (didn't want to buy eBay/Aliexpress caps for this due to their very low tolerance) thinking I would swap them all out, including the 3pF and 3.5pF caps for SSD_PWR_EN_CONN_L.
So I will definitely try this, first as you suggested with SSD_BOOT_CONN_L caps and then I'll do the same for the SSD_PWR_EN_CONN_L caps if the first attempt does not make any difference. Not sure when I'll get around to it, but I'll definitely...Leave a comment:
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Re: 820-00875 SSD only boots sometimes
It's also worth mentioning that there is a tool available in GSX for AASP that can upgrade the SSD firmware for these machines, but it's unavailable to the public.
See: [url]https://www.ifixit.com/Answers/View/715536/Manually+upgrade+the+SSD+firmware#answer716308[/url]
also see the last comment in that post.
I'd love to get my hands on that though to see if it includes a new firmware for my SSD also. If anyone here has GSX access, please PM.Re: 820-00875 SSD only boots sometim... <br /> It'sLeave a comment:
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Re: 820-00875 SSD only boots sometimes
I have the exact same issue with the exact same board and I've tried diagnose the problem several times, also swapped U8640 (chip responsible for SSD power enable and boot).
Others have also had the same issue, see:
[url]https://www.badcaps.net/forum/showthread.php?p=1092430[/url]
Apple does have an extended service program for these machines, see: [url]https://support.apple.com/13-inch-macbook-pro-solid-state-drive-service[/url]
...but I have the 512GB SSD and this program just covers...Leave a comment:
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Re: MacBook Air A1466 - 820-3437
I guess I could have saved myself some trouble checking resistance to ground on PPVCC_S0_CPU a bit before which is 0 ohm to ground.
Removed R7310 and R7320, still 0 ohm to ground, then injected ~0.9V into PPVCC_S0_CPU and it draws ~3.05A while none of the surrounding connected caps getting hot. I soaked them all (both sides of the board) in isopropyl alc to look for any fast evaporation. The CPU die does not get hot either, but guess it does not have to either since it's not really on and the short can be anywhere incl. BGA balls under....Leave a comment:
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Re: MacBook Air A1466 - 820-3437
Yes, had previous work done on it. I'm the one that did the ultrasonic wash though, so I did check everything carefully first.
The resistor I mentioned was basically the only component replacement I could see in addition to some scraping around the same areas. Also seemed the board had been "washed" in some weird way, maybe a brush and isopropyl alc.
I've already reflowed the SMC, so I'm thinking perhaps replacing it, have a donor board and the stencil for it and have done reballing with paste on a couple of...Leave a comment:
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Re: MacBook Air A1466 - 820-3437
Replaced U1950
Probed U1950
->ALL_SYS_PWRGD: 3.28V (one pulse)
->CPUVR_PGOOD_R: 3.28V (one pulse)
<-PM_S0_PGOOD: 3.44V (one pulse)
->SMC_DELAYED_PWRGD: 0V
<-SYS_PWR_OK: 0V
—
<-PM_PCH_SYS_PWROK: 0V
I'm not sure when SMC_DELAYED_PWRGD is supposed to go high, but this signal is needed to create SYS_PWR_OK and PM_PCH_SYS_PWROK. Is the problem missing SMC_DELAYED_PWRGD or does this come later and is irrelevant due to the other signals just pulsing...Leave a comment:
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Re: MacBook Air A1466 - 820-3437
After replacing Q8150, in addition to values in post above, there are now also:
ALL_SYS_PWRGD: 3.28V (one pulse)
I also checked U1930 which ALL_SYS_PWRGD goes into:
CPU_VCCST_PWRGD: ~1.00V (one pulse)
Then some of rest on S0 state flow chart
PCH_HSIO_PWR_EN: 3.36V (one pulse)
|
PP1V05_S0SW_PCH_HSIO: 1.04V (one pulse)
|
PP1V05_S0SW_PCH_VCCSATA3PLL: 1.04V (one pulse)
PP1V05_S0SW_PCH_VCCUSB3PLL: 1.04V (one pulse)
...and this is where I'm now stuck...Last edited by duxzero; 01-03-2022, 02:53 PM.Leave a comment:
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Re: MacBook Air A1466 - 820-3437
You have a lot of good info on logo.wiki Piernov, I read through your FAQ, and your 820-00165_Pulsing page and did a couple of measurements from info there:
Resistance between pins on U7100
17/18 = 3.2 ohm
27/28 = 19.8 ohm
So this seems OK.
Then I read the Bootup_Signal_Order flow chart, did most measurements there (checking for pulse) and this is the results for the signals marked in green on the chart.
P1V8S3_PGOOD: 3.28V (one pulse)
DDRREG_PGOOD: 3.28V (one pulse)...Leave a comment:
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Re: MacBook Air A1466 - 820-3437
So actually all these has one pulse after turning on power:
PM_SLP_S5_L
PM_SLP_S4_L
PM_SLP_S3_L
PM_SLP_S0_L
After the pulse and when signal is low, PM_SLP_S0_L is the only signal that seems a bit dirty low, it has tiny ripples.
Based on this info, is the S0 power rail the place to start looking?Leave a comment:
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Re: MacBook Air A1466 - 820-3437
Also PM_SLP_S5_L does in fact pulse for a few ms right after connecting power.
Can this at least rule out dead CPU/PCH, also since PCH actually provides PM_SLP_SUS_L ?
See attached screenshot from DSO201....Leave a comment:
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Re: MacBook Air A1466 - 820-3437
Thanks for the link to your faq, I understand, which also explains the other two values due to 330k pull-ups I guess.
I had some progress. So, R5503 was not replaced by me, checked it and it was shorted pads under resistor due to someone using 0402, replaced it now with 0201 from a donor.
Now there is power on some of the ones previously missing:
PM_SLP_SUS_L: 3.324v
PP3V3_SUS: 3.326v
PP3V3_SUS_EN: 3.324v
PM_RSMRST_L: 3.295v
PM_PWRBTN_L: 3.408v
But still missing:
...Leave a comment:
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Re: MacBook Air A1466 - 820-3437
Yeah, I tend to wait putting it in ultrasonic until fanspin, but this one I exhausted all options on and wanted to see if ultrasonic did the final magic.
Thanks for that flowchart, that's convenient. BTW: What does it mean what's written on the flowchart for the PCH_INTVRMEN, PCH_DSWVRMEN and PCH_INSTRUDER_L points that "measures ~3.xv due to probes"? And why would probes only affect measurements here and not on the other points?Leave a comment:
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MacBook Air A1466 - 820-3437
Having some issues with PM_SLP_S4_L on this board (hopefully not dead CPU/PCH).
The board had some minor liquid damage the usual places, replaced R5503 and did not find any other visible issues that needed component replacement. The board has now been in ultrasonic wash and looks very clean.
PPBUS_G3H: 8.6v
PP3V42_G3H: 3.42v
PP5V_S5: 5.0v
PP3V3_S5: 3.329v
PP3V3_S4: 0.045v
PM_SLP_SUS_L: 0v (99.6 ohms to gnd)
PM_SLP_S5_L: 0v
PM_SLP_S4_L: 0v
PM_SLP_S3_L: 0v
S4_PWR_EN: 0v
... -
Re: Macbook Pro 13 Non Touch 820-00875-A Can't See SSD
Any progress on this one? I have a 820-00875 laying around for years, I use it sometimes, and I say that because SSD is detected on boot only occasionally. I can try powering it on maybe 100 times or something with no SSD detected, and all of a sudden it's detected and boots. And when it first boots it can run perfectly fine for days/weeks no issues, however I have to prevent it from going into sleep mode, because if it does the SSD is again not detected on wake, and shutting it off and attempting reboot many times again is...Leave a comment:
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