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  1. smiba

    820-00164 wont get past S5

    Is it a pressure thing? Does it also happen if you poke at it with something like a wooden toothpick? No idea what it means if its not a pressure issue, odd. Posting this as a comment by the way since I don't want to derail the thread
  2. smiba

    820-3476 OSX killed every few days

    You need to use a 60W or higher charger for ASD to pass. The 45W charger gives 14V where the 60W gives 16V As for the sleep/wake event, you've probably touched something to wake it up again. Do not touch it for a couple of minutes in this test until it automatically turns itself back on again
  3. smiba

    [SOLVED]820-4668 - PP3V3_S4 low - If you power cycle the device ±50 times it will post

    No worries I did, thats why it hurts so much taking it apart again because they're not your regular $1 tapes. I still have nightmares about iPad screens so I'll never cheap out on tape haha Got apart with exactly the same amount of force then it came with, the tape is again easily removable and...
  4. smiba

    [SOLVED]820-4668 - PP3V3_S4 low - If you power cycle the device ±50 times it will post

    Thanks, I guess replacing it would be part of a quality repair anyways! Any tips on testing it on a bench? Because reassembling these boards in the iMac itself is a pain in the ass and I don't feel comfortable having the PSU with exposed 230V joints on my desk
  5. smiba

    820-3536 no chime no display

    Not important, its the clock for the camera. (Which is not enabled so probably about 0V) You can't really see if the clock is working properly by checking it with a multimeter, best to use is a oscilloscope or if you have a fancy multimeter it might be able to show the clock frequency (But most...
  6. smiba

    820-00426 Not booting

    A good 80% of the cases. The problem is that the power button on the keyboard will partially short so its pulling SMC_ONOFF_L halfway through ground. The voltage is probably floating around somewhere between 0V and 3.4V
  7. smiba

    [SOLVED]820-4668 - PP3V3_S4 low - If you power cycle the device ±50 times it will post

    [SOLVED]820-4668 - PP3V3_S4 low - If you power cycle the device ±50 times it will post Alright, first time repairing an iMac here (What is the best way to do so on a bench by the way? I've tried to use my 5A bench power supply but the inrush on bootup is too high) History of the device: The...
  8. smiba

    820-3536 no chime no display

    Most likely not, in my experience it will usually show this symptoms when the SPI ROM is bad: - Not enter S4 - Enters S0 and then goes back to S5 In some rare cases (bad ME) it might stay in S0 though, but this is probably one of the last things we should look into. I never had it happen for me...
  9. smiba

    820-00426 Not booting

    I never had the need to buy one but I'm quite sure that they are now becoming more widely available from suppliers and on aliexpress. No idea about the quality of the battery though...
  10. smiba

    820-3023 - Replaced motherboard, new motherboard can not boot from APFS filesystems

    Anyways installing 10.9 from a ISO and then updating to 10.13 caused the boot rom to get updated as well, its accepting the customer's SSD now. Resolved, thanks!
  11. smiba

    820-00426 Not booting

    If it works without the trackpad you most likely have a dead keyboard. Voltage of SMC_ONOFF_L? One with the trackpad plugged in and one without
  12. smiba

    Am i killing my resistors?

    Damaging a resistor is very hard, unless you abuse them there shoudn't be a reason for them to go way out of spec. You can use higher temperatures like 400 degrees without issues, just be nice to the board by pre-heating from a distance for ~10 seconds and slowly move closer to the object you...
  13. smiba

    820-3330 - No backlight - J9000 pin 38, 39, 40 (20V)

    Ok so let me get this straight, you just combined LCD_BKLT_EN and LCD_BKLT_PWM? Uhh alright LCD_BKLT_EN is a High or Low signal enabling the Backlight circuit LCD_BKLT_PWM (PWM being Pulse Width Modulation) is the signal that tells the backlight how bright it should be. Of course when shorting...
  14. smiba

    820-3023 - Replaced motherboard, new motherboard can not boot from APFS filesystems

    Alright, I was just wondering if there was a quicker way. The worst about this is that Internet Recovery installs OS X 10.7 by default, which can not upgrade to High Serria. (App stores says it requires 10.8 or higher to download). So I have to log in to my own iTunes account where I have a old...
  15. smiba

    820-3023 - Replaced motherboard, new motherboard can not boot from APFS filesystems

    Hey everyone, Replaced a 820-3023 board for a customer with one I had around, everything was alright and good until I figured out it could not boot from the internal SSD. If you boot a 10.13 recovery or installation it will happily see the APFS container and you're able to unlock it and browse...
  16. smiba

    ASD - Override file version = Base_?

    The system originally didn't show a serial number, but writing the one on the casing to the SPI ROM with BBS v1.1 made it appear.
  17. smiba

    820-2523 wont turn on motherboard have all power rails except for so rails

    I assume PP5V_S5 is around 5V? Is P5VS3_EN high? What is the voltage of PP3V3_S3?
  18. smiba

    ASD - Override file version = Base_?

    Alright got it, ASD fully passes on all chipset related tests. The system will work OK without the override file? I have no idea what its purpose is
  19. smiba

    ASD - Override file version = Base_?

    U8900 had pretty crusty looking connections, resoldered them nicely with new leaded solder. Tested the External GPU with ASD OS 3S156 with no issues so I think the display issues should be resolved. I ordered a SOIC8 Adapter from a European seller so I can easily modify the SPI ROM, usually I...
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