Search results

  1. M

    820-4924: Not powering up

    Have this board that doesn't power up, found PP5V_S0_CPUVR - 1.19v PP5V_S3 - 5.1v isolated to both Q7310 and Q7320 to be blow, short between pins 4 and 1,2,3 pins. Resistance reading of about 2ohms. Resistance reading of just pins 1,2,3 to ground is 12ohms, which matches a good board...
  2. M

    820-00045: No imaged on display

    I have this board that doesn't have image to the screen (no backlight or image). The owner states it had a Shorted out keyboard/trackpad and the has screen issues intermittently. I've tried a new display with the same outcome. Here are some measurements taken so far. This will be my first no...
  3. M

    820-01521: Reboots when power is plugged in

    Original issue was no power due to corrosion damaged capacitors, C6405, C6416 and C6482. Once power was restored, the computer boots up and runs fine with or with power adapter plugged in. But whenever the power adapter is plugged in, or power button is pressed to turn on, apple logo comes on...
  4. M

    820-00165: No powering on, usb test light flashing on and off rapidly

    Board originally had corrosion damage and not powering up. After cleaning, replaced U1900, U7600, U1950, C5125. Also repaired trace between C1950(1) and U1950(8). It worked for about a week and now not powering up again. When i place heat using a soldering iron directly on U1950 for about a...
  5. M

    820-00165: Fan spins, stops then starts but board won't boot

    Originally the board was dead which i isolated to the smc. Once replaced, the fan would spin for like 12 seconds, stop and then start spinning and stays spinning but no board activity, no usb activity either. I did noticed the bluetooth module was getting very hot so removed it but the board...
  6. M

    820-00928 - short on component not shown in boardview

    Have this board with Touch Bar issues. Found the short but the boardview for this board doesn’t seem to match this version. Anyone have an idea what other components these are ties to as I’ve removed both capacitors and a third on the other side of the board and the short is still there. See...
  7. M

    820-00850: Stuck in DFU mode

    Anyone seen this before, the board is constantly stuck in DFU mode, even without power applied. When power is applied, never goes into 20v. I've tried revive and restore with the same error coming up, see picture. Get this error with power applied and without.
  8. M

    820-00281: Not turning powering up

    This board came in with no sign of liquid damage but won't power up. Only things i've found so far is PP3V3_S0 reading 2.8 and the ssd chips are warm (not hot), but the red spot in the picture is ready about 104 degrees (F). So i ran the board through the ultrasonic just case there were some...
  9. M


    Have this board that's not powering up. I'm using the 820-01041 schematic also as it appears to be the same as this board, 820-01326. Anyway, i get PP20V and current pull when battery is connected, indicating battery charge and no current with battery removed. I'm still a bit rusty with these...
  10. M

    820-00840: No powering up

    Have a 820-00840 that isn't booting up. Owner said it was running fine the previous day and all of sudden won't power up. I've checked the board for corrosion or sign of spill, none. The board does get warm with PP20 present and about 70mA of current draw. I've flashed new ME as well with the...
  11. M

    820-00138: Not recognizing keyboard

    Have a board that doesnt recognize any keyboard, except external. Trackpad confirmed good. Tested on multiple frames with same results. Cap lock light doesn't come on either. Voltage on cap lock pin "WS_KBD15_CAP" is 2.4v. Since all keys aren't responding, is there a common items between both...
  12. M

    820-01040: Blown SSD module.

    Got a board that wasn't powering up, missing 20v supply. Isolated to blown U9080. Replaced the blown chip and now have 20v power, but board still won't power up. Isolated to U8900 with a short, about 1.5ohms on PP2V5_NAND_SSD0 line. After removing U8900, resistance on that line is now 20ohms. Is...
  13. M

    820-00239: Not recorgnizing ssd + critical update error on external storage

    Have this one that was sent in with the question mark folder. I was able to go into Recovery window and confirmed that the ssd wasn't being seen, only the portion that carriers the OS re-install file. While trying an external storage, it also won't load the OS, but gives the error about needing...
  14. M

    820-00609: Doesn't power on after shutdown

    Got this iMac 27 that owner had attempted some work on and now won't power on. What i noticed was after it's power on the first time and then shutdown, it won't power on until the power plug is removed for a few seconds. Looking at the board LED's, when i first power it up, all the LED's on...
  15. M

    820-01987: No backlight

    Got this board that had heavy corrosion damage on and around the backlight circuit. Found blow cap C8467 and also had to replace R8446 as pin 2 of the resistor along with the pad was corroded. Due to R8446 solder pads being damaged, i soldered it to C8457 and ran a line from pin 2 of the...
  16. M

    820-3787: Not powering up but fan spins/stops/then remains spinning

    Have this board, no liquid damage or corrosion found. The fan spins for about 10sec then shuts off, then starts spinning again and remains spinning. The fan then ramps up slowly until it reaches max speed. Theres no USB activity, only a initial flash of the usb light when connected Cpu voltage...
  17. M

    820-01700: No powering up (fan spins with battery)

    Have this unit that isn't power up. The fan will spin and slowly ramp up until it fully ramps to max speed. This only happens with the battery. Without the battery, the board never powers up or doesn't pull any current. With battery connected, current draw is present. History on this board is it...
  18. M

    820-3662: 3 beeps

    Before i start replacing the RAM chips, anything else to check? These are measurements i've taken so far. No corrosion or liquid damage on the board. PP0V75_S3_MEM_VREFDQ_A - 0.68 PP0V75_S3_MEM_VREFCA_A - 0.68 PP1V35_S3_MEM - 1.36 MEM_RESET_L - 1.36
  19. M

    820-01521: Not powering up

    Have this board, that appears to be good, just not booting up. When i attempt to revive i get this message, "Configurator could not perform the requested action because the device is not in recovery mode." When i attempt restore, i get this message, "Can't restore device in this state - please...
  20. M

    820-01958: Not powering up.

    Have this board that's not power up, not sure if i've successfully isolated it but compared to the 820-01521 version, on U7650 after plugging in the power and then removing it, pin 4 (P5VG3S_EN_DLY) has a resistance of 93ohms. On a good board, performing the same test, pin 4 remains at 47k. I've...