820-00850 20V 0.0amps

Collapse
X
Collapse
 
  • Page of 1
  • Time
  • Show
Clear All
new posts
Previous template Next
  • iMuhtaseb
    Senior Member
    • Jan 2017
    • 122
    • Palesine
    #1

    820-00850 20V 0.0amps

    - 820-00850 came in does not power on
    - cleaned it up by prior shop
    - takes 20v, then 0.200mA - 0.150mA and drops down to 0.00A
    - 20V is OK board, tested PPDCIN
    - PPBUS is 12.6V
    PP3V3_G3H is 3.3v
    PP3V_G3H_RTC is 3V
    PP5V_G3S is 5.1V
    PP3V3_G3S is 3.3v
    PP1V8_G3S is 1.8V
    PP3V3_AWAKE is 3.3V
    PP0V8_SLPS2R IS 0.78V
    PP1V2_AWAKE is 1.2V
    PP3V3_G3H_PMU_VDDMAIN is 3.3V
    PP1V8_SSD is 1.8V
    PP0V9_SSD is 0.9V
    PP3V3_S5 IS MISSING

    PMU_ONOFF_L = 3.3v
    PMU_RSLOC_RST_L = 3.3v
    CHGR_RST_IN_R = 0.0V


    From the schematics, PP3V3_S5 is generated by U700 the PMU..

    I'd appreciate a hint or lead on something I may have missed

    Checked for shorts, no shorts..
    Tags: None
    • mon2
      Badcaps Legend
      • Dec 2019
      • 14027
      • Canada
      #2
      Re: 820-00850 20V 0.0amps

      Hi.

      1) Do the posted voltage rails remain ON when you attach the adapter or do they power cycle ?

      2) Are you using the suitable power adapter for this logic board ?

      3) Post the voltage readings for:

      I2C_PWR_SCL
      I2C_PWR_SDA

      4) Remove all power. Meter in resistance mode. What is the resistance to ground for PP3V3_S5 ?

        Comment

        • iMuhtaseb
          Senior Member
          • Jan 2017
          • 122
          • Palesine
          #3
          Re: 820-00850 20V 0.0amps

          1) Do the posted voltage rails remain ON when you attach the adapter or do they power cycle ?

          • Yes, very nice and stable.

          2) Are you using the suitable power adapter for this logic board ?

          • Yes, an Apple original 97W USB-C with an Apple original USB-C to USB-C cable.

          3) Post the voltage readings for:

          I2C_PWR_SCL is 1.79V
          I2C_PWR_SDA is 1.79v

          4) Remove all power. Meter in resistance mode. What is the resistance to ground for PP3V3_S5 ?[/QUOTE]

          Resistance mode: PP3V3_S5 110 kOhms (black probe on ground, red probe on PP3V3_S5.
          Diode mode: PP3V3_S5 0.360 (red probe on ground, red probe on PP3V3_S5).

            Comment

            • mon2
              Badcaps Legend
              • Dec 2019
              • 14027
              • Canada
              #4
              Re: 820-00850 20V 0.0amps

              Do you see any voltage on PP3V3_S5 ?

              Perhaps PP3V3_S5 is pulsing during power up ?

              Also, review this thread:

              https://www.reddit.com/r/mobilerepai...rails_missing/

              which notes that from Louis' youtube videos, corrupt T2 firmware could be the root cause.

              The linked above case looks similar to yours. Do update this thread for future readers, either way.
              Last edited by mon2; 12-23-2021, 12:29 PM.

                Comment

                • iMuhtaseb
                  Senior Member
                  • Jan 2017
                  • 122
                  • Palesine
                  #5
                  Re: 820-00850 20V 0.0amps

                  Perhaps PP3V3_S5 is pulsing during power up ?

                  Sadly, my multimeter is not advanced to good enough to detect quick pulses.

                  Also, review this thread:

                  https://www.reddit.com/r/mobilerepai...rails_missing/

                  which notes that from Louis' youtube videos, corrupt T2 firmware could be the root cause.

                  I've attempted DFU revive but haven't gone to restore, since it has important data on the logic board.

                  This is the error I get after revive:
                  "The operation couldn’t be completed. (AMRestoreErrorDomain error -1 - Failed to handle message type StatusMsg (Generic error)) [AMRestoreErrorDomain – 0xFFFFFFFFFFFFFFFF (-1) [sys = 0x3F, sub = 0xFFF, code = 0x3FFF (16383)]]"

                    Comment

                    • mon2
                      Badcaps Legend
                      • Dec 2019
                      • 14027
                      • Canada
                      #6
                      Re: 820-00850 20V 0.0amps

                      Have you tested all Type C connectors ? Same behavior ?

                      How does this logic behave with a charged battery ?

                        Comment

                        Previous template Next

                        Related Topics

                        Collapse
                        • cind12
                          GTX 1080 TI Gigabyte Aorus low resistance on vmem
                          by cind12
                          Hi guys, i was wondering, i've got 9Ohms on Vmem, one of the mosfet was shortet to ground, so i've desoldered hi and low mosfets nad still low res, then i removed all of the memory chips, and the resistance is still low, so did you had maybe a card with that low res on memories, and the card was working fine ?
                          Removed the U1866Q and still without result, i dont have thermal cam so can't see where is hot spot when incjeting voltage.
                          The resistance on core is ok 0.1Ohm ((Power 0.8V when on)
                          Resistance on 12V 4K ohms (Power present when on)
                          Resistance on 12V PEX 4K ohms...
                          12-08-2023, 09:09 AM
                        • Jane
                          How do you test MOSFET in laptops ?
                          by Jane
                          I tried to use this method:

                          Testing an N-channel MOSFET:

                          Step 1: Discharge the Gate (turn off the MOSFET)
                          Place the black probe (COM) on the Source (S) and the red probe on the Drain (D). The multimeter should show no continuity (high resistance or "OL" – open line).
                          Then, touch the black probe to the Source (S) and the red probe to the Gate (G). This discharges any stored charge in the Gate, turning the MOSFET off.

                          Step 2: Charge the Gate (turn on the MOSFET)
                          Now, place the red probe on the Gate (G) and the black probe on the                          ...
                          09-27-2024, 03:31 AM
                        • Nagy Daniel
                          Lowest possible resistance on laptop motherboard rail - Guide Table request
                          by Nagy Daniel
                          Hi, I'm Daniel, and I'm new to the world of repairing motherboards.

                          I would like to create a table, or more likely a guideline about the voltage rails and their possible resistance rail.

                          I know that the motherboard design has a very big depend on the rail's resistance, but I would like to know what is the smallest value for a rail that can be acceptable. For example, I heard that some new gaming motherboards can have 0,5 Ohm resistance on the GPU rail, but on an older type, it could be a sign of a shorted GPU rail.

                          So, I generated a table with AI so I can...
                          03-04-2025, 08:24 AM
                        • perfm2
                          Wson8 spring pin probe WORKS
                          by perfm2
                          I couldn't find anywhere on the internet where someone had discussed actually using one of these newer wson8 probes for flashing your Wson8 BIOS chip without removing it from the MB.
                          I recently ordered one to give it a shot and it actually worked quite well.

                          The tricky part is obviously keeping the probe pins in place on the exposed Wson8 pads of the MB while reading/writing.
                          I used a larger binder clip attached to the top of the probe to create a large flat surface, then added about 1lb of weight to it.
                          This aided greatly in allowing the probe to stay in place...
                          03-30-2023, 11:19 AM
                        • Jane
                          What is the lowest acceptable resistance on a coil without considering a short on PCB
                          by Jane
                          I have Asus FA506 ( board DA0BKXMB8D0 Rev: D). Can you please roughly indicate what the lowest resistance I should measure on a coil? I know that a low resistance is allowed on coils in CPU or graphic circuits but can you provide acceptable values of resistance?
                          Thank you.
                          02-27-2024, 01:42 PM
                        • Loading...
                        • No more items.
                        Working...