thread top ad





In order for your account to be activated INSTANTLY, your PayPal email MUST MATCH THE EMAIL YOU USE TO REGISTER YOUR ACCOUNT ON THIS FORUM!! If your PAYPAL email address differs from your FORUM email address, your account will have to be activated MANUALLY when a customer service agent gets around to it.

I realize this sucks, and I do apologize.
See more
See less

820-00840, Liquid, Powers with high fan, no boot.

  • Filter
  • Time
  • Show
Clear All
new posts

  • 820-00840, Liquid, Powers with high fan, no boot.

    Working on a 2nd 820-00840 with very similar symptoms, but this one had liquid.

    -- PPBUS is present at 13v
    -- ALL_SYS_PWRGD is present at 3.3v
    -- 3v3_s0 and 5v_s0 both present and proper
    -- All CPU and memory rails I've checked all appear to be present and correct voltages.
    -- Board powers on, fan slowly gets up to full speed and there's no booting or other activity.
    -- No light on USB mouse when connected via USB-C --> USB adapter
    -- Should I try to load a different BIOS?

    A few general questions with regards to this model: What specific things could cause this model to run the fan at full speed? I have two boards now that do this, and I'm wondering if another component (trackpad, trackpad cable, etc) is the cause. Unfortunately I do not yet have another test assembly, which is a bummer because it would help to know if this tpad is good or not. I hate not having any sort of indication of chime or anything.

    Any advice appreciated as always.

    - - - - - - - - - - - -

    UPDATE: After resolving the high-fans (trackpad cable not fully connected on tpad-end), I have some more information:

    Unit powers and forcetouch activates and stays on until power is removed. However, no activity on USB drive (with power light) when connected via USB_C adapter.

    Any advice on where to go from here appreciated.
    Last edited by SMMRepair; 09-25-2018, 06:32 PM.

  • #2
    OK, I actually found that the trackpad cable was a bit crooked and not completely connected. I re-seated it (it appears to have been replaced at some point), and now the fan is not turning on, and the forcetouch actually works when the unit turns on. Now I just have no video and no light on a USB mouse when connected via USB-C --> USB adapter. Also no activity on a USB drive with light when plugged in, but ForceTouch trackpad remains "on" until power is removed.
    Last edited by SMMRepair; 09-25-2018, 06:31 PM.


    • #3
      Inspect for water damage on all USB-C drivers, if one dont work none will work, also check for water damage on display connector and cable....


      • #4
        Thanks, Aprendiz. If I have ppbus at 13v, does that not eliminate the USB-C drivers? Or could one of the drivers still be bad despite the board powering on (and trackpad clicking)? Display connector and cable both good. This is a board-only sent in to us for repair, so we're using our own test assembly.


        thread bottom ad