Air-conditioning unit power supply failing to power up

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • Gjackson
    Senior Member
    • Aug 2021
    • 134
    • Malta

    #1

    Air-conditioning unit power supply failing to power up

    Hi all, I managed to narrow down which PCB was causing my Haier AC to throw out an E7 error code (E7 indicates that the indoor unit and outdoor unit cannot communicate). I found that the outdoor unit power board which gives 5v and 15v to the outdoor unit module board fails to fully power up.. The power Led starts to fade in incredibly slowly and the 5v and 15v power buses jump around like crazy and never reach their required voltage. I unplugged the module board from the power board and the power board powered up fine! It had a steady 5v and 15v out and the power LED came on instantly and Bright. I assumed that there was a short on the module board from this however I reconnected the 5v and 15v cable while the power board was still powered and generating stable voltages and to my surprise it didn't shut off and the Voltages were still stable and the Error code went away. It seems that If I attempt to turn on the AC with the power board connected to the module board the power board fails to turn on and generates unstable voltages, but If I connect the module board after the power board has finished powering up it works just fine.. Is this a symptom of a bad cap somewhere? What could be the cause of such a symptom?

    Thank you.

    Here is the service manual if it helps :

    https://cdn.badcaps-static.com/pdfs/...2306ad82cb.pdf

    E7 error description starts from page 61 and schematics of outdoor unit start from page 71
  • R_J
    Badcaps Legend
    • Jun 2012
    • 9516
    • Canada

    #2
    Re: Air-conditioning unit power supply failing to power up

    I would start with replacing E4 (page 72) 22ยตf/50v capacitor. and maybe E5 470ยตf/25v
    E4 is the startup cap for the smps and they usually go bad over time.
    E6 is the +5v filter cap and that circuit also controls the feedback for regulation
    Last edited by R_J; 01-08-2022, 11:47 AM.

    Comment

    • CapLeaker
      Leaking Member
      • Dec 2014
      • 7991
      • Canada

      #3
      Re: Air-conditioning unit power supply failing to power up

      Could be also IC4 5V regulator going bad not handling the load anymore.

      Comment

      • Gjackson
        Senior Member
        • Aug 2021
        • 134
        • Malta

        #4
        Re: Air-conditioning unit power supply failing to power up

        I'll give these suggestions a try, Thank you!

        Comment

        Related Topics

        Collapse

        • Tynan Dill
          Vizio e601i-A3 - Has Sound and Display, But No Backlight - Bad Power Supply Board or Bad LED Bulbs ?
          by Tynan Dill
          I was given this TV from my great uncle. He said it just wouldn't turn on one day out of nowhere, replaced the TV, and gave it to me to possibly fix and use for myself.

          Upon bringing it home and plugging it up, it showed a standby light.

          I powered it on and without a flashlight, the display showed the "V" but the lighting is very dim, but visible.

          The screen seems to blackout and stay black, but with a flashlight I can see the display.

          With my Playstation 4 connected via HDMI, and running a game I can hear sound.

          Assuming...
          11-22-2024, 01:46 PM
        • PantherDave
          Microsoft Surface Pro (5th gen) model 1796 - no power
          by PantherDave
          Hi all!

          I'm trying to troubleshoot a Microsoft Surface Pro (5th gen) model 1796 that won't power on. Motherboard model is M1007506-015. My priority is retrieving data, but the SSD is integrated so it looks like if I can't repair it it'll need to go to a data recovery company. I've done a little basic board repair before, but nothing this advanced until now. So please forgive my ignorance in advance. ๐Ÿ˜…

          I found the boardview for this laptop in the forums here, and am able to open it on my PC with FlexBV.
          https://www.badcaps.net/forum/troubl...-hardware-devi...
          05-29-2024, 02:01 PM
        • GLISIT
          Asus Probook P5440UF-XB74 power issue
          by GLISIT
          Hi all,

          TL;DR - this laptop is driving me nuts with the oddball power-related behaviors. Appreciate any insight you can provide!


          I'm experiencing a power issue on an Asus Probook P5440UF-XB74. Although I've worked with electronics and computers for decades, this is my first attempt at getting into motherboard-level component troubleshooting. Any help the community can provide is greatly appreciated!

          A few weeks ago I was using the laptop (on battery power) for a Zoom meeting. The battery was running very low (long meeting) but I wasn't worried about...
          01-16-2025, 02:29 PM
        • sam_sam_sam
          Desoldering gun station modified to use a 18 volt @ 20 amp switching power supply
          by sam_sam_sam
          I have wanting to do this project for quite sometime now and I finally found a switching power supply that will work on this desoldering gun station ZD-915 that the original switching power supply took a shit and just was not worth trying to fix it because this switching power is not quite big enough to handle the heater element and the vacuum pump

          One note when I tested the switching power supply and the voltage control board I noticed that this desoldering gun heat up much faster than the original switching power supply which I was really surprised by to the point that I might buy...
          03-31-2024, 02:12 PM
        • Document Archive
          HP Pavilion Power Pavilion Power 15-cb009nl Notebook 15 Specification for Upgrade or Repair
          by Document Archive
          This specification for the HP Pavilion Power Pavilion Power 15-cb009nl Notebook can be useful for upgrading or repairing a laptop that is not working. As a community we are working through our specifications to add valuable data like the Pavilion Power 15-cb009nl boardview and Pavilion Power 15-cb009nl schematic. Our users have donated over 1 million documents which are being added to the site. This page will be updated soon with additional information. Alternatively you can request additional help from our users directly on the relevant badcaps forum. Please note that we offer no warranties that...
          09-06-2024, 05:59 AM
        • Loading...
        • No more items.
        Working...