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Honor Student
Posts: 2
Member Since: ‎06-22-2009
Message 1 of 2 (20,858 Views)

HP desktop - Power switch or power supply problem?

I am having trouble have with HTML fixing format - so hopefully this one works.   All help is appreciated.  Thanks in advance for reaching this post. 
  • We have an inconsistent power on problem with our HP a220n with XP home (?) edition.    I am sending from another HP.
  • I don't know if it is the power supply or the power switch.  Of course there is important stuff on this computer, and very little backup (very negligent here)  
  • The power switch on the 220n has been sticking for while.  The day before yesterday we had a storm and a 3 second power outage. We have a whole house surge protector, and a surge protector on all of our electronics.  Immediately after the short power outage, I unplugged the electronics as an extra safety measure. (we do this from a past bad experience)  
  • After reading all steps below that I have taken - what is next - do I take it to a PC repair shop for a full inspection and repair?   Or if there is a definite answer from the experts on this forum - get parts and repair on our own???  
  • I have been told I "know enough about computers to be dangerous"   I can a lot, but  someone to guide me step by step on other things.  My husband is extremely handy - will tackle pretty much anything, but doesn't want to attempt to fix the insides of a computer.     



  Situation and steps taken -  I love detail  :-))


  1. After the storm two days ago, I powered up other computers successfully.  I didn't need the a220n until yesterday.  The 220n tower is in our carpeted office, standing on a raised board.
  2. Yesterday morning, I pushed power button, no power. However everything else plugged into that power strip worked (monitor, printer, speakers, and the DSL router and modem).   
  3. Unplugged computer when a friend came, took off side panel and could see lots of dust, plugged it into another wall socket, no lights 
  4. I unplugged every cable from the back and carried tower to kitchen table, and used dif power cord directly into wall socket
  5. Green light glowed on back panel, pushed front power switch, and success!  Fan worked and I could hear hard drive start up.   Without monitor, keyboard, or mouse attached, I held power button in to shut off  
  6. Unplugged, took off side panel, cleaned out lots of dust 
  7. Carried back into office, placed on the raised board, used same cord as kitchen into office wall, no back light, and nothing when pushed power switch
  8. My husband checked wall switch circuit with meter – all OK.  We moved tower to small table so at eye level   
  9. I searched HP help for power problems, husband and I tried all listed, plugged cord back in, no power light on back or when pressed switch 
  10. Went on HP support chat, tech led me through several things, including removing power cord, taking side and too front cover off 
  11. The internal switch behind power button was dirty, and the plastic behind the power button had a broken tiny trim piece
  12. I tried internal switch, sticking a little, so cleaned it with a clean cloth.  Now no dust, no sticking, and could hear click.  Felt some success.
  13. Put front cover back on, still without power plug, pressed power button, could hear click. Again Yeah!
  14. Put power cord back in (side panel still off), had no power when pressing switch, and no light on back
  15. So the HP Rep told me that power supply had finally given out, and I needed to replace it.
  16. I thanked the person for time spent, left the side cover off, power cord plugged in (no accessories attached), and went to bed, planning to call a repair shop today.
  17. This morning, I woke up and walked into office.  Big surprise!  Green power light on back was lit.  
  18. So I pushed power switch button on front cover.  Green light on power switch, CPU powered up, fan worked.  I had to shut down by holding power button in since no monitor, or keyboard, and is still setting on the little table, plugged directly into the wall socket.  The side panel is still off and the green light has been on after several hours.
  19. I searched HP and found this support forum, and decided to send for help.
"professional volunteer"
was told "know enough about computers to be dangerous"
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Associate Professor
Posts: 1,250
Member Since: ‎01-27-2009
Message 2 of 2 (20,854 Views)

Re: HP desktop - Power switch or power supply problem?

The power switch is a normally open contact.  Closing the switch short the two power pins on the board.  You can trace the two wires back to the board.  Remove these two wires and short the two pins on the board with a metal screwdriver if you want to start the PC (same action as pushing the switch).


I'd reseat all boards and connectors inside the PC.  Connect only the mouse, keyboard, and monitor.  Remove the battery on the board for a few hours to clear CMOS.  If PC will not POST, then replace the PSU.  There's a decent unit on sale at Newegg for $25 after $15 rebate + free shipping.


HP's hardware quality is kinda cheap so it may not be a bad idea to upgrade the PSU anyway.

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