Thank you to the guys at HEGE supporting Badcaps [ HEGE ] [ HEGE DEX Chart ]

Announcement

Collapse
No announcement yet.

Benq Q9T3 FP937s-D does not switch on

Collapse
X
Collapse
 
  • Page of 1
  • Filter
  • Time
  • Show
Clear All
new posts
Previous template Next
    #1

    Benq Q9T3 FP937s-D does not switch on

    Hello to all and happy new year from Greece,

    It is my first post in this super forum so mind me if i make any mistakes.
    As you can see in the pictures the filter cap C605 blown and for sure C703 & C704 are bulged.
    The monitor was working fine untill some flickering a blackout and power on again from the electric company.
    The main fuse 2A @ 250V is not blown.
    Can anyone give me some tips.(I know for sure i have to check rect bridge BD601 and Mosfet Q601).
    Attached Files
    Tags: None
    #2
    Re: Benq Q9T3 FP937s-D does not switch on

    You seem to be well on the way to having it sorted. I'd suggest doing the complete job.

    1. Test the bridge rectifier and power FET. Inspect the thermistor for signs of damage - it took a current surge. Replace these components if damaged.

    2. Replace all electrolytic caps, even the small (<100 uF) ones with name brand low ESR caps.

    PlainBill
    For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

    Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

    Comment

      #3
      Re: Benq Q9T3 FP937s-D does not switch on

      Benq boards are also known for dry joints in the inverter section that will take out the driver transistors if left unchecked.

      Resolder the inverter transformer pins, the gray tombstone caps in between the driver transistors and the two inductors in the inverter section. I have almost always found cracks on the gray tombstone caps when by the time the drivers had finally failed.

      Then look over the inverter section for any other suspect joints and touch them up as well.
      Elements of the past and the future combining to make something not quite as good as either.

      Comment

        #4
        Re: Benq Q9T3 FP937s-D does not switch on

        primary side is probably dead, check the mosfet , the little ic near (1200ap40) and replace the big cap ,
        check too the two big resistors near

        you can desolder the outputs of the transformer for easy repair and mesure on the primary side.

        then , replace all caps on secondary side ,and resolder all pins on the two inverter transformers.

        sorry for my english.

        Comment

          #5
          Re: Benq Q9T3 FP937s-D does not switch on

          There also might be a picofuse protecting the inverter section. Check that as well.
          --- begin sig file ---

          If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post.

          We respectfully ask that you make some time and effort to read some of the guides available for basic troubleshooting. After you have read through them, then ask clarification questions or report your findings.

          Please do not post inline and offsite as they slow down the loading of pages.

          --- end sig file ---

          Comment

            #6
            Re: Benq Q9T3 FP937s-D does not switch on

            Thank you PlainBill , Krankshaft , cpp and retiredcaps for all your advises and your immediate answers.
            In order to update my situation , i made the orders for all the components you suggested exept the pico fuse on inverter side that is ok.
            Awaiting for the components to arrive and i will post back the results
            Thank you all for your support .

            Comment

              #7
              Re: Benq Q9T3 FP937s-D does not switch on

              Hi to all again ,
              I would like to thank you once more for all your advices and update this thread.
              Finally today my components arrived and started the repair .
              Main filter cap replaced , rect.diode checked foun ok , mosfet checked found ok , all elec. capasitors replaced (just in case).
              The monitor was re-assembled again plugged in and is working fine (untill now)
              I think the repair was succesful , so consider this thread as solved.

              Comment

              Previous template Next
              Working...
              X