Toshiba Equium U400-145 blank display. Inverter or CCFL?

By foxdelta
Nov 9, 2010
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  1. Fellow Techspotters,

    I am currently trying to repair a colleague's Toshiba Equium U400-145 Laptop. When the power switch is pressed, the laptop boots as normal and you can hear the windows (vista 32bit) welcome sound. The problem is that the screen very briefly shows the initial toshiba logo screen then goes blank whilst it boots. You can still see a very faint image on the display and the display works fine on an external monitor.

    I suspected that it was an inverter problem having 'googled' the problem - the majority of advice given on forums was that it pointed to an inverter problem. So far I have therefore changed the Inverter (twice); the first one worked for 3 weeks and then the same problem occurred. The second inverter lasted just 3 days. I am hoping that I have just been unlucky with the quality of Inverters that I have purchased (3rd one currently on its way gratis from seller), otherwise there may be another underlying cause for the screen display to keep failing (power surge, faulty ribbons?). Other forums mention CCFL failures but because the screen appears to be fixed with an inverter change (for a while anyway), I cannot see that it is the 'backlight' that is the problem. I may be wrong.

    So my learned friends - anybody had similar issues or can offer some sage advice?
    All comments and advice sincerely welcomed.

    Thank you in advance of time and thoughts.
  2. Tmagic650

    Tmagic650 TS Ambassador Posts: 20,673   +152

    From what you have said, the LCD (CCFL) is causing the inverters to fail. Entire laptop LCD panels are not that expensive any longer. You can buy the panels including the back light. The inverters are separate. EBay is a good source for all laptop parts...
  3. foxdelta

    foxdelta Newcomer, in training Topic Starter Posts: 47

    Solved!!

    I finally found out what the issue was:

    The inverters were being blown by a shorted CCFL bulb. Once I stripped the screen down and did a re-boot I noticed an orange spark coming from inside the LCD screen at the bottom left corner. The CCFL was briefly trying to light up but was being prevented by the sparking bulb. On further investigation the end of the bulb had burnt away the soft protection bung on it's end, hence the shorting.

    The only solution was to replace the LCD screen and I found a very well priced one on Ebay for £65. Fitted it along with a new inverter and 'hey presto' all working fine. So TMagic, you were right! Many thanks for taking the time to reply to the issue.

    Regards.
  4. Tmagic650

    Tmagic650 TS Ambassador Posts: 20,673   +152

    That's great foxdelta,
    Glad you got it fixed. I do a lot of laptop repairs...


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