I'm Trying To Determine Cause Of LCD Monitor Problem - Electrical - DIY Chatroom Home Improvement Forum

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Old 02-10-2009, 11:04 AM   #1
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I'm trying to determine cause of LCD monitor problem

I have an HP HSTND-2B02 19" lcd monitor that turns on but has no display. Both VGA and DVI connectors dont fix the display. The power comes on with a solid green light but there is no display. Not until after I took the monitor apart did I learn about the "holding a flashlight close to the screen" trick. I took the monitor apart just for the hell of it because its kind of old and it was given to me by someone who thought it was broken.

So anyways taking a look at how these things are made I got all the way down to the backlight bulbs and they atleast appear to look fine, doesnt mean they are though. Everything else seemed to be fine, no loose wires or broken pieces. Then I came to 1 of the 2 circuit boards and I noticed something. A little piece appears to be burnt out.

Here is the board in question...


and here is a closeup of the piece, its the little black square thing that has Q805 next to it...


Does anyone have any idea what this piece is and if it is in anyway related to the no display problem? There are two numbers/labels right next to the piece if it helps: Q805 & GDS

I dont have the tools to solder so just replacing this one piece really isnt an option, but if I can replace the whole circuit board for under $50 or so that might be an option becayse then I could probably sell the monitor for maybe $75 or so.


Last edited by konsole; 02-10-2009 at 11:51 AM.
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Old 02-10-2009, 11:16 AM   #2
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That looks like a transistor...good luck finding a new transistor, and if you do, more things are likely damaged. Maybe a power surge did this? A new board is probably your best bet.


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Old 02-10-2009, 12:08 PM   #3
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You can try searching eBay for replacement parts, people are selling broken monitors on there all the time usaully listed "for parts" in the title. Rgsgw is right about the more than one part issue, if the one is bad there are probably more. I wouldn't invest too much money into trying to fix it, ive been there done that and in the end it still didnt work. (My project was a big professional series color network printer)
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Old 02-10-2009, 01:46 PM   #4
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Q is a standard indication of a transistor. Only problem, the transistor that is burnt is not always the problem. Often some other component failed and took out the transistor.
That board appears to be a power supply board. Are there any numbers on the transistor?

Last edited by joed; 02-10-2009 at 10:23 PM.
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Old 02-10-2009, 02:27 PM   #5
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Those inverters are touchy and operate at moderately high voltages. See if you can just order a whole new backlight inverter board.
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