Question about BenQ FP71G 17" LCD Monitor
We recently come across this problem - and like many others - looked online for a solution without much luck. So it was a clear case of fault finding. The symptoms of the indicator changing from amber to green on signal indicated a problem with the powersupply/inverter board, and not the smaller signals processing board, so that's where we started. On careful testing it soon became clear that the black picofuse (just above the main transformer) was blown. This indicated a major fault in the backlight driver circuit. There are two independant yet identical circuits that drive the backlights - this made testing easy. We found that the two driver transistors marked C5707 were almost completely shorted. You will identify these as being two of four identical black components with a built in heat sink at each end of a grey 0.22 Microfarad capacitor - looking much like bookends! Replacing these C5707 transistors with BD139 transistors (Note: these are constructed mirror image to the original transistors - fit them backwards to the original transistors !) and replacing the 3 Amp picofuse with a 1 ohm 1 watt resistor completely solved the problem ! - Colin Knight, Radtvid Electronics, South Africa.
Posted on Dec 31, 2008
I have the same problem, I also openned the rear panel and examined the power pc board, there is definately burn marks on the board... not sure if it would be easier to order the main board from the company and re-install.. Also, could it be the smaller board I guess it would be a video pc board. Please let me know if you solve this problem. Thanks!
Posted on May 18, 2007
Check the following: http://www.electronicrepairguide.com/benq-fp731-lcd-monitor-repair.html Seems a likely solution - however did not work for me, I have something else . . .
Posted on Sep 21, 2007
For display off problem definitely first culprit is Inverter board.If readily available replacement will solve the problem.
Posted on Feb 16, 2008
Posted on Feb 13, 2008
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