No Power In BenQ T705 17″ LCD Monitor
This BenQ T705 LCD Monitor came in with no power symptom-power LED didn’t light up. The common fault for this monitor was short circuit in C5707 push pull transistor, FQU11P06 P-channel FET, high ESR in tuning capacitor .22uf 160v, dry joints in high voltage transformer and an open pico fuse. Normally after the replacement of the above parts, the LCD Monitor would start working again but this time “No” even though all the voltages now measured normal! I began to test the SMD Volt voltage regulator and found zero volt output. A-ha! at least i know the problem is in the Mainboard.
My concentration is 100% in the Mainboard and start checking why there was no voltage from the voltage regulator. Upon close inspection, i found two pins shorted together in the Scalar IC. I took a blade and separate the two pins (leg) from shorting and i got to use a magnifier glass to help me to do the job. To my surprised the LCD Monitor starting working when the front power switch was pressed! I don’t know why the two pins can short together perhaps it could be some touch up by repair technicians from other company. The reason i say that was because i could see a scratch mark underneath the front LCD cover.