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Solved No Power Problem In HP L1706 (PX849A) LCD Monitor
This Monitor came in with no power problem and found the main fuse 3.15 amp open circuited. As usual one has to find out whether other components have short circuit or not before you put a new fuse and retest the set. After scanning all of the primary and some of the major components in the secondary side of power supply i could not locate any shorted components. Placing a 100 watt bulb across the fuse and noticed that the bulb dims down and the big filter capacitor voltage did not drop even though the power jack already been removed.
Since the start up resistors are going to the power IC SG5841SZ (SMD IC) I suspect that this IC could be faulty causing the filter cap voltage remain high. Finding from my spare part compartment could not locate such part number thus i use SG6841SZ SMD IC as replacement to try it out. Before i put in the new IC, i did search from the internet and compare both spec and found that both of the IC’s were not much different from each other.
So the result was the LCD Monitor power came back a life after the replacement of the SG6841SZ IC and a fuse. This HP L1706 Monitor use some of the part numbers such as :
BIT3713 (INVERTER IC), 40P03GJ (FET), 2761I (Power FET), 817B (Optoisolator IC), 1506 (Voltage regulator IC) and AZ431 (Adjustable Precision Shunt Regulator IC). Please jot down in your diary book that the SG5841SZ can be replace with SG6841SZ.