September 22, 2007

A no-power NTC Monitor!

Problem Encountered: No Power

Service Done:Check fuse and power regulator transistor at primary of power suppyly section, I found out that everything is ok. I check the horizontal power transistor(supply signal to flyback transformer), it is busted(shorted).I remove the defective transistor from the pcb and test the unit again, the power is now restored. In this case, power was pulled down by the short circuit created by the transistor when still connected in the circuit. After replacing the defective transistor(Part no:C5521), monitor now funtions normally.

Take Note: When troubleshooting a particular no-power monitor unit (any screen size), make sure to check the horizontal transistor or disconnect your flyback out of the monitor circuitry first, before testing other components of your monitor.A shorted flyback or power transistor will pulled down the power of your monitor to zero thereby creating a no-power situation.In this way it will shorten the troubleshooting process, in case you have a defective flyback or horizontal transistor.
So thats all for this week! Happy weekend to all!

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