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Old 01-25-2018, 06:30 AM   #2
Behemot
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Join Date: Dec 2009
City & State: Prague, 504'52.22"N, 1423'30.45"E
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Default Re: Acer B326HUL power supply dead

It's very difficult to read anything in here but it seems like the PFC/quasi-resonant flyback controller is NXP, possibly TEA1751T. According to the datasheet, the startup voltage is 21-23 V so when it's at 18-19.6 that's too low.

The path goes from the auxiliary winding on primary side through inductor to an SMD diode, capacitor and than there is "K415 C200" TO-92 bipolar transistor. The 15V feed leads to its collector, the oscillating 18-19.6V output is on its emitter. Collector and base has 1002 SMD resistor in between and base is also connected through an SMD zener to return.

So it seems like some amplifier with zener feedback? And this is to feed the Vcc of the controller.
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