Re: Phillips 42PFL3704D/F7 - Power Up Issue

Problem Isolation:

IC 1401 – Texas Instruments UCC28060 -- [url]http://www.ti.com/product/ucc28060[/url]

Pin 9 PWMCNTL: From data sheet: "PWM enable logic output: This open-drain output goes low when HVSEN is within the HVSEN good region and the ZCDA and ZCDB inputs are switching correctly if operating in two-phase mode (see PHB Pin). Otherwise, PWMCNTL is high impedance."

I found when plugging in the power cord, the Pin 9 voltage to be 5.75 and after 7 seconds dropped slowly to...

Re: Phillips 42PFL3704D/F7 - Power Up Issue

Looking for some help in determining which area of the circuit is responsible for the shutting down of the power. If the power button is pushed after the initial cycle, the relay R1201 re-engaging, the voltages come back up as described in the original post and after 7 seconds, the relay and voltages drop as described above.

Re: Phillips 42PFL3704D/F7 - Power Up Issue

See attached photos...

Model: 42PFL3704D/F7
Serial: YA1A********

This TV is my daughter's TV until it completely stopped working.

Initial problem: no display. If left a while and/or opened connections checked would sometimes come back on and work for “weeks.”

Then started blowing fuse F1601 as soon as power cord plugged in.

By removing R1424, R1604, and C1507, would not blow fuse. Isolated the problem to Q1602 (2SK3561) and replaced (TK8A50DA). TV has problem described below. I have also replaced Q1601 with a TK8A50DA (because it was part of the...

Re: New Members - please post your introductions here

Great Forum. Glad I found it.