Question about Philips Magnavox 27MS343S 27" TV

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Philips 21" L01.2A Chassis HV Shutdown

TV set shutdown after few seconds of coming on. Set will stay on longer if you continuously change channel.Problem was intermittent before but goes hard now. I have done some resoldering thinking that is just some cold solder issue. Screen flickers with green, and sometimes red color before shutdown. I have checked the power supply section, voltages seems to be ok. The main supply output of SMPS(B+) bothers me because per schem. diagram it should be 130Vdc for the 21" set and I'm reading 139dc volts. What could be causing this "abnormal" voltage output of SMPS? I have replaced the swithcing regulator IC and some electrolytic caps in the horizontal driver ckt. I have read that most of the Philips product having this chassis no. encounter the same problem but no one seems to solve the problem. Glad if anyone from the masters can help. Thanks in advance. God bless. Thanks.

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Re: Philips 21" L01.2A Chassis HV Shutdown

I have the same problem on this chassis L01.2A.Still no solution.

Posted on Jan 11, 2008

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Re: Philips 21" L01.2A Chassis HV Shutdown

Hello bashlort, The increase in voltage may be to some circuit loading being removed this is a sign that something may have increased in resistance or something may have opened in the attached circuit. Have you taken any voltage measurements in the video section of the set, if not check the voltages on the pins of the video processor IC and follow the connections up to the CRT socket, be sure to pay special attention to the focus and screen grid voltages. If those are ok check the voltages in the horizontal section including oscilloscope measurements for drive signals. Please inform me of your findings. Thank you, Shuttle83

Posted on Oct 07, 2007

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Re:"shutdown after video comes up the green power light stays on but the set will not shut down while changing channels."


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