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From: reilly@motcid.UUCP (Patrick L. Reilly)
Newsgroups: sci.electronics
Subject: Re: TV damaged by Lightning
Message-ID: <4503@gypsum.UUCP>
Date: 27 Aug 90 18:27:15 GMT
References: <7737@helios.TAMU.EDU>
Reply-To: motcid!reillyp@uunet.uu.net
Organization: Motorola Inc., Cellular Infrastructure Div., Arlington Heights, IL
Lines: 31

jeff@cs.tamu.edu (Jeff Goldberg) writes:

:A couple of days ago I was watching my TV (1984 Sony Trinitron)
:during a Texas thunderstorm.  There was a lightning strike *very*
:close to my house and my TV went out.
:The TV acts like it is getting no power at all.  The circuit breaker
:in the house was not blown.  I assume lightning is a high voltage as


From the world of a former TV repairman...
Try checking the power suppply diodes. Should be near the
power cord and either consisting of 4 small black round
objects with a silver band at one end. OR, may be a
single square package with ~ & + symbols on it.

Diodes should read low ohms in one direction and very high ohms
in the other direction using the diode selection on your voltmeter.
I suspect one is shorted.

Another possibility is the start up circuitry that is used to
protect against excessive X-ray outputs when the high-voltage
circuit is defective. To check this, you will need a variable
voltage source. Try turning on the set at about 90 volts. As you
crank up the voltage the start up circuit will kill the set. 

Finally,
	I used to charge $50 EXTRA just to service a SONY TV!
Why? They are great sets when they work, but their elaborate
systems of closed loops causes plenty of troubleshooting grief.

Good luck.