Hitachi shut down

stokesb_at_cox.net
Date: 03/06/05 

Date: 6 Mar 2005 14:31:41 -0800

I posted this same problem a few times in the last 3-4 weeks. The set
will not power up. Model #50EX10B. I have checked, replaced, and
checked some more, various components. I have traced a problem to the
system IC0001 and eeprom IC0002. I should have 5 volts at pin #44 of
IC0001 (on/off) circuit, but I have 0 volts. I should have 0 volts at
pin 3,4 of eeprom, but I have 5 volts. I scoped the data lines on the
eeprom, but I don't see any type of data, only steady 5 volts. I am
aware that corrupted eeproms can cause many different problems for a
TV, and am suspecting this as the culprit to all my problems, since
some of the problems are intermittent. The B+ wasn't regulated (198
volts), kept blowing fuse, blew Hot twice, etc. Now the set won't do
any of this. Only relay clicks on/off with power button. Would a faulty
eeprom cause all these problems, including missing the 5 volts on pin
44 of system IC? Anything further I can check/test here before
replacing another component? Thanks a bunch group for all you responses
and help to this point.

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