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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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Hitachi shut down
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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