Tom's Hardware > Forum > Home Theatre > HDTV > 57H81 Toshiba Rear projection insanity

57H81 Toshiba Rear projection insanity

Forum Home Theatre : HDTV - 57H81 Toshiba Rear projection insanity

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A few weeks ago, my 57H81 RPTV stopped working.
It gave me the old red blinking light trick I heard the high voltage kick in, but no picture.

I replaced the convergence ICs (Originally STK 392-110's but I put in STK 394-250's) as that is usually the problem with this set.
There was no change.

At this point I am not sure if there was high voltage anymore.

I then noticed two blown fuses on the +16V and -16V rails of the main transformer.

I replaced them with 5A slo-blow's.

the blinking light stopped at this point and now gives a steady red light but there is no high voltage or picture

I replaced the largest Horizontal output transistor, this did not do the trick.

I then replaced the flyback transformer, again no change

the slo blow blew after the set was "on" for while, so I also replaced the vertical transistor

I have been measuring the voltages off of the +/-16V rail and the + has 5 volts on it all times from the standby 5V supply. The -16V jumps to ~-5? I don't have the proper equipment to take a measurement that fast. I then hear a quiet quiet click (not the power relay) then the -~5V goes to 0. The resistance from 16V to gnd is 1.4 ohms when the convergence yokes are plugged in, then it goes to 60 ohms when they are not plugged.

the flyback transformer is getting voltages in upwards of 150 volts to its inputs

At this point I am pretty sure the problem lays somewhere within the horizontal circuitry, what would be some recommendations? I'm going crazy here

Tell me if you want to look at the schematics, I have them

thanks
-nick

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