# Toshiba TP55E81 RP STK392-110



## frafreg (May 17, 2017)

Hi folks. I'm a new guy and just need some repair help with a rear projection set that lost the picture. I just replaced both STK392-110 chips on a Toshiba TP55E81 rear projection set that lost the picture. I ordered the chips for $21.95 from electronic-repair-kits because they say they only sell original Sanyo parts. I cleaned the old paste off the heat sinks and applied new paste to both chips. I also checked the resistors to make sure they were within 5% tolerance. I had to replace one 2.2 ohm resistor which was out of tolerance. I got the picture back and the set worked for about an hour. Then, I lost the picture again. I turned it off for a few minutes and turned it back on and the picture came back for a few minutes then I lost the picture again. Now, I can't get the picture to come back. While I did have a picture, I was able to adjust the red and blue convergence to get good center convergence. I was unable to adjust the outer edges where blue was out quite a bit. Is it possible I did not get original Sanyo parts? They looked like the ones I removed and felt about the same weight. Is there some way to tell the difference? Should I try another set of chips? Any help would be appreciated. Thank you in advance. Frank


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## frafreg (May 17, 2017)

Some additional information. The original STK392-110 chips failed the same way but lasted many years.


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## frafreg (May 17, 2017)

With the exception of one 2.2 resistor, all other resistors were tested and in tolerance within 5%. The surrounding resistors were 2.2 ohm and 68 ohm 2 watt metal film.


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## frafreg (May 17, 2017)

I am able to remove and reseat the convergence board PB3366-1 while the set is off and get the picture back for a short period of time. The PB3366-1 plugs into the main convergence board which I believe is referred to as the PB3366-2.


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## frafreg (May 17, 2017)

Any information or troubleshooting and schematic that can be provided would be much appreciated. Thank you.


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