Neotec NT-3501 Monitor

[slots]

I have a 37" Neotec NT-3501 monitor that just had a thin vertical line down the center. Cap C426 (1uf 250V) next to the flyback was bad (rubber plug blown out of the bottom of the can). I replaced it and within 10 seconds the new cap exploded. Polarity was correct. Also when I went to discharge the HV there was nothing. Any ideas?

 

[modessitt]

I had a Neotec monitor recently that had different polarity markings on the top and the bottom of the chassis for the same part. See if this cap has that issue. if so, change the polarity orientation to the other marking and see if it still blows up....

 

[slots]

I had a Neotec monitor recently that had different polarity markings on the top and the bottom of the chassis for the same part. See if this cap has that issue. if so, change the polarity orientation to the other marking and see if it still blows up....

Yea. I know there was a problem with that. On this location the markings on the top side of the board are correct. I made sure the the replacement went in the same as the old one. The old one has never been replaced before.

 

[modessitt]

Well, the best way is to follow the traces to find which is connected to the ground trace. That's usually the negative lead...

 

[slots]

Just had a chance to work on this again. Found diode D404 next to the flyback was shorted (this caused C246 to blow) and Capacitor C423 (0.94Uf @400V film) was open. Also had a 470K resistor on the small board that was open. Replaced all of those parts installed a cap kit and also had broken solder joints on the large diode next to C423 and the connector going to the yoke. Now everything is working 100%.