Take the back off and look for a small suction cup on the back of the tube. Attached to it should be a wire. Follow the wire to a gray box (maybe on the right side). This is the tripler. Look for any dark spots where it is burned through. This would tell you for sure if it is bad. If the tripler looks good, try powering it up again (although I don't recommend it), and see if you smell smoke from it. If you need a replacement, the part number might start with 212-. Try Moyer Electronics. You may have to call them with the part number so they could match it up. The part might be hard to find on their website.
http://www.moyerelectronics.com/Depa...-TV-Parts.aspx