[tab10672]

I would try using a hot air torch to heat your components one at the time until you find an area in the radio that is affected by the heat. You may be able to narrow down your search a little quicker that way. Check your solder joints and also any connections to the chassis (IF cans, tuning condensor, rivets, etc.) that may be loose or not propperly isolated, whichever the case may be.
Dave

I dont think it has anything to do with heat breakdown because you can time the failer to the second and when I would sub a tube it would start the 5 or so min. breakdown time over again even after being off just long enough to replace a tube. I have another chassis I could use but I still need to figure this out for thew next time it could happen.