'50 mercury radio stops working after a few mins

[jbivy]

So another car guy i know just had his radio rebuilt for 350 bucks... It worked for 30 mins and then didnt play. Now it only works for several minutes after turning on.

He asked me to take a look at it. I figured i can test the tubes, go through it with the photofact and see if theres anything obviously wrong.

So ive two questions.

What should i be looking for?

whats an easy way to power this on my stand? Perhaps a 6 volt lantern battery?