Problems With Fender Super Sonic

[fico123]

Today my amp started making high pitch noise when reverb was on. I disconnected guitar and amp was still making high pitch noise. Here it's video of my problem. What should I do?
Thank you for help.

http://www.youtube.com/watch?v=wJcylRq5GJo

[Structo]

First thing with a tube amp is check the tubes.
If you don't have a tube tester, take known good tubes of the same type and substitute it in each location, then try the amp.

I am not familiar with that amp but since it seems to be in the reverb circuit, try a good tube in that location.

[Tubetastic]

I'd also look at how tight the reverb pan is in the bag. If its too tight, it'll feedback.