Crate GT-200 loud hum

[firtree]

Folks,
I've tried to figure this out by looking through earlier posts but I am still stuck. I have a Crate GT-200 Tube/Solid State combo amp that is unusable because it hums (or buzzes) so loud that I can barely hear my guitar over it. It is a little noisey with nothing plugged in, but once I plug a cord into the jack it gets VERY loud. I have included a video that shows what is happening. If you have any advice I would really appreciate it. I would love to be able to use this amp (and it has all new tubes) but right now it is a giant paper weight. Thanks!

https://www.youtube.com/watch?v=oe6LjcAvo5g

[km6xz]

That buzz is as expected if the shield/ground connection was broken at the input jack. First off I would try another guitar cord because the same noise would be heard if the shield connection in the cable or plug on either end has a broken connection. If you have another cord, try that. if not try disconnecting the guitar end and short out the tip and metal barrel of the plug to see it the noise stays the same. If it is still low, remove the short and touch the tip of the plug that normally inserts into the guitar, and touching that tip to a metal chassis part of the amp to see if the noise goes away. I suspect it will. You will need to get into the amp to see if the input jack's ground connection is broken. If the connections around the jack are ok, a thin trace that connects to that input jack to other grounded parts of the circuit. Visual inspection is probably going to find the break.

[firtree]

You nailed it! I found 2 broken solder connections on the input jack/board connection. Now it's running great. Thanks!