tascam 238 problem

[doug deeper]

so my 238 recently started having this problem were no matter what you record into it, and at any level of recording there is a hum that pumps along with the music.
i imagine this is due to the dbx, but im not sure what happened.
anyone have any ideas?

 

[sweetbeats]

Bummer.

1. Does it do it when you have the dbx switched off? Try turning off the dbx and recording something new and playing it back.
   
2. Can you hear the hum if you are just monitoring the input through the 238?
   
3. Does it sound like your typical 60Hz ground hum? If so it might just be a loose ground inside.
   
4. Has the location or setup of the unit changed recently?