I recently got a Hallicrafters S-38A off of eBay. I know there are some
reccomended steps to do before powering it up but I couldn't resist. I
warmed it up and fiddled with it for a bit and got quite a few stations
including WWV.

Today I was looking in the back and noticed a lot of dead bugs and dust
and stuff so I vacuumed them out with the brush attachment. I plugged it
back in and turned it on and as soon as it warms up now there is an
electrical hum that is very loud. I tried tuning the stations to see if
they came in and they still do but the hum is overpowering the stations
and its like they are modulating the sounds together to make it sound
like a robot type voice.

I am not sure what I did and I am afraid to do anything at this point
since I don't know what is going on.

Does anyone know what happened to this radio and how to fix it?

Thank you,

Ka Nai`a