Upright Freezer

Hi,
I have Sears upright freezer (model #25321201102) about 6 yrs old. It recently has been giving me problems. The freezer on 2 occasions has been getting allot of frost build up (Within 3 months apart), and the contents would start to melt. After defrosting the second time i notice the outside and top of freezer was getting hot to the touch. I’m running a fan and deflecting it off the wall behind the freezer to cool the compressor and the freezer is working correctly. The freezer i have does not have a fan associated with it. It has a run capacitor and a controller mounted on the compressor. I’m thinking it is one of these components. What does each one do, run-capacitor and controller? Also when the freezer was new after the door was shut, i would here this wooshing or start-up sound. I don’t hear this anymore.
What do you think is wrong with the freezer?

Any help would be greatly appreciated.

Thanks,
Draco