Re: Blown amp?
Yes that is correct. However the power must exit the fuse, go through a diode, and provide source to the amp's power supply. A failed solder joint, connection or component between the fuse and power supply could render the unit inoperable. If you find all is functional there, you might consider powering the sub with an external amplifier. One with 100 - 150 watts RMS would surprise you with the performance. All you have to do is remove the amp from the tube and seal the back of it with 1/2 in MDF and a quality adhesive sealant.
"Acoustics is the study of sound; a branch of physics dealing with sound. The law of physics is constantly challenge. Therefore in relation to acoustics; You must study constantly, for you will be constantly challenged." ...... Rainmanspl