Jensen stereo/DVD not powering on

[PrellFamily]

We just got to the campground after getting out Jayco Eagle 5th wheel out of storage. The Jensen stereo system will not power on. All fuses in the camper have been checked. I have pushed the reset button on the system. We have pulled the system out and unplugged and plugged back in. We have not checked power to the unit because we do not have a volt meter with us.
Fyi: my husband did connect the camper battery in reverse , initially , when putting it in at the storage place
Anyone else have a problem getting their Jensen to power on?

[DocBrown]

Might a good time to replace it! Those Jensens are just junk. Better off with a decent branded automotive head unit.

[Jagiven]

Our radio has an inline fuse right before the radio. Did he check it? It is a round glass fuse like the picture shown. Do not recall what size it is, but it is written on the side of the fuse.

[seaswirl]

I just learned by mistake and hooked up the battery in reverse, it blown both 40 amp fuses on the smart converter, and blew the 2 fuses behind the radio