Worth repairing a Velodyne ULD-12 from the 90's?

@russ69 

"I don't think so, not a fan of down facing subs."

I've found that ugly woofers are more esthetically pleasing when they are down facing.

@sdberman 

"Not working" is a pretty broad description.  As @musicfan2349 suggests, refoam kits are very reasonable and CAN be a DYI project if you have a little patience.  If you have a non-working amp, you can send it off for repairs.  Can't imagine this being north of $200, including shipping. (We fix old stuff.  Not looking for additional work, but just a thought on repair costs). If it's not powering up, you might look for a blown fuse?

Sentimental value?  Who can forget "It's so fine, my VEL-O-DYNE?"

Probably not and besides, most all the new subs come with an app that makes setup a breeze.

All the best.

@waytoomuchstuff You mean that multi-purpose spray cleaner or a big block Chevy...?

there is a place in new jersey that fixed my servo board on my uld 18mk2.

https://www.ebcelectronics.com/

I have the ULD-15, a MK I and a MK II. 

On the MK II, the foam fell apart. 

I bought a kit from these guys:

https://www.springfieldspeakerrepair.com/collections/diy-foam-surround-repair-kits

It was far easier to do the repair than I imagined it would be, as the cone tends to just center itself.

It works like new.