The problem is, it sounds like it is an easily fixed problem, but a listing is going to read… does not work, and taking someone’s word that this is all it needs, well no one is going for that… making the value small.
The only way I can see getting a significant value out of it fixing it. Sounds like it might be only an hour of work. You find the info on line and order everything on line in minutes. Or making a deal with a local electronics store to fix and sell, or a friend to fix, then you sell.
If you apply yourself, you may be able to spend less time fixing than reading here. Upscale audio, or the tube store can supply tubes… what happened to your old ones? CJ should have a manual on line.