Glad you're seeing some racquets. They're really good money if you find the right models.

As for electronics, if I can't test something, or it's old (may have frail parts or broken belts inside), sell is "as is for parts/repair" at a discount. This will give you less revenue, but it'll secure the sale and prevent any losses.

Ask the buyer if they'll keep it for a large discount (try to cover your costs).