If I can offer advice regarding the selling of electronics specifically vintage gear, amps, receivers, tape decks, cd players etc that are working not those sold only as parts...
You must include a disclaimer in your listing or the unit's coming back. Too often return shipping outweighs the value of the item. Especially if you shipped it FREE! That hit to send it back is going to really sting.
You must say the" item," (unless it's completely restored) is from "x" year & is "x" years old (It's important to note how old it is). It is original. It is not restored or repaired (to your knowledge). This is very important, you must then say, "it is sold as is as described,"(& do not be so lazy as to not note every blemish, every thing that does or may not work...or it's coming back)
If you haven't tested it do not say you did hoping to score a quick sale. If there is the slightest issue you must mention it. This not only creates trust for this sale but if you regularly sell elecronics it further makes you look trustworthy for future sales. Look at any of my component sales to see how detailed the listing is. However, even then it can still come back to bite you because if what you say IS working doesn't when received & even with no returns ebay will most likely allow a return, or refund. Yes, it's unfair if you say a CD player works only for it to fail & since it's used that should just be the cost of buying a used electronic component & even when you say as I do, (copy & paste this) " no guarantee is made as to how long or how well the unit will continue to work as described because it is not restored but a "x" old component subject to age & wear both of which are beyond my control before & after the sale," it could easily come back or you could be asked to refund even partially.
If you're selling speakers you really should not say they "sound," great. If you have not shown the actual speakers, and yes sometimes the grills may be difficut to remove, you cannot say how nice they sound (sound is subjective) because once the buyer receives them & if they remove the grils & the woofers specifically require new foams or if there are other issues, unless you've said "I HAVE NOT REMOVED THE GRILLS TO INSPECT THE SPEAKER CONES & AS SUCH THEY ARE SOLD AS SHOWN," the buyer can return them.
If you sell refurbished or repaired units it is in your best interest to mention what was. Too often I see descriptions like completely refurbished or repaired...but there's no mention of what was. If I buy that unit based on such a limited description & something blows, it's coming back.
Selling vintage gear is tough because ebay is far too lenient when it comes to returns which should not be the case if you are detailed & thorough in your description.
The unit could be working as described only to have the buyer break it purposely because they're screwing around or think they can repair it or if they damage it accidentally they should own it for doing so but ebay will most likely allow a return or refund. Yes, you should not refund them before the item's returned but unless you can prove the buyer damaged it you will own it. Or worse, the buyer has no real issues, but they're hoping you refund them. They get a full refund & get to keep the item that's working therefore getting it for FREE or to resell.
