What Freddie said is spot on. You probably are reading what I said wrong. Nobody is blaming you Nikonfoo, you are most likely a victim here. What I'm saying is that based on what I know from what I've read here on this thread (and you obviously know more than I since you are directly involved), based on the other members responses here, at least 1 who seem to already have experience with this fella, based on this buyer's responses to you, and based on 15 years of eBay buying/selling experience, it seems to me that this particular buyer appears to know how to work the system and appears to be trying to extort whatever he can, from you as an international seller. Since eBay now requires sellers to pay return shipping (in the past, this was not the case) on items considered damaged or faulty, this will hit international sellers much harder than domestic sellers. Ergo, claiming the item is faulty means it is far more likely you will settle and eat a huge loss rather than accept a return. An unscrupulous buyer will bank on this. In fact, that appears to be exactly what he is doing. What I've observed is that he won't provide any details on the problem, does not show pictures of any actual damage, refuses to investigate the source of the noise, claims he doesn't know about these things, yet his history shows he deals with lots of electronic goods selling or buying, and he files return claim thinking that you won't accept and will just refund his money but to his suprise you did accept a return ruining his plans making him scramble to salvage the sale (he obviously still wanted it). So if he wanted it that bad, why ask for a return? The only reasonable conclusion is that there either is nothing wrong with the boombox (pictures seems to show it working), or whatever is wrong is minor and he planned to fix it all along, and wants to keep it but wants to extort as much as he can to get it as close to free as possible.
(IF IT WAS ME), after I've come to this conclusion, I would not negotiate with him. Providing him a return shipping label is easy and is good because it puts YOU in control of where it goes and what type of shipping service to use. eBay does not care where it goes, they will only track the item and when tracking shows it delivered, they will consider item returned, wherever it went doesn't matter. I would not have offered him one cent to ship it to whomever or wherever else I wanted it to go... that would've been none of his business. Now, when I stated that I would've offered $50 take/leave it offer, that served 2 purposes. It allowed him, as a scammer to accept a smaller refund but still have a scam victory, and allowed you to take a small but reasonable and minimal loss. Knowing that he wanted to keep the box, I bet you he would have taken a $50 off deal. The reason I said "out of principle" is because eBay does not protect sellers, they protect, enables, and even encourages unscrupulous buyers. I would say a small segment of eBay users does the majority of the scamming, whether on the buying or selling side. Large sellers take bad buyers into consideration and treats these transactions as "the cost of doing business" on eBay. For small and caring sellers like boombox enthusiasts, we have small volume take these transactions personally. That you had to run into and encounter this buyer is your misfortune. I personally do not want this buyer to claim a scam victory over me so I'd rather lose out on the shipping costs than to enable his continued behaviour. But again, this is ME and not you. What you should do is simply whatever you feel comfortable with. If you choose the less costly route, then this is exactly what scam buyers are counting on since the simple fact of claiming an item is faulty will mean you AUTOMATICALLY lose some money, and they are counting on you to take the least costly method by refunding him money, which is less than the high cost of international return shipping.
You are correct, I did state in other threads that you can not automatically villify every buyer as a scam artist, nor can you automatically write off every seller as dishonest and misrepresents their items. You need to consider what you know and in this case, there seems to be enough hints to make a reasonable decision. Sometimes, you might decide wrong, but no matter what, you do need to decide when you are pushed into it. With a case filed against you, you were forced to make a decision. By putting this before us, I presume you were asking for our feedback into this. But this does not mean that you need to abide by any opinion or consensus, that's for you to decide what to do. Still what I mentioned was what I personally would've done based on what I've read and know. Doesn't mean that I'm right, but in this case, I would've felt good about what I believe in my gut was a buyer who wanted to take advantage of the system and a $50 offer would've been fair.
Anyhow, you've already resolved this so it's all moot. Might as well forget about it now and put this behind you. For your own peace of mind, I suggest you block this buyer from bidding on any future auctions or you may regret it. I have already blocked him and am more than happy to live with lower selling prices due to less bidders. As least I sleep better.