When does seller's responsibility end?


I'm sure this has been discussed before, but a search could not find it.
I sold a Naim DAC (mentioning this because Naim is notoriously reliable) to someone on November 26, shipped on November 27, 2012.
Did not hear anything one way or another until December 19, when seller emailed to say one USB input would not work with his ipod. Well the input worked for me when I had it. I asked him to be sure he was doing everything correctly, including checking for bad cable. I am not sure the input really does not work.
No word again until December 25, when he asked if I would pay for repair. I answered no, because I felt the time period had been too long and my responsibility was over.
Now he has initiated a dispute/claim against me on Paypal. They have put my account in the negative for the amount of DAC until they resolve it.
Sorry for the long post, I just wonder if there is a consensus on how long a seller should be responsible for "sold" gear. I say a week, maximum.
What say ye?
Ag insider logo xs@2xmuzikat
Never buy anything without a CC or some type of recource. If the seller won't budge, leave them stuck with the item. There will always be another you can buy.
I think Brownsfan's comments cover things pretty well.
I would add, we all bear some risk when trading (both buying and selling) used goods. That is one reason I state in my ads for more expensive items that I will not trade with those having multiple negative feedback, and request conversation from those with no feedback or with one negative feedback. I think a person's experience and history in buying and selling shine a light on how they may respond when things don't work out perfectly, such as with the USB port. Just because someone has cash doesn't mean I have to trade with them.
As the seller, I would look at two solutions;
1. The buyer pay to ship the unit to an authorized Naim repair facility who can then evaluate it and report back as to whether there is in fact a problem and what repair costs will be. If there is not a problem then you are done. If there is a problem, seller should pay for repairs and shipping so the buyer has a functioning unit.
2. Buyer returns unit for a full refund.
I agree it has taken too long but if you accept PayPal for payment then you are stuck with their rules. These are the risks of trading in used gear. Fortunately, most of those we trade with here are honest and rational about things.
BTW, I failed to mention that the buyer in this case had one negative feedback. I overlooked this when offer was accepted. This is a quote from feedback:

"bad buyer, Accepted the deal and did not pay as promised,after one week waiting, just left a message to notice her financial emergency, and caused me a big loss for the listed item. Do not make the deal with this person."

So I guess it is my fault selling to this person in the first place.
Will have to see how it plays out.
I will definitely state in my future ads the time limit for returns.
BTW, I am not a dealer, just an enthusiast.
That said , Paypal is a different matter . They always side with the Buyer .

Not true. I speak from experience as a seller.
Muzikat, why didn't the buyer go through Audiogon's resolution center? They waited how long and went right to paypal?? Have you been in touch with any staff members? This is extremely fishy behavior on the buyers part for sure.

I have never had an issue here where it could not be resolved quickly. Only recently did I have a problem with a DIY speaker builder but it didn't go through A'gon unfortunetly.