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
It still amazes me that the US Govt. has not gone after PayPal and FleaBay for their criminal activities. And why do I say that they are criminals? Simple, open your wallet and look at ANY dollar bill of any denomination - it CLEARLY states on the left side of the bill: "This note is legal tender for all debts, public and private"

The fact that FleaBay requires that ALL tansactions be conducted using PayPal as the only form of payment is CLEARLY illegal.

It's very easy to think irrationally when you are angry.
2 dates are important here;

1. the date the DAC arrived to its destination.
2. the date the buyer layed hands on the DAC to test it.

All The Best.
I would say a couple of days from when it showed as being received. If UPS/ FedEx (whomever you used to ship it) has the number of days listed that you are allowed to report hidden damage, then I would say it should be based on that less a day so the seller has time to file a claim. If it truly isn't working now, but was when you shipped it, then it possibly got dropped or somehow mishandled during transit. It would not be fair to the seller to have to eat the cost of repairs when the seller would have missed a chance to file a claim against the shipper. I'm sure there are a dozen more scenarios for why it isn't working now, but this is what popped into my head.
Hopefully, in your case, it is as simple as him not doing something correctly.
When you asked the buyer for the name and phone number of the established repair facility who 1) evaluated the Naim unit, and 2) identified
both the problem and it's cost to repair... what did the buyer say?
Thanks to all.
Sgordon1 that is exactly the problem. Nothing has been diagnosed, nor has any cost of repair been put forth. It is all based on his word to Paypal.
I believe if the USB isn't working it is due to user error.