What to do when buyer claims sellers item broken?


I recently sold a Bottlehead Paraglows amp with AVVT 2A3 meshplates on Audiogon. The tubes were triple boxed and shipped separately via USPS Priority insured. The amps bases were shipped separately via Fedex Ground insured. I was very careful with all my packaging. I know these amps work perfectly before I shipped them out. Now the buyer received the amp and the tubes, and claims the tubes glow up then died. This is the first time I have had problem with selling my equipment, and I am not sure what to do here. If the amps and tubes arrived without any visible box damage, how can they be broken? There are minimal circuits in the amps to be broken, especially inside a wood box covered by thick foams and double thickness box. Please understand that I am not saying my buyer is doing anything to it, I just need advice on what to do next to rectify the situation. I don't sell a lemon, and I don't want a negative feedback from any buyer, ever.
PT
pt999
By the way:
Did the buyer send you or faxed you or e-mailed you the parts invoices that he spent the money for?
His responce as from the technical point of view seems to look like a responce from a confident person on that issue, but anywhay it needs to be checked for the "gipsy transaction". Being confident sometimes gives you a power to argue and flirt even if there is nothing to argue about and YOU are in the situation that you have to trust to what the buyer sais(pretty odd isn't it?)

Further on to avoid such situations follow Will's advice firmly.
After thinking about the situation for a day, I finally emailed my buyer offering to pay for the standard parts replacements costs or a refund if he sends the amps back to me in its original conditions. Attached is my email reply:

"I'm glad to find out that you are the competent technician for the repair job.

From what I understand, on one amp a resistor is open, on the other, the resistor was of wrong value. So the fix is to solder the open resistor on one amp and replace the wrong value resistor in the other. I can understand that the shipping process can cause a soldier joint to come loose causing the popping noise. I bought these amps preassembled, the wrong resistor can only happened at two places, either Doc B. put the wrong value in the kit when he shipped it out, or the previous technicians error in assembly.

As for the parts upgrade, I find that it is not fair to ask me to pay for the upgrades in place of the originals. It is fair to pay for the standard parts replacements as Doc B. would have included in his kit.

Used equipments are sold as is, that's why they are advertised as used, and the buyers save money buying them used, at the risks of no long term warranty or support. I do my best to describe my used equipment and provide the buyers with plenty of photos to describe its conditions as well as packaging. During my 2 years of using the Paraglows, I have not noticed obvious popping noises or any other side effects. If you think these amps are not in good conditions when I sold them to you, you can packed them up and send them back to me tomorrow in its original conditions for a refund."
PT
Good for you PT999 on your email reply. It is very fair of you. I do not think you should have to pay for Upgraded parts . If the original parts were bad then replace them with the same parts as they were sold with. Anything over that price as upgraded parts is not your responsibility but that of the buyer if he so choses the upgraded parts. It sounds to me like someone is trying to get away with upgrades at your expense.
Buyer should ask before he does work. Something smells a little funny. Bishopwill is a little off with his "as is" comment. I can assure you I would never buy a piece with that disclaimer. I have bought and sold hundreds of pieces of audio gear and 95% + If it worked when it left it worked when it arrived. Also be fair if a piece is a little shaky before it ships UPS can usually finish it off with a bump or two.FYI I think you may be able to save the pay pal fee with the Paypal refund option. Try to work it out either way and move on to the next piece. Remember it's all about the music!
Weiserb makes some good points but I stand by my guns. The responsibility of the seller is limited to communicating accurately and honestly to the buyer the condition and the performance of the equipment. No one can predict when a fault will occur--oh, that we only could!--so the notion that the buyer is entitled to make his own assessment and decide that the equipment is or isn't "good enough." is pretty fallacious.

As my friend Moe, the pawnshop owner, says, "You buy it, you bought it, baby." So long as the seller is ethical and honest, there is absolutely nothing inappropriate about that way of doing business.

I readily admit that I would LOVE to have the privilege to evaluate equipment and shove it back to the buyer if I didn't like it or it didn't perform the way I think it should. But to get that option, I go to a dealer and pay retail.

I fear that if Weiserb can't live with "as is, where is" we just will have to agree to be friends but not do business with each other. On the other hand, should I ever buy from him, I won't hold him responsible for anything other than honesty and accuracy.

I agree with one point, for sure: It's all about the music.

will