What to do when buyer claims sellers item broken?

Man, what a tough situation. I agree with taking it back and filing an insurance claim. The last thing a good seller needs is negative feedback.
I recently sold a CDP I had for 5 months. The buyer informed me the balanced outs were distorted. My pre is only RCA's so I had no way to know of this situation. I immediately refunded his money via paypal and included money to ship it to the manufacturer. I will pay for the repair, have it shipped back to him, then he will pay me the original price. He was a good sport about it as he could have just sent it back to me and bought somebody elses.
Good Luck,
Patrick

I had a similar situation with a pair of speakers I sold a few months ago. Fortunately the repair cost was relatively cheap ($42.00). Because I wanted to protect my feedback rating, I paid the repair bill on the buyer's promise to cooperate with me in attempting to get the money back from UPS. Two months and a small amount of paperwork later, I got a check!

The buyer emailed me and said he already fixed the amps: $150 in parts + free labor. I will have to reimburse the buyer to make him happy with this transaction. I sold the Paraglows with Cobalt transformers, standard transformers, and AVVT 2A3 meshplates for $1325 shipped, net only $1286 after 3% Paypal. I spent $35 on shipping and now $150 for repair, so my net now total $1101. I should have kept the amps!
Link to my Paraglows photos:
http://photos.yahoo.com/bc/pt999/lst?.dir=/Paraglows+2A3&.view=t

Reply email from buyer:
"Thanks for taking the time to look into this problem. Your advice to
contact a competent technician was good. I have been working with electronics for the past 20+ years first teaching and for the past ten years I have been repairing medical lasers.

I was very careful to install the 2A3 tubes with the large cathode pins in the proper holes. After taking the time to examine the amps, I found several problems. On one amp, the 2A3 cathode resistor was open causing excessive voltage across the bypass cap causing it to breakdown. This was the cause of the popping noises.

On the other amp, this same resistor was a high value, 7K versus a
nominal 3K.

I have repaired them both at a cost of about $150 in parts. I used some premium parts but do not feel this is inappropriate. This does not count the cost of my time. I spent the better part of a day repairing them. I do not think it would be possible to get them repaired at this price from a repair shop.

Given what I know about electronics and the condition of these amps, I find it hard to believe that both of these amps were in good condition when they left you. However, I am willing to give you the benefit of the doubt provided you cover my costs for parts. I will throw in the cost of my labor at no charge. You can send it back via Paypal if you wish."

...it seems like the primary reason on defected cathode resistors were bad tubes i.e. old and the amp needed re-tubing real urgent...