I buy a lot of gear on eBay and the overwhelming majority of sellers are excellent, but every now and then you meet the crooked ones.  This post is to help others avoid getting scammed by two bad sellers: flyxy2015 and 3c_topstore:

1) Seller flyxy2015 sold me a 10MHz OCXO distribution amplifier.  However, the OCXO I received was far off frequency and not within the correctable range.  The seller offered to ship a replacement for the internal Dapu OCXO; I took him up on this and of course what he really did was wait out the eBay return period without ever sending the replacement part.  Scam artists like fly-xy are part of why people are reluctant to use eBay.

2) Another seller (3c_topstore) sold me a scam graphics card.  The card had been altered to appear to be a more expensive card so it sort of worked, but it crashed whenever the driver tried to use the more advanced features or full memory of the card.  It was tricky to figure out what was wrong so by the time I understood the problem, the eBay return period had expired.  Fortunately, PayPal has a longer return period, but they require shipping the card back which would have cost 3c both the shipping and the original price in order for him to get his useless card back.  I thought I’d be a nice guy and offered instead just to split the loss with him…and sure enough, after I’d declined the PayPal return, he went silent and left me stuck with the card.

So in short, a popular eBay scam appears to be to sell you bad product that is either not obviously bad (so it takes you a while to discover it) or to otherwise stall until the return period expires.  eBay needs to do something about this because it is a growing problem that will ultimately hurt their reputation.  Until they figure it out, if you want to avoid crooks, stay away from eBay sellers flyxy and 3c_topstore.

Caveat emptor.