^in addition, it will cost more than the GPU in question.
Just my two cents:- As someone who has sold GPU's here and bought as well, I would like to say the following, seller reputation is important. GPU is a big ticket item(and as such not a easy item to troubleshoot if things go wrong) and as such be cautious about such purchases insist on certain testing parameters before such a buy, stress testing is an important parameter, and one should get a fair idea about the health of the said card. However its impossible to ascertain why a card fails, I had a 3080ti FE go on me a month back even though I had it in my custody for a year and a half, it was not overclocked, used very little and was cleaned regularly. But when the silicon gods are't with you there is very little you can do. About the daisy chaining, its recommended to use separate connectors, however it shouldn't cause failure, if at all, you can end up with a burnt connector. One thing is a fact here, we don't know what went wrong with the GPU, all else is just guess work and conjecture, the conversation around the rust-it can happen it humid environments, the 3080ti I bought was from a person who was in a coastal area, there was some indications of that on the cooler of the car(slight oxidation on the cooler), but it was very little and I discussed it with the seller. Since I am not from a coastal area, I don't know what environmental factors can come into play, why the rest of the cooler is not in as bad condition is best explained by the seller. GPU temperature are on the higher side but it also depends on other factors like ambient air temp, cooler orientation et al.
I have bought a 3080 FE from a FM here, and it needed to be repasted as well, the memory temps were touching 100 C, there was an issue of pad separation as is a common issue on FE cards. What I am trying to say here is until we know more about what's gone wrong with the card we can't say what happened.
The way the buyer describes it sounds like a short to ground from the card. Most probably from a memory chip, there seems to be no physical damage to explain this, so either the memory or the GPU chip has been reballed and not done properly, or there is a bigger reason to explain the short(I understand the buyer is not near any service centre etc to diagnose the root cause of the issue). Of course if the buyer and seller come to an amicable agreement, it would be a lesson learnt for both.
