Purchase breaks well within 30 days

The seller is not a dealer. A dealer might take it back to maintain a good working relationship with the purchaser but there is no such benefit for the seller. Patience is a virtue and this is the kind of deal you cut when buying used equipment. 

This doesn't seem to add up compared to the many transactions I have accomplished on this site. The OP's mention of a CC makes me wonder if this was a dealer of some sort (used equipment dealer maybe?) or maybe the OP is talking about PayPal. Also, the OP's discussion of 60 days and then 30 days implies some form of formal trial period, which is rare but not unheard of for used equipment resellers (such as The Music Room). However, that the OP doesn't seem to know if there was a trial period, how long that period was, or the exact terms, supports what has been assumed here, that the "member" the OP purchased from is a private seller.   If the OP is in fact a lawyer, he/she should have a better understanding of the need to review the terms of a deal.  In the future, the OP should probably purchase their gear new to receive the protections offered by working with a dealer.

ethically a refund is not appropriate...it's the chance you take buying used equipment...certainly is difficult with the covid repair delays...even though others have mentioned a refund may be legally possible...

Four to six months seems like a long wait.  I might try to politely talk with someone about the possibility of speeding things up.  Something mentioning it's the best DAC you ever heard and you are anxious to get it going again.

First of all I appreciate all the opinions surprised so many adamant ones.

Neither party is a dealer.

The transaction was not the one in my transaction history.

I have bought a lot of used equipment just not on Audiogon but rather from dealers in the past.

Nothing has ever broken in less than 30 days let alone 6 months.

My point perhaps not properly emphasized was that the repair is not trivial but rather necessitates replacement of the entire board of the dac.

I agree if repair minor of course return not appropriate.

But where repair substantial and will not be completed for 4-6 months and occurred so soon after purchase I would expect seller to be more understanding.

I guess you guys think the deal part of buying it used means you lucky it works at all.

I think its also relevant to consider that this dac purchase was expensive.  The dac sells new for 6K and I bought for 4K and was told its like new.

My expectations are higher if paying a lot and discount was good but not much more than some dealers give for new.

In conclusion I am not demanding anything from seller just expecting more for premium price sale but you guys have calibrated my expectations.  I would have taken back if repair substantial and wait long and premium product advertised as like new.

I will focus purchases from dealers especially now going forward as the prevailing sentiment here seems to be that you got a deal so you lucky it works at all or has a warranty is a bit too cavalier for my taste.