I find out that if you buy a tuner or whatever on e-bay and open it up to put a tube or light bulb in , you have cancelled all your rights to return it......I buy a McIntosh tuner , open it up to replace the light bulbs and notice that my purchase is a piece of junk, I contact the seller and tell them I either need a adjustment or I need to return this........After 15 e-mails with the seller and e-bay about this I am informed that if I take the cover off I am a owner no mater what it looks like inside.......So be careful what you do if you want to return something.........ANOTHER INTERNET LESSON 
Did you use paypal or a CC? Your CC Co makes the final decision if you state that the item is not as described.
I actually used Pay-Pal and I have been thinking of taking it up with them......I've always had good luck with Pay-Pal on bad deals.....E-bay doesn't let you use Pay-Pal resolution if it is a e-bay purchase.....At least I couldn't go in to Pay-Pal for this....
Since you decided to fool with it you should own it. Ebay is correct with this rule. Next time keep your paws off!
Wise up ebay is a bunch crap you pay crap prices you get garbadge wake up!!!
Paypal and Ebay are the same company. Neither company has your best interest in mind.

Its time to lie. Call them back and speak to a different rep. Just say it doesn't work and leave it at that. If they bring up a prior conversation, tell them you never opened it. No matter what they say, stick to the story.
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I have to admit that I buy a lot of music(CD's) on Ebay and my experience has been very positive. I usually buy new, unopened CD's but really, they have been great. I think you just have to understand what you're buying and you can always send the owner questions.
In my recent experience Ebay sides with the buyer. As a seller whenever a return request is done Ebay will do everything for the buyer. I got left negative feedback without any chance to defend myself. When a return request was opened up they refunded the jerk their money without any hesitation.

In your case I think you just need to open a return request and state that the product didn't match the sellers description.  You had to open up the electronics to verify condition. Buyers are fully protected by Ebay not the seller.
......I buy a McIntosh tuner , open it up to replace the light bulbs and notice that my purchase is a piece of junk

I am not sure I understand, was the unit not in original condition?  Someone removed the original parts or something? 

If you simply think the unit is a piece of junk and it is in the original factory condition then that is a manufacturers issue not the sellers issue.  If you open it up to make changes from the factory condition then you own it.  How would the seller know that what you did had no change on the unit?

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I don’t know about the US, but here in Australia, once you’ve lodged a Paypal dispute, you effectively freeze the sellers Paypal account, so he can’t use it, this get things rolling/sorted very fast as sellers need their Paypal accounts working.

Also if you let eBay or Paypal know that you’ve opened or dismantle any purchase, you loose any comeback rights on it. Best of keeping it to your self, and if you or anyone didn’t sign for it on delivery, you say you never ever received it, that fixes the p****k who sold it to you as ebay gives you an auto full refund, I believe from his account.

Cheers George
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The tuner looked fine on the out-side , but when I removed the covers it was all caroded from salt on the inside......The chassis was a green color.......That is where the problem is.......
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After spending some time with this tuner, I think that it will become a shop tuner on my work-bench and I will move on to something more productive.....Maybe work on my K-Horns or a couple amps I have orders for.......And listen to music........
Is this a vintage Mac tuner?  If so, it may come down to one's expectations of reasonable physical condition of a vintage unrestored item.  Does the tuner work?
Ones expectations of anything is relative, and I'm not sure if what one pays for something is relevant either....To answer your other questions, it does play nicely and looks pretty good, maybe that is all I can respect for 450.00.......I think given enough information would have helped if the seller knew what information to give.............Sometimes we assume too much from people that are not versed in HI-FI...........  
" Ones expectations of anything is relative, and I'm not sure if what one pays for something is relevant either."

Its relevant because they can use it as an excuse not to pay. They're argument will be that you paid too much for the item and they shouldn't have to pay for your mistake.
I stopped selling on Ebay because the rules are so skewed towards buyers. It plays nicely and looks good. That is all you should expect with a vintage piece on Ebay unless the seller mentioned it was refurbished or serviced. It is your responsibility to clarify the internal condition and ask the seller to for internal pics. If he refuses, don’t bid. Ebay is treating sellers as if they are Amazon and forces them to accept returns no matter what the situation.
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Schubert, I guess the only difference is there are still plenty of decent folks on Audiogon.  People on Ebay buy electronics, rob the parts they need and then initiate a return.  Sometimes, they break it on purpose to return the item.  That is what happened to me.  
" How is that different from here ? "

Amazon is a much safer place to buy from than ebay. Amazon sells merchandise directly to customers, and they also let independent business sell goods using they're system. You usually don't have any issues with Amazon's products, but with independent sellers, that's not always the case. What makes them a safe place to shop, is Amazons A-Z policy/system. When you file an A-Z claim, the issue gets resolved in a short amount of time. They don't play games. Amazon is one of the only companies that understands the value of a customer. If there's a problem, they want to know about it, and they want to make it right.

I would think you knew about this Schubert. They have a huge amount of your CD's for sale.
I thought everybody in world knew that, About like saying  Micky Mac sells hamburgers. Redundant .
Schubart, maybe everybody isn't as smart as you, I'm not going to spend a lot of time learning something that they will change in the near future to  suit there situation...........They sure don't care about mine.........
Change can be fast or it can be slow.
 Only sure thing for  humans in that equation is if you ain't getting better you are getting worse .
Ebay is a buyers market with very little protection for sellers.
Buyers remorse is no problem for a buyer...just come up with an excuse and the seller will have to accommodate so as to protect his rating.
Here`s a good story if you like bad endings.
I sold a nice Adcom 555 on Ebay. Right after the amp sold, the buyer asks me if I knew where he can get HIS repaired (said he had the same exact amp). Straight off the flags are going up.
I immediately inform both Ebay and PayPal that I`m concerned that the buyer will simply harvest the parts he needs then claim the amp didn`t work on arrival.
I explained that some parts are only available via another donor.
Both sides (Ebay/Paypal) said "we got your back"
Well guess what, the amp arrived with a "channel out" according the buyer.
Contacted Ebay and Paypal...To no avail. I had to take it back.

When I got it back it was obvious the top plate had been off. I Had to take my now broken amp back, refund him the entire amount AND pay the return shipping.
On top of that I had to pay Ebay their  selling fees because I contested it !!!   
And check this:
 Ebay told me that he could have sent me back a box of rocks and I would have no way to prove he didn`t send me back my amp.
She said it would be a  your word vs his and blah blah blah...
Ebay protects themselves.

Not everyone on eBay is a bad guy although there are plenty of them out there.

When you buy something from me on eBay, if you are in any way unhappy, I will make it right. If it involves returning the item, I would offer a complete refund, pay for shipping both ways and apologize for the inconvenience I've caused, whether eBay would make me do it or not. As it should be.
I have made plenty of great purchases and sold many items on eBay and have been a member for almost 20 years with over 400 transactions and 100% feedback.

To say things on eBay are crap just shows ignorance. You have to look at the seller’s feedback and do your research. Ask questions before buying that way it is logged as part of the sale.

I’m happy with my like new Macintosh C48 Preamp, Auralic Vega DAC, and Auralic Merack Mono block amplifiers I bought on eBay in the last two months. Again, I've been buying and selling for almost 20 years without one bad experience. ASK lots of questions!
Let me say this, I have been on e-bay for twenty years , I have 3000 100% feed-backs , I pend over 50,000.00 a year on e-bay so I know something about this.....The biggest trouble with e-bay is its not consistent with its rules, one day its one thing and the next day its something else.......Its nice to have good rules that are not forever changing.........Some people don't buy enough stuff to run into problems.......So there view point isn't as relevant as high volume buyers, most of the buyers and sellers on e-bay have no idea what they are doing......
I also no longer sell on eBay due to the way eBay treats it's sellers. My buyer was ticked the marantz he bought didn't come with a remote, despite the add specifically listing what came with the sale. So my buyer demanded to return and when I refused he broke the unit denting in the top and claimed it didn't work, even after admitting to me that it worked, and I got screwed. EBay's buyer protection pays the seller back out of eBay's pocket and then they take the money right out of the PayPal account of the seller. And if it's no longer in the account, they send you to there collections dept. I always thought eBay tried to resolve cases with fairness, but it's clear that it's a buyers world on eBay. You can also see this in the quality items listed on eBay, it's not like it used to be, it's mostly crap. Nor like it was years ago, smart sellers no longer sell there.
Autospec, sorry about your situation, but it could be possible that the seller himself didn't know how the inside of this unit looked, only that it powered up and seemed to perform properly.
As a buyer I know just how much both ebay and paypal side with protecting the buyer. About a year ago I bought a set of speakers from a seller in CA; I closed the sale on paypal and chose to drive out, several hundred miles, to pick up the speakers. on my way out I received a call from the seller asking if I could bring cash as he was informed by paypal that funds would be held up to 20 days. I explained that I couldn't do that as the money had already been pulled from my account but that I would contact paypal as the buyer as soon as we met and I picked up the speakers and was satisfied they were as described. The speakers looked very good and the seller seemed like s good and sincere person so I called paypal service and spoke to a rep who explained that payment could be expedited as soon as I returned, was satisfied with the sale and confirmed receipt and satisfaction with ebay. That satisfied the seller so I returned home with the speakers, set them up and they performed very well as promised. I promptly posted a confirmation with ebay and left positive feed back thinking the sellers funds would promptly be available - Wrong! I got a call from seller 3 days later telling me that funds were still being held. After me calling paypal, confirming
my account and letting them know I was completely satisfied with the purchase and had confirmed receipt and left positive feedback with ebay, it still took another 10 days and two more calls to paypal for a very good seller to get his funds, even though they had been held from my account instantly on first day of sale.