First of all a belated welcome to GeekHack, and sorry for not mentioning the welcome in my first reply. I personally especially welcome anyone with an interest in PC AT boards, as that's my favorite board myself.
So I hope my comments are taken correctly. Especially being you're new here, I don't want to scare you off or to make you think I'm at all picking on you or simply badmouthing your listing. I would though like to offer my comments to you as constructive criticism, so hopefully in the future you'll be able to get a higher price for your items, etc.
First of all, your picture in your eBay listing is horrible. You really need to take a group of pictures with a proper digital camera. Show the full keyboard top and bottom plus closeups. A closeup of the label on the bottom, a closeup of the problem keys, etc. You may have cleaned up the keyboard very well and it may be in excellent cosmetic shape other than the keys you described, but nobody will ever know it based on your photo that doesn't tell us anything except that it's an AT board. If it's truly an excellent or above average board, proper photos will prove this and people can bid accordingly. Nobody's going to bid extra for a board that you said you cleaned up well but have no real proof of. AT keyboards look great in my opinion and proper photos of a clean board have a lot of "sex appeal".
An AT board with damaged or missing keys in my opinion will likely not sell for more than $40. If you took the same keyboard and fixed it, it would sell for a lot more. I'd guess the price of the same board fixed, compared to broken would be about double. IMHO, putting something in the listing such as "easily fixed" or "easily replaced" is a huge no-no. If it was so easy to do, "why didn't the seller do it himself?" is the first thing I think of. And in the case of an AT board, it might be easy to do for someone who knows keyboards well, and has the spare parts, but for someone who doesn't, it could be quite difficult or impossible. In the case of broken keys, how would one go about repairing them? The answer is that you need to have a spare donor board with the parts to swap, and in the case of the springs, Model M springs are different. Even though it's a very minor part, for most it's not easy to obtain. That's why AT boards with problems are discounted to 50% or more compared to a board without problems - you need to buy two of them to make one complete board. That or you live with a less than fully complete and working board.
You only have two positive feedbacks on eBay. There's obviously nothing you can do about this unless you ask someone else to list the board for you. But just realize that some people won't bid on it, or won't bid very much simply because you don't have a proven track record. This especially holds true for any listing where there's anything remotely questionable about it, such as photos that aren't very clear, or comments about it being easy to fix.
As Ripster mentioned, your shipping is too low. The AT board is heavy and nobody lists them for only $10 shipping. Bump up the shipping a bit and lower the price by a comparable amount. That's what all the other sellers do.
What I'm trying to say as nicely as possible, without trying to sound like I'm trying to bash your listing is that I doubt even at $50 it will sell. Based on my experience, $30-$40 would be about right.
I'd recommend that you leave it as it is though and see if it sells. Sometimes there's people out there that suddenly decide that want something and don't want to wait for the next one to come along, so it might sell. If not, maybe come back and re-list it with some proper pictures and start out even lower. Or offer it for sale here on Geekhack.
Good luck to you! And I hope you're able to get a decent price for it.
