Hi Larry,
These unit are pretty robust but they can have a minor problems due to contacts.
I have been asked to sell one of mine for a lot more than you are trying to get rid of yours.
Really, it is such a wonderful item I fail to understand why you would part with it especially as you try to design a tape deck of your own and should have one to test your new deck with as well as other test equipment. The fellow I know who may still be looking for one I will ask if he still needs one and send him to this site.