Hard to open piano

[kitster@Polarnet.com]

Well, this is slightly embarrassing.  Went to tune an Acrosonic spinet this
morning and couldn't open the top.  This is an older piano, probably early
1950s, with a unique top that folds up just like a table when it's closed.
When it's open, the front folds back on itself and it looks pretty normal.

There are no hinges showing on the back of the piano, leading me to think
the top lifts off, somehow.  I couldn't find any screws, and I tried to
push the top forward and back, thinking it used screwheads in a friction
plate of some kind.  No luck.  

Anyone have experience with a Baldwin of this style?  If the answer is
really simple and will make me look foolish, you might respond privately.

Thanks
Kit Cleworth