Friden EC-130 Help

A friend of mine gave me a Friden EC-130. It's in pretty good shape, though it's missing quite a number of screws, as well as the bottom plate. Pictures here: http://imgur.com/a/OjxCn As you can see from the pictures, I don't get any distinguishable digits on the CRT. Thankfully, most of the logic does seem to be working; entering too many digits before the decimal place as set by the rotary switch results in an overflow upon hitting enter. Entering thirteen 9s and dividing by 1 takes about 2 seconds (the button stays depressed; quite cool), whereas simple adding and subtracting returns the result right away. Keyboard feels good, and you can see the CRT modulate differently depending on what's to be displayed. I've tried the obvious thing of reseating boards and rotating the pots back and forth a bit, to no avail. My understanding is that schematics are not available for the unit. Is that still correct? It wouldn't be a hard unit to reverse engineer; it's just a whole lot of components. If anyone has any advice to offer, it would be much appreciated. Thanks, Kyle