I cleaned this up, and gave it a drink of oil. The zig-zag was skipping stitches, so I took the bobbin area apart and gave it a good clean. Also replaced the needle. This machine is one of the most quieted machines I have...if I were to compare...I think it sounds a lot like my singer 201-3.
Feet can drop, but the button under the zig-zag width will not budge. I have tried oil but not heat...that will be next. I posted a pic the first day I picked it up but here is another after some TLC.
It is model 764 and reminds me of a 50s car! A quirk, the needle is an extreme left position when in SS mode, thus my 1/4 inch green tape guide on the metal plate. Think I will get some trendy washi tape to replace it.