[Hammarlund] Disassembling SP-600 Question

[DJED1 at aol.com]

I'm disassembling and cleaning my SP-600 and have a trivial  question:   I've 
unscrewed the top cover on the tuning unit (where the  nameplate is located) 
but am having trouble getting it off.  Should it come  off or am I missing 
something?  Maybe it just needs a tap from a big  hammer?  I'm going to clean and 
lube all the gears while it is apart.
Ed  WB2LHI