Vintage Hewlett Packard Model 608D VHF Signal Generator

Description

This is a Hewlett Packard VHF Signal Generator Model 608D .  It powers up.  In the last photo, thru the vents, you can see the inside tubes do light up.  When you turn the Module Selector knob, the Megacycle meter responds, so this machine is in at least some working order.   Please advise me thru eBay what other tests can be done.
Measures 20 inches by 12 and a half inches by 16 inches.
Local pickup only.   I don't have to tell you, this bad boy is heavy!
If long distance buyer wishes to arrange delivery, that is fine.