JFD Field stregnth meter

[6GH8cowboy]

I found a JFD 7200 Field Stregnth Meter in a Pickers shop and aquired it for the tidy sum of $10. I figured the parts alone would be worth that much if it turned out to be a big fail. When I replaced the batteries it was indeed DOA. However I plinked around with a meter and checked a few things and it turned out to be the meter movement connections were loose on the pcb they were directly screwed to.
Does anyone have a scan of the user manual or tips on use in the real world. I pluged a headset and can hear the digital 'noise' on UHF and audio of the local FM stations on VHF so I believe it's functional. Not nesseraly calibrated at this moment in time.

There was also a lot of antique meters from the 20's on up. These things look like they could measure milliamps or a pound of coldcuts. Big wooden, heavy, old.

Anyway any tips on the 7200?