R71A mystery switch and trimmer on bottom

[loss1234]

I bought an ebay R71a off of ebay a couple months ago. It has a few user modifications which I have not been able to figure out the point of. (i have not yet opened up the radio)

on the bottom cover there are a few strange changes:


One is a tiny little switch drilled on the BOTTOM right corner (basically below the PBT/NOTCH knob on the bottom of the plate) the switch says 4 on one side and 5 on the other. when i flip it, nothing SEEMS to change.


Another is a hold drilled in the middle of the bottom plate. down below the hole, I can see a plastic trimmer, and on either side of the trimmer someone wrote with a marker F and S.


Anyone have any idea what these might be?


thanks!

 

[loss1234]

OK

I figured it out by looking more closely at the pictures in the manual. Whoever owned this R71A really took scanning seriously! it seems both these mods effect scanning. One allows control over the SPEED of the scanning, and one allows you to clear Scan at STOP and another allows a timer.


interesting.