[R-390] Is this unusual?

[John Saxon]

Hi...I am dropping the front panel on my 390A.  I am new at this, my first time on the panel, so a bit nervous :-)

I have read the TM and am following Chuck's ER DVD closely.  So I need to remove the mcs knob...easy, right?  Nope.  Couldn't figure it out, couldn't get the setscrew loostened.

As it turns out, I finally realized, after doning my OptiVisor, that the setscrew is NOT a Bristol...someone had substituted an allen screw.  Not only that, it was metric...2 mm.

Is this uncommon?

Cheers,
John
K5ENQ