[Milsurplus] RMCA 8506-B Receiver

[brunneraa1p at comcast.net]

My new 8506-B receiver has an interesting challenge: The plastic(?) discs around the controls are slightly cone-shaped.  I think they tried to shrink and were restrained by the bolt in the middle, hence the cone shape. Maybe weight on them will eventually flatten them, but I fear cracking.  Maybe a steam iron?  Any experience here?

Richard Brunner, AA1P