[Morrow] MB-560 vs MB-560A?

[Colburn]

I now have one of each, but don't see a whole lot of difference.

The "A" appears to have benefited from some improvements to the internal
layout, minor ones by first glance.

There is a layer of thick dust across the top of the inside of both the
MB-560A and the MBR-5.  The bottom sides of both are spotless.

I am thinking of getting some compressed air and blow first from the
bottom and then across the top holding the rigs at an angle -- the goal
of these two efforts to get the dust off without driving it deep into
areas that are clean or deeper into hard-to-clean areas topside.

Suggestions, please?

Also, the white paint on the faces is dulled.  Given the infamous water 
solubility of the dial face I am afraid to try to clean the faceplate.

Suggestions, please?

Despite careful instructions and pleas to pack carefully the seller
stuffed the two rigs, power supply, mic, headset, and cables all
together inside a foam food shipping container inside a large cardboard
box.

Of course the supply with heavy transformers broke loose -- fortunately
it had little room to move.  Minimal damage to the rigs but the sheet
metal base of the supply was bent some, an electrolytic beat up, a
control of some sort on the side bent ... sigh.

The supply base appears homebrew but the layout looks a lot like the
RTS-600 circuit design.  I wonder if the original case was rusted or if
this is a knockoff of the original.  Hmmm.

Lots of work ahead ...

73, doc kd4e