[GreenKeys] What are these odd devices on 28RO

[ad7i]

Greetings --

I have a model 28 RO that came out of an engineering or architectural firm
near NYC about 20+ years ago.  I've run it a couple of times over the
years, but have recently greased and lubricated it again and hope to run it
a lot more.

There are a couple of items under the hood that I don't understand and I
wonder if people here could give me some info about them.

First is a Maintenance switch that's under the lid on the right hand side,
on an aluminum panel.  It looks like there's an AC transformer and other
components behind this panel.  Does anyone know the purpose of this
switch?  Or the function of the electrical components on the back side of
the switch panel?

I don't know if attached photos are allowed, so instead here's a link to
the photo on Dropbox:

https://www.dropbox.com/s/c1y32kg3clkdnyt/m28ro%20switch.jpg?dl=0

Second, there's some sort of a wheel arrangement on the paper roller, on
the left side of the printing mechanism.  Is this some sort of a form-feed
system, or something else?  There a small lever at the bottom of the photo
(see smaller red arrow) that seems to disengage this device, and it has
been disengaged by a small wire that holds the lever down.

https://www.dropbox.com/s/a5f38odydara7z6/m28ro%20wheel.jpg?dl=0

Thanks to all those who can provide some insight into what these things do.

73, Paul, ad7i
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