Front Panel Update A and B panels

Bob Rosenbloom bobalan at
Wed Jun 24 16:28:40 CDT 2015

On Wednesday, June 24, 2015 1:35 PM, Vincent Slyngstad <v.slyngstad at> wrote:


 From: Paul Birke: Tuesday, June 23, 2015 10:59 PM
> Can anyone recommend suitable rotary switches for either the A (vertical)
> or B (angled) configuration?

Unfortunately I don't have any leads on a modern equivalent.
(Just the fairly useless DEC part numbers.)

The construction is dead simple, though.  Essentially, mine are 
a set of reed switches mounted at 36 degree intervals, a couple 
of end plates, and a central shaft with a magnet on it.  Some 
detents which make the shaft tend to want to stay where you 
put it.  The newer ones presumably used an angle of 30 degrees 
instead of 36.

It's probably achievable to create something with a 3D printer 
and some modern reed switches that would fit the original form


My 8/e had the reed switched based one which had broken reeds and a weak magnet.I replaced the reeds with small one found on ebay and also the magnet to get it working.It has a sloppy feel to it.
My 8/m has a mechanical switch. It has a much nicer feel than the reed based one.Probably the different way the panels are marked is because of these two ways of makinga rotary switch.
I have no idea why DEC made their own switch out of the reeds. Seems like it would cost more than a standard switch so they probably had a reason. Possibly they thought it would not wear as much with thereeds having millions of operations rating.

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