19 Nov
2015
19 Nov
'15
9:24 a.m.
On 11/17/2015 2:03 PM, rod wrote:
Thanks yes they do look similar. I'll download the
data sheet.
What I forgot to explain was the problem is not the switch itself but
the additional part on top into which the two pivot pins locate.
My policy is to produce form factor replacements. In this case the lever
arm.
If they can then be incorporated into other assemblies then good.
Here the lever rotates about a pivot point formed by the two sides of
the additional structure on top.
A missing segment in the lower semi-circular part of the lever engages
with the slide switch and moves it.
So there being no known source of the switch with the extra part on top
and not wanting to change the lever.
What do we do? It would not have been feasible to make the top part and
attach it, as its spring steel.
Its horrible stuff to work with. Pretty much you are limited to die
stamping it in a heavy press.
If the contacts are bad, then, after removal, perhaps you could unfold
the tabs that hold the fiber/phenolic piece with the contacts in it and
then swap that contact piece and maybe the switch post piece, and bend
the tabs back, keeping the original mechanical parts?
JRJ
They would have punched the shape and the holes out
with a hardened die
and then before or after spot welding it to an empty switch body hit it
again with a folding die to bring the sides up.
That would be too expensive to get set up. So I am looking at alternatives.
Rod
On 17/11/15 18:38, Jay Jaeger wrote:
On 11/17/2015 2:34 AM, rod wrote:
Now to the slide switches themselves.
They are mounted by the screw hole lugs having been slid into a groove
in two aluminum bars which in turn are attached to the PCB by pillars
and screws.
There are six connection pins on the bottom of each switch that go into
holes in the PCB. (not all used) Switch replacement would be easy and a
complete switch and lever sub module not too difficult. I hear a voice
from the distant past saying 'Micro switches'
Thats all for to-day
Rod
The ones I have seen (on my PDP-8/L and PDP-12) are simple stock
old-school slide switches (definitely not Micro-Switch switches), that
typically look like this one:
http://www.digikey.com/product-detail/en/GF-1126-1110/SW105-ND/948
(I did *not* check dimensions to see if this particular one is right or
not - there were standard size and miniature versions. But the photo
looks about right).
JRU