Space War /s keyswitch solution

I am planning to produce a new webpage on my site on this
topic but I wanted to mention this asap in case it will help
anyone who owns a VB Space War or Cine Space Wars machine
that has some buttons that don't work.

I saw an online store not long ago that was selling
individual NOS keyswitches for $25 each (or more). Unless
you are missing the entire button (or the cap) or your
button has badly cracked plastic parts, I can't see paying
this much. You could buy an entire control panel on eBay
for about the same price as one keyswitch from that store
although granted maybe not on demand.

Anyway, here's the thing. After I got my Space War, I
noticed that one button stopped working. I assumed it was a
bad reed switch and I swapped it out with a switch from an
old control panel. I started playing with the original reed
switch on my bench and it worked okay so I started wondering
what the heck the issue could've been. A few months later,
another button stopped working. I decided to disassemble
all of the keyswitches on my spare control panel and compare
them. I also looked at photos of the switch parts on other
people's pages. I found that what they all had in common
was that they all were made with two little split-ring
magnets. The magnets are super cheap material, sort of like
a fridge magnet that was chopped into little strips and
curled into a circle and then piled two-up to create a
strong enough magnetic field to operate the reed switch.
After 30+ years, these little rings have almost zero
magnetism left in them.

I measured the original magnets and I had a batch of 100
custom Nicke-plated Neodinium ring magnets made. They're
actually a bit too strong for the application (but new &
less sensitive reeds would compensate for that) but you only
have to install one magnet, not two. They fit the switch
plunger perfectly and they work great. I've sourced a new
compatible reed switch from Digikey. I was thinking of
selling the magnets and switches as kits if there is any
interest. I won't be making money off of these but maybe
it'll restore some functionality to some machines out there.
 I had the magnets made because I wanted an exact
replacement and I didn't want to hack the game by installing
leaf switches or something like that. Since I had my
control panel out and on the bench, I just replaced all of
the magnets at once. The reeds were all fine. I suspect
that a lot of people end up swapping or replacing the reeds
even though it's more than likely that the magnets are the
root cause of failure. They are so marginal due to age that
some reeds will work and some won't. A critical factor is
the precise depth at which the center contacts of the reed
are installed. If the reed is slightly too far in or out,
it won't work properly no matter what else you do.
Pre-forming the leads precisely is very important. I'll
probably make a little assembly drawing and post it as a pdf
on my site at a later date.

If anyone needs some of these custom magnets, please email
me directly.

Bill Boucher
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Received on Fri Oct 2 10:35:16 2009