27 Dec
2005
27 Dec
'05
7:35 p.m.
The SOL-20 has powered up, but the keyboard is sorta FUBARed. The
LEDs work, but none of the keys do. I pulled the keyboard, and shorted
a couple row & column drivers, and the keystrobe strobed. I ended up
removing the PCB from the key assembly, and determined that pads inside
the keys are shot to hell.
They look like they should be mylar coated or silvered Kapton discs
with a foam backing. The foam is mostly decayed, and there's virtually
no silvering left on any of the discs. They few that do have only the
slightest fragments. I assume this is supposed to be conductive,
because pressing a disc against the PCB pads doesn't trigger a key,
while touching the PCB with my finger does.
Can these be rebuilt, or are replacement switches available?
--jc
27 Dec
27 Dec
10:30 p.m.
They look like they should be mylar coated or silvered Kapton discs
with a foam backing. The foam is mostly decayed, and there's
virtually no silvering left on any of the discs. They few that do
have only the slightest fragments. I assume this is supposed to be
conductive, because pressing a disc against the PCB pads doesn't
trigger a key, while touching the PCB with my finger does.
Can these be rebuilt, or are replacement switches available?
They are capacitive, not conductive. i.e. you should not short the PCB
pads. They can be rebuilt, either by homemade pads or
, if you can find them, replacement pads. Google for sol20 keyboard.
Jos Dreesen
28 Dec
28 Dec
10:59 a.m.
They look like they should be mylar coated or
silvered Kapton discs
with a foam backing. The foam is mostly decayed, and there's virtually
no silvering left on any of the discs. They few that do have only the
This sounds like a Keytronics capacitive keyboard. The disks are
assembled silver-side up (away from the PCB), they don't actually make
contact. But when you press a key, the conductive metal on the disk
increases the capacitance between the 2 pads on the PCB.
Failure of these assemblies is, alas, well known. There are 2 problems --
the first is that he foam decays, the second is that the metalisation
goes. It looks like you've got both at once.
At one time you could buy replacement disk/foam assemblies and they were
quite cheap. Then the price skyrocketed, then they became, I believe,
unavailable. Pity, as I need to re-do a PERQ keyboard sometime soon (same
design).
-tony
4:59 p.m.
The following site seems to think that you can use junker Sun 4 keyboards
for parts:
http://www.thebattles.net/sol20/keyboard.html
--Chuck
6:04 p.m.
Yea, been there. I actually managed to order the pads and a couple
switch assemblies from Mike Stephens at Mil-Key. He's not a happy
camper. Apparently he's had a number of requests from SOL owners
looking for pads. He was saying the big problem is the people calling
him don't want to spend any money, and it was costing him to deal with
them/us.
At one time Keytronics was selling pads for $0.10. I don't know
what others were paying from Mike, but I bought 260 pads at $0.35, plus
10 keyswitch assemblies at $2/ea. He wasn't willing to sell me the pads
until I told him the quantity I was willing to take.
According to him, the pads aren't made anymore. I imagine he has
quite a few thousand in stock, though, since they're still making or
repairing keyboards that use these pads. I found this article, <URL:
http://www.spokanejournal.com/index.php?id=article&sub=598 > that
mentions him. He's a 20 year veteran of Keytronic.
From the way he was talking, and his tone of voice, I think this may
have been his final sale of pads, or at least at the price I paid.
Oh, and I checked eBay for Sun Type 4 keyboards, and found two hits,
both way more than I was willing to pay for 10 year old keyboards in
unknown shape. Maybe someone else has an "in" to type 4 keyboards. If
they were cheap, I'd buy a dozen, just to stash them for the benefit of
other SOLsters.
--jc
Chuck Guzis wrote:
The following site seems to think that you can use
junker Sun 4 keyboards
for parts:
http://www.thebattles.net/sol20/keyboard.html
--Chuck
6:29 p.m.
What bothers me about the aspect of replacing those little foam pads is
that unless you're a stickler for authenticity, it's a pretty safe bet that
they're going to need replacing again, particularly if you live in an urban
area with high ambient ozone levels.
Cheers,
Chuck
29 Dec
29 Dec
4:20 a.m.
The following site seems to think that you can use junker Sun 4 keyboards
for parts:
Keytronics keyboards turn up on all sorts of machines (I've come across
them on PERQ 2's, Apricots, Tekky workstations, etc). And from what I've
seen the mylar/foam disk assemblies are all the same size
However, these parts decay naturally, whether the keyboard has been used
or not. I'd be a bit careful about spending money on an old keyboard to
get them. They may well be useless, or fail again in a short time.
-tony
2:12 p.m.
On Thu, 29 Dec 2005 12:20:28 +0000 (GMT)
ard at p850ug1.demon.co.uk (Tony Duell) wrote:
Also, it could turn into a scene of enthusiasts for one type of
machine butchering the last extant keyboard for some other
hard-to-find machine for these components.
Someone needs to come up with a solution using current available
materials.
The following site seems to think that you can use junker Sun 4 keyboards
for parts:
Keytronics keyboards turn up on all sorts of machines (I've come across
them on PERQ 2's, Apricots, Tekky workstations, etc). And from what I've
seen the mylar/foam disk assemblies are all the same size
However, these parts decay naturally, whether the keyboard has been used
or not. I'd be a bit careful about spending money on an old keyboard to
get them. They may well be useless, or fail again in a short time.
-tony
2:41 p.m.
I'm not familiar with the SOL-20 keyboard. Is the output scan-code or
ASCII?
It's still possible to find some really nice Hall-effect ASCII keyboards on
the surplus market. It wouldn't be "authentic", but it might work.
Cheers,
Chuck
3:16 p.m.
It's ASCII, but with a couple extra signals for reset and "local".
There are a couple extended keycodes (>= 0x80) for load, mode select,
the arrow keys, home cursor, and clear.
It would be very easy to add a keymapping table to my KeyMapper
project so that a PS/2 keyboard could be used. It might even be
possible to find a keyboard that would fit into the cut-out, with a
little creative work.
--jc
Chuck Guzis wrote:
I'm not familiar with the SOL-20 keyboard. Is the
output scan-code or
ASCII?
It's still possible to find some really nice Hall-effect ASCII keyboards on
the surplus market. It wouldn't be "authentic", but it might work.
Cheers,
Chuck
3:29 p.m.
Also, it could turn into a scene of enthusiasts for
one type of
machine butchering the last extant keyboard for some other
hard-to-find machine for these components.
This is another problem. And even though I am a PERQ-fanatic and would do
almost anything to keep my PERQs running, I really don't want to have to
ruin another rare machine to do so (now a PC clone keyboard is another
matter...)
To tie in to the collecting-ICs thread, the current issue of Elektor (at
least in the UK) has a meniton of rare ICs and the fact that some people
collect them. It also says they don't know of any major commercial unit
that contained the 8008. Many of us here, I am sure, know of such a
device, but I am not going to write in to tell them because I'd rather
those machines carried on computing _with a working frontpanel_.
Someone needs to come up with a solution using current available
materials.
Agreed...
-tony
28 Dec
28 Dec
6:41 p.m.
--- "J.C. Wren" <jcwren at jcwren.com> wrote:
The SOL-20 has powered up, but the keyboard is
sorta FUBARed. The
LEDs work, but none of the keys do. I pulled the
keyboard, and shorted
a couple row & column drivers, and the keystrobe
strobed. I ended up
removing the PCB from the key assembly, and
determined that pads inside
the keys are shot to hell.
They look like they should be mylar coated or
silvered Kapton discs
with a foam backing. The foam is mostly decayed,
and there's virtually
no silvering left on any of the discs. They few
that do have only the
slightest fragments. I assume this is supposed to
be conductive,
because pressing a disc against the PCB pads doesn't
trigger a key,
while touching the PCB with my finger does.
Can these be rebuilt, or are replacement
switches available?
JC, please see my web page on the subject:
http://www.thebattles.net/sol20/keyboard.html
6939
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6940
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