28 May
2017
28 May
'17
8:50 a.m.
Hello!
I recently received a HP9816 machine. The previous owner originally got the
machine without a keyboard but subsequently sourced a keyboard off ebay.
Unfortunately this keyboard was not in the best shape. One key was stuck
and when taking it apart it was evident that it has taken a bath for quite
some time. At least the electronics around the space bar were quite
affected with corrosion. Luckily this keyboard is quite simple design with
only CMOS 4XXX IC, and better yet, Tony Duell has already reverse
engineered it (together with the rest of this little machine). Thanks a lot
Tony!
But the stuck key appeared to be cause by the "plunger" (is that the
correct english word?) is slightly cracked in the corner. When the keytop
is inserted it is not sliding very well.
I have not found a method of repairing it so I am asking the community if
there are anyone that has spare "plungers" for the HP9816 keyboard.
http://i.imgur.com/q5aRQnC.jpg?1
http://i.imgur.com/67xWZ8q.jpg?1
http://i.imgur.com/cGWCKFw.jpg?1
This is the keyboard at the hpmuseum.net page:
http://www.hpmuseum.net/images/200serieskeyboardsmall-35.jpg
/Mattis
28 May
28 May
8:56 a.m.
On Sun, May 28, 2017 at 4:50 PM, Mattis Lind via cctalk
<cctalk at classiccmp.org> wrote:
Hello!
I recently received a HP9816 machine. The previous owner originally got the
machine without a keyboard but subsequently sourced a keyboard off ebay.
Unfortunately this keyboard was not in the best shape. One key was stuck
and when taking it apart it was evident that it has taken a bath for quite
some time. At least the electronics around the space bar were quite
affected with corrosion. Luckily this keyboard is quite simple design with
only CMOS 4XXX IC, and better yet, Tony Duell has already reverse
engineered it (together with the rest of this little machine). Thanks a lot
Tony!
IIRC it's a very odd design electronically, in that the keyswitches
are not wired
as a matrix. Rather they are each wired between ground and an input of a 4051
multiplexer. I have no idea why it was done this way.
But the stuck key appeared to be cause by the "plunger" (is that the
correct english word?) is slightly cracked in the corner. When the keytop
is inserted it is not sliding very well.
I have not found a method of repairing it so I am asking the community if
there are anyone that has spare "plungers" for the HP9816 keyboard.
I believe the same plungers were used on many other machines. I know for
a fact that a VT52 keycap will fit an HP9816 keyboard, so the plunger is
very likely to be the same as that machine. Other likely ones are VT100,
early TRS80 model 1, TI99/4A, HP85 (etc). That may help you find a scrap
keyboard to raid.
-tony
4:40 p.m.
----- Original Message -----
From: "Tony Duell via cctalk" <cctalk at classiccmp.org>
To: "Mattis Lind" <mattislind at gmail.com>; "General Discussion:
On-Topic and Off-Topic Posts" <cctalk at classiccmp.org>
Sent: Sunday, May 28, 2017 11:56 AM
Subject: Re: HP9816 keyboard plunger wanted.
----------------
They may not all be the same; I have a bunch of DEC assemblies and although I'm sure
they'd take the same keytop, at least the plungers I have are quite different. There
are latching and non-latching versions but unlike the ones in the picture they don't
have slots in the side and instead of being retained by a protruding little latch as in
the picture these are held in by a tiny L-shaped piece of wire that rides in a closed slot
or a latching triangular slot. They're also black.
But perhaps DEC used different types...
m
On Sun, May 28, 2017 at 4:50 PM, Mattis Lind via
cctalk
<cctalk at classiccmp.org> wrote:
> Hello!
...
But the stuck
key appeared to be cause by the "plunger" (is that the
correct english word?) is slightly cracked in the corner. When the keytop
is inserted it is not sliding very well.
I have not found a method of repairing it so I am asking the community if
there are anyone that has spare "plungers" for the HP9816 keyboard.
I believe the same plungers were used on many other machines. I know for
a fact that a VT52 keycap will fit an HP9816 keyboard, so the plunger is
very likely to be the same as that machine. Other likely ones are VT100,
early TRS80 model 1, TI99/4A, HP85 (etc). That may help you find a scrap
keyboard to raid.
-tony 
2:34 p.m.
Mattis, the problem you have is very common on these and HP85 keyboards and is usually
caused by one side of the square plunger cracking in a corner and bowing out.
It's normally fixed by gently bending the affected side towards the centre of the
square. A little bit of heat from a hair dryer while bending helps it stay in place. Be
careful when you reinsert the keycap so you don't bend it out again.
Although it's not really recommended as it can attract dust, I also give the plunger a
squirt of silicone or WD40 to keep it moving smoothly.
Hope that helps.
David Collins
HP Computer Museum
On 29 May 2017, at 1:50 am, Mattis Lind via cctalk
<cctalk at classiccmp.org> wrote:
Hello!
I recently received a HP9816 machine. The previous owner originally got the
machine without a keyboard but subsequently sourced a keyboard off ebay.
Unfortunately this keyboard was not in the best shape. One key was stuck
and when taking it apart it was evident that it has taken a bath for quite
some time. At least the electronics around the space bar were quite
affected with corrosion. Luckily this keyboard is quite simple design with
only CMOS 4XXX IC, and better yet, Tony Duell has already reverse
engineered it (together with the rest of this little machine). Thanks a lot
Tony!
But the stuck key appeared to be cause by the "plunger" (is that the
correct english word?) is slightly cracked in the corner. When the keytop
is inserted it is not sliding very well.
I have not found a method of repairing it so I am asking the community if
there are anyone that has spare "plungers" for the HP9816 keyboard.
http://i.imgur.com/q5aRQnC.jpg?1
http://i.imgur.com/67xWZ8q.jpg?1
http://i.imgur.com/cGWCKFw.jpg?1
This is the keyboard at the hpmuseum.net page:
http://www.hpmuseum.net/images/200serieskeyboardsmall-35.jpg
/Mattis
2766
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ard.p850ug1＠gmail.com -
davidkcollins2＠gmail.com -
mattislind＠gmail.com -
mhs.stein＠gmail.com