26 Feb
2005
26 Feb
'05
8:29 a.m.
I just picked up a lk201 keyboard today that wouldn't work with a vt320
Unlike my other lk201's this one has blue strip across the top, an orange pf1
key, f20 is labeled Hyph Push
PN: LK201BA
One site selling them says it is a word processing keyboard.
red lights and an error 4 on a VT 330.
How many variations of LK201 were produced?
Are they interchangeable?
Also heard about a PLATO system now online, I'm waiting for more details.
--
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26 Feb
26 Feb
11:03 a.m.
I just picked up a lk201 keyboard today that wouldn't work with a vt320
Are you sure it's not defective? An LK201 (any LK201) with a matrix short
(very common) will behave as you described.
Unlike my other lk201's this one has blue strip across the top, an orange pf1
key, f20 is labeled Hyph Push
PN: LK201BA
One site selling them says it is a word processing keyboard.
I've seen something like that used on a DECmate II. AFAIK it was a
standard LK201 apart from the labels and keycaps and would work on a
VT320, etc.
red lights and an error 4 on a VT 330.
How many variations of LK201 were produced?
Are they interchangeable?
AFAIK they all had the same internal ciecuit and firmware and were
interchangeable. Of course the LK250 is something totally different....
-tony
27 Feb
27 Feb
4:17 a.m.
>>>> "Mike" == Mike <kenziem
at sympatico.ca> writes:
Mike> How many variations of LK201 were produced? Are they
Mike> interchangeable?
Lots, but they are all interchangeable. The differences are in the
keycap labels. A given key position produces the same code no matter
what.
Mike> Also heard about a PLATO system now online, I'm waiting for
Mike> more details.
See www.cyber1.org.
paul
28 Feb
28 Feb
8:07 a.m.
Mike wrote:
I just picked up a lk201 keyboard today that
wouldn't work with a vt320
Unlike my other lk201's this one has blue strip across the top, an orange pf1
key, f20 is labeled Hyph Push
PN: LK201BA
One site selling them says it is a word processing keyboard.
There were several word processing keyboards, depending on which
software you were using. DecWord, WordPerfect, All-In-One, etc.
red lights and an error 4 on a VT 330.
Usually indicates a bad keyboard. (Error 4=keyboard)
Check the keyboard-terminal cable. Check for stuck
keys.
You could try disassembling it, cleaning the contacts
connecting the logic board to the main keyboard,
then try to reassemble it. Sometimes (rarely) it helps.
They are a bitch to disassemble/reassemble (You WILL
need to disassemble the connectors (bend out the pins
holding them to the circuit board, releasing the connector)
to re-insert the clear flat plastic cables.
How many variations of LK201 were produced?
Are they interchangeable?
Many. They should all be interchangable.
9:37 a.m.
>>>> "Kevin" == Kevin Handy
<kth at srv.net> writes:
Kevin> Mike wrote:
> I just picked up a lk201 keyboard today that
wouldn't work with a
> vt320
>
> Unlike my other lk201's this one has blue strip across the top, an
> orange pf1 key, f20 is labeled Hyph Push
>
> PN: LK201BA
>
> One site selling them says it is a word processing keyboard.
>
>
Kevin> There were several word processing keyboards, depending on
Kevin> which software you were using. DecWord, WordPerfect,
Kevin> All-In-One, etc.
I doubt that DEC ever made keyboards for WordPerfect. And I haven't
heard of All-In-One keyboards either. The keyboard Mike mentioned is
a DECword keyboard.
Kevin> Check the keyboard-terminal cable. Check for stuck keys.
One possibility: you could make an adapter to plug it into a UART
port, then write a test program to see what's wrong with it. The
protocol is simple (4800 baud 8 bit messages) and well documented in
the Pro 300 series technical manual.
Then again, if it's a stuck key or something like that, the keyboard
is beyond repair. LK201 keyboards are cheesy low quality membrane
switches that cannot be disassembled or cleaned or repaired. If
moisture ever gets in them, your only option is to scrap the board. I
found this out the hard way.
paul
11:40 a.m.
Paul Koning wrote:
Kevin> There were several word processing
keyboards, depending on
Kevin> which software you were using. DecWord, WordPerfect,
Kevin> All-In-One, etc.
I doubt that DEC ever made keyboards for WordPerfect. And I haven't
heard of All-In-One keyboards either. The keyboard Mike mentioned is
a DECword keyboard.
WordPerfect used to make them. I can't remember if it
was complete keyboards, or just replacement keycaps.
I also don't know of anyone who bought one.
Kevin> Check the keyboard-terminal cable. Check for
stuck keys.
One possibility: you could make an adapter to plug it into a UART
port, then write a test program to see what's wrong with it. The
protocol is simple (4800 baud 8 bit messages) and well documented in
the Pro 300 series technical manual.
Then again, if it's a stuck key or something like that, the keyboard
is beyond repair. LK201 keyboards are cheesy low quality membrane
switches that cannot be disassembled or cleaned or repaired. If
moisture ever gets in them, your only option is to scrap the board. I
found this out the hard way.
It's usually easier to just find a new one. I only tried to repair
one when I was desperate for a working one, having used up
whatever good spares I had. At that it just was swapping to
get a good keyboard/logic board combo.
Most of the keyboards I looked at had been built using the
"melted-plastic-post" method to hold it together, iirc.
Nearly impossible to take apart and expect to be able
to put back together. Not worth the effort.
paul
3:06 p.m.
Then again, if it's a stuck key or something like
that, the keyboard
is beyond repair. LK201 keyboards are cheesy low quality membrane
switches that cannot be disassembled or cleaned or repaired. If
moisture ever gets in them, your only option is to scrap the board. I
found this out the hard way.
They can be dismantled... Getting them back together is the difficult bit :-)
What I would do is take off the casing (2 hex-head bolts under the feet,
unlatch the plastic clip in the bottom section and slide the keyboard
assembly out), then separate the PCB from the keyboard membranes. From
what I remmeber there's a clip that holds a regulator to the chassis, one
screwm and you then bend up the tabs on the metal clips over the membrane
tails and take the whole lot apart.
With said clips removed, you cna conenct the PCB to the terminal with the
normal modular cable. If it now gives no errors (very likely), you've got
a matrix problem.
You can remove the keycaps -- slightly twist them to free the locking
hooks. There's even a special DEC tool for this -- I have it somewere, it
came as part of a custom blank keycap kit.
Now, the thing is heat-stakeed together. There are plastic housings with
metal springs under them, then a rubber sheet, then the mebrane, them a
metal base. Pegs on the plastic housings go through the whole lot and are
moulded over on the back.
It's triviel to take apart. The problem is leaving enough peg to be able
to fix it all back again. I have wondered about making a hollow tubular
cutter to remove the moulded-over bit from each peg, then putting said
bits back on at the end and trying to melt the plastic together again. I
am told this method has worked on HP handhelds with similar heat-staked
assembiles
-tony
7188
days inactive
7190
days old
6 comments
4 participants
participants (4)
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ard＠p850ug1.demon.co.uk -
kenziem＠sympatico.ca -
kth＠srv.net -
pkoning＠equallogic.com