On 12/22/2010 12:56 PM, terry stewart wrote:
Alex, so you really think this might be the cause?
The web-info I've
read on the Lisa suggests it's usually the pads that wear out causing
non-responsive keys and that these should be replaced. However what's
odd is...
1. All the keys feel very firm, with no sign of the "mushiness"
mentioned in some of the info.
The mylar disks can still go bad. There maybe be dirty areas where the
mylar disks go down, there might be a short.
2. ALL the keys expect for one (in two keyboards) are
not working AT
ALL no matter how hard you press. Yet the '4' in one and the '/' in
another are working fine and with no pressure needed at all? In the
third keyboard NONE are working.
It would be great if the problem wasn't the pads, but something more
easy to fix.
Laziness is only a virtue for programmers. :-) Whatever's broken is
whatever must be fixed. Could be pads, could be something else.
It's hard to believe the pads could deteriorate
100% on all keys bar
one. And on that one they are fine? Anyone on the list had
experience with Lisa keyboards and could comment?
Yes, of course. Why do you think I keep sending you to
lisafaq.sunder.net for repair info? :-) Those are my repair
experiences. It's much easier to write up a FAQ and point people to it
than to individually write answers for specific repair questions. It's
a fairly easy repair.
Another thing to do: Get a can of contact cleaner, the spray kind.
Unplug the Lisa. Get some paper towels and lay them down under the
Lisa. Spray the stuff nice and thick into the keyboard jack, wait a
minute, flip the Lisa forwards so the stuff can run out, hold it like
that for 15-20 minutes until dry. Might be the jack.
Also wipe down the contacts on keyboard jack too.
I'll be opening them up in the next day or so so I guess I'll soon see.
When you do, check all 3 the wires in the keyboard connector against
where they hook up to the keyboard electronics. Maybe the wires are broken?
Carefully clean the "contacts" (quotes because they're not really
contacts, they're capacitance sensors.) on the board. Make sure there's
no shorts from ancient dust/debris/etc.
Look at all the mylar disks, if they're not intact, replace them. Odds
are, this is your issue.
The foam is easy to fix, just buy double sided foam tape. Hardware/Home
repair stores should have it.
The only hard part is cutting them into rounds of the right shape.
Terry
----- Original Message ----- From: "Alexandre Souza - Listas"
<pu1bzz.listas at gmail.com>
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Sent: Thursday, December 23, 2010 12:46 AM
Subject: Re: apple Lisa2. Any advice on non-working floppy drives?
Well, not
quite. One has the '4' key working on the keypad, the
other has the '/' key working. But that's it.
Terry, if ONE of the keys is working, there must be a stuck key or
a bad contact in the connector betweek the controller board of the
keyboard (inside it, of course) and whatever brings the switch
contacts to it (probably a membrane). I'm sure you'll be very lucky
on that :)