Dead Model 4 keyboard
Blake Patterson
http://flickr.com/photos/blakespot/2451238320/
....could this explains the other keys, not just ; ???
Where can I get a new Model 4 keyboard? Tnx.
bp
Frank Durda IV
: So I wondered why 2 r ; z b were dead on my Model 4 keyboard.
:
: http://flickr.com/photos/blakespot/2451238320/
:
: ....could this explains the other keys, not just ; ???
:
: Where can I get a new Model 4 keyboard? Tnx.
Fix it. That's a common injury, something really heavy dropped
(or stepped) on the keyboard. It got Model III/4s and DT-1s which used
the same case. Assuming the other side of that key is okay, this is
certainly repairable (I've fixed several) but you may need a photo of a
non-damaged one to compare to make sure you jump wires to neighboring
locations to get around the damaged etches. It is a single-layer
circuit board, so you don't have any internal etches to worry about.
Depending on the location of the damage, an etch break can isolate up
to seven keys so that they can't be scanned. A shorted etch can cause
false key reports or even squaring, the condition where a key that
wasn't pressed is reported in place of or in addition to keys that
were pressed. Normally three keys pressed at the same time triggers a
squaring error and they have to be certain ones: two in the same row
and two in the same column of the matrix causes the key in the
remaining corner of that square to appear to have been pressed but
it was not. Matrix keyboards that don't use diodes have this problem.
Software can detect that squaring is occurring and simply not display
anything until you release enough keys, but most of those machines
didn't have drivers smart enough to do that check and quite a few
could not even do N-key rollover.
That's why some instructions for pressing multiple keys down
at the same time in some Tandy manuals direct you to use a specific
SHIFT key, so that squaring is avoided. The other keys in the
sequence must share a row and/or column with the shift key they
didn't want you to use.
Frank Durda IV - send mail to this address and remove the "LOSE":
<uhclemLOSE.jun08%nemesis.lonestar.org> http://nemesis.lonestar.org
"Like the HitchHikers Guide to the Galaxy, when the Internet is
inaccurate, at least it can be said to be definitively inaccurate."
Copyright 2008, ask before reprinting.
Blake Patterson
<uhclemLOSE.ju...@nemesis.lonestar.org> wrote:
> Blake Patterson <blakes...@gmail.com> wrote:
> : So I wondered why 2 r ; z b were dead on my Model 4 keyboard.
> :
> :http://flickr.com/photos/blakespot/2451238320/
> :
> : ....could this explains the other keys, not just ; ???
> :
> : Where can I get a new Model 4 keyboard? Tnx.
>
> Fix it. That's a common injury, something really heavy dropped
> (or stepped) on the keyboard. It got Model III/4s and DT-1s which used
> the same case. Assuming the other side of that key is okay, this is
> certainly repairable (I've fixed several) but you may need a photo of a
> non-damaged one to compare to make sure you jump wires to neighboring
> locations to get around the damaged etches. It is a single-layer
> circuit board, so you don't have any internal etches to worry about.
Ok, I'll give it a try. Thanks for the info.
Could you point me to a photo of a non-damaged model 4 keyboard for
reference?
The damage is between the L and ; keys. Currently I have 5 non-
responsive keys. I am hoping they're all tied to this.
Thanks.
bp
Blake Patterson
sandpaper then just solder patch cable to bare points on either side
of crack? How difficult is this to do? I am "ok" with a soldering
iron, but no ace.
Where can I get super tiny wires like I'd want? Is Radio Shack still
useful enough to offer them or...no? I am guessing not.
I can't seem to find a photo of the proper layout of that section of
keyboard (between L and ; keys). Anyone have such a pic?
Tnx.
bp
Knut Roll-Lund
I did look through my pictures without any luck, also checked the
technical reference for model III and for model 4 and there is no
diagram or layout there either.
Wirewrap thread would probably be the perfect choice for lead. But you
could probably use any normal lead (120V) and take it apart using only
one of the strands. (Kordel would be the proper word in Norwegian, is
something similar the proper word in English?) I would use a scalpel to
scrape away the lacquer.
--
Knut
(delete 'nogarbage.' for email)
marmotking
I'll look through them and see if I can get you a photo...
Frank Durda IV
: And how does one patch solder a trace? Scrape off the green layer w/
: sandpaper then just solder patch cable to bare points on either side
: of crack? How difficult is this to do? I am "ok" with a soldering
: iron, but no ace.
Solder jumpers between the destinations. Don't bother with trying
to fix the broken etch itself, just bypass it and the damaged area as
much as possible. Hopefully you can see where a given etch was going
to/from, so just latch on a nearby spot, like the solder point on the
next key that etch went to. Similarly, in the area around the damaged
part of the PCB, just solder a replacement wire/wires directly on to
the pin on the key. Get the soldering iron on and off that pin fast
so that you dont melt or deform any of the plastic parts in the key
switch assembly.
On most of those key switches, each contact had two wires (so a
single-pole switch had four legs). This was done to help anchor the
switch and allow PCB designers some ways to route wiring around to avoid
having to use jumpers and still produce a single-layer PCB design.
So, if one leg on the key is broken off or badly damaged, another
should be there that you can connect both wires that would have gone
to that side of the switch to the remaining leg.
: Where can I get super tiny wires like I'd want? Is Radio Shack still
: useful enough to offer them or...no? I am guessing not.
Radio Shack still sells wire wrap wire (30AWG) (as does DigiKey,
Mouser, Frys, Anixter, Granger, Allied, etc), but you will probably
need a wire-wrap stripper also to avoid driving yourself nuts trying
to get the teflon insulation off with pliers. You also need
a low wattage soldering iron and some fine, no-acid solder. Do not
try to use soldering irons meant for radiator or plumbing repair, or the
gas powered soldering irons here.
For the keyboard, 26 and even 24AWG solid wire will work fine.
24AWG is multi-pair, station and cross-connect telephone wire, and
that is quite easy to work with and available widely. Use solid,
not stranded wire. You don't need that extra headache.
: I can't seem to find a photo of the proper layout of that section of
: keyboard (between L and ; keys). Anyone have such a pic?
I don't have one at the moment.
Frank Durda IV - send mail to this address and remove the "LOSE":
<uhclemLOSE.jun08%nemesis.lonestar.org> http://nemesis.lonestar.org
"The Knights who say "LETNi" demand... A SEGMENT REGISTER!!!"
"A what?" "LETNi! LETNi! LETNi!" - 1983
marmotking
photo. I'll wait to hear from you on whether it's sufficient before I
put it all back together. It's a very high resolution photo, so you
should be able to see every little detail...be sure to zoom in...
http://download.marmotking.com/IMG_0102.JPG
http://download.marmotking.com/IMG_0101.JPG
and, just for good measure...
http://download.marmotking.com/IMG_0099.JPG
BTW, the background in the photo is the top of my newly acquired
PDP-11. Woo hoo!
marmotking
Blake Patterson
> Here you go...I pulled the keyboard out of a dead Model 4 and took a
> photo. I'll wait to hear from you on whether it's sufficient before I
> put it all back together. It's a very high resolution photo, so you
> should be able to see every little detail...be sure to zoom in...
>
>
> and, just for good measure...
>
> http://download.marmotking.com/IMG_0099.JPG
>
> BTW, the background in the photo is the top of my newly acquired
> PDP-11. Woo hoo!
>
> marmotking
Excellent. Just what I needed. In fact...do you want to sell that
Model 4 keyboard off your dead Model 4 ... ?
Tnx.
bp
marmotking
> Model 4 keyboard off your dead Model 4 ... ?
>
> Tnx.
>
> bp
Thanks, but sorry, I do plan on repairing all the dead machines I
have. I can think of nothing more satisfying! Besides, it seems that
most of the Model 4 keyboards I have are the folded over plastic sheet
types and they don't seem to work. This is a (seemingly hard to find)
key switch type that can with great effort be repaired...
Glad to help.
winston19842005
On 4/30/08 12:57 AM, in article
dde40eee-96cf-4efe...@x35g2000hsb.googlegroups.com, "Blake
Patterson" <blak...@gmail.com> wrote:
You should be thankful it looks like an easy repair...
I have quite a few TI-99's, with newer keyboards - they die with non-use,
the keycaps do not come off, and the keyboards are sealed. When they die,
they are dead...
Blake Patterson
> On 4/30/08 12:57 AM, in article
>
>
>
> Patterson" <blakes...@gmail.com> wrote:
> > On Apr 30, 12:13 am, marmotking <tr...@marmotking.com> wrote:
> >> Here you go...I pulled the keyboard out of a dead Model 4 and took a
> >> photo. I'll wait to hear from you on whether it's sufficient before I
> >> put it all back together. It's a very high resolution photo, so you
> >> should be able to see every little detail...be sure to zoom in...
>
> >> _0101.JPG
>
> >> and, just for good measure...
>
> >>http://download.marmotking.com/IMG_0099.JPG
>
> >> BTW, the background in the photo is the top of my newly acquired
> >> PDP-11. Woo hoo!
>
> >> marmotking
>
> > Excellent. Just what I needed. In fact...do you want to sell that
> > Model 4 keyboard off your dead Model 4 ... ?
>
> You should be thankful it looks like an easy repair...
>
> I have quite a few TI-99's, with newer keyboards - they die with non-use,
> the keycaps do not come off, and the keyboards are sealed. When they die,
> they are dead...
I'll give it a shot tonight. Hitting Radio Shack momentarily to get
some wire wrap. Maybe I should bring in the Model 4 for repair. :-)
I guess the guys behind the counter wouldn't possibly even recognize
the system - they'd just try to talk me away from my iPhone and onto
some cell plan they peddle. Aye, how the mighty have fallen.
I've done some TI-99 repair, myself...
http://flickr.com/photos/blakespot/sets/72157604286436870/
bp
winston19842005
On 4/30/08 1:17 PM, in article
9c2fd069-b0ca-401f...@26g2000hsk.googlegroups.com, "Blake
Patterson" <blak...@gmail.com> wrote:
http://flickr.com/photos/blakespot/2379757535/in/set-72157604286436870/
This on your TI?! ;)
Blake Patterson
> > I've done some TI-99 repair, myself...
>
> >http://flickr.com/photos/blakespot/sets/72157604286436870/
>
> http://flickr.com/photos/blakespot/2379757535/in/set-72157604286436870/
> This on your TI?! ;)
Heh. That would be the Sega Saturn up on the shelf. :-)
That PEB is built like a tank though. It hardly feels that 20-inch
TV.
bp
Blake Patterson
<uhclemLOSE.ju...@nemesis.lonestar.org> wrote:
> Radio Shack still sells wire wrap wire (30AWG) (as does DigiKey,
> Mouser, Frys, Anixter, Granger, Allied, etc), but you will probably
> need a wire-wrap stripper also to avoid driving yourself nuts trying
> to get the teflon insulation off with pliers. You also need
> a low wattage soldering iron and some fine, no-acid solder. Do not
> try to use soldering irons meant for radiator or plumbing repair, or the
> gas powered soldering irons here.
>
> For the keyboard, 26 and even 24AWG solid wire will work fine.
> 24AWG is multi-pair, station and cross-connect telephone wire, and
> that is quite easy to work with and available widely. Use solid,
> not stranded wire. You don't need that extra headache.
>
The smallest they had (highest gauge) was 22 gauge solid. I picked
that up. Should work fine, right?
No 24 or 26, etc. gauge. Tnx.
bp
Mike Y
"Blake Patterson" <blak...@gmail.com> wrote in message
news:4ea7d586-488c-4fdb...@y21g2000hsf.googlegroups.com...
The wire-wrap isn't with the wire, it's back with the tools and such...
Also, they sell a tool that looks like a big jewelers screwdriver. It's
a wire-wrap tool. The tool comes apart, and there's a wire stripper
for wire-wrap wire inside. The tool's about $6 or so.
Blake Patterson
> "Blake Patterson" <blakes...@gmail.com> wrote in message
What I got is a spool of 22 gauge Hook-Up Wire rated to 300 volts.
Will this work for me or do I need to go back and get Wire Wrap?
Thanks.
bp
Blake Patterson
To clarify my last post, this is exactly what wire I purchased:
http://www.crystalradio.net/beginners3/rswire3.jpg
bp
Mike Y
>
> To clarify my last post, this is exactly what wire I purchased:
>
> http://www.crystalradio.net/beginners3/rswire3.jpg
>
>
>
> bp
That will work, but then, so would 12ga solid copper house wiring. The
issue is how difficult it will be to work with.
I've done jumper repairs with 22ga, but it's going to be a pain. Wirewrap
is THIN and very easy to work with. Although it will be VERY tiny. One
thing about wirewrap, it's 'pre tinned'. That is, it's very easy to solder
down. The wire you bought won't be.
Mike
Gary
http://www.radioshack.com/product/index.jsp?productId=2062642&cp
http://www.radioshack.com/product/index.jsp?productId=2062641
http://www.radioshack.com/product/index.jsp?productId=2062640
for your use this tool is overkill, but the stripper is useful...
http://www.radioshack.com/product/index.jsp?productId=2103243
As mike said the heavier stuff is harder to work with & if you're not
careful,
you can damage the traces (twisting the heavy wire twists the traces more
I've seen enough butchered boards)
Gary K
"Blake Patterson" <blak...@gmail.com> wrote in message
news:4ea7d586-488c-4fdb...@y21g2000hsf.googlegroups.com...
Blake Patterson
> Best would be something like this
>
> http://www.radioshack.com/product/index.jsp?productId=2062642&cp
>
> http://www.radioshack.com/product/index.jsp?productId=2062641
>
> http://www.radioshack.com/product/index.jsp?productId=2062640
>
> for your use this tool is overkill, but the stripper is useful...
>
> http://www.radioshack.com/product/index.jsp?productId=2103243
>
> As mike said the heavier stuff is harder to work with & if you're not
> careful,
> you can damage the traces (twisting the heavy wire twists the traces more
> I've seen enough butchered boards)
>
> Gary K
Well, I just went back to Radio Shack. That place is so lame now.
The young guy there, of course, had no idea what wire wrap was. After
showing me their plastic ties, I showed him where I thought it should
be (over by the solder tools) and it was nowhere to be found. He
finally looked it up on the computer (spelling it out "wire rap tool")
and we found what I was after, but apparently no stores in the region
sell it. Mail order only.
So I got a stripper to help me w/ my 22 gauge wire and will just go
that route. I'll solder at the post points rather than to the traces
mid-run, and hopefully it should be ok.
Anyway.
bp
Frank Durda IV
: What I got is a spool of 22 gauge Hook-Up Wire rated to 300 volts.
: Will this work for me or do I need to go back and get Wire Wrap?
That size is massive overkill and you may have difficulty getting it to
heat enough to stick at the points where you want to solder quickly.
You don't want to heat things up so long that the good etches come
unstuck from the board (which will happen) or the heat melts something
in the keyswitch on the other side. You typically have less than
ten seconds of soldering time, and trying to stay under five seconds
is better.
Unless you are really good and fast at soldering, I suggest
that you locate smaller wire. It will heat faster and be
easier to work with.
Radio Shack White #30 Model: 278-502 | Catalog #: 278-502
Red Model: 278-501 | Catalog #: 278-501
Blue Model: 278-503 | Catalog #: 278-503
each #3.99 US
Wire-Wrapping tool Model: 276-1570 | Catalog #: 276-1570 $6.99 US
The Radio Shack web site is stupid and doesn't find anything under
"wire-wrap" or "wrap", but they all appear under "wire-wrapping".
I have no idea what this new "Model:" designation is that has the
same value as "Catalog #:". Apparently there are still idiots in
merchandising...
Blake Patterson
<uhclemLOSE.ju...@nemesis.lonestar.org> wrote:
> Blake Patterson <blakes...@gmail.com> wrote:
> : What I got is a spool of 22 gauge Hook-Up Wire rated to 300 volts.
> : Will this work for me or do I need to go back and get Wire Wrap?
>
> That size is massive overkill and you may have difficulty getting it to
> heat enough to stick at the points where you want to solder quickly.
> You don't want to heat things up so long that the good etches come
> unstuck from the board (which will happen) or the heat melts something
> in the keyswitch on the other side. You typically have less than
> ten seconds of soldering time, and trying to stay under five seconds
> is better.
All fixed!
the problem:
http://www.flickr.com/photos/blakespot/2451238320/in/set-72157604743399188/
the fix:
http://www.flickr.com/photos/blakespot/2456185118/in/set-72157604743399188/
the pudding:
http://www.flickr.com/photos/blakespot/2455356101/in/set-72157604743399188/
Good times!
Thanks everyone.
bp