Hi,

I have a very old synthesiser where the top panel rubber contact switches no
longer work, because the owner has removed the contact strips.

This is the synth:
http://www.vintagesynth.com/sci/stk.php


The contact rubbers are pretty much 10cm x 10cm x 10cm cubes, but they have
a rather large contact footprint.
The corresponding PCB contact gap between the two lands that need to be
bridged is also rather large.
http://tinypic.com/r/14xdmo3/9



So, I am looking into the possibility of replacing the missing buttons by
cannibalising a somewhat more contemporary keypad that has extra large
contacts.

Here's a typical example I found at Farnell. It might be possible to cut it
up and glue it to the keyboard and make things work, if the contacts are
large enough.
http://uk.farnell.com/storm-interfac...rey/dp/9810064



Anyone any such experience here?

I know it's a long shot.



Cheers,


Gareth.

On Thu, 14 Jan 2016 23:01:20 -0000, "Gareth Magennis"
wrote:

Anyone any such experience here?
I know it's a long shot.

Google for "mold your own rubber parts" or "cast your own rubber
parts". Lots of lousy videos on YouTube on how to mold rubber parts.
I use Plaster of Paris for the mold, Devcon Flexane 94 Liquid 15250
two part urethane rubber
http://www.devcon.com/products/products.cfm?family=Flexane%C2%AE%2094%20Liquid
http://www.amazon.com/Devcon-15250-Black-Flexane-Liquid/dp/B00065TLJK
and Vaseline or silicon grease for mold release. Careful when storing
the stuff as the stuff in the bottle attacks the bottle and causes it
to leak. It cures in 10-15 mins, so be prepared to work fast.
Although it's made for making flex molds, it's also the right stuff
for making fairly hard rubber buttons, gaskets, shock mounts, seals,
etc.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

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On Thu, 14 Jan 2016 17:11:25 -0800, Jeff Liebermann
wrote:

On Thu, 14 Jan 2016 23:01:20 -0000, "Gareth Magennis"
wrote:

Anyone any such experience here?
I know it's a long shot.

Maybe a kit would be better than doing it from scratch:
http://www.alumilite.com
(I haven't tried these).
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

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On 2016-01-15, Jeff Liebermann wrote:
On Thu, 14 Jan 2016 23:01:20 -0000, "Gareth Magennis"
wrote:

Anyone any such experience here?
I know it's a long shot.

Google for "mold your own rubber parts" or "cast your own rubber
parts". Lots of lousy videos on YouTube on how to mold rubber parts.
I use Plaster of Paris for the mold, Devcon Flexane 94 Liquid 15250
two part urethane rubber

The resin part of this evidently contains some isocyanate monomers;
careful with that!

On 15/01/16 12:11, Jeff Liebermann wrote:
On Thu, 14 Jan 2016 23:01:20 -0000, "Gareth Magennis"
wrote:

Anyone any such experience here?
I know it's a long shot.

Google for "mold your own rubber parts" or "cast your own rubber
parts". Lots of lousy videos on YouTube on how to mold rubber parts.
I use Plaster of Paris for the mold, Devcon Flexane 94 Liquid 15250
two part urethane rubber
http://www.devcon.com/products/products.cfm?family=Flexane%C2%AE%2094%20Liquid
http://www.amazon.com/Devcon-15250-Black-Flexane-Liquid/dp/B00065TLJK
and Vaseline or silicon grease for mold release. Careful when storing
the stuff as the stuff in the bottle attacks the bottle and causes it
to leak. It cures in 10-15 mins, so be prepared to work fast.
Although it's made for making flex molds, it's also the right stuff
for making fairly hard rubber buttons, gaskets, shock mounts, seals,
etc.

It's a good idea to de-air the mix in a vacuum flash for a while after
mixing. It's amazing how much air gets in - until you see the bubbles
magically appear as you apply vacuum it's hard to believe.

On Fri, 15 Jan 2016 02:56:51 +0000 (UTC), Kaz Kylheku
wrote:

On 2016-01-15, Jeff Liebermann wrote:
On Thu, 14 Jan 2016 23:01:20 -0000, "Gareth Magennis"
wrote:

Anyone any such experience here?
I know it's a long shot.

Google for "mold your own rubber parts" or "cast your own rubber
parts". Lots of lousy videos on YouTube on how to mold rubber parts.
I use Plaster of Paris for the mold, Devcon Flexane 94 Liquid 15250
two part urethane rubber

The resin part of this evidently contains some isocyanate monomers;
careful with that!

Beware the smell of bitter almonds (apologies to Sherlock Holmes):
http://news.wustl.edu/news/Pages/20916.aspx
I've smelled them while plating some copper PCB edge connectors with
electroless silver, which is basically silver cyanide. When I tasted
the rotten almonds, I was already in a stupor and had to be dragged
from the building for some fresh air. I've worked with Flexane 94 a
few times and survived. Wear gloves and don't inhale the vapors:
http://www.actiocms.com/VIEW_MSDS/view_language_kits2.cfm?edit_msds_id=4328&dbname=p roduction&language=1&format=16&CFID=11369918&CFTOK EN=1c713f7731a98b98-A229D917-9DA3-18D9-6BC94692623356A2
At 10-20% of solution by weight, it's not going to be very potent.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

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On 14/01/2016 23:01, Gareth Magennis wrote:
Hi,

I have a very old synthesiser where the top panel rubber contact
switches no longer work, because the owner has removed the contact strips.

This is the synth:
http://www.vintagesynth.com/sci/stk.php


The contact rubbers are pretty much 10cm x 10cm x 10cm cubes, but they
have a rather large contact footprint.
The corresponding PCB contact gap between the two lands that need to be
bridged is also rather large.
http://tinypic.com/r/14xdmo3/9



So, I am looking into the possibility of replacing the missing buttons
by cannibalising a somewhat more contemporary keypad that has extra
large contacts.

Here's a typical example I found at Farnell. It might be possible to
cut it up and glue it to the keyboard and make things work, if the
contacts are large enough.
http://uk.farnell.com/storm-interfac...rey/dp/9810064




Anyone any such experience here?

I know it's a long shot.



Cheers,


Gareth.




What is the minimum resistance/mm of gap required?

In article ,
says...

Beware the smell of bitter almonds (apologies to Sherlock Holmes):

Sounds like you would not want to be under the influence of a "seven
percent solution" at the same time!

Mike.

On 1/14/2016 3:01 PM, Gareth Magennis wrote:
Hi,

I have a very old synthesiser where the top panel rubber contact
switches no longer work, because the owner has removed the contact strips.

This is the synth:
http://www.vintagesynth.com/sci/stk.php


The contact rubbers are pretty much 10cm x 10cm x 10cm cubes, but they
have a rather large contact footprint.
The corresponding PCB contact gap between the two lands that need to be
bridged is also rather large.
http://tinypic.com/r/14xdmo3/9



So, I am looking into the possibility of replacing the missing buttons
by cannibalising a somewhat more contemporary keypad that has extra
large contacts.

Here's a typical example I found at Farnell. It might be possible to
cut it up and glue it to the keyboard and make things work, if the
contacts are large enough.
http://uk.farnell.com/storm-interfac...rey/dp/9810064




Anyone any such experience here?

I know it's a long shot.



Cheers,


Gareth.


I'm having a hard time reconciling your text with your picture.
Looks more like 1cm cubes?
And the contact is the circular spot on the bottom of the key?
Rather large???
What part got removed by the customer?

I've had some success with very thin tinfoil glued to the bottom
of the conductive pad on the key.
But, I've not worried about longevity of the fix.
Not sure that would be a good thing for a paid repair for a customer.

I did try conductive silver paint, but that flaked off rather quickly.

Also need to clean the pads on the board well, without scraping off
the black conductor.

Another thing I thought about trying was a piece of "zebra strip"
used to connect calculator boards to their display.
Lay it sideways and properly oriented, because you need a long
conductive path to connect the pads
on the board.

"Jeff Liebermann" wrote in message
...

On Thu, 14 Jan 2016 23:01:20 -0000, "Gareth Magennis"
wrote:

Anyone any such experience here?
I know it's a long shot.

Google for "mold your own rubber parts" or "cast your own rubber
parts". Lots of lousy videos on YouTube on how to mold rubber parts.
I use Plaster of Paris for the mold, Devcon Flexane 94 Liquid 15250
two part urethane rubber
http://www.devcon.com/products/products.cfm?family=Flexane%C2%AE%2094%20Liquid
http://www.amazon.com/Devcon-15250-Black-Flexane-Liquid/dp/B00065TLJK
and Vaseline or silicon grease for mold release. Careful when storing
the stuff as the stuff in the bottle attacks the bottle and causes it
to leak. It cures in 10-15 mins, so be prepared to work fast.
Although it's made for making flex molds, it's also the right stuff
for making fairly hard rubber buttons, gaskets, shock mounts, seals,
etc.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

---


Thanks, might give that a go.

Is there a tried and trusted way of adding a conductive contact pad?


Cheers,


Gareth.

I'm having a hard time reconciling your text with your picture.
Looks more like 1cm cubes?
And the contact is the circular spot on the bottom of the key?
Rather large???
What part got removed by the customer?






Sorry, that's a typo, that should be 10mm x 10mm x 10mm cubes, as the ruler
in the photo shows.
That same photo with the ruler shows the round pad to be about 5mm diameter,
much larger than the key contact strips and button pads I find on
contemporary equipment.
This is old school manufacturing.




Gareth.

I'm having a hard time reconciling your text with your picture.
Looks more like 1cm cubes?
And the contact is the circular spot on the bottom of the key?
Rather large???
What part got removed by the customer?







The customer has ripped out all the contact buttons on the right side of the
keyboard, the left side set is still in place and working.
The photo shows the right hand side of the PCB with 2 buttons from the left
side put in the photo to show the size of things.



Gareth.

On 1/15/2016 1:22 AM, Gareth Magennis wrote:
I'm having a hard time reconciling your text with your picture.
Looks more like 1cm cubes?
And the contact is the circular spot on the bottom of the key?
Rather large???
What part got removed by the customer?







The customer has ripped out all the contact buttons on the right side of
the keyboard, the left side set is still in place and working.
The photo shows the right hand side of the PCB with 2 buttons from the
left side put in the photo to show the size of things.



Gareth.
OK,
I can't imagine you can manufacture new keys at a repair price the
customer could tolerate.

There's a guy who shows up at local ham radio swapmeets and sells
radio attachment gizmos.
He has a 3D printer and claims to be willing and able to make custom gizmos.
I never asked the price.
All his samples were rigid.
Unknown whether he could make the bottom section springy enough
to effect a pushbutton spring.

I have a stupid question.....are keyboards connected to a connector ? is there an assembly area into the registering circuit ?

On 2016-01-15, Gareth Magennis wrote:
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

---


Thanks, might give that a go.

Look, you quoted Jeff without using the correct characters,
*including his signature*, and put your reply after the signature!

Without the characters, it looks like your posting is a plagiarism
of Jeff.

When I went to reply to you, your entire reply disappeared, because
your reply looks like an extension of Jeff's signature, and a proper news
client removes everything after the "-- " signature mark when you reply. I had
to copy and paste the above from the terminal.

Please use Usenet correctly or FOAD.

On Fri, 15 Jan 2016 09:11:00 -0000, "Gareth Magennis"
wrote:

Is there a tried and trusted way of adding a conductive contact pad?

Search for a rubber keypad repair kit:
http://www.amazon.com/MG-Chemicals-8339-Rubber-Keypad/dp/B0081SGM8M
http://www.amazon.com/Keypad-Restore-Conductivity-Carbon-Copper/dp/B0026PRMVM
http://www.amazon.com/Caig-BCG327782-Caikote-44-Kit/dp/B00E1QYYC4
http://www.mcmelectronics.com/product/CAIG-LABORATORIES-K-CK44-G-/200-315
http://www.ebay.com/bhp/keypad-repair-kit
http://www.ebay.com/bhp/keypad-fix
There are videos on YouTube on how to apply the stuff. My favorite
mistake was to apply too much graphite paint. It's not very flexible
and will tend to crumble around the edges. Loose pieces of conductive
graphite inside the switch is not a good thing.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

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In article , says...

[snip]

I can't imagine you can manufacture new keys at a repair price the
customer could tolerate.

There's a guy who shows up at local ham radio swapmeets and sells
radio attachment gizmos.
He has a 3D printer and claims to be willing and able to make custom gizmos.
I never asked the price.
All his samples were rigid.
Unknown whether he could make the bottom section springy enough
to effect a pushbutton spring.

One of the guys at the makerspace brought
in some NinjaFlex 3D filament. It is quite
flexible, and a test cube was quite spongy.
I have no data on how durable it would be
in the OP's application, though.

--- news://freenews.netfront.net/ - complaints: ---

On Thu, 14 Jan 2016 17:11:25 -0800, Jeff Liebermann
wrote:

On Thu, 14 Jan 2016 23:01:20 -0000, "Gareth Magennis"
wrote:

Anyone any such experience here?
I know it's a long shot.

Google for "mold your own rubber parts" or "cast your own rubber
parts". Lots of lousy videos on YouTube on how to mold rubber parts.
I use Plaster of Paris for the mold, Devcon Flexane 94 Liquid 15250
two part urethane rubber
http://www.devcon.com/products/products.cfm?family=Flexane%C2%AE%2094%20Liquid
http://www.amazon.com/Devcon-15250-Black-Flexane-Liquid/dp/B00065TLJK
and Vaseline or silicon grease for mold release. Careful when storing
the stuff as the stuff in the bottle attacks the bottle and causes it
to leak. It cures in 10-15 mins, so be prepared to work fast.
Although it's made for making flex molds, it's also the right stuff
for making fairly hard rubber buttons, gaskets, shock mounts, seals,
etc.

Oops. The Devcon Flexane 94 is probably too hard and stiff for your
rubber button that has to bend and act as a spring:
http://oi65.tinypic.com/14xdmo3.jpg
Something more like RTV (silicone rubber) will be more flexible. I
have a Shore A Durometer (rubber hardness meter) and can measure a few
random rubber buttons and see what's appropriate. Well, the assorted
TV remote controls run 53 to 60. Various other rubber buttons vary
from 50 to 65. All my music keyboards have hard plastic buttons, so
that's not going to work.

I found a part I had made using Flexane 94, which shows 85, so that's
much to hard to flex. I don't have something handy that will work,
but I'll do some catalog searching this weekend. Offhand, I would
suspect that bathroom caulk, rain gutter seal, or other commonly
available silicone rubber compound might work but might also be too
soft (typically 25 to 30 durometers). Structural silicone might be
harder. Digging:
http://www.siliconeforbuilding.com/pdf/structuralglazing/Data_Sheet_SSG4000_UltraGlaze.pdf
Argh... only 39.

These might help:
"Using Silicone Caulk as a Mold Material"
http://forums.gardenweb.com/discussions/1472166/using-silicone-caulk-as-a-mold-material

Durometer Hardness Scales:
http://www.paramountind.com/pdfs/paramount_durometer_scale_guide.pdf

MasterBond Adhesive hardness:
http://www.masterbond.com/properties/hardness


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

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In article ,
Gareth Magennis wrote:

Is there a tried and trusted way of adding a conductive contact pad?

For what it's worth: I've had pretty good luck restoring conductive
pads using a product called Neolube #2. It's a water/alcohol
suspension of extremely fine graphite, with a small amount of a
thermoplastic resin (possibly cellulose acetate?) as a binder. It can
be applied with a fine brush or Q-tip.

I recently purchased a bunch of surplus Kenwood UHF mobile radios.
About half of them had intermittent or non-working keys on the molded
keypads. The pad sheet had originally been made with some sort of
sprayed-on or molded-on conductive coating, and I could see where it
had been worn off the keys in question (the rubber was shiny and I
could actually see the shapes of the corresponding PC-board traces).

Cleaned with alcohol, painted on a couple of thin coats of Neolube,
and they work fine.

I can't swear as to how long it will hold, but Neolube seems to have a
respectable "grip" on the surfaces I've painted it onto. Its info
sheet is interesting... they talk about how its carbon is so pure than
neutron activation of contaminants isn't an issue, and so it's rated
for use in nuclear reactors.

"Kaz Kylheku" wrote in message ...

On 2016-01-15, Gareth Magennis wrote:
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

---


Thanks, might give that a go.

Look, you quoted Jeff without using the correct characters,
*including his signature*, and put your reply after the signature!

Without the characters, it looks like your posting is a plagiarism
of Jeff.

When I went to reply to you, your entire reply disappeared, because
your reply looks like an extension of Jeff's signature, and a proper news
client removes everything after the "-- " signature mark when you reply. I
had
to copy and paste the above from the terminal.

Please use Usenet correctly or FOAD.






I would direct your juvenile rantings to Microsoft instead.
It is they who have made Live Mail do this, and they won't fix it.


Most of us seem able to cope with this though.

On 01/15/2016 11:30 AM, Dave Platt wrote:
In article ,
Gareth Magennis wrote:

Is there a tried and trusted way of adding a conductive contact pad?

For what it's worth: I've had pretty good luck restoring conductive
pads using a product called Neolube #2. It's a water/alcohol
suspension of extremely fine graphite, with a small amount of a
thermoplastic resin (possibly cellulose acetate?) as a binder. It can
be applied with a fine brush or Q-tip.

I recently purchased a bunch of surplus Kenwood UHF mobile radios.
About half of them had intermittent or non-working keys on the molded
keypads. The pad sheet had originally been made with some sort of
sprayed-on or molded-on conductive coating, and I could see where it
had been worn off the keys in question (the rubber was shiny and I
could actually see the shapes of the corresponding PC-board traces).

Cleaned with alcohol, painted on a couple of thin coats of Neolube,
and they work fine.

I can't swear as to how long it will hold, but Neolube seems to have a
respectable "grip" on the surfaces I've painted it onto. Its info
sheet is interesting... they talk about how its carbon is so pure than
neutron activation of contaminants isn't an issue, and so it's rated
for use in nuclear reactors.




I can't find a distributor in Canada for Neolube, however MG Chemicals
makes a product for renewing rubber contracts:

http://www.mgchemicals.com/products/...pair-kit-8339/

Available in Vancouver from Main Electronics and RP Electronics.

Not cheaper than the US stuff...

In the US you can get it from Micro-Mart:

http://www.micromark.com/neolube-2-fl-oz,8383.html

John :-#)#

--
(Please post followups or tech inquiries to the USENET newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
(604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."

In article ,
John Robertson wrote:

I can't find a distributor in Canada for Neolube, however MG Chemicals
makes a product for renewing rubber contracts:

The lawyers might have something to say about enforceability in that
case :-)

In the US you can get it from Micro-Mart:

http://www.micromark.com/neolube-2-fl-oz,8383.html

That's where I got mine.

Warning: for a tools junkie, the Micro-Mark catalog is dangerous.

On Friday, January 15, 2016 at 2:47:08 AM UTC-8, mike wrote:
On 1/15/2016 1:22 AM, Gareth Magennis wrote:

The customer has ripped out all the contact buttons on the right side of
the keyboard, the left side set is still in place and working.

I can't imagine you can manufacture new keys at a repair price the
customer could tolerate.

There's a guy who shows up at local ham radio swapmeets and sells
radio attachment gizmos.
He has a 3D printer and claims to be willing and able to make custom gizmos.

It ain't quick, but you could digitize the shape of an ideal key set, get a 3D print of
its upper and lower surfaces (actually, just the lower surface is critical, the upper
can be done with hand tools), and mold your own key sheet.
If left-side and right-side match, you can (with care) dupe a left-side sheet,
building molds by (if necessary) bronzing the model item.

It'd be easier to get an off-the-shelf product, but most manufacturers (google on
"elastomer kepad" aren't big on stocked items.

http://www.eecoswitch.com/wp-content/uploads/2011/08/ElastomerKeypads.pdf

So, are there any similar keypads on any items that have spare-parts departments?

"whit3rd" wrote in message
...

On Friday, January 15, 2016 at 2:47:08 AM UTC-8, mike wrote:
On 1/15/2016 1:22 AM, Gareth Magennis wrote:

The customer has ripped out all the contact buttons on the right side of
the keyboard, the left side set is still in place and working.

I can't imagine you can manufacture new keys at a repair price the
customer could tolerate.

There's a guy who shows up at local ham radio swapmeets and sells
radio attachment gizmos.
He has a 3D printer and claims to be willing and able to make custom
gizmos.

It ain't quick, but you could digitize the shape of an ideal key set, get a
3D print of
its upper and lower surfaces (actually, just the lower surface is critical,
the upper
can be done with hand tools), and mold your own key sheet.
If left-side and right-side match, you can (with care) dupe a left-side
sheet,
building molds by (if necessary) bronzing the model item.

It'd be easier to get an off-the-shelf product, but most manufacturers
(google on
"elastomer kepad" aren't big on stocked items.

http://www.eecoswitch.com/wp-content/uploads/2011/08/ElastomerKeypads.pdf

So, are there any similar keypads on any items that have spare-parts
departments?






Yes, that is exactly the question here.

I need to cannibalise a contemporary keypad assembly that has conductive
pads at least 5mm diameter.

Failing that, I need to make my own rubber knobs, and somehow incorporate
conductive rubber 5mm pads to operate the PCB switch pads.



I don't think this is actually possible in any kind of reasonable
time/effort scale.



Gareth.

First, clean the PCB with domestic alcool or the good old KF from
Siceront KF (Now F2).
Second, rip the keys contacts with fine abrasive so it is clean.
Third apply some (silver) conductive ink (Microworks for instance).

It's done (let dry 10mn).

I did it for a TV remote control and it works perfectly.

The more simple is often the best !

Contacts are around 0.1 ohm !

Gareth Magennis a écrit :
Hi,

I have a very old synthesiser where the top panel rubber contact
switches no longer work, because the owner has removed the contact strips.

This is the synth:
http://www.vintagesynth.com/sci/stk.php


The contact rubbers are pretty much 10cm x 10cm x 10cm cubes, but they
have a rather large contact footprint.
The corresponding PCB contact gap between the two lands that need to be
bridged is also rather large.
http://tinypic.com/r/14xdmo3/9



So, I am looking into the possibility of replacing the missing buttons
by cannibalising a somewhat more contemporary keypad that has extra
large contacts.

Here's a typical example I found at Farnell. It might be possible to
cut it up and glue it to the keyboard and make things work, if the
contacts are large enough.
http://uk.farnell.com/storm-interfac...rey/dp/9810064




Anyone any such experience here?

I know it's a long shot.



Cheers,


Gareth.

On 2016-01-15, Gareth Magennis wrote:
I would direct your juvenile rantings to Microsoft instead.
It is they who have made Live Mail do this, and they won't fix it.

Using Live Mail even though it sucks and you know it is *your* choice.
Why *should* they fix it when hordes of lemmings will use a free piece
of crap as-is? You're the reason they won't fix it.

The responsibility for conforming to Usenet guidelines is yours alone;
you can't deliberately use some program you know is broken and blame
it on the programmers.

*That* is juvenile; a seven-year-old can easily be found who has a more
sophisticated view of the world than this.

On 15/01/2016 08:24, N_Cook wrote:
On 14/01/2016 23:01, Gareth Magennis wrote:
Hi,

I have a very old synthesiser where the top panel rubber contact
switches no longer work, because the owner has removed the contact
strips.

This is the synth:
http://www.vintagesynth.com/sci/stk.php


The contact rubbers are pretty much 10cm x 10cm x 10cm cubes, but they
have a rather large contact footprint.
The corresponding PCB contact gap between the two lands that need to be
bridged is also rather large.
http://tinypic.com/r/14xdmo3/9



So, I am looking into the possibility of replacing the missing buttons
by cannibalising a somewhat more contemporary keypad that has extra
large contacts.

Here's a typical example I found at Farnell. It might be possible to
cut it up and glue it to the keyboard and make things work, if the
contacts are large enough.
http://uk.farnell.com/storm-interfac...rey/dp/9810064





Anyone any such experience here?

I know it's a long shot.



Cheers,


Gareth.




What is the minimum resistance/mm of gap required?


Is it simple on/off contacts or is change of R monitored for key "action"

On Fri, 15 Jan 2016 11:15:52 -0800, Jeff Liebermann
wrote:

I found a part I had made using Flexane 94, which shows 85, so that's
much to hard to flex. I don't have something handy that will work,
but I'll do some catalog searching this weekend. Offhand, I would
suspect that bathroom caulk, rain gutter seal, or other commonly
available silicone rubber compound might work but might also be too
soft (typically 25 to 30 durometers). Structural silicone might be
harder. Digging:
http://www.siliconeforbuilding.com/pdf/structuralglazing/Data_Sheet_SSG4000_UltraGlaze.pdf
Argh... only 39.

One of my customers, who customizes automobiles, recommended this
stuff:
https://www.freemansupply.com/products/liquid-tooling-materials/mold-making-silicone-rubber/bluestar-addition-cure-silicone-rubber/v-340-mold-making-silicone-rubber-low-viscosity
http://www.miapoxy.com/p-124-bluestar-v-340-silicone-rubber.aspx
Note the 400% elongation before tearing. Ideal would be 45 to 50
durometer, so methinks the 45A version might work best. He didn't
have a cured sample, so I dumped a blob on a piece of wood. We'll see
what it looks like on Tuesday.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

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On Sat, 16 Jan 2016 10:32:36 +0000, N_Cook wrote:

Is it simple on/off contacts or is change of R monitored for key "action"

http://oi65.tinypic.com/14xdmo3.jpg
The piano keys on a synthesizer might require some form of velocity
sensing which most assuredly is NOT resistive. The buttons in the
above photo are for turning things on/off and are therefore simple
on/off connections.
http://www.dummies.com/how-to/content/key-feel-and-response-of-keyboards.html



--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

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On 16/01/2016 18:44, Jeff Liebermann wrote:
On Sat, 16 Jan 2016 10:32:36 +0000, N_Cook wrote:

Is it simple on/off contacts or is change of R monitored for key "action"

http://oi65.tinypic.com/14xdmo3.jpg
The piano keys on a synthesizer might require some form of velocity
sensing which most assuredly is NOT resistive. The buttons in the
above photo are for turning things on/off and are therefore simple
on/off connections.
http://www.dummies.com/how-to/content/key-feel-and-response-of-keyboards.html




I don't know how many contacts are required.
I just tried taking a standard simple 10x10mm footprint click switch
apart , parts just clipped together. Cutting a disc of thin 1mm
silicone rubber, placing over the dome contact and reassembling , the
click noise and abrupt click action disappears, but still functions.
If they can be soldered to the pcb, ignoring the resistive pads, then
only a matter of fudging the right size and height of top protrusion to
glue over the stem of the switches,if necessary .
Well thats my halfpennyworth

"N_Cook" wrote in message ...

On 16/01/2016 18:44, Jeff Liebermann wrote:
On Sat, 16 Jan 2016 10:32:36 +0000, N_Cook wrote:

Is it simple on/off contacts or is change of R monitored for key "action"

http://oi65.tinypic.com/14xdmo3.jpg
The piano keys on a synthesizer might require some form of velocity
sensing which most assuredly is NOT resistive. The buttons in the
above photo are for turning things on/off and are therefore simple
on/off connections.
http://www.dummies.com/how-to/content/key-feel-and-response-of-keyboards.html




I don't know how many contacts are required.
I just tried taking a standard simple 10x10mm footprint click switch
apart , parts just clipped together. Cutting a disc of thin 1mm
silicone rubber, placing over the dome contact and reassembling , the
click noise and abrupt click action disappears, but still functions.
If they can be soldered to the pcb, ignoring the resistive pads, then
only a matter of fudging the right size and height of top protrusion to
glue over the stem of the switches,if necessary .
Well thats my halfpennyworth







Look at the photo, I need to replace the 0-9 data entry keypad on the far
right of the panel, and the four buttons to the left of it.
http://www.vintagesynth.com/sci/stk.php


The customer has said he wants the keyboard for his own use, so doesn't
require it to be restored to original condition, so I am now thinking I
might be able to find a 16 way keypad and wire it directly to the switching
matrix, and pretty much glue it to the top panel.
(He now realises ripping out the old pads because they didn't work properly
was not a good idea. I think he has been using a screwdriver to operate the
pads)

It will need some hacking because from memory, 0 - 7 have a common line, 8 &
9 use part of another, and the other switches I think are kind of random in
the matrix.



Gareth.

"Kaz Kylheku" wrote in message ...

On 2016-01-15, Gareth Magennis wrote:
I would direct your juvenile rantings to Microsoft instead.
It is they who have made Live Mail do this, and they won't fix it.

Using Live Mail even though it sucks and you know it is *your* choice.
Why *should* they fix it when hordes of lemmings will use a free piece
of crap as-is? You're the reason they won't fix it.

The responsibility for conforming to Usenet guidelines is yours alone;
you can't deliberately use some program you know is broken and blame
it on the programmers.

*That* is juvenile; a seven-year-old can easily be found who has a more
sophisticated view of the world than this.





Yawn.

Get over it. Everyone else can adjust and read it just fine.

On Sat, 16 Jan 2016 20:32:28 -0000, "Gareth Magennis"
wrote:

How to quote properly with Windoze Live Mail:
http://www.dusko-lolic.from.hr/wlmquote/
Mo
https://www.google.com/#q=windows+live+mail+usenet+quote

The customer has said he wants the keyboard for his own use, so doesn't
require it to be restored to original condition, so I am now thinking I
might be able to find a 16 way keypad and wire it directly to the switching
matrix, and pretty much glue it to the top panel.
(He now realises ripping out the old pads because they didn't work properly
was not a good idea. I think he has been using a screwdriver to operate the
pads)

Well, if you're going to butcher the synth, then it might be possible
to just solder in some switches with a long shaft. Something like
these:
http://www.ebay.com/itm/221708447229
Yes, that's 100 pcs for $1.74. I bought 1,000 and no problems. The
extra long shaft is handy for attaching a push button. If it sticks
through the synth panel, you win.

It will need some hacking because from memory, 0 - 7 have a common line, 8 &
9 use part of another, and the other switches I think are kind of random in
the matrix.

No hacking required with the above suggestion.

Am I getting a commission on this deal?

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

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"Jeff Liebermann" wrote in message
...

On Sat, 16 Jan 2016 20:32:28 -0000, "Gareth Magennis"
wrote:

How to quote properly with Windoze Live Mail:
http://www.dusko-lolic.from.hr/wlmquote/
Mo
https://www.google.com/#q=windows+live+mail+usenet+quote

The customer has said he wants the keyboard for his own use, so doesn't
require it to be restored to original condition, so I am now thinking I
might be able to find a 16 way keypad and wire it directly to the switching
matrix, and pretty much glue it to the top panel.
(He now realises ripping out the old pads because they didn't work properly
was not a good idea. I think he has been using a screwdriver to operate
the
pads)

Well, if you're going to butcher the synth, then it might be possible
to just solder in some switches with a long shaft. Something like
these:
http://www.ebay.com/itm/221708447229
Yes, that's 100 pcs for $1.74. I bought 1,000 and no problems. The
extra long shaft is handy for attaching a push button. If it sticks
through the synth panel, you win.

It will need some hacking because from memory, 0 - 7 have a common line, 8
&
9 use part of another, and the other switches I think are kind of random in
the matrix.

No hacking required with the above suggestion.

Am I getting a commission on this deal?





Er, no, because it is not possible to solder these switches, or even mount
them, to the conductive pads on the PCB.


I am still in favour of a 16-way keypad glued to the synths top panel, with
flying leads/ribbon cable (hidden beneath such keypad) attached directly to
the keyscan ports.



Gareth.

On Sun, 17 Jan 2016 00:48:23 -0000, "Gareth Magennis"
wrote:

Er, no, because it is not possible to solder these switches, or even mount
them, to the conductive pads on the PCB.

They don't need a low resistance connection. Just a connection. You
can probably glue them in place with some hot melt glue. Or, if you
want something better, solder tiny squares of sheet copper to the
switch legs, and glue that in place. If you like spending your
customers money, try some conductive graphite flake or silver "paint"
and bury that under a layer of hot melt glue.

I am still in favour of a 16-way keypad glued to the synths top panel, with
flying leads/ribbon cable (hidden beneath such keypad) attached directly to
the keyscan ports.

Common decency, aesthetics, and my moral obligation to clean living
prevent me from offering an opinion of that idea. Sure, it will work,
but will be seriously ugly and messy. It's ok to fix something but
when you're done, it has to look good. Perception is everything,
which begs the question of whether the customer is going to pay for a
hacked keypad fix.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

"Jeff Liebermann" wrote in message
...

On Sun, 17 Jan 2016 00:48:23 -0000, "Gareth Magennis"
wrote:

Er, no, because it is not possible to solder these switches, or even mount
them, to the conductive pads on the PCB.

They don't need a low resistance connection. Just a connection. You
can probably glue them in place with some hot melt glue. Or, if you
want something better, solder tiny squares of sheet copper to the
switch legs, and glue that in place. If you like spending your
customers money, try some conductive graphite flake or silver "paint"
and bury that under a layer of hot melt glue.

I am still in favour of a 16-way keypad glued to the synths top panel, with
flying leads/ribbon cable (hidden beneath such keypad) attached directly to
the keyscan ports.

Common decency, aesthetics, and my moral obligation to clean living
prevent me from offering an opinion of that idea. Sure, it will work,
but will be seriously ugly and messy. It's ok to fix something but
when you're done, it has to look good. Perception is everything,
which begs the question of whether the customer is going to pay for a
hacked keypad fix.





Well, exactly. Though I'm privy to information you are not, being as I have
talked to the customer.

He knows he has really f888ed up this keyboard, but is really only
interested in having some way to program it, now he has destroyed the input
capability.
He just wants some way of using it in his studio, aesthetics are not part of
the equation.

I'm thinking I could perhaps knock up a 16 way keypad and hardwire it in,
say, 5 hours? (not counting the hours of research I am currently
undertaking)
Then I would be charging him something like 2 or 3 hours, and we would all
be happy.



Sometimes Work and hobby, and just trying to help someone out, merge into
something you actually might quite like to attempt!




Gareth.

On Saturday, January 16, 2016 at 5:40:15 PM UTC-8, Gareth Magennis wrote:

...really only
interested in having some way to program it, now he has destroyed the input
capability.
He just wants some way of using it in his studio, aesthetics are not part of
the equation.

I'm thinking I could perhaps knock up a 16 way keypad and hardwire it in,
say, 5 hours? (not counting the hours of research I am currently
undertaking)

Oh, just buy a 4x4 keyypad, they[re not completely unavailable

https://www.adafruit.com/products/1611

Hand-wiring would be one way. If the buttons magically line up, just cut the membrane
part off and do a transplant.

On 16/01/2016 19:40, N_Cook wrote:
On 16/01/2016 18:44, Jeff Liebermann wrote:
On Sat, 16 Jan 2016 10:32:36 +0000, N_Cook wrote:

Is it simple on/off contacts or is change of R monitored for key
"action"

http://oi65.tinypic.com/14xdmo3.jpg
The piano keys on a synthesizer might require some form of velocity
sensing which most assuredly is NOT resistive. The buttons in the
above photo are for turning things on/off and are therefore simple
on/off connections.
http://www.dummies.com/how-to/content/key-feel-and-response-of-keyboards.html





I don't know how many contacts are required.
I just tried taking a standard simple 10x10mm footprint click switch
apart , parts just clipped together. Cutting a disc of thin 1mm
silicone rubber, placing over the dome contact and reassembling , the
click noise and abrupt click action disappears, but still functions.
If they can be soldered to the pcb, ignoring the resistive pads, then
only a matter of fudging the right size and height of top protrusion to
glue over the stem of the switches,if necessary .
Well thats my halfpennyworth

I read original ref as top manual for top pannel. The above idea was for
unobtainium contacts under piano keys, rather than just a controls
pannel where any old switches , in place of pcb pad contacts, would do