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Restoring Datanetics Keyboard Switches [message #368183] Sat, 26 May 2018 16:08 Go to next message
Anonymous
Karma:
Originally posted by: groink_hi

I have an Apple II 2nd version keyboard with Datanetics switches - the ones with the 15-degree angle on the shaft. This keyboard came with my Apple II J-Plus.

90-percent of the switches are not functioning well. When you press the shaft down, it only pops up half-way. When pressing the shaft down, it feels sticky, as it doesn't push down smoothly. Every now and then the shaft does pop up all the way. Because the buggers are sealed, I can't open them.

I've removed all the switches from the PCB, attempting to thoroughly clean the PCB. This keyboard had a hard life!!! So with the switches sitting in a box, what are some methods of restoring them? Leave them in 99-percent iso alcohol? Any lubes that are safe for the plastic?
Re: Restoring Datanetics Keyboard Switches [message #368184 is a reply to message #368183] Sat, 26 May 2018 17:53 Go to previous messageGo to next message
Michael J. Mahon is currently offline  Michael J. Mahon
Messages: 1767
Registered: October 2012
Karma: 0
Senior Member
groink_hi <groink1@gmail.com> wrote:
> I have an Apple II 2nd version keyboard with Datanetics switches - the
> ones with the 15-degree angle on the shaft. This keyboard came with my Apple II J-Plus.
>
> 90-percent of the switches are not functioning well. When you press the
> shaft down, it only pops up half-way. When pressing the shaft down, it
> feels sticky, as it doesn't push down smoothly. Every now and then the
> shaft does pop up all the way. Because the buggers are sealed, I can't open them.
>
> I've removed all the switches from the PCB, attempting to thoroughly
> clean the PCB. This keyboard had a hard life!!! So with the switches
> sitting in a box, what are some methods of restoring them? Leave them in
> 99-percent iso alcohol? Any lubes that are safe for the plastic?
>

You can clean them with contact cleaner, either sprayed into the shaft or
even by immersion.

Work every switch many times while it’s wet. Dry all switches thoroughly
and reassemble.

--
-michael - NadaNet 3.1 and AppleCrate II: http://michaeljmahon.com
Re: Restoring Datanetics Keyboard Switches [message #368189 is a reply to message #368183] Sat, 26 May 2018 22:30 Go to previous messageGo to next message
Anonymous
Karma:
Originally posted by: Michael Mann

Hi. I have an alternate answer for you, one that's not so upbeat. "No, they cannot be cleaned or repaired." The problem is that the Datanetics DC-50 switches have two copper tangs that are encased between two very thin sheets of mylar. The contacts are encased inside the mylar sandwich, so no type of cleaning fluid can access them. You can press them repeatedly, and maybe rub off some of the oxidation in there, but more than likely, a key that's flaky will remain flaky, and a dead key must be replaced with a key from a donor keyboard.

Search for: "Datanetics_DC-50_Series_Key_Switches.pdf"

From the manual: "Switch Contacts: the switch contacts are cadmium copper alloy with gold-over-nickel plating. Switch Element: the switch element, which encloses the switch contacts, is a mylar and stainless steel sandwich permanently bonded with thermo-activated adhesive to protect the switch contacts from dirt and environmental damage."

In a nutshell: no amount of cleaning fluid can reach the copper tangs; Datanetics DC-50 (canted stems) switches cannot be repaired.
Re: Restoring Datanetics Keyboard Switches [message #368193 is a reply to message #368183] Sun, 27 May 2018 05:36 Go to previous messageGo to next message
Anonymous
Karma:
Originally posted by: groink_hi

I've seen some of Charles' 3-D printed stems on his web site. Which then got me thinking...

Has anyone considered printing a stem adapter or stem replacement that fits a Cherry or other modern key switch, and also allow it to retrofit the 15-degree angled key caps? The key caps I have (remember mine the J-Plus key caps with the katakana characters) can fit certain makes/models of switches. The problem is that all the key switches I've seen sit flat, which then changes the angle, and therefore the usefulness of the key caps from the Datanetics keyboard.

For example, the later keyboard switches on the Apple IIe are easily serviceable. If someone with Charles' 3-D design skills can design a stem adapter or replacement for the old key caps, I could then design a new keyboard PCB layout to use the replacement switches, and still fit my Apple II. I was going to re-make the old Version 2 PCB to replace the one I have, but since I can't repair the switches that I currently have, the 3-D stem replacement idea would the next best thing.
Re: Restoring Datanetics Keyboard Switches [message #368194 is a reply to message #368183] Sun, 27 May 2018 05:41 Go to previous messageGo to next message
Anonymous
Karma:
Originally posted by: groink_hi

On Saturday, May 26, 2018 at 10:08:11 AM UTC-10, groink_hi wrote:
> I have an Apple II 2nd version keyboard with Datanetics switches - the ones with the 15-degree angle on the shaft. This keyboard came with my Apple II J-Plus.
>
> 90-percent of the switches are not functioning well. When you press the shaft down, it only pops up half-way. When pressing the shaft down, it feels sticky, as it doesn't push down smoothly. Every now and then the shaft does pop up all the way. Because the buggers are sealed, I can't open them.
>
> I've removed all the switches from the PCB, attempting to thoroughly clean the PCB. This keyboard had a hard life!!! So with the switches sitting in a box, what are some methods of restoring them? Leave them in 99-percent iso alcohol? Any lubes that are safe for the plastic?

This is what I'm going to do:
http://retroconnector.com/products/apple-ii/apple-ii-keyboar d-alps-short-stem-12-adapter/

I'll design a PCB replacement that will utilize the Alps short-stem switches, use this 3D printed adapter, and fit the Apple II case.
Re: Restoring Datanetics Keyboard Switches [message #368195 is a reply to message #368194] Sun, 27 May 2018 06:35 Go to previous messageGo to next message
Anonymous
Karma:
Originally posted by: groink_hi

On Saturday, May 26, 2018 at 11:41:21 PM UTC-10, groink_hi wrote:
> This is what I'm going to do:
> http://retroconnector.com/products/apple-ii/apple-ii-keyboar d-alps-short-stem-12-adapter/
>
> I'll design a PCB replacement that will utilize the Alps short-stem switches, use this 3D printed adapter, and fit the Apple II case.

In addition, what I'm going to do is, instead of relying on the keyboard encoder MM5740AAE/N chip, I'm going to make this re-design work with Victor Briel's super encoder. Might as well modernize the keyboard!
Re: Restoring Datanetics Keyboard Switches [message #368198 is a reply to message #368189] Sun, 27 May 2018 11:40 Go to previous messageGo to next message
Michael J. Mahon is currently offline  Michael J. Mahon
Messages: 1767
Registered: October 2012
Karma: 0
Senior Member
Michael Mann <gmail@ware4.com> wrote:
> Hi. I have an alternate answer for you, one that's not so upbeat. "No,
> they cannot be cleaned or repaired." The problem is that the Datanetics
> DC-50 switches have two copper tangs that are encased between two very
> thin sheets of mylar. The contacts are encased inside the mylar sandwich,
> so no type of cleaning fluid can access them. You can press them
> repeatedly, and maybe rub off some of the oxidation in there, but more
> than likely, a key that's flaky will remain flaky, and a dead key must be
> replaced with a key from a donor keyboard.
>
> Search for: "Datanetics_DC-50_Series_Key_Switches.pdf"
>
> From the manual: "Switch Contacts: the switch contacts are cadmium copper
> alloy with gold-over-nickel plating. Switch Element: the switch element,
> which encloses the switch contacts, is a mylar and stainless steel
> sandwich permanently bonded with thermo-activated adhesive to protect the
> switch contacts from dirt and environmental damage."
>
> In a nutshell: no amount of cleaning fluid can reach the copper tangs;
> Datanetics DC-50 (canted stems) switches cannot be repaired.
>

I stand corrected.

Interesting that the “high reliability” construction of these switches
renders them unrecoverable.

--
-michael - NadaNet 3.1 and AppleCrate II: http://michaeljmahon.com
Re: Restoring Datanetics Keyboard Switches [message #368201 is a reply to message #368183] Sun, 27 May 2018 16:09 Go to previous message
Anonymous
Karma:
Originally posted by: James Davis

On Saturday, May 26, 2018 at 1:08:11 PM UTC-7, groink_hi wrote:
> I have an Apple II 2nd version keyboard with Datanetics switches - the ones with the 15-degree angle on the shaft. This keyboard came with my Apple II J-Plus.
>
> 90-percent of the switches are not functioning well. When you press the shaft down, it only pops up half-way. When pressing the shaft down, it feels sticky, as it doesn't push down smoothly. Every now and then the shaft does pop up all the way. Because the buggers are sealed, I can't open them.
>
> I've removed all the switches from the PCB, attempting to thoroughly clean the PCB. This keyboard had a hard life!!! So with the switches sitting in a box, what are some methods of restoring them? Leave them in 99-percent iso alcohol? Any lubes that are safe for the plastic?

M.J.M.'s method should work for cleaning the shafts without damaging the sealed contacts. (If you ask him, he might have a suggestion for the proper lubricant, too.) As long as the sealed contacts still work, then cleaning and lubricating the rest of the mechanisms should work for you.
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