Repair (Maybe) or Replace Mouse?

[fine-tune]

The microswitches inside a mouse are called "Snap" switches by Omron. They
manufacture switches and relays by the truck load. The tiny bump on the switch
that goes "Snap" is an appropriate name!

A few years ago I purchased two Kensington 72121 corded mice. I liked the
design immediately. The thumb button was large, and the rubberized coating
encouraged you to barely touch the mouse when it was moved. All the problems
I had with other mice seemed to be gone forever.

When 72121 was still being manufactured it was cheap. I will never understand
why I didn't buy several more.

What I want now, is something similar. I don't need or want mice with two or more
thumb buttons. I know they're for navigating web pages, but I want a single, easy
to press thumb button.

During a quick Google search I found a mouse called the Rockfire 4-Button Wireless
Optical Mouse. Model RM-802. I prefer corded mice, but wireless is ok too. Notice
the large thumb button.

There were two possible sources in the USA. One business was destroyed in a flood
and the other is out of stock. There are several other listings in Europe.

Guys, save me from a brand new disease call "Mouse Madness." Can someone help
me find a full size mouse with one thumb button?

The alternative is to replace the Snap switches in my old Kensington mice. I have
no idea if it can be done. If the same switch is common to many different brands
then finding and replacing the switches might be possible.

Obviously, finding a substitute for 72121 is the best way to go.

Any thoughts or ideas would be appreciated.

[Janitor Tzap]

I've replaced switches on Kensington First Generation TrackBalls with Cherry Switches.
See if you can find a number on the Omron Micro-Switches, then go to www.digikey.com
and look through there Catalog, of Omron Micro-Switches.

Or........

Do a Google search on Ebay, Amazon, etc......
For your model Kensington Mouse.
{There are three listed on Ebay $60 each.}

I stopped Mousing Around years ago, once I found the Kensington Trackball K64215.

But the new Kensington trackballs are not as well made as my current one.
And I can't get my old one too work with Windows 7 64-bit very well.


Signed: Janitor Tzap

[Lenp]

Unless the switch has a mechanical fault odds are the contacts are tarnished since the current is so low there is no arcing to help break the oxide layer.
So try this...
Remove the switch and its wiring. Determine the switch's electrical rating from the switch
itself or from the spec sheet. Rig up a low voltage transformer and some lamps to get close to the rating. Hook up the switch and operate it many times.
The small arc from the load will break down the oxide on the switch contacts. The lights should come on and off with each press of the switch. You can stop there but the next step may give long term success. Get a good contact cleaner, I prefer Caig Labs products. You will probably not get he cleaner into the switch by spraying, but put enough cleaner into a small zip bag to cover the switch. Heat he switch with a hot air gun without melting it then drop the hot switch into the cleaner in the bag.
What happens is basic science! The air in the switch expands when it is heated. When the switch is dropped into the cleaner it cools, the air inside contracts and pulls the cleaner in through any opening. Shake the switch to distribute the cleaner. wipe off any excess and cross your fingers!

The same technique works to lubricate those small 'sealed' clock like motors, just use a light oil instead of cleaner.

[Janitor Tzap]

I've cleaned Omron Micro-relays on old VCR's with Denatured alcohol and a Ultrasonic Cleaner.
But you really had to watch the time.
Anything longer than 20 seconds, and you melt the plastic.

Lenp,

Your Arcing technique may not work on all micro switches.
Especially if it's one of the cheaply made ones that the current rating is only like half of what is actually stamped on the outside of the switch.
I know this, because I came across a bunch of Alps Power Switches on some cheap off brand portable TV's.
They were stamped 10 amp Max, but they couldn't even take the 2 to 3 amp draw when the set powered up.
{At least not for very long.}

Does your cleaning technique work on all, or only a few micro switches?

Reason I ask, is I was asked to fix a Industrial Push Button switch on a garage winch.
It had rubber seals in it to keep dirt, oil, or grease out of it, and it was sonically sealed.
Thus, you couldn't open it up, without destroying the switch.

Instead of trying too get some cleaner inside it, I just replaced the switch.
Which was expensive!


Signed: Janitor Tzap

[fine-tune]

Kensington 72121 is listed as a "normal" product on dozens of websites.
For whatever the reasons might be, an uncountable number of companies
never update their websites! You can actually order this mouse and
millions of other long gone products.

I sent several quick emails to some of the companies that are still taking
orders for 72121. If they replied, it was always "discontinued" or "out of
stock."

What makes all these millions of dead web pages almost criminal are the
payment methods. PayPal is great. I feel safe paying through their site.
However, a lot of money (billions, I'm sure) is transferred into oblivion
because so many fully functional web pages are completely out of date!
Yes, PayPal will credit your account for merchandise not delivered, but
it's best to be 100% sure about product availability before ordering.

Since my old Kensington mice began to fail, I've searched eBay many times.
Ususally, there are zero listings for 72121. Occasionally, a used 72121 is
listed. The seller always says, "it's just like new."

The msrp for 72121 was $30.00. I think I paid about $20.00 for the two I
have. Janitor Tzap, you say there are a few listed on eBay for $60.00. Well,
if they are brand new (still in the box) I might consider buying one.

The smart thing is to find an acceptable substitute for my old mice.

I have several different brands of switch and contact cleaners. There is no
doubt that these solvents prolong the life of all electromechanical components.
I tried cleaning the switches in my old Kensington mice. It helps for a few
days, but all switches have a finite life cycle. It's a miracle that something
so cheap lasts for years.

[Janitor Tzap]

Yeah,

It's a pain when the website doesn't update the info or simply pull the old AD.

This is the site that suppose too have the mice.
http://www.wayfair.com/KENSINGTON-Mouse ... fgod9UcAEQ

I'd try contacting them first, before clicking on the "CART" to make sure they still have them.
I'd Call: 800-316-2207
Part #: KMW72400
SKU #: UMX1261


Signed: Janitor Tzap

[Lenp]

Janitor Tzap...
There are no guarantees, but what's to lose since the switch is defective to start with. If the switch is really sealed then it probably won't work, but, If there is a dust boot around the operator than taking that off may reveal a place for the cleaner to get in. In desperation I have made an opening into the switch body for the chemical to enter. I peck drill part way through, taking a 'educated' guess as to what's inside, then if the housing is thermoplastic I use a pointed soldering tip to melt it the last bit, or an awl, so chips don't enter the switch. Sure. it's a crap shot, but like I said, what's to lose?

Hey, I go back far enough that I used to repair contacts on relays and switches with a burnishing tool!

[Janitor Tzap]

Janitor Tzap...
There are no guarantees, but what's to lose since the switch is defective to start with. If the switch is really sealed then it probably won't work, but, If there is a dust boot around the operator than taking that off may reveal a place for the cleaner to get in. In desperation I have made an opening into the switch body for the chemical to enter. I peck drill part way through, taking a 'educated' guess as to what's inside, then if the housing is thermoplastic I use a pointed soldering tip to melt it the last bit, or an awl, so chips don't enter the switch. Sure. it's a crap shot, but like I said, what's to lose?

I too have taken desperate measures too clean expensive switches, or switches that were no longer being made.
From disassembling, cleaning, too even repairing the contacts.
It's just the first, I heard of your technique for getting the cleaner into switch without disassembling it.

Hey, I go back far enough that I used to repair contacts on relays and switches with a burnishing tool!

Hee, Hee.
I still got my burnishing tool as well.
Used it a lot on relays, and the points on small engines, and old cars.


Signed: Janitor Tzap

[Lenp]

Dos the name PK Neuses ring a bell?

If not look here....http://www.pkneuses.com/index.html
I still have several of their items, including the marking kit, in an 'official' Bell System green metal case!