[time-nuts] Racal-Dana tactile switches

GandalfG8 at aol.com GandalfG8 at aol.com
Sat Apr 5 17:32:06 EDT 2014

In a message dated 05/04/2014 22:10:50 GMT Daylight Time, bix at jimbixby.com  

I  finally had to dive into my Racal Dana 1992 counter, after it had  
developed several bad switches. I found that through-hole 6x6mm tactile  
switches with four leads will fit in the counter pcb holes diagonally.  
is, if you trim off the leads from two opposite corners, the other  two 
are very close to the required distance to go into the existing  pcb holes. 
just ordered some of these switches from ebay with a long  plunger that 
to be perhaps 2mm round. I'm going to drill holes into  the back of the 
existing keycaps to be a press-fit to the plunger on the  new switches. I 
think it will all hold together. If this works, it is a  cosmetically and 
functionally perfect solution. I'll report back after  I've tried it.

The switches I picked are 6x6x10.5mm Tactile Pushbutton  Switches, 
ebay item 161008571229, 

Hi Jim
Below is a copy of a post I made to the list in April 2012, with a link at  
the end that you might find useful.........

I made a successful repair of a Racal 1991 counter that I  originally 

bought as a spares unit, the original switches and switch caps  had already 

removed and discarded, but decided after all that it was too  good to just 

use for parts, especially as all that ever seems to fail  anyway are the 



As I believe others have also suggested I found that 6mm square  tactile 

PCB switches could be modified to fit in place of the original Racal  


Refitting the original switch caps wasn't an option for me, but whilst  

trying to devise some convenient method of operating the normally very  

PCB switches through the front panel I came across some  switches on Ebay 

with extended actuators.

Using a switch with an overall height of 13mm allowed the actuator to  

protrude approximately 3mm through the panel and this works remarkably  


It's obviously not totally ideal, one downside for many would be that  the 

keypad numbering is normally only on the switch caps, although I was  lucky 

with this unit and the numbers were part of the panel markings, but  it did 

restore the 1991 to being a perfectly usable counter.


However, given that most users contemplating something similar would  

probably still have the original switch caps, and that it shouldn't be  too 

difficult to refit these to the longer actuators, I think such  switches 

provide at least one answer to the problem.


Anyway, I've written up a few notes to go with some photos I took whilst  

fitting the switches to my unit and have uploaded these to Rapidshare  just 

in case anyone might be interested......





Please feel free to share or bin this as you think fit:-)







More information about the time-nuts mailing list