[Premium-Rx] Cubic R-3030: Problems and WTD original manual

[GandalfG8 at aol.com]

In a message dated 11/07/2012 02:20:22 GMT Daylight Time,  
hbreuer at debitel.net writes:

The  Cubic R-3030 is actually two identical receivers in a single 
cabinet.  Overall the cosmetic condition is good but the foil keyboards 
are  annoying. There is either no contact or the key bounces. Anybody has 
a  solution for it?
 
Hi Heinz
 
There are two issues with the keypads, firstly that the value of the  
keybounce suppression cap in the interface module is too low, and secondly that  
the keypad plastic overlays become detached from the keypads and bulge in  
the middle because they are held in place by machine cut double sided tape 
that  has a relatively small contact area on the thin frames separating the 
individual  keys.
 
Issue one is dealt with by increasing the value of C2 in the Panel  
Interface Module from 3.3uF to somewhere closer to 10uF.
This cap goes from pin 7 of U6, the 74C923 Keyboard Encoder to ground, and  
I found it easier to leave the existing capacitor in place and fit another  
in parallel across the top of the IC and soldered to the actual IC pins. I  
used 6.8uF but 4.7 uF would probably be ok too, or perhaps it was the other 
way  round it was a few years ago now:-)
 
In the case of the keypad overlays, I found it was possible, if very  
careful, to remove them without damage and to cut some replacement double sided  
tape and reinstall them.
However, this sounds a lot more straightforward than it is in  practice, it 
is NOT a fun job but may be your only option.
A few years ago Cliff, W4NJ and also on this list, had some  replacement 
overlays made to the original spec and if he still has any available  this is 
by far the best option for replacement, but I'd try the capacitor mod  first 
just in case that's all you need.
 
Finding original extenders would indeed be a long shot but it may not be  
too difficult to make your own.
The R3030 uses either standard DB25 connectors or DB25 coax shells with  
varying numbers of inserts.
The DB25 wired connectors are easy enough to extend and the inserts do not  
need to be mounted in a shell for test purposes.
Both male and female inserts are available and you should never need more  
than five coax extenders for a single module.
 
Regards
 
Nigel
GM8PZR