[Premium-Rx] Racal 9400 reference osc "jumpy"

[Dan Rae]

Stein-Olav Lund wrote:
> Hello,
>
> I have an older VHF transceiver tester from Neuwirth which uses a Racal
> 9400 reference oscillator at 5 MHz.
>   
> Are these oscillators possible to open for repair without destroying
> anything? Any tips are welcome.
>
>   
Stein-Olav,

These can generally be opened and fixed, just be careful about the very 
fine wires that go through to inside the foam.  I don't think any of 
this series were soldered up so opening them is a lot simpler than the 
ones that are sealed.  Also there have been a lot of the later 9420 and 
smaller 9442 units on eBay, often at very reasonable prices, you will 
just need to know what Voltage your unit operates at; some are 5 and 
some 12 Volts.   There is a 5 Volt 9421 up at the moment from the UK: 
item  250404798046 , as well as a 9442.   The 9442 is a rapid warm up 
type with the same footprint, but not as tall.

If there is an intermittent jump like you describe then the trimmer 
itself may be at fault, and working it a bit back and forth before doing 
the adjustment may cure it.  

Dan