[time-nuts] Racal 9420 OCXO

paul swed paulswedb at gmail.com
Wed Aug 24 21:09:45 UTC 2011


Kind of amazing what time-nuts have in there secret documentation.
Though I do not need this thanks for sharing.
Regards
Paul
WB8TSL

On Wed, Aug 24, 2011 at 4:05 PM, Robert Atkinson <robert8rpi at yahoo.co.uk>wrote:

> Hi,
> I've attached a copy of the catalogue specification for Racals OCXOs. They
> do have electronic trim as standard. They are used in the 9478 frequency
> standard. The 9478 service manual specfically states that no information on
> the OCXOs is provided and they must be returned to Racal or appointed agents
> for repair.
>
> Robert G8RPI
>
> --- On Wed, 24/8/11, GandalfG8 at aol.com <GandalfG8 at aol.com> wrote:
>
> From: GandalfG8 at aol.com <GandalfG8 at aol.com>
> Subject: Re: [time-nuts] Racal 9420 OCXO
> To: time-nuts at febo.com
> Date: Wednesday, 24 August, 2011, 16:03
>
> In a message dated 24/08/2011 00:03:19 GMT Daylight Time,
> danrae at verizon.net writes:
>
> I don't  think Racal released circuit diagrams of any of their ovens.  I
> have  traced out the circuit of the rapid warm up oven found in a lot of
> receivers, the 9442-12 and have fixed those, there is a ceramic cap that
> frequently goes wonky.  The two 9420s I have fixed were just broken
> wires; they seem to have used PVC insulated wire which degrades...  I
> haven't done the homework on those yet.
>
> The 9420s I have do have an  EFC input as well as a stabilised Voltage
> out to feed it, and in the  receivers I have that use it [RA1795] the
> fine setting is done from that,  coarse setting from the top adjustment.
> -------------------------
> Hi Dan
>
> I've taken a further look at the RA1794 manual and see now that it does
> confirm a fine tune pot being available when using the 9420.
> Having opened up this oscillator I find there are  connections to every pin
> on the B7G connector so will assume until proven  otherwise that it does
> meet the interface spec shown in the 1794 manual.
> I suspect the comments I've seen claiming most do not have the EFC  option
> is more a case that in many installations it isn't used, which  isn't quite
> the same thing.
>
> Thanks again for your comments.
>
> regards
>
> Nigel
>
>
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