[time-nuts] SRS FS700 questions

GandalfG8 at aol.com GandalfG8 at aol.com
Sat May 3 21:05:32 UTC 2014

Hi Stan
Many thanks for the advice, I was a bit concerned about making any  
adjustments until I'd confirmed it at least appeared to be working correctly but  
I've just taken another look at the manual and can't see any reason why I  
One of my reasons for concern was that although this isn't an option 01  
unit SRS seems to have upgraded the OCXOs to beyond the original basic  spec, 
it's currently fitted with an SRS low noise SC10, and as it stands I'm  
getting the impression I'd be better off just killing the Loran input and  
letting it free run:-)
BTW, the SC10 OCXO manual seems to be one of the few SRS manuals available  
online that does contain the schematic.
Thanks too for the feedback on the LCD backlight, I've found nothing so far 
 to suggest it should be backlit but it could certainly do with it.
In a message dated 03/05/2014 20:19:14 GMT Daylight Time,  
stanw1le at verizon.net writes:

Hello  Nigel,

I would consider doing the maintenance/calibration/performance  
verification procedure in the manual.
A procedure will show if you have  equal swing on the VCXO about the 
center freq needed.
The VCXO can be  mechanically adjusted for center of the VCXO electronic 
control  range.

I recall no backlight on the LCD on mine.

It has been  awhile since I last turned mine on.

Stan, W1LE

On  03-May-14 12:57 PM, GandalfG8 at aol.com wrote:
> My FS700 arrived  yesterday, complete with bonus artistic  effects due to
> the  sender believing a thin coat of bubble wrap  with an outer layer  of
> cardboard cut from a box and just taped on top,  no padding or  air gap, 
would be
> the obvious way to ship   it:-(
> Physically at least it seems to have  survived remarkably well, no damage 
>   the BNCs and the  front panel trim, outer covers and transformer cover 
> looking  pretty good again after a couple of hours work.
> Not having any rack  ears attached was probably quite a bonus with it
> shipped like  this!
> The only obvious internal "damage", and it might have been that  way 
> shipping anway, are three vertical inductors held to the  circuit board by
> silicon rubber or hot melt adhesive that are loose  but still seem to be
> electrically connected
> Anyway, it powered up ok and is indicating it's locked onto Anthorn  in 
> Lessay chain, even if it does believe it's found the never  built station 
> Loop  Head in Ireland:-), but I'm not sure if  it's functioning properly.
> It's close enough that  I don't want to start pulling it apart for the 
> of it without  being sure, and it may just be a case of waiting for it to
>  settle,  but after showing as "locked" for several hours the 10MHz  
output, as
> indicated  both by the internal display and an  external counter, is 
> back and  forth quite rapidly  anywhere within approx +/- 3 parts in  
> There was an obvious  change in the crystal oscillator frequency as the 
>    warmed, and another when the conditioning seemed to take over, but  
> been  "hunting" like this ever since it first indicated lock  and with no
> obvious  change, just when I do think it might be  converging it "opens 
up"  again.
> So first  question is, can anyone tell me please if this is "normal" or
> close  enough that I should expect it to settle eventually, or do I need 
>  start  investigating further?
> Second  question, could somebody confirm please whether or not the LCD
> display  is supposed to be backlit?
> This one isn't, but it's not immediately  obvious from photos I've found
> online whether or not it should be, and  although the contrast range on  
> seems to be fine it's  certainly not easy to see.
> Last question, for now  at least:-), this unit has the FS800 PCB rev C, 
>    revision 2.0 firmware, does anyone know if any later firmware is  
> that  includes Anthorn, or at least Rugby, as part of  the Lessay chain?
> Regards
> Nigel
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