[time-nuts] Need a schematic of Trimble 2003 era Thunderbolt RX

GandalfG8 at aol.com GandalfG8 at aol.com
Wed Oct 23 04:42:11 EDT 2013


Hi Bob
 
As far as I'm aware there is no schematic available for the Thunderbolt,  
I'm pretty sure it would have been shouted here with glee is anyone had found 
 one:-)
 
If your specific requirement though is to monitor for failure of the 10MHz  
output then monitoring the DC conditions before any output capacitor 
doesn't  strike me as being adequate.
Whilst it's quite possible that a DC failure in the output circuit, or  
perhaps a significant change in DC operating conditions, could indicate a  loss 
of the 10MHz signal, the reverse would not seem to be necessarilly  
implied, oscillator failure, for example, or other component failure earlier in  
the signal path, might leave any output section fully functional with DC  
conditions unchanged but still with no output.
 
Are you sure there's no 1 PPS signal available?
Observing short pulses at relatively long PRFs is notoriously difficult and 
 has been commented on here on many occasions. A modern digital scope 
generally  has no problem but triggering an analogue scope requires a bit more  
practice. Again though, even if you confirm that the 1 PPS signal is 
available  and healthy that in itself doesn't guarantee that the 10MHz output is the 
 same.
 
It really comes down to just how important this is to you, if you  really 
want to be sure whether or not there's a 10MHz output then  that's what you 
need to monitor.
It shouldn't be at all difficult, just a highish impedance pick off  from 
the circuit board should do it, or a coax coupler on the output to  pick off 
a small sample of the signal, plus a detector of some kind, perhaps  even a 
10MHz filter if you wanted a degree of confirmation that the frequency  
hasn't jumped significantly, you could probably do it all with off the shelf  
parts from Minicircuits without even opening the box, perhaps even on the 
cheap  via Ebay:-)
 
Regards
 
Nigel
GM8PZR
 
 
In a message dated 23/10/2013 07:12:50 GMT Daylight Time,  
Bob.Burchett at EEonTheWeb.com writes:

Anyone  have a link or PDF of the T-Bolt schematic? We are "never satisfied"
with  how things that seem to be working fine might fail one day in our
critical  environment SO: 

The object of the game is so if the T-Bolt fails to  provide the 10 MHz
signal that the loss of it will trigger a fail-over  mechanism to a backup
source so we built up a monitor-keys-a-controller  circuit that watches the
10 MHz and while we DO have the Trimble PDF manual  it doesn't have a
schematic AND: 

Issue 1 is: We are monitoring the  10 MHz output of the T-Bolt and it 
appears
to be AC coupled so this isn't  as easily detected and we want to tap-in
before the coupling capacitor to  get a straight DC coupled signal for our
special signal monitor circuit;  that is one reason for schematic need 
PLUS: 

Issue 2 is: We see NO  signal coming from the 1 PPS BNC jack and we hear 
that
this is a port that  can be enabled/ disabled and we are hoping one of you
know how to enable it  to output the 1 PPS which we might use to drive the
monitor circuit OR:  

Optionally: how we might rewire it so we can get 10 MHz out of that  
"unused"
jack to feed our monitor  circuit.



Thanks!



Robert L. "Bob" Burchett  WB6SLC

Certified Communications Engineer

Enterprise  Electronics

22826 Mariposa Ave. 

Torrance CA 90502

Direct  line: 310.534.4456

FAX: 310.534.1233

Website:  www.EEonTheWeb.com



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