[time-nuts] powering Trimble Thunderbolt with -5V rather than -12V

Arthur Dent golgarfrincham at yahoo.com
Thu Oct 31 23:11:53 UTC 2013


Having dismantled a good number of the wireless locator units 
that these Trimble Thunderbolts were in I can tell you that the 
DC-DC power supply in these units did not have a -12VDC output 
but put out -7VDC instead. 

If I recall the DAC output voltage of almost all the T-bolts I tested 
was between about +0.1 and +0.8VDC and this has allowed some 
people to use just a +5 and a +12 supply and not even connect the 
-12 line or ground it. If the EFC required for the OCXO to output
10Mhz was a negative voltage (which it was for some people), not 
having a negative supply would cause a problem. I don't recommend 
not using a - supply but the level of the negative regulated supply 
doesn't appear to be that critical. 

-Arthur


More information about the Time-nuts_lists.febo.com mailing list