[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
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