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 _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.