[time-nuts] Thunderbolt no usable sats.

Arthur Dent golgarfrincham at yahoo.com
Sun Jun 12 10:04:34 UTC 2011

"I bougth an Thunderbolt off E-bay some time ago, to use as 
reference for my spectrum analyzer and signal generators.
I had it connected up with a couple of power supplies and it 
worked as it should. Today I put together an voltage inverter 
to get the -12V to the GPS in order to use it with an single 
12V power supply."
The -12 requires 10 ma according to the manual but in reality 
probably draws about 2 ma so loading shouldn't be a problem.
You didn't mention the 5 volt supply at all. The +5 VDC should 
be able to supply at least 400 ma and the  +12 VDC 750 ma. 
Ripple and noise should be around 15 MV max for the +5 VDC
and 20 MV for the +/-12 VDC.

The -12 VDC is used for the RS-232 so if that was giving you 
the problem you wouldn't see anything on your com port (note 
it will work at -7 VDC or so) and if the +5 VDC was off you 
wouldn't see anything on Lady Heather. The +12 VDC is for 
the oven.  

If the unit was working before on the other supply, go back to 
that supply and make sure it still works to see if it is your new 
supply setup or maybe you accidently fried something. If it 
works on the old supply, connect the new supply and recheck 
all connections and voltages both with a meter and a scope 
(or your spectrum analyser) to see if there is anything unusual.

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