[time-nuts] Thunderbolt no usable sats.

Thomas S. Knutsen la3pna at gmail.com
Fri Jun 17 00:58:31 UTC 2011


Thanks for all the information, this is an great group.
Does anyone have the shematic on the box?

BR.
Thomas.

2011/6/12 Ed Palmer <ed_palmer at sasktel.net>:
> Is there more than one hardware version of the T'bolt?
>
> Mine has U18 (right behind the RS-232 connector) as an Intersil ICL232IBE.
>  This is a dual RS-232 transceiver that includes a doubler and inverter to
> generate plus and minus 9 to 10 volts from the +5 input.  It appears to have
> the required capacitors on the bottom of the board.  The open circuit RS-232
> voltages on mine are just under 10 volts which seems a little low for a 12
> volt source.
>
> I didn't try to run mine without -12, but the presence of that chip and
> messages on this list made me think that the -12 was only used for the DAC.
>
> Ed
>
> WarrenS wrote:
>>
>> I've run test of the effect of the Neg supply on a Tbolt's operation and
>> the effect on it's noise.  (It would seem I'm one of few nuts that actually
>> test things) The Neg supply effects the RS232 neg swing and the neg output
>> of the DAC.
>> As long as the Dac out (OSC EFC input) is > than a couple of volts above
>> the neg supply (or the EFC is positive)  all worked fine at any Neg supply
>> down to -3 volts.
>> This is because most RS232 receivers don't need their input to swing
>> negative.
>> Your -7 volts statement agrees well with my test. You can go even lower on
>> the neg supply with no ill effects IF you do not need the DAC output to go
>> all the way to neg -5Volts.
>>
>> ws
>> PS I did not test for the effects with a Neg supply less than -3 volts, It
>> may of been able to go even lower, I just wanted to insure it was reliable
>> with -5 volts for my application.
>>
>>
>> ******************
>>
>> [time-nuts] Thunderbolt no usable sats.
>> Arthur Dent golgarfrincham at yahoo.com
>> "It may or may not be used for tuning voltage but what I said is
>> 100% correct. The Andrew/Grayson units these T-Bolts were
>> used in provided -7 VDC for this negative supply and the same
>> T-Bolts work properly on -12 VDC. If this voltage is missing, the
>> com port will not work."
>> +++++++++++++++
>> Please read what I actually said. Do you disagree that these units will
>> not run on -7 VDC or that the com port will not work if the negative supply
>> is missing?
>>  -Arthur
>>
>>
>
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