[time-nuts] ?Death of TBolt?

J. L. Trantham jltran at worldnet.att.net
Sun Oct 26 17:44:32 UTC 2008


I have developed a problem with one of the TBolt's that I got through TAPR.

I was using it with the supplied power supply to provide a 1 PPS to a Brooks
Shera controller to discipline an HP105B 5 MHz oscillator.  I also have a
Z3816A that I was using to clock a 5370B and a 5372A and to compare the 10
MHz out of the TBolt and the HP105B.  It had been on for about 3 weeks and
all was well, talking to TBoltMon, 'locked' lissagous figure on a Tek 485
scope, frequencies of 10.000 000 000 00 and 5.000 000 000 00 MHz,
respectively, +/- about 50E-11, etc.

I turned all equipment off last night, getting ready for the next step of
installation of the equipment in racks.

This AM, I turned the TBolt back on and no communication with TBoltMon.  It
did have a sine wave out around 10 MHz.  I did not check the 1 PPS.  I
switched power supplies and same response.  I turned on the 3816A and
allowed it to get to a FFOM of 0 and watched the 10 MHz signals on the
scope.  The TBolt 10 MHz is way off, but after a while, it does eventually
come close to the 3816A but never 'locks'.  It also seems to heat up
appropriately further indicating that the oven is heating.  My other TAPR
TBolt fired right up, no problem, and 'locked', with the lissagous figure
'frozen'.  I also tried the 'suspect' power supply (after verifying
voltages) on the 'good' TBolt and all was well.

Any ideas?  An on board power issue failing the receiver and the RS232?  The
power supply not a good choice for long term use?  Any circuit diagram
available?

I opened the TBolt and no obvious issues.

All suggestions welcome.  

Thanks,

Joe




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