[time-nuts] Dead Thunderbolt Explored - Any Chance of Resurrection?

[J. L. Trantham]

Many months ago, I lost a TBolt when it was connected to a small 'laptop
like' power supply.  As I recall, this power supply came with the TBolt as
part of the Group Buy but I could be wrong.  The failure occurred at a time
when my workshop was experience very frequent power outages and thus
frequent cycling of the 110 VAC.

Yesterday, I had to opportunity to explore it.  The only externally
noticeable difference between it and a functioning unit is that the 5 VDC
current is high at about 410 mA instead of about 220 mA and U22, a Xilinx
XC5202 256 cell FPGA, gets quite hot.  Functionally, it puts out 10 MHz and
the OCXO functions as expected with the +12 VDC current exceeding 550 mA
(the limit of my power supply) for a few minutes then settling at about 140
mA.  However, there is no ability to communicate via the serial port, it
does not discipline (as judged by observing the output frequency vs. a
functioning unit) and there is no 1 PPS output.  There is + 4.9 VDC on the
antenna connector.

In spite of being 'dead' it does have some  redeeming qualities.  It has the
Trimble OCXO, the rev. D DS1620, and F.W. = 3.00.

Therefore two questions.

1.  Is it likely that the FPGA is the culprit or just the victim of another
failure?

2.  What is the likelihood of repair?

Any and all thoughts appreciated.

Thanks in advance.

Joe