[time-nuts] Thunderbolt power supply open heart surgery

J. L. Trantham jltran at worldnet.att.net
Tue Feb 17 12:46:45 UTC 2009


I had a TAPR Thunderbolt connected to the power supply that came with it and
left it on for several days.  My location is bothered by various power
spikes and outages.

After one power outage that tripped the circuit breaker to the work shop, I
discovered the Thunderbolt injured (no communication, no 1 PPS, but 10 MHz
out was present) but the power supply was OK, at least as measured by a
voltmeter.  I have since powered up a second unit using a nice linear power
supply and no problem leaving it on for weeks at a time.

I have yet to dig in to the Thunderbolt to chase down the problem.


-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Jim Palfreyman
Sent: Tuesday, February 17, 2009 4:13 AM
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] Thunderbolt power supply open heart surgery

Hi folks,

Well I woke up the other morning at 2am to find all the power off in the
house. I was about to ring the power company and thought I'd better check my
meter box. Turns out one of the RCDs had tripped. I reset it and all was

What puzzled me was what tripped it. It took out my workshop, speaking
clock, various GPSDOs and an HP rubidium I've borrowed. However all was
working upon reset.

Today I downloaded Lady Heather and went to test it and noticed the
should-be-running Thunderbolt was cold. I checked the voltages from the
power supply and - nothing. Ignoring the life-or-death dire warnings on the
power supply case I opened it. It had *that* smell. You know the smell of
that special smoke that keeps all electronic components working because when
it's released they stop.

R1 is black and charred.

Can anyone tell me what value R1 is and/or where I might get a new power
supply (just in case it took other components with it)?

Has anyone else had this problem?


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