[time-nuts] Tbolt failure modes

shalimr9 at gmail.com shalimr9 at gmail.com
Fri May 11 16:56:41 UTC 2012


The -12V is only used to support the RS-232 driver. The CPU should be running and you should have discipline even without the -12V

Didier KO4BB

Sent from my BlackBerry Wireless thingy while I do other things...

-----Original Message-----
From: "J. L. Trantham" <jltran at att.net>
Sender: time-nuts-bounces at febo.com
Date: Tue, 8 May 2012 21:29:06 
To: 'Discussion of precise time and frequency measurement'<time-nuts at febo.com>
Reply-To: Discussion of precise time and frequency measurement
	<time-nuts at febo.com>
Subject: Re: [time-nuts] Tbolt failure modes

I had a failure of my -12 V supply that interrupted communications that was
resolved by fixing the -12 V supply.  You might want to make sure you are
getting the -12 V supply in the unit.  I suspect your 24 V supply provides
power to an internal supply that generates +12, +5 and -12 V.

Might want to check if that is the case for your unit and if the -12 V is
present.

Hope this helps.

Joe

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of bg at lysator.liu.se
Sent: Tuesday, May 08, 2012 4:52 PM
To: time-nuts at febo.com
Subject: [time-nuts] Tbolt failure modes

Hi group!

Just got a few Thunderbolts. It is a few PN 39448-61 and one PN 38223-61.
Date codes from 9932 to 0025. This is the "normal" version with a 24VDC
power board and Tbolt board integrated in a small AL box with red
markings. One of the receivers is having a problem. Measuring from the
outside there is:

  1) Takes the same amount of power as the working units.(to the
resolution measured)
  2) Has 10MHz output.
  3) Has 4.9VDC on antenna center pin.
  4) -8.9VDC stable on rs232 Tx pin (pin2 in DB9)
  5) 10MHz is 0.7Hz off after many power on hours with known good antenna
  6) TP9 & TP10 (close to the GPS board power connector) has 4.9VDC
  7) Tboltmon will not talk to the board.
  8) There is no serial output at all from the Tbolt.

Differences compared to a good Tbolt

  1) Tboltmon will ofcause communicate.
  2) After locking 10MHz will be very close to nominal
  3) TP9 and TP10 shows a square wave (ca 7V pp, 9.795625000kHz)

I have looked at Tom's page at

    http://www.leapsecond.com/tbolt-faq.htm

Brooke's at

    http://www.prc68.com/I/ThunderBolt.shtml#IC

and John's at

    http://www.ke5fx.com/tbolt.htm

Are there other good Thunderbolt sites?

Has anyone done debugging of faulty Tbolts? Comments on what might be
wrong with my faulty unit? (I am not that experienced in hardware
debugging...)

--

    Björn






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