[time-nuts] Tbolt failure modes

[Azelio Boriani]

Agreed, the CPU is not working... check the 3.6864MHz crystal under the
CPU. If it is possible to locate the reset signal...

On Wed, May 9, 2012 at 12:23 AM, <bg at lysator.liu.se> wrote:

> Hi Bob,
>
> The DB-9 looks fine even with magnifying glass.
> The good one has a MAX232EWE IC, the faulty has a TC232EOE. I see
> RS232-level coming in at pin 13 and going inside the Tbolt at pin 12 (ttl
> level).So there should be no problem there.
>
> Have also swapped PSU board, so the problem is inside the actual GPSDO
> board.
>
> The 232 level IC is a dual channel RX/TX translator. Anyone know what the
> second 232 port is used for?
>
> --
>
>   Björn
>
> > Hi
> >
> > The first thing to check is the soldering job on the DB-9 connector.
> > Second thing to check is the RS-232 level translator IC. (RS-232 in
> should
> > create TTL etc)
> >
> > Bob
> >
> > On May 8, 2012, at 5:52 PM, bg at lysator.liu.se wrote:
> >
> >> 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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>
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