[time-nuts] Thunderbolt serial port

[bjones0 at mindspring.com]

I got around to tearing into the Thunderbolt this afternoon and after
testing the serial port and traces in every way I could I found the
problem... The power supply (which got with it in the TAPR buy) went
south apparently.  I got a 24v difference between pins 1 & 6 but when
you checked them against the common the +12v line was @ +6v and the -12v
line was -18v.  The 5v line did not even register.  I pulled a computer
power supply and modified it slightly and once I was providing proper
voltage it works like a champ.  
I never thought to suspect the power supply because when I added the
plug it tested (voltages) okay and once I hooked up the Thunderbolt the
first time it exhibited the same behavior (no serial and the 9.9999978
Mhz on the 10Mhz output). 

Is there anything wrong with running the Thunderbolt from a Computer
PSU?

Thanks for all the help!
Brian


And just passing some unrelated info along... While looking for some
weather related info I ran across someone who was selling new Trimble
active GPS antennas w/ a nice long cable (PN 40767-40) for $15 and now
that my Thunderbolt works I was able to test it and it seems to work
fine (even indoors!).  If anyone want to contact him: Eric Wolf
eric.n5ebw at gmail.com .  Also he emailed me this after I told him it was
working:
"I wanted to pass along something that I have had in my inventory for
about 6 months but cannot find the use for.  It's an AVCOM Microwave
Distribution Module that basically splits a 1575 MHz GPS signal, and
amplifies it to 8 different antennas.  The exact model is MDM-1575-8 and
the description reads:
"The MDM-1575-8 is an 8-way, amplified, 1575 MHz power divider.  The
INPUT port has +5VDC on connector and the 8 OUTPUT ports are DC
Blocked." "




> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
> Behalf Of Brooke Clarke
> Sent: Friday, 20 February 2009 2:35 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Thunderbolt serial port
> 
> Hi Brian:
> 
> There have been a small number of problems related to poor solder joints on
> U9 
> (RS-232 chip) or the serial connector. see:
> http://www.prc68.com/I/ThunderBolt.shtml#Maint
> 
> Have Fun,
> 
> Brooke Clarke
> http://www.prc68.com
> 
> bjones0 at mindspring.com wrote:
> > I'm tired of banging my head against the wall so I think it is time to
> > ask.. Is there a way to test if the serial port on the Thunderbolt
> > works?  I know the Thunderbolt itself powers up and works (I get a
> > 9.9999978 Mhz signal out of the 10Mhz output when it is on) but I have
> > been unable to talk/listen to it in Windows (tboltmon or Lady Heather)
> > or in Linux (even looking at the raw serial port state).  I stuck my
> > breakout box on the line but I get no lights on the Thunderbolt side.
> > 
> > Thanks,
> > Brian
> > 
> > 
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> 
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