[time-nuts] ?Death of TBolt?

[J. L. Trantham]

Neville,

Thanks for the reply.  I forgot to give the details of the computer.

I am using an old Dell running Win2000 Pro that has two serial ports and
allows me to monitor the 3816A and the TBolt at the same time.  As I said,
the other TBolt works fine when connected the same way.

I still think the problem is in the TBolt but I am not sure why it is there.
I wonder about the power supply somehow going over voltage or something.

Joe

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Neville Michie
Sent: Sunday, October 26, 2008 5:44 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] ?Death of TBolt?

HI,
I had a TBOLT that developed communication problems and I assumed the  
TBOLT
was at fault. Nothing seemed to make it give out PPS or 10MHz.
It turned out that my PC running VISTA had messed with the com port  
allocations on
the serial to USB converter and although I thought that I had tried  
everything I must
have missed the vital combination of checks and settings.
Ultimately I fired up an old PC running windoze 2000 with a serial  
port as I
suspected the USB-serial converters of not working and I
managed to get a replacement TBOLT to run. When I plugged the 1st TBOLT
into the same set up it ran TBOLTMON OK and has never looked back.
Once I knew the problem was in the COM port emulation I soon got it  
right
and finally got the laptop to run TBOLTMON through USB-serial  
converters.
There seem to be several levels of settings needed in VISTA to get a  
COM port
to work through the USB-serial converter.

I tried two different brands of USB-serial converters on my laptop  
and both work perfectly well.
I hope this may help you,
Neville Michie






On 27/10/2008, at 4:44 AM, J. L. Trantham wrote:

> I have developed a problem with one of the TBolt's that I got  
> through TAPR.
>
> I was using it with the supplied power supply to provide a 1 PPS to  
> a Brooks
> Shera controller to discipline an HP105B 5 MHz oscillator.  I also  
> have a
> Z3816A that I was using to clock a 5370B and a 5372A and to compare  
> the 10
> MHz out of the TBolt and the HP105B.  It had been on for about 3  
> weeks and
> all was well, talking to TBoltMon, 'locked' lissagous figure on a  
> Tek 485
> scope, frequencies of 10.000 000 000 00 and 5.000 000 000 00 MHz,
> respectively, +/- about 50E-11, etc.
>
> I turned all equipment off last night, getting ready for the next  
> step of
> installation of the equipment in racks.
>
> This AM, I turned the TBolt back on and no communication with  
> TBoltMon.  It
> did have a sine wave out around 10 MHz.  I did not check the 1 PPS.  I
> switched power supplies and same response.  I turned on the 3816A and
> allowed it to get to a FFOM of 0 and watched the 10 MHz signals on the
> scope.  The TBolt 10 MHz is way off, but after a while, it does  
> eventually
> come close to the 3816A but never 'locks'.  It also seems to heat up
> appropriately further indicating that the oven is heating.  My  
> other TAPR
> TBolt fired right up, no problem, and 'locked', with the lissagous  
> figure
> 'frozen'.  I also tried the 'suspect' power supply (after verifying
> voltages) on the 'good' TBolt and all was well.
>
> Any ideas?  An on board power issue failing the receiver and the  
> RS232?  The
> power supply not a good choice for long term use?  Any circuit diagram
> available?
>
> I opened the TBolt and no obvious issues.
>
> All suggestions welcome.
>
> Thanks,
>
> Joe
>
>
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