Re: [time-nuts] Tbolt failure modes

2012-05-12 Thread Ed Palmer
Joe, Interesting tests. So, in your previous problem, loss of -12V caused loss of communication while in your recent tests, you didn't lose communication, regardless of whether the -12V failure was open or grounded. Okay, now I'm totally confused! Regarding the frequency / locking

[time-nuts] Accubeat AR-40A manual

2012-05-12 Thread Magnus Danielson
Fellow time-nuts, I was just asked to assist on the debugging on a Accubeat AR-40A. He has serial port interface, but not knowing the commands it's a bit hard to get started. He has 2 working and 1 failing, so comparing readings is possible. Does anyone has manuals for it? I looked at the

Re: [time-nuts] AccuBeat AR-40A manual

2012-05-12 Thread Rob Kimberley
Hi Magnus, Have you tried contacting AccuBeat? I believe that Avi Stern is still with them. Try him, I'm sure he will be able to help (and please give him my kind regards). Rob Kimberley -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf

Re: [time-nuts] AccuBeat AR-40A manual

2012-05-12 Thread Magnus Danielson
Hi Rob, On 05/12/2012 11:59 AM, Rob Kimberley wrote: Hi Magnus, Have you tried contacting AccuBeat? Not yet. I believe that Avi Stern is still with them. Try him, I'm sure he will be able to help (and please give him my kind regards). OK, will try to contact him then. Cheers, Magnus

Re: [time-nuts] Tbolt failure modes

2012-05-12 Thread J. L. Trantham
Ed, Looking back on the message, I see your confusion. I guess a better descriptor is 'TBolt Failure' rather than 'failure to communicate'. Clearly, under both scenarios, it was communicating, as indicated by the 'green' COM 1, though not in all areas. I did not notice the DAC or EFC voltage

Re: [time-nuts] Tbolt failure modes

2012-05-12 Thread Robert Atkinson
I'd suggest that when the -12V line is open leakage currents allow it to become positive causing problems (parasitic diodes conducting etc), while if it is tied to ground only the -12V specific functions fail. Robert G8RPI. From: Ed Palmer

Re: [time-nuts] Tbolt failure modes

2012-05-12 Thread shalimr9
Ooops, thanks for the correction... Then I assume that if the voltage is too low for the negative reference headroom, severe stability problems could result. Didier KO4BB --Original Message-- From: Mark Sims Sender: time-nuts-boun...@febo.com To: Time-Nuts ReplyTo: Time-Nuts Subject:

[time-nuts] Tbolt failure modes

2012-05-12 Thread Mark Sims
It sounds like the -12V supply is used to generate the DAC low voltage reference. If it is floating, the DAC output will be unstable. If it is at a solid voltage, the DAC output will be stable. The standard EFC range for a tbolt is -5V to +5V, but since almost all Tbolts are running the

Re: [time-nuts] Tbolt failure modes

2012-05-12 Thread Bob Camp
Hi I have never fully traced out the DAC on the TBolt. I have gone far enough to see that it's a sum of several sort of circuit. My guess is that they sum and then measure the result with a good ADC. If so, the DAC would likely function fine as long as the ADC was not impacted by the loss of

Re: [time-nuts] Tbolt failure modes

2012-05-12 Thread Magnus Danielson
On 05/12/2012 03:37 PM, Mark Sims wrote: It sounds like the -12V supply is used to generate the DAC low voltage reference. If it is floating, the DAC output will be unstable. If it is at a solid voltage, the DAC output will be stable. The standard EFC range for a tbolt is -5V to +5V,

Re: [time-nuts] Tbolt failure modes

2012-05-12 Thread bg
Thanks everyone! On 05/12/2012 03:37 PM, Mark Sims wrote: It sounds like the -12V supply is used to generate the DAC low voltage reference. If it is floating, the DAC output will be unstable. If it is at a solid voltage, the DAC output will be stable. The standard EFC range for a tbolt

[time-nuts] Differences between the Trimble Resolution-T and -SMT timing receivers

2012-05-12 Thread Mark Sims
Our friends from Old Cathay sell two versions of the Trimble Resolution timing receiver: the -T and the -SMT. The -T is a 12 channel receiver built of discrete components on both sides of the PCB. It is spec'd at +/-20 ns accuracy (the sawtooth correction range). It can be set up operate

Re: [time-nuts] Tbolt failure modes

2012-05-12 Thread J. L. Trantham
Today I 'failed' the -12 V supply again and got screen captures of the TBoltMon GUI with the TBolt operating normally, -12V failed short and -12V failed open. I used a 5372A referenced to a Z3816A to measure the 10 MHz output frequency of the TBolt for normal operation followed by -12V failed

[time-nuts] Tektronix Manuals

2012-05-12 Thread J. Forster
Hi, I fround this site this evening: http://w140.com/tekwiki/wiki/Main_Page The scans are not as good as some commercial pones, but the price is right. It has manuals that are not available on BAMA or the other sites I checked. Best, -John

[time-nuts] Time Nuts at the Dayton Hamvention

2012-05-12 Thread Robert LaJeunesse
Those of you going to the Dayton Hamvention next weekend should be aware that there will be other Time Nuts (and a Volt Nut or two) to be found there. Don't be surprised if you see the Febo administrator himself relaxing in the flea market beside the trailer in spaces 1901-1904. If you go past,