[time-nuts] thunerbolt, 2 problems

[Bryan _]

May be worth going over the board carefully with a loupe or microscope. FPGA could be fine but a input and some discrete components may be telling the FPGA to not turn on the pps, or dragging one of the inputs or outputs down to ground. Too bad there wasn't at least a block diagram available, or is there?

-=Bryan=-

________________________________
From: time-nuts <time-nuts-bounces at lists.febo.com> on behalf of Bob kb8tq <kb8tq at n1k.org>
Sent: January 17, 2020 4:45 AM
To: Discussion of precise time and frequency measurement <time-nuts at lists.febo.com>
Subject: Re: [time-nuts] thunerbolt, 2 problems

Hi

There are no schematics for the TBolt. This is pretty typical of modern
devices from a number of outfits. From doing a bit of basic circuit
tracing, most of the “stuff” heads into or comes out of the FPGA or MCU.
Once you get past the basic interface chip you probably are looking at an
output pin on one or the other. In this case the FPGA is a pretty good bet.

Since there are no firmware images around for the FPGA or MCU, replacing
one is not practical. The firmware issue is  on top of dealing with getting a
crazy package off (and then back on) the board.

My *guess* is that Trimble “repaired” these parts by throwing the broken
one away and sending out a new one. That also has been a very common
thing for several decades now.

Bob

> On Jan 17, 2020, at 12:32 AM, Brian Lloyd <brian at lloyd.aero> wrote:
>
> On Thu, Jan 16, 2020 at 9:20 PM Bill Beam <wbeam at gci.net> wrote:
>
>> Brian,
>> LH can do this.  Issue the command "p" to bring up the PPS control menu.
>>
>
> Thank you. LH does so much but finding the right command is a challenge.
>
> I did finally find a copy of tboltmon.exe. That and LH both report that
> 1pps is turned on. Nothing coming out. The Tbolt is locked and 10MHz is
> within range when compared with my other GPSDOs and my Rb. So it appears
> that the 1pps has failed. It appears that the 74AC04 is being used as a
> buffer to drive the output. I am seeing no pulse on the inputs or outputs
> of that chip so the 1pps is lost somewhere else.
>
> Does anyone have a schematic that I can use to trace back the 1pps?
>
>
>> On Thu, 16 Jan 2020 20:44:43 -0600, Brian Lloyd wrote:
>>
>>> After quite some time I dragged out my Tbolt and fired it up. Comes up
>>> OK. Lady Heather is happy. 10MHz is spot on (after an hour or so).
>>> Problem is, 1pps is missing. 1pps is enabled (or appears to be).
>>> Suggestions?
>>
>>> I am running Trimble Visual Timing Studio 2.03.12. It seems to know
>>> about the Thunderbolt-E but not the original thunderbolt. Not sure it
>>> will do the right thing. Does anyone have an older copy of the program
>>> for configuring the T-bolt?
>>
>>> Thanks in advance.
>>
>>> --
>>
>>
>>> n++ <https://www.lloyd.aero>
>>
>>> Brian Lloyd
>>> 706 Flightline
>>> Spring Branch, TX 78070
>>> brian at lloyd.aero <mailto://brian@lloyd.aero>
>>> +1.210.802.8359
>>
>>
>>> _______________________________________________
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>>
>>
>> Bill Beam
>> NL7F
>>
>>
>>
>>
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>>
>
>
> --
>
>
>
> Brian Lloyd
> 706 Flightline
> Spring Branch, TX 78070
> brian at lloyd.aero
> +1.210.802-8FLY (1.210.802-8359)
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