[time-nuts] Thunderbolt question

Chris Waldrup kd4pbj at gmail.com
Fri Aug 4 18:27:28 EDT 2017

Thanks guys. 
I've opened up my T bolt and noticed a SOT23 packaged part has the top blown off. 
The PPS BNC jack has U19 beside it. 
The next part is blown. Could someone take a closeup of the five parts around U19?
The intact parts are marked:
and two 2Az parts. 


> On Aug 4, 2017, at 4:13 PM, Arthur Dent <golgarfrincham at gmail.com> wrote:
> Actually that isn't my photo I linked to but one I just Googled. That is
> probably a board revision most people don't have but it was the first one
> I saw so I used it just to show that the GPS receiver is part of the
> only circuit board and not another easily replaceable board like in some
> other units.
> I just took a couple of photos of the later revision of the board for
> anyone interested in seeing what might be fried. In the photo of the
> top of the board the signal comes into a filter then to a 25db amp
> marked AM50002 by Macom. Above the filter near the input is where the
> decoupled +5VDC for the antenna is connected. If you are only reading
> 0.5VDC, if your're lucky it might only be the amp is fried and that
> could be an easy fix. If the 5VDC is ok with the amp input pin lifted,
> it might be the only problem. I wouldn't bet on it though. The 4031 I
> believe is a 1575.42 SAW filter
> The photo of the bottom of the receiver area shows a Sawtek filter and
> other parts. At the bottom of the photo is C460, a feedthrough capacitor
> and that might be where the receiver output is but where my Tbolts are
> working I don't feel the need to look into whether you could connect
> the output of a seperate GPS receiver there to make it work.
> I do have one Tbolt that has no oscillator. I brought the EFC and 10Mhz
> connections to SMA connectors on the back so I can test other oscillators
> or GPSDOs that don't have an easy way to monitor of graph the stability
> of those units and using Lady Heather gives me a good way to compare the
> graphs to ones I'm used to. You might possibly be able to replace the
> built-in receiver but it might be easier to buy a working Thunderbolt.
> http://i906.photobucket.com/albums/ac262/rjb1998/GPS%20top%201_zpslgxunnyw.jpg
> http://i906.photobucket.com/albums/ac262/rjb1998/GPS%20bottom%201_zpschvruppt.jpg
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