XG2 low output

[Andrew Moore-3]

Output on my XG2 3-frequency test oscillator appears to be down (by a
different amount on all 3 frequencies). Tried replacing battery.
 Suggestions on what part(s) might be faulty?

--Andrew, NV1B
..
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[Don Wilhelm-4]

Andrew,

Check to see if you have 1.22 volts at the cathode of U1.  If not,
replace U1.
Other than that, check the soldering (re-flow if in doubt) - there are
just not that many components to give trouble.

73,
Don W3FPR

On 7/22/2011 9:21 AM, Andrew Moore wrote:
> Output on my XG2 3-frequency test oscillator appears to be down (by a
> different amount on all 3 frequencies). Tried replacing battery.
>   Suggestions on what part(s) might be faulty?
>
> --Andrew, NV1B
>
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[Alexey Kats]

Andrew,

One more suggestion - check if either D1 or D2 (near the output socket) are
shorted. (Tony KT0NY had somewhat similar problem recently and in his case
D2 was shorted, besides of other reasons.)

On Fri, Jul 22, 2011 at 10:29 AM, Don Wilhelm <[hidden email]> wrote:

> Andrew,
>
> Check to see if you have 1.22 volts at the cathode of U1.  If not,
> replace U1.
> Other than that, check the soldering (re-flow if in doubt) - there are
> just not that many components to give trouble.
>
> 73,
> Don W3FPR
>
> On 7/22/2011 9:21 AM, Andrew Moore wrote:
> > Output on my XG2 3-frequency test oscillator appears to be down (by a
> > different amount on all 3 frequencies). Tried replacing battery.
> >   Suggestions on what part(s) might be faulty?
> >
> > --Andrew, NV1B
> >
>

--
Alexey Kats (neko)
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[Andrew Moore-3]

Problem solved!

Thank you in particular to Tony KT0NY, Don W3FPR and Alexey.

Turns out that D1 was the problem.  Note!  It wasn't due to a short as some
had suggested, but rather, checking the errata sheet revealed that on the
Rev. A board (like mine), the silk screen was backwards.  The banded end of
diode D1 (1N4148) should be nearest to R7, which is the opposite of what the
silkscreen suggests.  Turns out my XG2 was assembled incorrectly from the
start (I'm guilty).  Not sure if the errata was issued yet when bought my
XG2 or if that came afterwards, but in any case, I cut out D1 and replaced
it in the opposite direction and instantly have a proper 50 uV signal.

I did also remove D2 (the rectangular "output" LED) but I'm not sure if that
was a problem or not.

Thank you all; I would never have noticed this problem unless you mentioned
it.  Now I will proceed with calibrating the K3 using this reference signal.

--Andrew, NV1B
..
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[Andrew Moore-3]

I forgot to mention... thanks Chuck W5UXH....

--Andrew, NV1B
..


On Fri, Jul 22, 2011 at 10:03 PM, Andrew Moore <[hidden email]>wrote:

> Problem solved!
>
> Thank you in particular to Tony KT0NY, Don W3FPR and Alexey.
>
> Turns out that D1 was the problem.  Note!  It wasn't due to a short as some
> had suggested, but rather, checking the errata sheet revealed that on the
> Rev. A board (like mine), the silk screen was backwards.  The banded end of
> diode D1 (1N4148) should be nearest to R7, which is the opposite of what the
> silkscreen suggests.  Turns out my XG2 was assembled incorrectly from the
> start (I'm guilty).  Not sure if the errata was issued yet when bought my
> XG2 or if that came afterwards, but in any case, I cut out D1 and replaced
> it in the opposite direction and instantly have a proper 50 uV signal.
>
> I did also remove D2 (the rectangular "output" LED) but I'm not sure if
> that was a problem or not.
>
> Thank you all; I would never have noticed this problem unless you mentioned
> it.  Now I will proceed with calibrating the K3 using this reference signal.
>
> --Andrew, NV1B
> ..
>
>

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