[Elecraft] KAT500 ANT1 problem

[Dave]

If it were me, I'd replace the SO-239 on the tuner...  That way, you 
know the issue won't come back to haunt you later.

73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist, RFI
ARRL Asst. Director, NW Division, Technical Resources

On 7/11/21 1:48 PM, kd4iz at frawg.org wrote:
> Many thanks to Ken (K6MR), Joe (4X1RV), and Kirk (K6KAR) for your quick
> answers and for providing the schematic information.
> I pulled the unit and did some poke and prod testing with a DVM here on the
> anti-static mat. My fear was that K18 had a bad contact in the ANT1
> position. -Not!-
> What had apparently happened was that I had a batch of the offshore made
> "Amazon Special" PL-259s that appear to have a slightly oversize center pin.
> The patch cable used until recently had one of them on one end. It had
> spread the leaves on the ANT1 SO259 just enough that a good connector, when
> perfectly centered and seated, did not make contact! Gentle recentering of
> the leaves with a miniature flat blade screw drive yielded relief and a
> self-administered head smack.
> Jack Spitznagel - KD4IZ
> Science River LLC
> Biomedical Consulting Services
> 
> 
> 
> -----Original Message-----
> From: kirk.harding at k6kar.com <kirk.harding at k6kar.com>
> Sent: Sunday, July 11, 2021 14:07
> To: kd4iz at frawg.org
> Subject: RE: [Elecraft] KAT500 ANT1 problem
> 
> Jack,
> 
> The KAT500 schematic is on line (partial)
> https://www.qsl.net/wb4kdi/Elecraft/KAT500/KAT500_RevA_page1.png
> https://www.qsl.net/wb4kdi/Elecraft/KAT500/KAT500_RevA_page2.png
> https://www.qsl.net/wb4kdi/Elecraft/KAT500/KAT500_RevA_page5.png
>   Although all schematics aren't available, this may be enough to get you
> going.
> 
> 73,
> 
> Kirk, K6KAR
> 
> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net <elecraft-bounces at mailman.qth.net> On
> Behalf Of kd4iz at frawg.org
> Sent: Sunday, July 11, 2021 12:38 PM
> To: Elecraft at mailman.qth.net
> Cc: 'Elecraft Support' <support at elecraft.com>
> Subject: [Elecraft] KAT500 ANT1 problem
> 
> All,
> 
>   
> 
> This is likely something very straight forward, but I do not have a
> schematic to follow and troubleshoot.
> 
> Symptom: ANT 1 circuit seems to be dead. No match and fault on switch from
> ANT2 to ANT1. No receive signal.
> 
> Tests:
> 
> Took KAT500 out of line to by-pass tuner, antenna on ANT1 is OK and will
> match normally with rig's internal ATU.
> 
> With KAT500 back in line, selected each tuning position (AUTO, MAN, BYP) no
> difference
> 
> With KAT500 still in line, ANT2 and ANT3 work nominally.
> 
> Checks:
> 
> Reset to factory defaults, restored last working Configuration, no change in
> above behavior.
> 
>   
> 
> If I was a betting guy, I'd guess a relay or switching diode was open,
> however - no schematic, don't really know.
> 
> Did I miss something
> 
>   
> 
>   
> 
> Does this little beastie need to go back to the mothership?
> 
>   
> 
> Thanks,
> 
> Jack Spitznagel - KD4IZ
> 
> Science River LLC
> 
> Biomedical Consulting Services
> 
>   
> 
>   
> 
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> 
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