[Icom] IC 746 tuner

Tue, 17 Dec 2002 21:46:18 -0500

A guess would be that one of the tuning relays has developed some contact
resistance or pitting and lets go during times of high RF current.  If it
only happens above a certain band or below a certain band you might use that
to help determine which group of relays are suspect. I believe this is a
common problem with most autotune radios.

I had a similar problem with the tuner in my IC-746 that was repaired under
warranty. It would continuously hunt for a match on 160 meters. One of the
relays was replaced.

Pat,
wa4tuk

> -----Original Message-----
> From: [email protected] [mailto:[email protected]]On
> Behalf Of Guillermo
> Sent: Tuesday, December 17, 2002 8:20 PM
> To: Icom
> Subject: [Icom] IC 746 tuner
>
>
> 	Hello, a friend of mine owns a 746; he uses internal tuner to feed a
> multiband dipole. In a few bands, we noted that even if SWR (as seen in
> 746's SWR meter) is not more than 1.2 (full carrier out, RTTY mode),
> when he speaks in SSB mode, TUNE label starts to blink, and after a few
> seconds, tuner is disengaged. It is like that at a higher peak output
> (which?, because at RTTY we have full power out, peak SSB can't exceed
> this) tuner still detects standing waves and try to re-tune, with no
> success.
> Later we found that also at RTTY, tuner has the same behavior after a
> few seconds key down.
> Any hint?
>
> Thank you in advance
> Best regards
> Guillermo - LU8EYW.
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