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Author Topic: Yaesu FT 101ZD low PO on 1 band  (Read 4180 times)

AA0UT

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Yaesu FT 101ZD low PO on 1 band
« on: July 27, 2005, 09:17:27 PM »

I bought an FT 101ZD recently. It's in great shape, putting out good power on bands 80 thru 10. However, only about 1 watt of power can be coaxed out of the 160M band. Is there anything that a neophyte such as myself can check before having a pro look at it?
Thanks... Mike AAØUT
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WB2WIK

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Yaesu FT 101ZD low PO on 1 band
« Reply #1 on: July 28, 2005, 08:22:38 AM »

With the driver stage tuning peaked and the rig transmitting on 160m with the drive control turned all the way up, what does the grid current indicate?

If there's a lot of drive and very little output, then the problem isn't in the driver stage or anything before the 6146s.  The problem would be after the 6146 plates, somewhere in the output network, plate RF choke, plate coupling/blocking capacitor, etc.

If there's very little drive even with everything cranked all the way up, then the problem is likely to be before the 6146s, in the driver stage or possibly even before that.

At least this simple test helps isolate the problem to a part of the chassis.

WB2WIK/6
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AA0UT

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Yaesu FT 101ZD low PO on 1 band
« Reply #2 on: July 31, 2005, 09:11:03 PM »

Thanks very much for the advice.  However, I have discovered that this problem was due to "airhead error";  the VFO was set well below the 160 meter band.  When I adjusted the VFO and tuned up in band, I was able to obtain 70 watts of output. This is still somewhat less than the other bands, but certainly better than 1 watt!
Thanks again... Mike AAØUT
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KB8NJH

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Yaesu FT 101ZD low PO on 1 band
« Reply #3 on: September 20, 2005, 06:35:32 PM »

  You may want to use tuner cleaner to clean the Band
Switch. Also pull the 160 Crystal from the socket and
clean the posts with a piece of fiberglass (such as in
House insulation). It is a simple fix often looked over
as it can't be THAT simple...your wattage should be quite a bit higher than 70 watts. Good Luck OM..kb8njh
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