Yaesu FT991A Keyline Problem

Discussion in 'Amateur Radio Equipment Reviews' started by KC0JBZ, Apr 1, 2018.

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  1. KC0JBZ

    KC0JBZ XML Subscriber QRZ Page

    Has anyone had an issue with the amp keyline not releasing the amp back to full receive mode? I connect my 991A from the LIN/TUN jack with the proper cable and connect to the key jack on my Alpha 9500 I lose the receive when I put the amp in "operate" mode. As soon as I put the amp in "standby" or unplug the keyline my receive returns. Service manual doesn't show a TX/RX relay but a switching transistor and diode. What a poor design! I love the radio but now it's junk. It works fine without an amp but when you spend thousands on an Alpha I'd like to use it. The radio is fourteen months old so it's out of warranty and I assume it'll take many weeks to get repaired... how pitiful!
  2. KM4FVI

    KM4FVI Platinum Subscriber Platinum Subscriber QRZ Page

    They come with a 3 year warranty!
  3. N8VIL

    N8VIL Ham Member QRZ Page

    Possible polarity of the keyline to the amp reversed. Just a thought.
  4. AD7I

    AD7I Ham Member QRZ Page

    put a mA meter in series with the AMP keyline from the 991A to your amp, to see what the difference in current is between TX and RX. You'd probably expect 10s of mA in TX and less than 10 uA in receive. if you have a second meter then also look at the voltage on the keyline to ground in both conditions. that may give a hint as to what's going on. Also, did you set 991A menu item 141 to LAMP when using the external amplifier?
  5. N4MU

    N4MU Ham Member QRZ Page

    Above is a good point but it is Function 143 (not 141). It has caused me many torn out hairs when I switched between internal tuner and LAMP. I forgot a couple times and was about to tear down my antenna when it wouldn't work properly. I cannot see the TUNER icon well either One time the 143 was in "internal"...because it had locked up there for unknown reasons and until I remembered to check 143 the hair was flying! That time it was NOT me changing it. Hasn't happened since. Please double check, reset #143!
  6. VE3TMT

    VE3TMT XML Subscriber QRZ Page

    Had this issue with an Icom. Curious to know issue. You may get more responses posted in the Mods & Repairs section.
    Last edited: Nov 15, 2018

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