Discussion in '"Boat Anchor" & Classic Equipment' started by VU2JLH, Sep 16, 2010.

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  1. VU2JLH

    VU2JLH Ham Member QRZ Page

    Hello All,

    Some days back I have a problem with my FT 101 zd in CW mode. When I press the key down, the transceiver sends out carrier. However, when I key up, the carrier continues until the delay times out. I'm unable to get cw
    with the key,only continuous carrier. So I can't send morse code. Anybody out
    there see this problem before?

    Warm Regards
    Jay, VU2JLH
  2. KA4DPO

    KA4DPO Platinum Subscriber Platinum Subscriber QRZ Page

    First, check the VOX delay setting and make sure it is down all the way. Next make sure the VOX circuit is operating correctly, you can test it on phone. Next, make sure the TX relay isn't getting stuck.
  3. WA4FNG

    WA4FNG Ham Member QRZ Page


    I just picked up a FT101ZD (early version) and discovered I have the same problem. I thought there was something wrong with radio, but determined it has something to do with my old Heathkit Keyer. It works fine with a straight key, but if I use the old Heath Keyer it keys OK but on key up there is still a background carrier at lower power until time out -- and if you listen in another receiver the background carrier has a rough note, more like a squeal or feedback sound.

    I've used this Heath Keyer on lots of rigs over the years and never had a problem this strange.

    Anyway, I just sorted this out a few minutes ago and had a good QSO using just a straight key. Have you tried a straight key? Or just plug in a 1/4 phone plug and short the connections to test if you don't have a key.

    If I learn more, come up with a reason/solution - will post here. Anyone else have any thoughts on this?

  4. W5HTW

    W5HTW Ham Member QRZ Page

    I would think this could be poor adjustment of the delay, Vox trip and anti-vox controls. If they have been working before, but now have changed, there could be a defective transistor or capacitor. Or a change in voltage.

    I would return all VOX controls to their minimum setting. Then, leave the anti-trip and the vox delay there, and start increasing the VOX gain until the key in the Key jack puts the radio into transmit mode. Release the key and see if the radio drops back to receive mode. It should, and it should do so immediately since the Delay is set to zero. If it does not, you could have a sticking relay. Certainly that is the next place I would look. But only after testing it with the Delay and AntiTrip set to zero.

    If the above works, then start increasing the Delay, slightly. Keep pressing and releasing the key so you know when it starts locking up, or getting way too long in holding the carrier. Find a time that fits your style and put the Delay there. Don't make it really, really short, but try to keep it at or around one second.

    With that working, turn up the anti-trip. This will dramatically affect the vox gain, which it is indeed supposed to do. So you will have to increase vox gain to override the anti-trip. But do it in small increments!

    Once set (provided nothing is broken in the radio) these settings should also work on SSB.

    This sounds like a delay problem, but it could be a bad transistor or a sticking relay, as already mentioned. The VOX gain and VOX Anti-trip are very relational, one affecting the other. Also, the Carrier level pot should be turned fully up for these tests. And the rig should, needless to say, be in correct tune.

    Something else that can give the affect you describe, so I need to include it, is high SWR. Be sure that is correct before making any VOX adjustments. In fact, come to think of it, that is probably the first thing I would check. I have seen keyers totally lock up due to high SWR. While the 101 does not have a built in keyer, the keying circuitry is sensitive, which means also to RF

  5. VU2JLH

    VU2JLH Ham Member QRZ Page

    Hello Sir,

    I checked the vox and delay settings. It is fine and have no problem with phone.In CW mode it turns back to receive mode after the delay. So I think it is not related to sticky relay or vox problems. When I press for a dot on Key, Tx is keyed carrier is continuous until the delay is out, no break in carrier with key up. That is the problem Sir, and ofcourse I am using a straight key here. Now I think may be some thing wrong with keying circuit. Any how the transistors are old 2SA733 and 2SC 372Y difficulty in finding equivalents here
  6. W5RKL

    W5RKL Ham Member QRZ Page

    I doubt the problem is the VOX circuit settings or the VOX circuit itself.

    Remove the CW cable at the keyer, leaving the other end of the cable plugged into the CW socket on the transceiver. Short the center conductor and shield of the cable with a screw driver. This will simulate a straight key and will key the transceiver in CW mode. If the transceiver keys properly, meaning the problem disappears, then the problem is the keyer. I suspect you will find the problem is the keyer.

  7. VU2JLH

    VU2JLH Ham Member QRZ Page

    Hello Sir,

    I am using a straight key not a keyer. Looking into the keyer section does not reveal anything. Transistors and other components seems to be OK.Any other thought in this regard?
  8. VU2JLH

    VU2JLH Ham Member QRZ Page

    FT 101ZD MK 1 CW


    Problem solved. It was due to a faulty diode in the AF Board. Now I can work on CW. Many Thanks for the valuable suggestions by K4DPO, WA4FNG, W5HTW, and W5RKL.

    Warm Regards
    Jay, VU2JLH
  9. WA4FNG

    WA4FNG Ham Member QRZ Page

    Can you identify the diode you changed? I have a similar problem but only with a certain keyer. Straight key works fine.
  10. VU2JLH

    VU2JLH Ham Member QRZ Page

    Hello Milt,

    Yes, It is a diode in AF Board PB 1964A, designated as D06 ( IS1007) and was showing a very low forward resistance .It is connected to the key line through pin No.2 of J502.I replaced it with a 1N914. Now everything fine here. Meanwhile I am using a straight key here.

    Thanks and Regards
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