kenwood th-78a open squelch on vhf side

Discussion in 'General Technical Questions and Answers' started by KV4D, Oct 5, 2009.

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  1. KV4D

    KV4D Ham Member QRZ Page

    hello,
    i have a kenwood th-78a that has a small problem. the vhf side squelch stays open no matter where the knob is at. the green light stays on and full bars on the meter. there is no sound coming out of the speaker. this is only on the vhf side. i can use the uhf side fine, also can change positions with the 2 and uhf works, vhf wont, right or left side. the vhf will transmit tho. i have searched the internet without finding the problem yet. seen the other common problems but not this one specifically. the c-17 problem usually is on the right side. this problem follows the vhf no matter which side its on.
    thanks in advance
    KV4D
     
  2. KV4D

    KV4D Ham Member QRZ Page

    anybody have any ideas?
     
  3. K7MH

    K7MH XML Subscriber QRZ Page

  4. KB7OSW

    KB7OSW Ham Member QRZ Page

    Repair issues?

    I have had Cliff repair one of my Th78a's in the past. Goog work, at a good price....http://www.avvid.com/ Good Luck
     
  5. N8CPA

    N8CPA Ham Member QRZ Page

    I hope this helps.
    http://www.radioamateur.eu/schemi/TH78_user.pdf

    Read page 9. There is a key sequence that changes the function of the tuning knob, which I believe changes the function of the squelch knob as well. IF all else fails, reinitialize the rig.
     
  6. KV4D

    KV4D Ham Member QRZ Page

    thanks for the ideas guys. still no control tho. it will tx on the left side but the squelch is wide open no matter what i do. factory reset no luck, i done the c17 thing, with no luck either. this must be a problem that is kinda rare cause i have read nothing about it yet.
    i can tx and rx on the right uhf side, tx on the left. no squelch control. i may pull it apart again to see if its the squelch knob??? cold solder joint on the back of the board....maybe??
    thanks again guys
    troy
    BTW i noticed its more like it is receiving a signal on vhf, full scale on meter but no noise. it is quiet with no squelch noise. green rx light is on. no signal to receive tho verified by another ht. even with antenna pulled from th-78
    thanks
    KV4D
     
    Last edited: Nov 19, 2009
  7. G0IWF

    G0IWF Ham Member

    TH78E squelch problem

    KV4D

    I have a TH78E the european version with exactly the same symptoms that yours has. Mine had been unused for about six years - I took it out of the box and it had no sound on VHF, signal indicating maximum, squelch indicator on and squelch control did nothing. UHF side worked fine. I reinitialized, recharged the battery but still faulty. The next day picked up again tried it and it worked okay!!
    This happened two days ago and so far it is still working well on both bands.
    I'm sorry that I can't offer advice but thought my experience could in some way be useful.

    G0IWF
     
  8. KV4D

    KV4D Ham Member QRZ Page

    LOL.... well at least im not alone...i hope yours stays fixed.
    troy
    KV4D
     
  9. G0IWF

    G0IWF Ham Member

    My TH-78E is not fixed. I've tried it each day since the last post to you and after switch-on it has no sound on vhf, squelch indicator on etc. If I leave it on then after say 10 -20 minutes the sound gradually returns, the indicator goes off and the radio functions correctly. If I leave it on then after about an hour the sound goes off, so does the squelch indicator but the signal bar has gone. If I then switch it off and then back on the radio starts the cycle again with no sound, indicator light on etc.
    G0IWF
     
  10. DL7AHW

    DL7AHW Guest

    Hi dear friend, have you founded a solution for the problems with th78E?

    dl7ahw
     
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