FT-8000 No RX audio issue

Discussion in 'Radio Circuits, Repair & Performance' started by K9TSU, Apr 7, 2012.

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  1. K9TSU

    K9TSU Ham Member QRZ Page

    Hi all...
    My FT8000 works fine, aka, it TX's. It, however, no longer spits any RX audio (or key bleeps) back out at me. Also, the fan doesn't kick on when I TX. (No, this is NOT a bad speaker, or a jack plugged in.)

    I'm 15 and paid good money for it, and it seems like the previous owner doesn't care. I was told I was buying a working radio. ANY...ANY, suggestions are encouraged! THANKS
  2. KO6WB

    KO6WB Premium Subscriber QRZ Page

    There are so many things that could be wrong. Let's try to narrow this down.
    First, does the S-meter indicate you are receiving a signal but you don't hear it?
    If that is happening then you can check for an audio problem by tracing the schematic back from the speaker to the device that produces the sound.
    If you never get an S-meter indication then you would start your troubleshooting by checking all the voltages that are supposed to be supplied to the receive section.
    From there you would do what is called the half split method of troubleshooting.
    The middle of the receiver is the IC that converts the 10.7Mhz IF signal down to 455Khz and then demodulates it. That would be Q1009. It's a TK10930V intergrated circuit. What you do here is to find another rig that can tune 10.7Mhz and copy FM. Using a short piece of coax between the rig that is the receiver and your rig. Connect the shield of the coax to the case of your rig and put a blocking capacitor on the center conductor of the coax, about 100pf would do nicely. take the end of the blocking capacitor and touch it to pin 24 of Q1009. You should hear the testing receiver pickup a signal if there is one there to detect. If you do detect a signal there then put the test receiver in the SSB mode and tune that receiver to 10.245Mhz. Using a small length of wire as an antenna for the test receiver bring the antenna close to Q1009 and see if you can detect the 10.245Mhz crystal oscillator. If you get that then connect an audio amplifier to pin 12 of Q1009. Use a blocking capacitor from pin 12 to the audio amplifier input, about 1 ufd will work well. If it is an electrolytic capacitor then make sure the positive lead is the one going to pin 12. Now do you detect the signal? If yes then you have an audio problem.
    These are just suggestions and you may want to have someone help you.
    If you don't have the schematic for the FT-8000 you can get it here; http://elektrotanya.com/cgi-bin/download2.cgi.
    Like I said there could be a lot of things that will cause the receive section to fail.
    Get back to us and tell us what you did and how your troubleshooting is coming along.
  3. KF5FEI

    KF5FEI Ham Member QRZ Page

    Not familiar with this particular model, but these things apply to other Yaesu models, so they may be an issue for you. Are the beeps turned off / down? Is the tone set for RX as well. Is the RF squelch turned way up?
  4. K5AHH

    K5AHH Ham Member QRZ Page

    --In a previous thread, I had told him that it probably was the actual squelch/volume knobs. Either the quality of the knobs were bad or they just need re-soldering. The vast majority of people I have heard of that have this radio and have the "no audio" coming from the speaker problem, the volume/squelch knobs just needed resoldering. The right side of my FT-8000 just started having the "no audio" problem on the right side. Now, the fan problem? I have no idea. Try moving the fan blade and see if it starts to move after you move the blades. The fan could be getting "gummed up" with dirt and might just need a little help. Then again, the resoldering advice I gave you might not work (your vol/squelch knobs might be in good shape), but you will have fun troubleshooting your radio. The other two Hams' advice above me might just work, and like KF5FEI said, it is quite possibly something as simple as overlooking that squelch knob turned all the way clockwise. We all make mistakes. If you get sick of messing with the radio, I might be interested in buying it. I like the fact that the FT-8000 has the functions of the buttons on the screen. The newer FT-8800/8900 radios do not have this feature and they should. However, I really want the FT-8900, just wish it had more receive coverage. Our Highway Patrol in this area operate in the 44 Mhz range but the 8900 ONLY covers 50-54 Mhz. Oh well. Good luck with your FT-8000! How do you like your new FT-7900?
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