Ft 857 low Rx Audio

Discussion in 'Radio Circuits, Repair & Performance' started by 8P6ET, Oct 5, 2018.

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  1. 8P6ET

    8P6ET Ham Member QRZ Page

    Good evening, has anyone encountered the FT 857 having a low rx audio on all bands and modes. The loudest sound heard is the beep when going through various selections.
    Nothing is heard from the speaker , the rf gain and squelch are working as they should.
    I am looking forward to any suggestions
     
  2. N0DBX

    N0DBX Ham Member QRZ Page

    Is this with the internal speaker? Did you try an external?

    I replaced the speaker in a buddies 817 and believe they are the same part and therefore "Known to Fail". The service manual is available on-line and these radios are very serviceable.
     
  3. 8P6ET

    8P6ET Ham Member QRZ Page

    Good morning, I did try a external speaker and nothing heard.I did here a extremely faint rx with the headphones. I did a full reset to factory defaults and still no change. I will download the service manual and see what I can do from here but I believe the best thing is to it state side to have a complete run through as it will be in use for Emergency Communications for Hurricane Season mainly.
     
  4. KB1CKT

    KB1CKT Ham Member QRZ Page

    Is the beep volume loud, or is it as muted as the other audio? Odd that the internal speaker would work better than an external speaker, but it sounds like an amplifier problem to me (bad audio amplifier or the support parts around it).
     
  5. 8P6ET

    8P6ET Ham Member QRZ Page


    Good morning, the beep is loud for sure and even with S 9 + signals you cannot hearing anything on the internal or external speaker. What I can say with the Headphones you can hear signals very very faint with the volume up to all.
     
  6. KA9JLM

    KA9JLM Ham Member QRZ Page

    If you open the squelch while on FM what do you hear ?

    Good Luck.
     
  7. KB1CKT

    KB1CKT Ham Member QRZ Page

    I am not familiar with the radio but what I would do is check HF, 6m, 2m and FM broadcast. I do not know what RX path shares what parts with each other, but if you can find one working path then you validate a portion of the RX chain. Whatever isn't working has to be common to all. Could be a bad amplifier or bad solder joint, or bad relay.

    Wild guess: it's something close to the front end. Radios can have huge amounts of gain, and I'm guessing it's receiving across a really small capacitance. I'm thinking, bad cap, bad solder, bad relay, bad inductor maybe.

    Do you have an RF generator? In lieu of one, sticking your finger on parts may work to inject noise.
     
  8. WD8BWW

    WD8BWW XML Subscriber QRZ Page

    try this: tune to the FM radio band and dial a local radio station. If the volume is still low then do a full reset, but remember a full reset will wipe the channel memory. tell me/us what happened
     
  9. 8P6ET

    8P6ET Ham Member QRZ Page

    Good evening, i don't have a rf generator, I will enquire to see who may have one.
     
  10. 8P6ET

    8P6ET Ham Member QRZ Page

    Good evening, I have done as you suggested and not hearing anything from headphones , internal or external speaker.
     

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