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FT-857 S-meter not working in FM narrow mode only

Discussion in 'Radio Circuits, Repair & Performance' started by OK1BIL, Apr 2, 2012.

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  1. OK1BIL

    OK1BIL Ham Member QRZ Page


    I have Yaesu FT-857 for some time but lately I have noticed that my S-meter is not working. Further examination shown that this only happens in FM narrow mode. In FM wide or AM/CW/SSB works ok.

    If i listen to local hams in FM (wide or normal) I can see S-meter moving, showing accurate readings in my opinion. But when I press NAR button in M menu all the S units get lost. I don't see any reading even when listening to local 2m repeater which is usually 59++. I tried different bands but still the same.

    I read some info about this problem caused by random change in service menu settings. I checked and mine seems ok. Here you can see example, number in the left column is some reference I found on the internet number in right is my setting.

    NO-009 FM-S1 68 74
    NO-010 FM-FS 99 103
    NO-013 FM-TH1 100 101
    NO-014 FM-TH2 100 100
    NO-015 FM-TI1 10 5
    NO-016 FM-TI2 10 7

    What I understood from menu is that FM S-meter calibration is done for general FM. There is no extra menu for wide or narrow.

    Any hints or tips on this issue? I should say that the radio receives signals ok I guess, I dont see any changes in its sensitivity.
  2. KO6WB

    KO6WB Premium Subscriber QRZ Page

    There is an analog meter out jack that sends the S-meter signal to a 1ma meter movement. If you hook up a meter to this connection and the S-meter is now working then it's something in the FT-857 that is preventing the S-meter from working. If the S-meter does not work then it is still the FT-857 doing this. The answer to this problem may be to do a full reset and then check if your readings came back. I know it's not the thing that most folks want to do because it will destroy all of the settings you have changed in the menus and you will lose the memory channels. This is something that becomes difficult since you have to remember to write down all the settings you want to keep or you will have to go through the process of getting the FT-857 performing the way you wanted, one menu item at a time.
    BTW S-meters are not really an important part of the rig. If you can hear the stations you want then you can judge for yourself what their RS(T) is.
    Hope this helps
  3. OK1BIL

    OK1BIL Ham Member QRZ Page

    Ok Gary, thank you for your reply. I tried complete reset and it did not help. My external "analog" meter also does not work.
  4. OK1BIL

    OK1BIL Ham Member QRZ Page

    So I googled and googled and read some russian forums and I guess I found possible failure:

    There are 4 ceramic filters onboard the main unit:

    CF1002 TOKO ALFYM455E (FM - probably wide)
    CF1003 TOKO ALFYM455G (FM - probably narrow)
    CF1004 (SSB filter)
    CF1005 TOKO ALFYM455H (AM filter)

    I read that units made in 2007, 2008, 2009 have common problems with filters CF1002, CF1003, CF1005 because some coupling capacitors are missing.

    My unit was made in July 2008 (ser. nr. 8Ixxxxxx)...

    So I guess that CF1003 is faulty in my FT-857.
  5. KO6WB

    KO6WB Premium Subscriber QRZ Page

    I don't know if that is the problem or not. If the filter for narrow FM was bad then you would not receive any signal on that setting at all or it would be very scratchy. Since you have full receive capability and the receive signal passes through the filter then that is not the problem. I do know that the filters during that time were performing poorly but usually they were showing up on other modes. I'll do some more searching and see if there is something I missed.
    Good luck
  6. OK1BIL

    OK1BIL Ham Member QRZ Page

    Sorry for confusion, I forgot to add some information. Yesterday I did some further testing during our club net on a local repeater and I found that when in narrow mode I hear shattered signal. It sounded to me like overdriven amp or heavy QRM. Wide FM seemed ok.

    And as long as there are only settings for both narrow and wide FM in service menu, but filters are separate, I suspect filters.

    I would be really happy if you can find some further info on this topic!
  7. KO6WB

    KO6WB Premium Subscriber QRZ Page

    Yes indeed. With that new bit of information you may be right. There are replacement units available from Icom. You could also look at the various electroics parts vendors on the net. They will be much cheaper then Icom.
  8. KO6WB

    KO6WB Premium Subscriber QRZ Page

    Well I had more information on the filters and I thought I posted them but they are not here. So the data sheets for them can be found at; And this; I found a vendor that has the CFWS455G in stock. I'm not sure they will sell you just one. They are listed at 72 cents and they have over four thousand of them. There may be a place that has the CFWS455E and that is; Again I am not sure they will sell you just one.
    Don't forget to try Yaesu for the parts. They may be easier to deal with.
    Hope this helps
    Last edited: Apr 4, 2012
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