1. You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
    Dismiss Notice
Dismiss Notice
This forum does not allow a single user to have more than one username. If anyone wants to change their username contact an admin and it will be done. Multiple accounts belonging to the same member will be deleted without warning.

DX-99v2 - 690011D board - Same as DX-959 — No AM receive

Discussion in 'General CB Services Discussion' started by CbRadiosPRONTO, Feb 23, 2019.

  1. CbRadiosPRONTO

    CbRadiosPRONTO Performance Ready Radios

    Joined:
    Mar 21, 2014
    Messages:
    348
    Likes Received:
    70
    No AM Receive
    No FM receive
    USB and LSB receive works fine

    TX works on all modes
    Everything else works
    PA Works

    New radio. Didn’t notice issue til after frequency alignment and open clarified mod. Reverted back to stock. Rechecked work.


     

  2. OldTech03

    OldTech03 Sr. Member

    Joined:
    Dec 15, 2017
    Messages:
    602
    Likes Received:
    956
    Is the AM/FM rec totally dead absolutely no sign of even a very weak signal? And is it on freq. and modulating the way it should across all modes?
     
  3. CbRadiosPRONTO

    CbRadiosPRONTO Performance Ready Radios

    Joined:
    Mar 21, 2014
    Messages:
    348
    Likes Received:
    70
    Yes
    Yes
    Yes
     
  4. sp5it

    sp5it Master of puppets

    Joined:
    Jul 9, 2009
    Messages:
    1,511
    Likes Received:
    1,329
    AM/FM rx patch starts on FL2 through Q8 to FL1.
    If you touch FL1 legs can you hear broadcast AM stations come through speaker?
    Check D4, 5, 6.
    Mike
     
    Shadetree Mechanic likes this.
  5. nomadradio

    nomadradio Analog Retentive

    Joined:
    Apr 3, 2005
    Messages:
    3,587
    Likes Received:
    4,039
    That's where I start, with the "Manual Digital Signal Injector".

    Lay one finger (digit) alongside the shaft of a small screwdriver, and touch the input, then the output pins of FL1.

    Should hear a lot of noise on the output pin, typically including any nearby AM-broadcast stations.

    Input pin should still yield some noise, but not as much.

    Checking voltages on TR8 would be next if it passes the MDSI test.

    And if you get no noise this way, a shorted C19 is common in old radios. Pretty rare in a new one, though.

    73
     
    Shadetree Mechanic likes this.
  6. CbRadiosPRONTO

    CbRadiosPRONTO Performance Ready Radios

    Joined:
    Mar 21, 2014
    Messages:
    348
    Likes Received:
    70
    Thanks for the info guys. I’ll be back on it on Monday after I get a few radios out.
     
  7. Handy Andy

    Handy Andy Do Your Research First, Then Decide...

    Joined:
    Apr 23, 2018
    Messages:
    3,321
    Likes Received:
    3,670
    When you did the Clarifier mod, did you use R113 feeder?

    Else AM and FM uses J14 to "feed" the X4 Oscillator for SSB Conversion as well as AM and FM - so best to check and locate D53 - for 8 volts - part of that Oscillator that sends RF at TP6 . As well as Double-Double check J14 work.

    IF you don't have any power for X4, you won't get any IF either.

    So locate X4 and TP6 - is FM and AM show up as signal on TP6 - well, you have a heartbeat, but D36 may have got "zapped" it's used as a PIN diode switch at TP6.

    (Now some of you may think it's a little offbeat, yes, considering the TX side works, But R113 feeds clarifier on RX, so if RX is not right or J14 header is off, or D36 is zapped or just plain not soldered in correctly - a carrier shows up instead of a deconversion signal as you would with SSB - silencing the RX in FM and AM modes - but you would not hear it or see it in AGC or S/RF meter actions - it's downstream from it...)
     
    #7 Handy Andy, Feb 24, 2019
    Last edited: Feb 24, 2019
  8. CbRadiosPRONTO

    CbRadiosPRONTO Performance Ready Radios

    Joined:
    Mar 21, 2014
    Messages:
    348
    Likes Received:
    70
    Andy
    For the open clarified I lifted leg to d68 and r123, then, ran jumper from 8 volt rail. I do a couple every day just like that. Again, put back to stick when I noticed no RX during Alignment. Silly me. Should have check RX beforehand but ya know...saving time ‍♂️.

    Thanks...I’ll go back on Monday if I’m not too busy. If so...warranty.
     
  9. Handy Andy

    Handy Andy Do Your Research First, Then Decide...

    Joined:
    Apr 23, 2018
    Messages:
    3,321
    Likes Received:
    3,670
    Good luck - Hope it's something simple - Cold Soldering does come to mind...
     
  10. CbRadiosPRONTO

    CbRadiosPRONTO Performance Ready Radios

    Joined:
    Mar 21, 2014
    Messages:
    348
    Likes Received:
    70
    462B4B5E-2D94-4704-BDB9-B80B28CF793E.jpeg Thanks guys. FL1 Cold solder joint straight from the factory. Should have looked there first.
     
    TM86 and Shadetree Mechanic like this.
  11. nomadradio

    nomadradio Analog Retentive

    Joined:
    Apr 3, 2005
    Messages:
    3,587
    Likes Received:
    4,039
    Yeah, what we call "Galaxy Syndrome".

    Good to hear you nailed it.

    73
     

Share This Page

  • About Us

    The WorldwideDX Radio Forum was originally established in 2001. We pride ourselves on welcoming Radio Hobby enthusiasts of all types, while offering unbiased, informative, and friendly discussion among the members. We are working every day to make sure our community is the best Radio Hobbyist's site.
  • Like us on Facebook

  • Premium VIP Member

    The management works very hard to make sure the community is running the best software, best designs, and all the other bells and whistles. Care to buy us a beer? We'd really appreciate it!

    Donate to us!