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.

Galaxy Saturn

Discussion in 'General CB Services Discussion' started by Kung Fu Panda, Feb 22, 2021.

  1. Kung Fu Panda

    Kung Fu Panda Member

    Joined:
    Jul 5, 2018
    Messages:
    18
    Likes Received:
    7
    Hello everyone have a Saturn here giving me the blues. No carrier or modulation found the finals were blown. Changed them out now I have 2 watts carrier no matter where I set the pots. Still no modulation. It receives great shows carrier but no modulation. Put it in PA works great mic gain works echo works. Checked D77-65 ok. IC 4 voltages ok. Am regulator ok. Even had a fellow tech look at it and come up with no answer either and help would be appreciated.


     

  2. nomadradio

    nomadradio Analog Retentive

    Joined:
    Apr 3, 2005
    Messages:
    4,216
    Likes Received:
    5,236
    If the old finals overloaded the modulator circuit, TR51, the 2SB754 may be damaged. The smaller transistor that drives it, TR50 may also be bad. Whenever we replace TR51, we also replace TR50 without bothering to test it.

    Do you have a way to test TR51?

    73
     
  3. Kung Fu Panda

    Kung Fu Panda Member

    Joined:
    Jul 5, 2018
    Messages:
    18
    Likes Received:
    7
    TR50 - TR51 both test ok..
     
  4. nomadradio

    nomadradio Analog Retentive

    Joined:
    Apr 3, 2005
    Messages:
    4,216
    Likes Received:
    5,236
    Next one I would check is TR52. If it shorts, you'll get way too much AM carrier, no modulation and sideband will be okay on transmit.

    Simply removing the solder from the center pin of TR52, so the pin doesn't touch the rim of the foil pad will reveal if it's the culprit.

    If it still does the same thing, try the same trick isolating the center pin of TR49 from the solder pad.

    And if that makes no difference, we're running out of likely suspects.

    73
     
  5. Kung Fu Panda

    Kung Fu Panda Member

    Joined:
    Jul 5, 2018
    Messages:
    18
    Likes Received:
    7
    Checked those no dice. PA works but with echo on makes a bad hum.echo off nice and quiet.
     

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!