3SK73 in TS-530SP

Discussion in 'Radio Circuits, Repair & Performance' started by N9XAW, Mar 26, 2019.

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  1. N9XAW

    N9XAW Ham Member QRZ Page

    Being an old tube man this solid state stuff baffles me sometimes. On transmit Q2 in the RF board gets a signal into G1 but nothing out of the drain to the next stage. voltage on G2 is low (-38) on transmit but again there is no transmitter output. (The resistors in the final stage are all new.) Apparently 3SK73 are hard to find. Am I on the right track? When I place the unit in send mode and the meter is on ALC it pegs it. The meter works fine in receive mode. Hv is ok, RF is zero.
     
  2. WB5WPA

    WB5WPA Ham Member QRZ Page

    -38 what - volts? Something is wrong ... that kind of voltage exceeds specs for any pin on that device ...
     
    KD8DEY likes this.
  3. KD8DEY

    KD8DEY Ham Member QRZ Page

  4. N9XAW

    N9XAW Ham Member QRZ Page

    My bad. I was looking at the wrong part. voltage is more like 2.0 and 1.6
     
  5. N9XAW

    N9XAW Ham Member QRZ Page

  6. N9XAW

    N9XAW Ham Member QRZ Page

    These things are not cheap. I don't want to replace it if it is not bad. but.. the RF signal goes in and does not come out. I am thinking it may be an ALC problem?
     
  7. KD8DEY

    KD8DEY Ham Member QRZ Page

    What goes in, must come out. If your not getting anything at the output pin....
    are you checking right at the output pin or is there a cap between stages involved?
    (Rare but capacitors between stages have been known to go bad)
     
  8. G4COE

    G4COE Ham Member QRZ Page

    N9XAW likes this.

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