TS-530s can't peak load control

Discussion in '"Boat Anchor" & Classic Equipment' started by KD5NDQ, Apr 14, 2019.

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  1. KA9JLM

    KA9JLM Ham Member QRZ Page

    Is your SG switch on or off ?
     
    Last edited: Apr 16, 2019
  2. W5RKL

    W5RKL Ham Member QRZ Page

    It appears there is IP meter indications which eliminates the rear panel "SG" switch being in the
    OFF position.

    If the SG switch were to be in the OFF position then there would be zero IP meter indication in any
    mode transmit. In the OFF position the final tube screen voltage would be "negative" resulting in
    any electrons to be repelled back towards the cathode.

    If the SG switch were to be in the ON position then there would IP meter indication in any mode
    transmit. In the ON position the final tube screen voltage is positive allowing electron flow from
    the cathode to the screens and plates.

    73
    Mike W5RKL
    www.w5rkl.com
     
    KA9JLM likes this.
  3. W5RKL

    W5RKL Ham Member QRZ Page


    At what position is the CAR control knob set? If it's at 10 o'clock with 75ma indicated on
    the IP meter in CW mode transmit, rotate the CAR control clockwise in CW transmit to see if the
    IP meter increases. Next rotate the PLATE control both CW and CCW, throughout its range.
    Do you see a dip in IP meter indication? If not then I still suspect the band switch coupler
    could be cracked or broken causing the final amplifier band switch wafer to not rotate to the
    proper setting for the band selected, hence no dip in IP meter when rotating the PLATE knob.

    Perform the "check" on the final amp band switch assembly to see if it moves exactly like
    the long band switch shaft and RF Unit wafer switches rotate.

    73
    Mike W5RKL
    www.w5rkl.com
     
  4. KD5NDQ

    KD5NDQ Ham Member QRZ Page

    ON
     
  5. KD5NDQ

    KD5NDQ Ham Member QRZ Page

    2 o'clock position
     
  6. KD5NDQ

    KD5NDQ Ham Member QRZ Page

    Makes no difference where I set CAR control knob.
     
  7. K7TRF

    K7TRF Premium Subscriber QRZ Page

    I've kind of lost track of where you are in all of this, but is this correct?

    - You get good ALC response when you peak the Drive control even with the Carrier control at 12 oclock or thereabouts?
    - You get around 80 mA of plate current when keying the rig in SSB mode but not talking into the mic or having mic gain all the way down? (If so adjust the bias till that reads 60 mA per the manual)
    - When you key in CW mode with the load control fully counter clockwise you see maybe 100 mA of plate current and you don't get a pronounced dip in the plate current with the Tune control?
    - Advancing the Load control has little to no impact on plate current while keying the rig in CW mode?

    Earlier in this thread I thought you had solid plate current as in 200mA or so when keying in CW mode but if you really can't get good plate current regardless of Load and Tune settings (and SG switch is on as you've posted) then I'd strongly suspect either the final tubes themselves or the cathode and screen resistors. Those cathode resistors are also the plate current meter shunts so if they drift high in value (they often do) then your plate current readings are all out of whack. Make sure the combo of cathode resistors reads 5 ohms (4 resistors, 20 ohms each in parallel in the TS-830 and TS-530). If they read much higher than that, replace them. Check the screen resistors while you're in there as they can also get cooked and screw up finals power.

    If all the resistors on the finals board check out then I'd strongly suspect final tubes assuming the point above about not getting more than 80 to 100 mA or so of plate current while keying the rig in CW is correct.

    If you can get a lot of current but no RF output and no Tune dip as I originally thought then we're back to band switch wafer output relay, coupling cap or associated wiring.
     
  8. KD5NDQ

    KD5NDQ Ham Member QRZ Page

    The band switch coupler is not cracked and when in the "10" setting the rotor wiper on the S22 switch shows it to be in the 1 o'clock position which as I understand is the correct one. Switching to different bands the switch makes solid stops & clicks; it takes a fair amount of torque to change the band setting. While the knob has a little bit of "give" in it without changing bands I see no movement in the rotor wiper on the S22 switch at all when I observe this "give".
     
  9. KD5NDQ

    KD5NDQ Ham Member QRZ Page

    Yes
    Roughly 60mA
    Yes no dip in plate current, but only roughly 60mA of current in CW mode. In TUNE mode it shows roughly 90mA.
    Correct
     
  10. K7TRF

    K7TRF Premium Subscriber QRZ Page

    Yeah, I'd test the cathode and screen resistors, replace them if necessary and order up a new set of tubes.
     

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