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TS-530s can't peak load control

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

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  1. KD5NDQ

    KD5NDQ Ham Member QRZ Page

    Had my TS-530s off for a couple of months while replacing antennas (everything disconnected). Today I turned it back on and was hooking up a keyer and going through the normal tune up procedure but when I get to peaking the load control (meter switch set to RF), I get no movement on the meter while turning the load knob. It should be noted that on the previous step I did not see any "dip" in the meter when trying to dip the plate. These steps have all worked in the past whenever I tuned up. Does this mean my final and driver tubes need replacing? I've tried the tune up step several times according to the book to make sure I haven't had anything mis-set due to being away from the radio for a while and forgetting something.
    Thanks
    Bob
    KD5NDQ
     
  2. N7WR

    N7WR Subscriber QRZ Page

    try replacing the driver tube first before investing in the finals
     
  3. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Not enough info.

    If you switch to SSB and key the mike PTT, what does the plate current meter indicate?

    What does the high voltage meter indicate?

    Can you peak DRIVE for a peak in the ALC meter reading when in TUNE?

    I'd want a lot more information before drawing any conclusions...
     
    K9ASE and WQ4G like this.
  4. KD5NDQ

    KD5NDQ Ham Member QRZ Page

    With SSB, keying the mike the meter reads ~85.
    HV says 88?
    Yes, I can peak the DRIVE with ALC meter in TUNE.
     
  5. K7TRF

    K7TRF Premium Subscriber QRZ Page

    Then your driver tube is fine.

    Sounds to me like either bad final tubes or one of the typical bad components in the final cage. If your DC plate current while keying in CW mode is up around a couple of hundred mA or so then I'd expect something in the RF output coupling chain.

    I had a TS-520SE (basically the same finals section design as the TS-530) that showed symptoms much like what you're describing, tough time getting a definable plate current dip and very strange Load control behavior. After a bunch of troubleshooting it turned out to be a bad relay socket to the T/R relay right underneath the finals cage. There was plenty of DC plate current but the Tune and Load knobs didn't behave properly.

    After replacing the RF output blocking cap (another common culprit in these rigs) and swapping in a known good relay, on a whim I used a clip lead to jumper from the transmit output side of the T/R relay to the antenna jack and suddenly everything worked properly. Turned out the lead from the output stage to the relay socket was drawn super tight during assembly and I suppose over time the socket contacts became intermittent. Replacing the socket and re-dressing the associated leads correctly fixed things and the original relay turned out to be fine as well and is back in there.

    Point of all that is that any break in the RF output chain to the antenna connector or even a bad coax jumper out of the rig can lead to symptoms similar to what you're describing. IOW, if you can't transfer power out to the antenna system or dummy load then finals tuning will be screwy even if you see DC plate current up about where you'd expect, it's basically the same as trying to tune up with no antenna load connected.
     
    WQ4G likes this.
  6. KA9JLM

    KA9JLM Ham Member QRZ Page

    I would try cleaning ALL sections of the band switch.

    I use ISO alcohol to clean, Then you can add the magic contact juice of your choice.

    Good Luck.
     
    W1BR and K9ASE like this.
  7. KQ9J

    KQ9J Premium Subscriber QRZ Page

    Are you getting power out? As in while observing an external swr/wattmeter?
     
  8. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    85 mA idling current is a bit high, but not a big deal.

    The "88" on HV indicates 880V, which is in range of what it's expected to be with only idling current.

    What does Ip (plate current) indicate when you "tune up," key down with CARrier control advanced?

    At a "dip" with normal drive it should be a couple of hundred mA, but if out of resonance (not dipped) it can be higher than that.

    Although something in the rig may well have failed, sometimes when you can't get the rig to load properly, there's something wrong with the load (like the antenna, or transmission line, or jumper cable, or coax switch, or anything else that may be in line following the rig's antenna connector).
     
  9. KD5NDQ

    KD5NDQ Ham Member QRZ Page

    Contacts cleaned, no change in results. :-(
     
  10. KD5NDQ

    KD5NDQ Ham Member QRZ Page

    Plate current reads ~90mA in TUNE mode when testing in different bands. I'm not sure what you mean by with the CAR control "advanced". It's currently set at around the 10 o'clock positon. I am tuning into a 300 watt dummy load.
     

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