Help w/ KW TS570 power output issue

Discussion in 'Radio Circuits, Repair & Performance' started by W4LLZ, May 23, 2019.

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  1. W4LLZ

    W4LLZ Ham Member QRZ Page

    Hey all,
    I've got a Kenwood TS570 that is only putting out 60 watts (max power is 100). Having the rig at 100 watts hooked to a dummy load (as well as my hf antenna) it only puts 60 watts. Any ideas what the problem could be and whether or not its fixable? I'm not a electronics-type-guy, just a user of ham radio. Thanks for any help in advance to determine if its fixable.
    W4LLZ
     
  2. KA5IPF

    KA5IPF Ham Member QRZ Page

    Most likely the voltage at the back of the radio is dropping to the ~12 level and causing low power out With your DMM, don't have one?, Harbor Freight has them for $6. Measure the voltage at the power supply, it should be 13.8-14v. Key it in CW mode and it shouldn't drop. Next measure at the back of the radio. It shouldn't drop more than 1v max. If more find the bad connection in the power cord.

    If that all checks out look at the meter and see what SWR and ALC it's showing. All tests done in CW mode set for 100w.
     
  3. WG7X

    WG7X Premium Subscriber QRZ Page

    If I may add to what Clif said: make sure that you have a good watt meter and a dummy load. If you see 100 watts on CW into the dummy load and only 60 when on SSB it's more likely to be a metering problem.

    Clif is the expert though. Do what he said and you can't go wrong.
     
  4. W4LLZ

    W4LLZ Ham Member QRZ Page

    I actually get 60 watts on FM and SSB on both the antenna and then separately on the dummy load...using the power meter on the radio. I'll hook it up to a inline SWR meter (and not use the SWR meter on the radio) and see what that meter reads. I'll also check the voltages at both the power supply (kenwood) and if that checks out i'll switch power cords and see if that doesn't make a difference. If that doesn't solve it, i'll report back here and seek additional ideas and possible solutions. Thanks.
     
    WG7X likes this.
  5. KA5IPF

    KA5IPF Ham Member QRZ Page

    First check the voltage drop at the power supply to rule it out. Then check at the radio. On the external SWR meter that doesn't count as the radio depends on the internal SWR meter for shutdown info.
     
  6. W4LLZ

    W4LLZ Ham Member QRZ Page

    Clif - I did check the power supply and the voltage at the radio. All good. I put it on an external SWR/Power Meter and it reads a tad over 100 watts on CW, with the radio at 100. It then tracks the same power outage as the radio - meaning as I lower the power output on the rig the SWR/Power meter equally measures the same power output. I think the meter on the radio is out of adjustment for some reason.
     
  7. KA5IPF

    KA5IPF Ham Member QRZ Page

    There-in is the problem. There is no adjustment for the internal power meter. Something is screwy here.

    Hook up the external wattmeter and dummy load. If available put an ammeter in the power lead or check power supply if it has meters. Do a reset on the radio. Put the radio on 14.200 MHz in CW mode.

    Key the radio and record the readings for Power, ALC, & SWR on the internal meter. Check power on external meter. Also check current draw. Tell me what those reading are.

    Have you ventured into the service menu or do you know if someone has? Many hams want "just a little more power" and go into the service menu and turn up the power using one of the steps. Can't do that. It has individual power settings for each band. If any are changed then the entire TX alignment must be followed, which includes ALC meter settings and SWR meter settings.
     
    KA9JLM likes this.
  8. W4LLZ

    W4LLZ Ham Member QRZ Page

    Below are images of the radio, swr/Power Meter, and Power Supply readings on CW, 100 watts power setting on radio, freq 14.200 attached to a dummy load. Three tests at different power settings done, results below.
    4C00EFC6-5C57-4B94-B697-A0E3F4C64CC4.jpeg 7882B09F-C03A-499E-894F-3D74AF1D915F.jpeg No, I have not gone into the service menu, and don’t know how to either.

    Readings:
    #1 Test
    Radio set at 30 watts power, CW, freq 14.200
    Radio Power Meter indicates: 27 watts
    Radio ALC Meter Pegs to max
    Radio SWR Meter indicates: 1.2:1
    External SWR/Power Meter indicates: SWR 1.1:1, Power of 22 watts
    Astron Power Supply indicates: 8 amps draw when radio keyed

    #2 Test
    Radio set at 60 watts power, CW, freq 14.200
    Radio Power Meter indicates: 60 watts
    Radio ALC Meter pegs to max
    Radio SWR Meter indicates 1.2:1
    External SWR/Power Meter indicates: SWR 1.1:1, Power of 50 watts
    Astron Power Supply indicates: 11 amps draw when radio keyed

    #3 Test
    Radio set at 100 watts power, CW, FREQ 14.200
    Radio Power Meter indicates: 60 watts
    Radio ALC Meter pegs to max
    Radio SWR Meter indicates 1.2:1
    External SWR/Power Meter indicates: SWR 1.1:1, Power of 110 watts
    Astron Power Supply indicates: 15 amps draw when radio is keyed

    Note: Astron Power Supply indicates no drop in voltage from its initial indication of 13.8 volts at the PS volt meter.
    Note: The ALC did not peg to max when I switched to USB and spoke into mic on same frequency, and was capable of being adjusted using the internal mic gain setting.

    Thanks,
    W4LLZ
     
    Last edited: May 31, 2019
  9. KA5IPF

    KA5IPF Ham Member QRZ Page

    Someone has been in the service menu. On the voltage the power supply is fine, BUT the drop has to be measured at the radio. Once the PS is confirmed good.
     
  10. W4LLZ

    W4LLZ Ham Member QRZ Page

    No one has been in the service menu. I’ve owned this radio for years and it has not been touched by anyone, and the problem has recently started. I’ve not been in to the service menu and I don’t even know how to get in to it. Thanks for trying to help identify the problem but at this time I think I’ll just have to live with it.
     

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