TS-480sat no AT and no Transmit

Discussion in 'Radio Circuits, Repair & Performance' started by KD4TWP, Aug 3, 2019.

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  1. KD4TWP

    KD4TWP Ham Member QRZ Page

    Hello all
    Seems my 480 has a problem. here's what it does or doesn't do.

    1. Little or no readable transmit. (It is transmitting to a shortwave radio in my shack) but not reading on the meter of the radio.

    2. Auto tuner wont tune anything, to include a dummy load. I have tried 3 dif antennas on both so239 out puts. dummy load doesn't tune either.

    I have done the factory reset also but no change. Still running old software no updates installed. Was working fine one day next day the problem started.

    receives great as always.

    We have had a lot of storms lately.I`m thinking I may have got hit by lighting ??? but all the other radios in the shack work fine.

    I have done a factory reset (nota)

    I have a dummy load hooked to it.

    thanks for any help
    Last edited: Aug 3, 2019
  2. KA5IPF

    KA5IPF Ham Member QRZ Page

    With no power the tuner can't operate. If you can check the current draw in TX. If less than 5a most likely a predriver in the final.
  3. KD4TWP

    KD4TWP Ham Member QRZ Page

    well if I am doing this right it is 1.03 amp with radio in receive and transmit 2.49 amp at 25 watts on am.
  4. VE1IC

    VE1IC Ham Member QRZ Page

    13,8V @ 2.5A with 25W output on the antenna jack??? Umm... No!
  5. KD4TWP

    KD4TWP Ham Member QRZ Page

    hi cliff
    the tuner engages like it is trying to tune but gives you the cannot tune this because of high swr`s beeps and after hooking it up to a dummy load I see that it will transmit maybe a 1/2 watt and I can hear myself on another receiving radio. what I have noticed is when I looked inside I noticed one of the protection diodes glass cover is smoked on antenna 1 coax, so this may be the issue but my fingers cant feel tiny things like that any more so I don't mess with repairs any more. time to send it off. thanks
  6. KD4TWP

    KD4TWP Ham Member QRZ Page

    um no what? no 2.5 isn't right or no 2.5 is a bad readying care to explain?
  7. WA9SVD

    WA9SVD Ham Member QRZ Page

    25 Watts on AM sounds about right...
  8. KD4TWP

    KD4TWP Ham Member QRZ Page

    guess im not explaining this right.
    there is 1/2 watt output on am. @13.8 volts and 2.5 amp draw.
  9. KA5IPF

    KA5IPF Ham Member QRZ Page

    Once again, the tuner WILL NOT work unless the radio is capable of putting out power.
  10. VE1IC

    VE1IC Ham Member QRZ Page

    Now that sounds about right. You just can't draw 2.5A @ 13,8V and have 25W output on the antenna jack. But 1/2W drawing 2.5A from the PSU, that is correct.
    However unless you get power out of the PA, the tuner won't tune, period. Do you get power from the radio without the tuner being engaged straight to a dummy load? Try all the bands. If you're missing power just on one or two bands, look at the bandpass filter board.

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