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Thread: High Initial Power Draw

  1. #1
    "Island Bartender" KG4CGC's Avatar
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    High Initial Power Draw

    I have a Ten Tec ArgoV which I purchased through a very nice ham here on the Island. No issues there. Great deal and full disclosure. Great receive and that was my main interest for it.
    My question is: Recently within the last few months it pulls about 7 amps when I turn it on. Kept blowing the inline fuse is how I found it. I put in a 10 amp fuse and watched the amp meter spike up to about 7 amps when I turn it on. After the initial micro second of this spike it immediately drops back down to normal draw.
    So, what's causing it to do this? Is the diode across the incoming DC power on the verge of ceasing? Will it soon desist as a diode and abstain from its duties?
    Is it something else? Hoping it's something simple. It still works but now in my mind I'm picking apart the performance, thinking and overthinking and causing me to think it doesn't perform as well on the receive as it used to. It's a strange power I have, making cars and equipment breakdown just by thinking there's something wrong with them but that's beside the point.

  2. #2
    Whacker Knot WØTKX's Avatar
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    The max current draw on TX is 6 amps nominal. Yikes.

    Try undoing the power to the PA section and then power it up.

    FETs can be fussy. There is necro chatter on the that some diodes get off with high SWR.
    Not saying that's what happened, but Something is Zucky (love that expression).
    Wasn't specific. If you can unplug sections of the radio, you may narrow it down fast.

    I've been fixing 70's "vintage" audio stuff for a few months. Getting close with a monster receiver.
    Wattage in your cottage.
    Kenwood KR-8050 | Classic Receivers
    "Where would we be without the agitators of the world to attach the electrodes
    of knowledge to the nipples of ignorance?" ~ Professor "Dick" Soloman



  3. #3
    "Island Bartender" KG4CGC's Avatar
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    Of note, the TX dropped to 1-5 watts before I bought it. I never intended to TX on it anyway.
    I've had it for 4 or 5 years now. The amperage spike is new.

  4. #4
    Administrator N8YX's Avatar
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    Look at any high value electrolytics on the DC supply rail. As Dave suggested, have a look at the PA (disconnect).

    Do you have a monitor scope and dummy load? I'd look at the output of the rig on power-up and see if an RF transient is present. Perhaps a parasitic due to flaky coupling or bypass caps in the RF section.
    "Everyone wants to be an AM Gangsta until it's time to start doing AM Gangsta shit."

  5. #5
    Island Canuck VE7DCW's Avatar
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    Yes...electrolytics my guess as well.A 40 year old Yaesu FT 101ZD did the exact same thing to me and it was re-capping time.All large value electrolytic caps in the power supply circuits should be be swapped out in vintage equipment.The noticeable difference in performance afterwards is worth the effort!
    Why,driving into a brick wall at 60 miles per hour, would I expect it not to hurt! :roll:

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