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PALOMAR TX-5200 QUESTION

Discussion in 'Amplifiers' started by TonyV225, Dec 24, 2008.

  1. TonyV225

    TonyV225 Supporting Member

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    I try my QRP 5200 on 2 different radios and it works on 11 meters but when I hit the other ham bands I unkey and the damn thing takes a second to key then it stays keyed kind of the key like stays lit and recieve drops down then I turn of the amp and then back on light goes out and recieve coms back.

    The amp is staying keyed I guess now would this be due to a tune some one did to run it out of band would I have to reset the variable pot at the front by the band selector while in each band or is there a happy medium I need to find but then not beable to run it on 11 meters which I actually dont and it wouldnt matter anyways.



    Heres a link to a site with pics of my exact amplifier notice in front by band selector theres a silver variable I guessing this is what needs adjusting?
    Palomar TX5200 for sale pictures from hobbies & interests photos on webshots
     
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  2. paws264

    paws264 Active Member

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    Yes, it is a multi-band "Amateur" amplifier but, it does not have tuned input for each band, to run that thing, you need a tuner between the radio and the amp.


    .
     
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  3. TonyV225

    TonyV225 Supporting Member

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    Im thinking about actually digging this out and playing around with it. I need to find specs on what input drive power it reccomends. I guess I can use one of my radios with a internal tuner for input tuning but I will have to setup another tuner for inbetween the amplifier and the inverted antenna.
     
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  4. paws264

    paws264 Active Member

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    Tony, here is the answer to OUR question about why our Palomar 5200s occasionally hang up (Thaks Bob).

    Maybe if we add negative feedback (my amp does not have it in there from the factory) it might affect that "un-keying" issue.

    .
     
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  5. TonyV225

    TonyV225 Supporting Member

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    I still have to hook my 5200 up and run it a little. Mine has 4 x 2SC2290 Transistors in it and was like that when I got it. I know they are not the original transistors that came with these amplifiers the ones that are supposed to be in the amp I am not the least bit familiar with.
     
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  6. hitechluddite

    hitechluddite Member

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    Tony, if your still checking this link here is my experience.

    the 2290 takes less drive than the stock transistors so what I would do is hook the thing up to a dummy load and give it some low drive. adjust the input 16-150pf cap for your lowest SWR on the rig at the highest op freq. and adjust the 16-150pf cap on the 10-15M band pass for the maximum output.

    Next you could design a 50 Ohm 3DB input attenuator out of some 3 Watt metal film resistors and insert it on your input in place of the 27 ohm 5W, if that doesn't drop the output enough go 6db. This will lower the SWR to the rig and make the amp more stable.

    I would probably remove the fixed caps on 20-80 the band pass filters and install trimmers like there is on the 10-15M filter.

    Lastly you could install trimmers across the output transformers but without the proper test setup they are a bitch to balance in a multiple push pull config.

    Good luck and thanks for the schematic links!
     
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