Yaesu Fl2100 bypass may be stuck ??

Discussion in 'Amateur Radio Amplifiers' started by KG4RSF, Mar 18, 2018.

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  1. KG4RSF

    KG4RSF Ham Member QRZ Page

    no rf out when keyed. can receive ok and transmit ok but as soon as you activate relay, sound goes almost silent on rig (normal) butno output on my drake wh7 or ldg1000 tuner ???

    Moved bias verible resister back to orig. meter for ip (left meter) moves ever so slightly when i turn reading swr to ip. less than .01

    tubes 572-b o'malely look brand new except base look old. guy i bought from rig from said he just installed these in this amp and i may have to adjust bias
    --------------------------------------------------------------------------------------

    I bought this amp and ham flea. told widow died and selling for her. He said he found tubes with the amp and installed and converted to 120 and told me it worked.

    Next Step. ????
     
  2. KG4RSF

    KG4RSF Ham Member QRZ Page

    ok tubes were in wrong. working but low out put not even 100, and i have to turn loading to 0
     
  3. KG4RSF

    KG4RSF Ham Member QRZ Page

    what does it mean that i can take load low enough ?
     
  4. KA9JLM

    KA9JLM Ham Member QRZ Page

    What band ? Are you testing into a dummy load ?
     
  5. KG4RSF

    KG4RSF Ham Member QRZ Page

    ok 14.310 fm carrier into well tuned antenna, using ldg 1000 watt auto tuner swr 1.4
    100watts in plate dial 6, loading 1,

    60 watt out ip reads 0 at idle .11 when keyed.
    plate voltage 2kv idle, 1.5 when keyed
     
  6. KA9JLM

    KA9JLM Ham Member QRZ Page

    It sounds like the power supply has problems. The HV should not drop that much.

    If it has the original caps I would replace them.

    Good Luck.
     
  7. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    2kV at idle and 1.5kV keyed indicates something very wrong.

    Buying an unknown entity from an unknown buyer is what we used to call "a pig in a poke.":)

    However, it's a very simple amp and as long as the power transformer is good, anything in there can be fixed for probably $25 (in parts, assuming you do the labor part).
     
  8. G3YRO

    G3YRO Ham Member QRZ Page

    Yes, first thing is to measure the HT voltage . . .

    Do you have a suitable multimeter and leads to measure 2.5 kV?

    (most decent ones are designed to go up to this voltage)

    Roger G3YRO
     
  9. KA9JLM

    KA9JLM Ham Member QRZ Page

    I don't think so. You need a HV probe to play it safe.
     
  10. KG4RSF

    KG4RSF Ham Member QRZ Page

    have to buy a meter that can measure that. Any suggestion on amazon or ebay.. Although amazon is easier. I only have a harbor freight cen-tech p37773. I'd lke to find auto ranging and dig for sure
     

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