FL 2100B Tuning issue

Discussion in 'Amateur Radio Amplifiers' started by N4DXX, Nov 7, 2018.

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  1. N4DXX

    N4DXX Ham Member QRZ Page

    Just got finished rebuilding a power supply in my fl2100 and now have an issue when tuning up the amp..When tuning the load sometimes i see around 300 watts out with 50 watts drive.Then if i touch the load conrol my power output dissapears..Re tune and it's back.I traded for this amp and it was down with the power supply caps shorted..I also had a 33 ohm resistor blown.I know that could indicate issues with the tubes..Would a bad tube cause this weird behavior while tuning?I assume it would..Thanks for any input
    Never mind i need to start overlooking my work better..I had a blob of solder fell onto the tank coil..Blind as a bat.
    Last edited: Nov 7, 2018
  2. G3YRO

    G3YRO Ham Member QRZ Page

    Glad you found the problem!

    These are well-constructed and generally very reliable Linear Amps.

    Just make sure you take the fan motors apart every few years to clean and lubricate them, to kep them running at full speed.

    Roger G3YRO
  3. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    Good extension lamp with a magnifier helps a lot.

    When I was young I didn't need that.:p
  4. VE3TMT

    VE3TMT XML Subscriber QRZ Page

    Best thing I ever bought, Makes working on surface mount components a walk in the park!
  5. N8CMQ

    N8CMQ XML Subscriber QRZ Page

    Be sure to inspect ALL of the band switch contacts.

    I had 2 burnt on the output wafer and the input wafer needed cleaning.

    Is the load cap loosing connection to the rotor? I would pull the knob outwards while turning to see if it cleans up the spring contact. Use a little deoxit on the spring.

    My FL2100b is no longer a Yaesu product, I have changed so much of it it isn't funny.
    N8VIL likes this.

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