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Yeasu FL-2100F schematic and or manual...

Discussion in 'Amateur Radio Amplifiers' started by K5ABB, Nov 4, 2017.

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  1. G3YRO

    G3YRO Ham Member QRZ Page

    Yes the relays, as well as other components, often fail on those FL2100Z boards . . .

    That's why I prefer the much simpler circuit used in the original FL2100 models.

    Roger G3YRO
    N8VIL likes this.
  2. K5ABB

    K5ABB XML Subscriber QRZ Page

    Well, a little update here... and thanks to all who've participated... I've been away from the project due to family obligations, but am getting a chance to dig back into it again now.

    This 2100F amp definitely has the 2100z bias board installed, and that seems to be the problem. The bias voltage measures -1.8vdc at the grid pins (r202,r201), the "bias" terminal on the pc bias board, and the "grid" terminal on the same board. That's a long way from -50vdc or even -18vdc, so it seems for all intents and purposes, the grids are unbiased. That said... the amp still functions normally enough, except when it goes into oscillation (go figure?)

    The tricky bit now, is to get to the back side of the pc board to be able to test individual components. The wires are all pretty short, probably for a compact installation and general tidiness on the chassis, but it looks like I'm going to have to unsolder at least a half dozen connections just to get a good shot at the backside (trace side) of the board (sheesh!). All of the components "look" ok visually with nothing obviously bad or toasted, so I guess it's just going to be a matter of working through it, and testing all the components.

    But first I AM going to make sure that the proper supply voltage is present feeding the board. It would suck to dismount and go through the whole board only to find the problem was further upstream...

    Back at it again,

    N8VIL likes this.
  3. LU4HK

    LU4HK Ham Member QRZ Page

    Hello everyone, I am reviewing the trippler circuit of my FL 2100Z and changing the high voltage capacitors and I do not know how to measure the voltages.
    -50 volts at the grid point and -18 volts at the bias point with the variable resistance of 30 ohms 10 watts disconnected .
    Now if I connect the adjustable resistance, the 2x56 ohm resistors heat up the rest.
    What could happen?
    When the high voltage source is not connected and the valves are polarized or the relay is defective.
    I'm going to put in a couple of new 572b valves and I do not want them to break.
    Can you help me? Thank you
    Luis LU4HK / L73H

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