BTI amplifier

Discussion in 'Amateur Radio Amplifiers' started by N2ZD, Nov 24, 2019.

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  1. N2ZD

    N2ZD Ham Member QRZ Page

     

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  2. W1QJ

    W1QJ Ham Member QRZ Page

    RESTING plate current is in transmit with no drive, not in stand by.
     
    N2ZD likes this.
  3. N2ZD

    N2ZD Ham Member QRZ Page

    Okay then! Lol I’ll keep poking around. I did stop to read your bio on king conversions :)
     
  4. N2ZD

    N2ZD Ham Member QRZ Page

    I just came from YouTube and was looking over your 8877 conversion 2K-4. Nice job!!
     
  5. N2ZD

    N2ZD Ham Member QRZ Page

    I’m watching this thing and the plate current is slowly dropping and the plate voltage is going up.
    It’s been sitting a long time I know that. The Henry amp did not have tubes. I pulled these From another amp that was also sitting around rather dormant. I’m going to cook everything a while.
     

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  6. HS0ZED

    HS0ZED Ham Member QRZ Page

    I don't know this model, I have a couple of 2K-Classic X amps though.

    Is this thing drawing current in the Standby (i.e. no key line activated)?
    Or is this what you are seeing in keyed state but with no drive?

    Wasn't fully clear from what I read.

    The Classic-X draws nothing in Standby (receive mode) and the stated 150-200mA in idle (keyed with no drive) depending on plate voltage which can be set to one of two or three values.

    I have never had it sit running for any length of time in the idle condition but 3000 volts at 200mA is 600 watts and it's not RF so it must be heat, pretty good 1 bar electric fire and not what you would want.
     
  7. N2ZD

    N2ZD Ham Member QRZ Page

    Thanks for the reply, it stopped drawing plate current after cleaning the relay. I am also unfamiliar with this amp as well which is why I asked about the draw. At no time did I take my eyes off of the amp nor did I leave the room while it was doing this. I shut it off until the relay was cleaned and once she started to draw a negligible amount of current, I let it run for 4 or so hours with no cherry red tube issues.
    It’s basically an overgrown sb-220 with about 3.4kv on the plates using oil filled caps and a ginormous transformer. 2x3-500z tubes. Which are a few years old but were not used in a while. So all of this needed to be exercised a bit. I’m sure the Henry amp sat dormant for at least 5-10 years without tubes.
    I got this amp and another (see above,) both in unknown condition. It turned out after careful setup, they both should work ok with minor sparks and flames lol. The BTI trips the breaker on 120v so I’ll just leave it In the corner with my other unusable 220 amps lol
    The only thing with this one is it’s missing the aluminum cage under the main cover so I may have to make one or watch ebay.
    The link drive is good and it has the brass drive mechanisms for the controls.
    My 922a is the current amp in my operating position. It’s marshmallowy HV is low enough not to trip my breaker and it’s real quiet. So these are just interesting amps to get running again.
    Apparently, the relay, as Lou said, was controlling the cutoff bias and caused the draw in plate current. Once I keyed it a few times, it drew less and less and after a good cleaning, it stopped altogether.
    Next step is to get it in line and see how she performs on the air.

    The draw was while it was unkeyed, by the way.
    Regards Richy N2ZD
     
  8. W1QJ

    W1QJ Ham Member QRZ Page

    the relay, as Lou said, was controlling the cutoff bias and caused the draw in plate current. Once I keyed it a few times, it drew less and less and after a good cleaning, it stopped altogether.

    OK, what is your address so I can bill you?;)
     
  9. N2ZD

    N2ZD Ham Member QRZ Page

    Im good on Qrz lol thanks!
     

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