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lafayette HA-270

Discussion in 'Amplifiers' started by Lt Dan, Oct 13, 2009.

  1. Lt Dan

    Lt Dan Mud Duck

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    OK, I just aquired a Lafayette HA-270 linear amplifier

    This is my first experience with tube type amplifiers and so far it has not been a good experience. (not that I'll let one bad experience ruin the rest)

    Ok, so I hook it up. Put the coax from my radio to the input, coax from the output to my meter and meter to antenna. I have two 12gauge wires running from my van's battery to it. All hooked up, so far so good.

    So i fire it up and the tubes glow. From what I understand I'm supposed to let it warm up for like 2 minutes, So I do before trying it.

    Here's the part that confuses me. I key down and it emits a loud click, sometimes a squeal, but no signal comes out.... None... Zip, zilch... When I key the needle on my meter wiggles alittle then just sits at zero.



    Now there are two knobs on the front. One says "Plate tune" and one says "Ant load" (Whitch i assume means antenna load). I've adjusted both to like every position and would re-try keying up... no luck.

    My assumption:
    I'm guessing that My battery isn't pushing enough power. I had A battery charger running on the battery so it wouldn't die. I'm willing to assume that maybe i need to have the van RUNNING so i get the full 13.7 volts? (van won't start, new fuel pump to be installed this weekend)

    I don't know, maybe its just old junk to put on my shelf and look at.

    also, anyone know how much power this is supposed to put out?


    Any suggestions?
     

  2. packrat

    packrat Active Member

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    First, tube mobile amps eat a lot of power, so yes, the vn should be running.LOL. Second, you tune it the following way. Hook everything up as you stated, let it warm up, key the mic while watching the [ower / swr meter in power reading position, unkey for a minute or so. Re keyand turn one knob lookang for highest power output on swr meter, un key. Do this quickly as the tubes will die if kept keyed too long. 10-15 seconds is good. Let it cool down. Re key turning the other knob for highest output. unkey and let her rest. Do this a few times til you dont see any improvement. That should do it as far as the amp goes, and you will have to do this every time you change frequency, so get used to it. The squeel is probably feedback, which is a whole nother story.
    It is a whole lot easier to use a solid state amp when mobile, and that is my recommendation.:D

    JMTC

    PR
     
  3. Slam Dunk

    Slam Dunk Member

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    Hey Kid,

    You have a 200 watt pep 2 tube amplifier that has a transistor switching power supply to make the 700-900 volts that the tubes need to operate. The sound that you hear is the transistors oscillating and it is normal. It was made for four watts drive input. Expect to see about 100+ watts out. That was a big deal in it day.

    Tune it up like the fellow says and have some fun with it until you can get a transistor amp; be sure to turn it off, the tubes will pull down your battery if left on and the engine is not running.

    .
     
    #3 Slam Dunk, Oct 13, 2009
    Last edited: Oct 13, 2009
  4. W5LZ

    W5LZ Crotchety Old Bastard

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    First, you are right, the best thing you could possibly do is leave it alone until you know what you are supposed to be doing. Tube type amplifiers are not 'plug-n-play' by any means, you really do have to know what your are doing.
    Knowing nothing about that Lafayette HA-270, other than it's older than you are, and that Lafayette never made any CB amplifiers (can't remember any ham amplifiers either), it's only value is it's collector's value. You have three choices, do more learning than you'd ever believe to run the thing, put it on a shelf to wait for someone who really collects these things, or beat it to death with a hammer. I really think that second choice is your best bet. Sorry 'bout that.
    - 'Doc
     
  5. Lt Dan

    Lt Dan Mud Duck

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    I do have a solid state kicker. an old siver eagle 200...

    I traded a record player and a cheap spring action BB pistol for it, so no big deal.

    I might play with it some more when i get home :bdh:


    Thanks for the feedback
     
  6. Beetle

    Beetle Sr. Member

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    Are you using AM or SSB?

    SSB has no carrier, so you won't see any output until you speak into the mike.
     
  7. Tucker442

    Tucker442 101E

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  8. Tucker442

    Tucker442 101E

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    I still have a HA270 A I bought it new in 73. I also bought the matching power supply which probably weighs 30 pounds so you could use it in the house. Depending what frequency you’re going to use it for there’s a wire soldered to the tank coil in the front you have to put it different places for what frequency you’re going to talk on and there are some things here that will show you. When mine was new it never did 100 watch it did maybe 70 or 80. It still does the same it works like it did when it was new the power supply still works fine in Lafayette had them made to their specs in Japan. They do make an HA 250 or I should say they did it took different tubes and didn’t have as much output but it did draw quite a few amps. First off if you’re gonna tune it you need something with a carrier either an a.m. or an FM radio and go from there I used to use mine on sideband and if I whistled in the mic I could get it almost 100 watts but on a.m. it would only do about 70. Do you know in the day first off it was expensive but if you had one of them in your mobile you were the man because nobody had a 100 watts. The tank coil issue is very important depending what frequency you’re going to use it on if you look up an HA250 here’s a picture of the tank coil with two places to put the wire I think the 270 is just a little different. Good luck and like the guys said don’t hold the key down more than about 10 seconds or you’ll fry the tubes
     
    Shadetree Mechanic likes this.
  9. Shockwave

    Shockwave Sr. Member

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  10. Captain Kilowatt

    Captain Kilowatt Professional Amateur
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    Shadetree Mechanic likes this.

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