ad: elecraft

Raytheon Tubes

Discussion in '"Boat Anchor" & Classic Equipment' started by KF5DDW, Sep 24, 2020.

ad: L-HROutlet
ad: l-rl
ad: Left-3
ad: Left-2
ad: abrind-2
ad: Subscribe
ad: L-MFJ
  1. KA9JLM

    KA9JLM Ham Member QRZ Page

    Most getters are activated at the manufacture when the tube is made.

    Operating just the filament will not getter them, Or put the vacuum back in. o_O
    AI3V likes this.
  2. W1VT

    W1VT Ham Member QRZ Page

    I've heard work in the lab when folks repaired receivers. Transmitting tubes are different.
    But, it does require patience. Which often seems to be in short supply.

    Zak W1VT
    Last edited: Oct 4, 2020
    KA9JLM likes this.
  3. KF5DDW

    KF5DDW Ham Member QRZ Page

    I was walking through the alignment procedures before making any adjustments, learned this from experiance.
    When it says disconnect the screen and power leads to finals, how is that accomplished, I don't find a connector, unless it means removing the leads on top of the tube.
    On the receiving I.F. alignment, the top tuning lug on T-11 is missing and I also found the same for v-2.
    Is there a trick to removing the cover for them, I want to see if the tuning lugs fell down inside or if I need to start looking for replacements.
  4. AI3V

    AI3V Ham Member QRZ Page

    You heard wrong.

  5. WA1GXC

    WA1GXC Ham Member QRZ Page

    The leads for screen 250V lead and plate B+ are passed thru a vertical metal plate below the chassis, at the edge of the P.A. cage. You need
    to positively identify both by tracing with an ohmmeter, then disconnecting by de-soldering from the feed-thrus and safely taping-up.

    OM, this is not meant to be a criticism and does not reflect upon you . I am very concerned that you'll be working with lethal high voltage and
    hi-power RF on this unit. The questions you are asking are perfectly fair, but reflect a lack of familiarity with older vacuum-tube equipment like this.

    This gear uses B+ at over 700V DC when it's unloaded, and your power supply will put out 500 mA and more, easily. To quote a phrase from an old
    ARRL Handbook, "There is no such thing as a slight electrical shock from..." this kind of unit.

    Please, for your own safety, enlist the aid of another ham or technical person familiar with this era of equipment who can point you to good safety procedures and how to
    slowly go about walking through the process of bringing this equipment back. Sometimes, the answer is, 'This is beyond my abilities at this time'.

    I would be remiss if I didn't give it to you straight. It's just not worth getting severely hurt, or worse.

  6. KF5DDW

    KF5DDW Ham Member QRZ Page

    Thank you for your concern. You are right on my lack of knowledge working on old tube rigs. However, before I retired I was a biomedical equipment repair tech both during active duty military and after. Most equipment that I worked on I learned as I went using service manuals and speaking to manufacturers reps for clarifications, only specialty equipment received formal training.
    I have a very healthy respect for electrical power both regular and high power. That is why I am asking questions.
  7. WA1GXC

    WA1GXC Ham Member QRZ Page

    FB! I didn't mean any disrespect. Sometimes folks new to here have no prior exposure to anything but 13.8V, and I erroneously thought that could be the case with you. I'm glad you have the experience.

    Any of the IF/RF transformer can assemblies can be removed intact by releasing the spring-loaded bayonet "ears" inserted thru the chassis, from below. Disconnect all leads below.

    It's sometimes possible to work the 'can' loose while leaving the wired assembly in-place, but it's hit-or-miss. Often, the friction-fit with the bakelite base won't allow you to do it easily,
    but it's worth a try. Release the two spade spring devices and see if the can slips easily up. Be v e r y careful and gentle and pull straight up.

    If the transformer slug lead-screws have snapped-off, it's because a previous owner man-handled them.

    You are the recipient of good luck, though. In true Drake fashion, there is an error in the manual photo. What is identified as "V-2" is actually T-13 which does not have an external screw, but the
    ferrite slug has a hexagonal hole in it which requires a special plastic alignment tool. It's standard to the TV industry but the tool is almost impossible to find today. See if you can borrow one
    from another ham. Just leave it as-is and see if you can get by. There should be another top-mounted transformer can with the same configuration, no slug adjustment screw.
    You can probably get by without touching it.

    Drake schematics and manuals are riddled with errors which never got corrected even in later editions. How could expensive gear like that have that associated with it? Don't know, just is.
    If something makes no sense, sometimes it was just Friday afternoon in the drafting department.

  8. KF5DDW

    KF5DDW Ham Member QRZ Page

    Now that you mentioned the missing adjusting screw I went back and looked closer at the top view photo of the chassis and sure enough it shows no adjusting screw. Drake instructions a very vague. I saw an alignment tool in a box that came with the radio, hopefully it is the one I need. I will do a search for it.
    I remember one piece of equipment that had 7000, that's right thousand volts that had to be verified using a high voltage probe and multi meter. That would knock your turtle in the mud if not carefull. But the saying was it's not the volts but the amps that kills you.
  9. WA1GXC

    WA1GXC Ham Member QRZ Page

    My personal limit for discomfort working around gear is 800V. Buddy had an old National NCL-2000 amplifier that runs, I think at 2.5 kV and we were trying to fix it up. He didn't know enough to be scared and
    stand waaay back when we flipped the switch.
    I am not embarrassed to say I am just plain scared up there, in those numbers.

    The hexagonal alignment tool is probably still made and available but hard to obtain. It was commonly made by G-C Rockford Illinois and worth 1 dollar. Cheap red plastic. Again, if that's all that remains to
    be adjusted, you can probably get by without touching it. Those ferrite slugs get brittle and do stick after 45-48 years. Don't attempt to move it with a miniature screwdriver (how would I know that?)
    or other inappropriate tool-it will fracture into unsalvageable pieces.

    And again, yes, the manual and schematic vagueness and outright errors have nothing to do with you. Specific sections of service procedures are horribly written. Do your best; when in
    doubt, don't touch anything and skip it. It probably won't be that far-off.
    Last edited: Oct 5, 2020
    KD2ACO likes this.
  10. KD2ACO

    KD2ACO Platinum Subscriber Platinum Subscriber Life Member QRZ Page

    If you can't find the coil alignment tool, here's a complete set.

    We had a running gag on the Zed a few years back about the bad marketing decision for an "anti-static coil alignment kit" after someone got zapped trying to neutralize a Kenwood hybrid with a 'carbon black, anti-stat' alignment screwdriver.

    Stick with the red or white nylon ones! :eek: :p

    Sometimes, you need to put the tip of your soldering iron into the slug for a few seconds to heat it up and soften the beeswax. Be gentle though. Crumbling a coil is painful.
    Last edited: Oct 5, 2020
    WA1GXC likes this.

Share This Page