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Quick update on the Collins S Line project

Discussion in 'Discussions, Opinions & Editorials' started by AE5DX, Nov 13, 2012.

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  1. AE5DX

    AE5DX Premium Subscriber QRZ Page


    The 75S-2 lives. The S meter is pegging low for some reason, not sure why yet.

    One thing I've already noticed is it's excellent selectivity and sensitivity. I'm hearing perfectly clear QSOs on 80m with a 20/40 dipole.

    Tomorrow I should have my variac (USPS). Then it's time to reform the huge cap in the 516F-1 and hopefully the 32s-1.

    After 3 weeks of cleaning, recapping, checking, replacing, double and triple checking everything, I'm totally jazzed. I've got my fingers crossed on the next steps.


    steve S Line/
  2. K9STH

    K9STH Ham Member QRZ Page

    Clean the S-Meter zero potentiometer. It may have to be replaced.

    Also, clean the sensitivity setting potentiometer.

    There may be a leaky capacitor in the AVC circuit. If you have not already replaced all the paper capacitors, you really need to do that.

    Glen, K9STH
  3. AE5DX

    AE5DX Premium Subscriber QRZ Page

    I got it, I tapped a few tubes and tweaked the S meter pot. I'll have to re-cal it, but it's working now. All paper and electrolytics have been replaced. Lemme tell ya, changing out that multi-cap can is not for the faint of heart. Flipping over the chassis, I couldn't even see the terminals.
  4. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    Is the pilot lamp for the S-meter working? It doesn't look illuminated.
  5. KB2FCV

    KB2FCV Ham Member QRZ Page

    Wow, great progress!! That looks like a completely different radio from the first pics you posted. Fantastic, hope you'll be able to make your first QSO with it soon!
  6. K9STH

    K9STH Ham Member QRZ Page

    It looks lit to me! The pilot lamp in the 75S- series receivers doesn't give off a whole lot of illumination. Look at the "half moon" under the meter scale and you will see illumination.

    Glen, K9STH
  7. AE5DX

    AE5DX Premium Subscriber QRZ Page

    Yes, new #51 lamp installed!
  8. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    Yeah, it was just a weird angle, I see it now.

    Good job.

    No restoration is complete until the pilot lamps work!:eek:

    I remember "in the old days" when I had a large shack filled with older ham gear from the 40s-50s-60s-70s and everything had pilot lamps in dials and meters...hardly a week went by I didn't find myself replacing a pilot lamp! Of course, over time a lot of them were operating at a voltage they weren't designed for, as AC line voltages crept up from 110V to over 120V.
  9. AE5DX

    AE5DX Premium Subscriber QRZ Page

    Thanks! :) I took the meter movement out and re-painted the white inside the housing. It had faded so much it wasn't reflecting at all. I don't like handling them, they're super fragile, but it had to be done. :)
    Last edited: Nov 13, 2012
  10. AE5DX

    AE5DX Premium Subscriber QRZ Page

    Tonight, tonight....I'll try to power up the transmitter, that is, if my variac arrives. Cross your fingers, and thanks!
  11. AE5DX

    AE5DX Premium Subscriber QRZ Page

    Thanks a million, Glen, for all your help this past month. Let's hope I get the 32S-1 going as well :)
  12. K9XR

    K9XR Ham Member QRZ Page

    Nice!. Open the top, get your little screwdriver out, unhook the antenna, and set the S meter Zero with no signal. Something probably changed with time or different components, but it's pretty easy to adjust.
  13. AE5DX

    AE5DX Premium Subscriber QRZ Page

    Got the 516F-1 and 32S-1 up and running last night, no smoke!

    However, I couldn't get much else going after that. Most of this is probably due to my inexperience with this rig. I hooked the transmitter and receiver together using patch cords that came with them as per the 32S-1 manual, but could not get past the first step, "Initial Checks" where PA plate current is to be set to 40mA via the Bias Adjustment on the PS. No amount of adjusting one way or the other affected the meter at all.

    I'll keep reading the instructions and see what to do next, but so far so good, I'm not complaining!
  14. K9STH

    K9STH Ham Member QRZ Page

    Check and make sure that there is a jumper between the two RCA jacks on the rear of the chassis marked "PA Disable". There is a permanent connection made at the factory that is removed either to neutralize the final amplifier tubes or to use the 62S-1 transverter. If there is no connection between these jacks, either make a jumper using 2-each RCA plugs or else adding a wire on the inside of the unit.

    To set the bias, put the transmitter in LSB or USB. Then, turn the microphone gain control all the way down. Finally, key the transmitter with the PTT and then set the bias with the potentiometer that is on the power supply.

    If the current on the meter is still zero, then check the bias voltage to make sure that it not only varies but goes down to at least -60 volts.

    Glen, K9STH
  15. N3AWS

    N3AWS Ham Member QRZ Page

    Great job, Steve!
  16. AE5DX

    AE5DX Premium Subscriber QRZ Page

    This will be my next step. Installing a jumper didn't help. Still nothing, and the vox relay goes nuts when the transmitter is first turned on.

    Since this thread has turned technical, I'll be moving any further topics on this subject to the Boat Anchor Forum!

    Thanks to all!


  17. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    "Jumper!" he said, so jump her I did, that's why I don't work there anymore...
  18. AE5DX

    AE5DX Premium Subscriber QRZ Page

    Same thing happened to me once, 'cept she was the one who instructed me. Boom, I was out the door! :D
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