Heathkit SB-200 and Kenwood TS-590s

Discussion in 'Amateur Radio Amplifiers' started by K3HMG, Apr 27, 2021.

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  1. K3HMG

    K3HMG Ham Member QRZ Page

    Greetings y’all,

    I recently had the opportunity to pick up a SB-200. She currently is functional and in very good shape, but in need of a few modifications before I put her online in my station as she is mostly unmolested. The 572’s are new from CRT.

    Going to be doing the PM upgrade, soft start mod, diode mod on the alc Jack, meter protection mod, and softkey. What other equipment (like cables, etc) or mods should be done before connecting her to my Kenwood and getting her online? Being that I have a newer radio do I have to hook up ALC? Or the antenna relay? How are most of you guys with newer radio hooking up the older amps?

    some here may already know me I have been asking a lot of questions here as I am a “greenhorn” and learning. Once the SB-200 is freshened up a bit I want to put her online, but I want to make sure I have everything I need to do so. I want to enjoy the new addition to the shack and not destroy my TS-590 or any other equipment in line.

    thanks in advance, everyone has been very helpful in my past posts and I am extremely grateful!

    73,
     
  2. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Why not just key the amplifier using a footswitch (or any kind of switch, or even a clip lead) with the TS-590S connected (coax from rig to input, coax from output to dummy load) to confirm it works absolutely perfectly before performing any of the updates or modifications??

    It's way easier to start there, knowing everything is fully functioning (no need to connect the ALC line) before changing anything. That way, if it doesn't work properly later, you know it's something you changed, and not the amplifier's fault.

    I'd also always recommend making one change at a time, testing the amp again to confirm the operation, before making the next change. Making 4-5-6 changes all at the same time leaves too much to guesswork if afterwards it fails to perform properly.
     
    WG7X and K3HMG like this.
  3. K3HMG

    K3HMG Ham Member QRZ Page


    I will definitely do that for sure before I make any modifications. If all checks out with that test I could just key the amp with the foot pedal when I need the power right? Just tune her up when I jump on a band and stay off the pedal unless I need the juice. In that case I would not need the soft key mod or a box in between the rig and the amp right?

    an example of the set up in my case would be coax from rig to amp rf in, coax from amp rf out to my LDG1000 auto tuner in , coax from tuner out to my autek wm1 in, coax from wm1 out to a coax switch, switch to antenna on A and my 1500w dummy load on B? Sound right to you?
     
  4. N0NC

    N0NC Premium Subscriber QRZ Page

    If you're going to use the WM-1 meter, put it between the amp and the tuner so you will see the SWR after the antenna tuner has done it's job. If it is after the tuner, you will see the SWR of the antenna, but not the effect of the tuner. Also, the WM-1 will not read too accurately see it will be in the circuit where the impedance could be quite different from 50 ohms.

    73, Chuck
    N0NC
     
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  5. K3HMG

    K3HMG Ham Member QRZ Page

    my bad, had a dyslexic moment lol. I will correct that now.
     
  6. K3HMG

    K3HMG Ham Member QRZ Page



    an example of the set up in my case would be coax from rig to amp rf in, coax from amp rf out to my my autek wm1 in, coax from wm1 out LDG1000 auto tuner in , coax from tuner out to A coax switch, switch to antenna on A and my 1500w dummy load on B? Sound right to you?
     
  7. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Yeah.

    The "press the pedal switch for more power" approach can work if you're careful. But if you accidentally start transmitting first and press the foot switch while you're sending or talking, you can really damage the amp, and possibly even the rig.

    However, the Heil FS-2 footswitch can help solve that problem: It actually has two switches internally, and one closes before the other one, then they open in the reverse sequence. You wire the "first key" switch cable to the amplifier to key it, and the "second key" switch cable to the Kenwood to key that. When you release the switch, it will unkey the Kenwood first and then the amp. The "delay" is only milliseconds, you don't even notice it, but that delay can be important for equipment survival.

    To "key" the Kenwood using the switch, that's done via the REMOTE connector on the rear panel, using pins #2 and #3 of the 7-pin DIN plug.

    The order of connections you listed above is correct.
     
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  8. K3HMG

    K3HMG Ham Member QRZ Page


    Understood sir, thx I will look at those foot pedals. Would I need to ditch the hand mic then and get a quality broadcasting mic right? Any suggestions? I would also need a din connector right? It looks like the switch has two connectors one to the amp and the other it’s claiming it goes to the Heil Mic.
     
    Last edited: Apr 27, 2021
  9. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    No.

    It has two cables, alright: But you can use whatever kind of mike you wish, including a Heil or anything else.

    The cable to key the amplifier has an RCA phono plug at its end, which plugs right into the amp. The "other" cable has a 1/4" monaural "phone" plug, which you could use to interface directly with a Heil mike cable adapter cord if you wish; you can also just cut that off, strip the two wires, and connect them to pins 2 and 3 of the REMOTE connector DIN plug.

    If Kenwood didn't supply that plug as a standard accessory with the rig, shame on them (I don't know). One thing I liked about my Ten Tec transceivers is they always came with every plug that would fit every jack on the radio, so nobody had to go looking around to find any...provided you didn't lose the little plastic bag with all the plugs in it.:p
     
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  10. WA9FZB

    WA9FZB XML Subscriber QRZ Page

    IIRC, Kenwood does supply all the plugs. You just have to be able to solder the danged little bitty pins. . .
     

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