SB 200 Heathkit Amplifier

Discussion in 'Amateur Radio Amplifiers' started by KD4JBL, Jun 10, 2021.

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  1. KD4JBL

    KD4JBL Ham Member QRZ Page

    My Heath Kit SB 200 working.
    When I key radio I get a loud chatting sound from amp.

    KD4JBL
     
  2. W1QJ

    W1QJ Ham Member QRZ Page

    Maybe low voltage power supply capacitor is leaky.
     
  3. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Or using an amp that doesn't have a soft-key modification and trying to key it with a rig that doesn't have an isolated relay internally so the rig cannot pull -120V to ground and is ready to blow something up.:p
     
    WQ4G likes this.
  4. W1QJ

    W1QJ Ham Member QRZ Page

    Good point Steve!!!! Many people burn out the switching transistors in their radios with SB220 and SB200 amps!
     
  5. KD2ACO

    KD2ACO Platinum Subscriber Platinum Subscriber Life Member QRZ Page

    KABOOM.jpg
     
    WQ4G likes this.
  6. WA8ZYT

    WA8ZYT Ham Member QRZ Page

    Need the softkey kit from Harbach.
     
  7. WA2EIO

    WA2EIO XML Subscriber QRZ Page

    I would suggest the softkey unit to protect whatever rig you connect to the amp anyway, but at least you may narrow down the possible causes with this simple test:

    Take the amp's 'key' lead out of the rig, and short the ends of that cable to key the amp and see if it still chatters. If so, then the problem is elsewhere. You can also check the voltage across the amp's 'key' terminals and see if it is at/near specs. (-120 VDC)
     

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