Heathkit SB-200 Rebuild

Discussion in 'General Technical Questions and Answers' started by KK0Y, Aug 22, 2019.

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  1. KK0Y

    KK0Y Ham Member QRZ Page

    I bought a replacement filter board for an SB-200. There is a white wire, soldered to the board that is marked meter switch. Does anyone know where this wire is supposed to go? Or has anyone ran into this before?
     
  2. W9GB

    W9GB Ham Member QRZ Page

    SB-200 / SB-201 HF Linear Amplifier
    Heathkit of the Month #33
    by Bob Eckweiler, AF6C
    http://www.w6ze.org/Heathkit/Heathkit_033_SB200.pdf

    Heathkit SB-200 Linear Amplifier : Assembly / OperationManual (63 pages)
    Schematic Diagrams (Last Pages)
    https://www.qsl.net/wa0kke/manuals/SB-200 Manual.pdf
    ==
    A number of third-parties produce HV Power Boards (some by Knowledgable Designers/Engineers, others just Clone/Copy-Cats looking for a Quick $$)
    The Quality & Instructions of these Boards Vary Widely.

    CONTACT the Kit Re-Seller for Your Answer (They took your $$ .... No Support for Your Question?)

    766AA97E-D921-47D8-B772-DC2189A8D19E.jpeg
    Harbach Electronics PM-200 Power Supply Module for SB-200 HF Amplifier
    https://harbachelectronics.com/shop/heathkit-sb-200-sb-201/pm-200-replacement-power-supply-module/

    Harbach PM-200 Power Supply Module v3.2
    Assembly & Installation Instructions
    https://harbachelectronics.com/wp-content/uploads/2017/03/PM-200-v3.2.pdf
     
    Last edited: Aug 22, 2019
  3. K9STH

    K9STH Ham Member QRZ Page

    Without seeing the schematic for the board, the wire probably goes to the HV terminal on the meter switch.

    Glen, K9STH
     
  4. WA9SVD

    WA9SVD Ham Member QRZ Page

    Or perhaps, directly to the operator? :eek: The OP bought a "partly" assembled. or partly "disassembled" amplifier. Anyone knows what other "gotcha's" await. When wired correctly, the SB-200 is a decent 6-800 watt linear amplifier.
     
  5. K9STH

    K9STH Ham Member QRZ Page

    For longest tube life, keep the output down to around 600-watts. The "other" station will not really be able to tell the difference between 600-watts and 800-watts. However, the tubes will know it.

    Also, the higher power mainly contributes to your electric company's "bottom line".

    I had an SB-200 in the late 1960s into the 1970s and have another one right now. They are definitely a "workhorse"!

    Glen, K9STH
     
  6. WA9SVD

    WA9SVD Ham Member QRZ Page

    Since I don't currently have a 220VAC outlet handy, my SB-200 is at 0 Watts.:( I guess it may outlast me, for sure.
     
  7. K7TRF

    K7TRF Premium Subscriber QRZ Page

    Posting the schematic or at least photos showing both sides of the board or even information on who made the board (Harbach?) would help a lot.

    I suspect Glen is right and that white wire comes from a tap on the resistor divider chain used for HV metering but it could also come from the plate current or grid current meter shunt if that's supported on your replacement board. Hard to guess without some additional information or photos of the board.
     
  8. K5DH

    K5DH Ham Member QRZ Page

    I ran an SB-200 successfully for years on 120 VAC. No operational limitations. Never tripped a breaker. Rewire the connections inside the amp, change the plug on the end of the cord, and let 'er rip! At the 600 Watt power level, it will do just fine.
     
    K7TRF likes this.
  9. KM1H

    KM1H Ham Member QRZ Page

    Ive repaired, built for Heath Stores, plus converted to 6M hundreds of the SB-200/221 over the past 50 years or so. All were on a 120V 15A line
     
    W9GB likes this.
  10. K9STH

    K9STH Ham Member QRZ Page

    Although I now run my present SB-200 on a 240 VAC line, my previous SB-200 was run from the 120 VAC line without any problems.

    Glen, K9STH
     

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