3-500z shorted after shut down

Discussion in 'Amateur Radio Amplifiers' started by K4ATR, Jan 18, 2018.

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  1. W1QJ

    W1QJ Ham Member QRZ Page

    There are thousands upon thousands of SB-220 amps that still have the original tubes. The filament voltage is fine in those amps. Neither poor de gassing or filament voltage would generally cause a G-F short. G-F shorts happen as a fact of life and often times inside the warranty period especially on Chinese tubes. They should cover it under warranty however they usually make you jump through fired hoops before they do.
  2. AI3V

    AI3V Ham Member QRZ Page

    Since you didn't mention anything about the current(s) or power measured during this dance, we might assume you don't know them.

    Which would, along with the usual BS about running the tubes untill they start glowing some or another shade of red or yellow,

    Would lead me to believe that the tube failed from abuse and not some sort of manufacturing defect.

  3. K4ATR

    K4ATR Premium Subscriber QRZ Page

    Well I do know them and they were not out of the normal even with the shorted tube only thing that was noticed was loss of output. I don't abuse my equipment the backup set of tubes are original to the amp and they are still perfectly fine just a little less on output but they are 40 years old. I honestly think it was just a bad tube and it' really not a big deal even if they don't want to warranty it.
    73'S K4ATR

    And god less
  4. KB4MNG

    KB4MNG Ham Member QRZ Page

    Just curious, have you ever had to replace the capacitors during the 46 years?
  5. K4ATR

    K4ATR Premium Subscriber QRZ Page

    All caps diodes bleeders and boards in supply are brand new
    K0OKS likes this.

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