Sanken STV3H-Y Testing and Installation??

Discussion in 'Exclusively Sansui' started by Juan9568, May 14, 2018.

  1. Juan9568

    Juan9568 Member

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  2. tnsilver

    tnsilver AK Subscriber Subscriber

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    In diode test mode with red (+) probe on the anode and black (-) probe on the cathode (yellow dot) you should be reading about 1.4V of forward voltage.
     
  3. clinic-audio

    clinic-audio all on YAMAHA untill 1990

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    yes , those components are diodes (some are with 3 diodes in the same package)
     
  4. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    Your meter may not have enough test voltage to start them conducting. The diode test range on your meter is expecting one P-N junction to test, an STV3 is 3 junctions, which gives some meters problems. You could try the 'ohms' range but cross check any readings you get with the old diodes before drawing any conclusions from the readings you are getting.

    You could set up a very simple test circuit using a 9V battery (for example) and using a series limiting resistor (- important), and then reading the volt drop across the device when it is conducting.
     
    Last edited: May 16, 2018
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  5. Juan9568

    Juan9568 Member

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    Still, I don't get any reading. Not even in ohms range...could it be my meter?? I have a cheap one DT830D :(
     
  6. tnsilver

    tnsilver AK Subscriber Subscriber

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    or the battery, or dirty probes, or meter fuse, or wrong probe terminals, or you're just near the south pole in the midst of a solar flare :dunno:
    It's all more likely than all of these diodes gone bad at once.
     
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  7. Juan9568

    Juan9568 Member

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    haha I mean that maybe I need a pro meter to test these diodes? cause 2 of them are new the other 2 are the original ones but none of them give me a reading. Meter is new (but cheap), everything else is new, black probe in COM, red probe in V/Ohm/mA Fused...fuse is fine too
     
  8. tnsilver

    tnsilver AK Subscriber Subscriber

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    Well, John gave you a pretty good reason in #4 why this may not work. I don't think you need a pro meter, but if the battery is good you definitely need a better meter. If it's any consolation, I've purchased dozens of Sanken STV-3HY's from the same German seller. They all came neat and tidy in their blue cardboard boxes and the amount I found bad was a flat zero. In fact... I never found a stock one that went bad either.
     
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  9. tarior

    tarior Dirty pool, old man? Subscriber

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    What was wrong with the old ones?
     
  10. Juan9568

    Juan9568 Member

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  11. tarior

    tarior Dirty pool, old man? Subscriber

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    Too bad you aren't in the US, I would ask you to send me the old ones. They very rarely ever fail.
     

     

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  12. kevzep

    kevzep Its all about the Music Subscriber

    STV3 diodes are not a failure point, I have never actually seen one fail all all the years I have been around electronics...
     
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  13. tarior

    tarior Dirty pool, old man? Subscriber

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    Neither have I. Even on units with the amp torched all the way back to the VAS stage.
     
  14. Overundr1

    Overundr1 AK Subscriber Subscriber

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    Much more common to find one miss-handled with a broken lead
     
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  15. sregor

    sregor AK Subscriber Subscriber

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    Best way to test (IMO) would be to get a 9 volt battery and an 8.2K resistor, and measure voltage drop. Should be 9 volts in reverse direction (no current) and 1.3 (or more based on my reading, not my experience) in the forward direction. Meter should be in volts measuring mode. I've never had occasion to change these. We used to keep them as replacement for the little bead 3 diode bias diodes. YMMV
     
  16. ghazzer

    ghazzer Sansui addict Subscriber

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  17. kevzep

    kevzep Its all about the Music Subscriber

    Just use your meter guys, its very simple, diode test function, the STV3 has a forward voltage of about 1.4V....Easy, job done.
     

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