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Test Rectifier with Selenium

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conpiar Posted messages 15 Registration date   Status Member Last intervention   -  
conpiar Posted messages 15 Registration date   Status Member Last intervention   -
Hello,
On my old tape recorder, I am in the process of replacing its selenium rectifier and, to do this, I would like to test the spare part I just received, as it is used.
I have a digital multimeter with a "diode" function, but I don't know how to test the rectifier before soldering it onto my device.
Can someone tell me how to do it?
Thanks in advance.

2 answers

  1.
    baladur13 Posted messages 47322 Registration date   Status Moderator Last intervention   14 387
     
    Hello,
    In ohmmeter, a diode conducts in the direction of the arrow so if you connect the positive lead of the ohmmeter (red)
    to the - terminal
    you should find continuity (conducting) on all other terminals
    on the + terminal
    you should find open on all other terminals
    on a ~ terminal
    you should find conducting on the + terminal and open on the - terminal
    2
    2. conpiar Posted messages 15 Registration date   Status Member Last intervention  
       
      By the way, before marking it as resolved, I would like to know if possible why with the ohmmeter, only on 2M, I always measure a current passage on the 4 contacts (between + and ~; + and —; ~ and —; as well as + and —)
      Thank you
      0
      1. baladur13 Posted messages 47322 Registration date   Status Moderator Last intervention   14 387 > conpiar Posted messages 15 Registration date   Status Member Last intervention  
         
        2MΩ is a very high resistance value (2000000 Ohms).
        That's why a slight current is flowing through.
        0
    3. conpiar Posted messages 15 Registration date   Status Member Last intervention  
       
      Very well, thank you very much.
      0
  2. jeannets Posted messages 28397 Registration date   Status Contributor Last intervention   Ambassadeur 6 603
     
    Hello,

    This equipment must be really old, as the selenium rectifiers date back to the 1950s or 60s...

    There were also lamp diodes known as "Valves" which were replaced by silicon diode bridges, say since the 1960s or 70s... And unless restored to their original state, replacing them with diodes or diode bridges would have been simpler, cheaper, and with less hum noise...

    The test can be done either with an ohmmeter or in "Diode" position. There is some sort of continuity in one direction (around 640mV in Diode) and infinity in the other direction... Moreover, there is often a + sign on one end and - on the other.

    It is also feasible with a flashlight test... In the forward direction, the light turns on and in the other direction, it does not turn on at all.
    1
    1. conpiar Posted messages 15 Registration date   Status Member Last intervention  
       
      Thank you, by the way I would like to know where to point: + and - ? ~ and ~ ?
      0