Part title

Discussion in 'General Electronics Chat' started by Onilll, Jul 1, 2011.

  1. Onilll

    Thread Starter Member

    Oct 25, 2010
    38
    0
    Need information about diode. On board printed DZ3, probably it zener. On diode first line CRL, second HS-7.
    [​IMG]
    Thank you.
     
  2. DerStrom8

    Well-Known Member

    Feb 20, 2011
    2,428
    1,328
    Perhaps it is a 7 volt zener? The CRL and HS probably stand for other electrical characteristics. I'm afraid I don't very often use zener diodes, but I hope you can get the answers you're looking for :)
    Good luck!
    Der Strom
     
    Onilll likes this.
  3. MrChips

    Moderator

    Oct 2, 2009
    12,449
    3,365
    Looks like a point-contact diode to me similar to a 1N34.
    Can you post another picture with the writing to the back so we can see inside?
     
    Onilll likes this.
  4. Onilll

    Thread Starter Member

    Oct 25, 2010
    38
    0
  5. Onilll

    Thread Starter Member

    Oct 25, 2010
    38
    0
  6. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Are you thinking that the diode is not good anymore?

    It's difficult to tell from the image, but it does not look "fried" to me.

    On the other hand, the image of the board you linked to ... those old cylindrical brown-body carbon resistors can radically change their values over the years - even if they are not in use. I would consider every one of them to be suspect until I had at least measured their resistance.

    I had a collection of mil-spec precision carbon film resistors that were left over from a project back in the 1970's; they were unused and in hermetically sealed pouches. I was very surprised to find that some of them measured almost twice the resistance that they were supposed to measure; and almost all of them had increased in resistance significantly.

    Zener diodes require a certain amount of current flow through them to establish the correct voltage. If the current flow is insufficient, the voltage drop across the Zener may be considerably lower than expected.

    I would check each and every resistor in the current path for that Zener to ensure that they were reasonably within specifications.

    Replacing all of those brown-body resistors with similarly rated carbon film "dumbbell" resistors would be a good idea; as these newer type of resistors are very stable over time.
     
    Onilll likes this.
  7. Onilll

    Thread Starter Member

    Oct 25, 2010
    38
    0
    Thanks.
    I check resistors, they are good.
    Check "zener" one more time, show 1,17v one side and infinity other. I thought 1,17 are too much for diode. If it OK, may be its good?
     
  8. MrChips

    Moderator

    Oct 2, 2009
    12,449
    3,365
    Thanks for the picture. No, it does not look like a point-contact diode.
    As SgtWookie says, what would make you think that this diode was faulty?
    It might help if you told us from where this board came. What was the function of the circuit?
    Send us a photo of the whole board if you can.
     
  9. Onilll

    Thread Starter Member

    Oct 25, 2010
    38
    0
    Picture of PCB:

    http://s43.radikal.ru/i102/1107/d4/93f30fa46bce.jpg

    Made in India, have no idea where it sitting and what doing. Manufacturer didn't answer. Have to repair. I thought it faulty because testing with Fluke 115 and get 1.16V (infinity other-side) and think its too much. Now I am not sure about it.
     
  10. MrChips

    Moderator

    Oct 2, 2009
    12,449
    3,365
    Syntron Controls - one-shot relay board? Made in India circa 1973?
    Relay turns on for a preset time?

    ...my guesses
     
  11. Onilll

    Thread Starter Member

    Oct 25, 2010
    38
    0
    Looks pretty old. I don't know, because didn't connect board, just check components. Already change 3 caps. May be now it will work.
     
  12. Onilll

    Thread Starter Member

    Oct 25, 2010
    38
    0
    Оne more question. Have a PCB:

    [​IMG]

    There are dead FB9N60A MOSFET.

    [​IMG]

    I did order it, but also dead SMD diode. Тhey do not have connection.



    [​IMG]

    One of this blue-red. No letters, no numbers on it. How to know what kind is it?
    Thank you.
     
    Last edited: Jul 7, 2011
  13. Onilll

    Thread Starter Member

    Oct 25, 2010
    38
    0
    nobody can help?
     
Loading...