mystery component

Discussion in 'General Electronics Chat' started by bonsaimaster1, Feb 27, 2013.

  1. bonsaimaster1

    Thread Starter New Member

    Feb 8, 2013
    10
    1
    Yes hello fellow members does anyone know what type of components these are, they are black with white dot on one end, please help.
     
  2. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
    6,357
    718
    What is this circuit out of? Vintage? At a guess, tantalum capacitors.

    Especially if they are across the power rails on the other side of the board.
     
  3. tshuck

    Well-Known Member

    Oct 18, 2012
    3,531
    675
    I thought tantalum capacitors as well. Seconded.
     
  4. #12

    Expert

    Nov 30, 2010
    16,261
    6,768
    I think the chip next to them has a code date of 7810 (10th week of 1978).
     
    tshuck likes this.
  5. JDT

    Well-Known Member

    Feb 12, 2009
    658
    85
    Look like diodes to me. White mark = cathode.
    Can't tell what sort of diode. Could be zeners.
     
  6. t06afre

    AAC Fanatic!

    May 11, 2009
    5,939
    1,222
    To me it looks like some kind of diode in a Sinterglass SOD-64 package
     
  7. Dodgydave

    Distinguished Member

    Jun 22, 2012
    4,974
    744
    I would say they are diodes, also the chip is a CD4017 and looks like pin 8 is not soldered.!
     
  8. MrChips

    Moderator

    Oct 2, 2009
    12,429
    3,360
    I have seen tunnel diodes that look like those. But why would they use tunnel diodes in that circuit? It would help if we knew the function of that unit.
     
  9. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    5,435
    1,305
    They are rectifier diodes as the transformer rectifier.

    ie split secondary winding -> dual rectifier diodes.

    And one looks a bit cooked. :)
     
  10. GopherT

    AAC Fanatic!

    Nov 23, 2012
    5,997
    3,756
    I'm going with rectifier diode too. The two white wires say 24AC, so I am guessing that is the input from the transformer.

    Who ever correctly predicts what this device does befor the OP tells us, wins! You only get 24 hours of bragging rights as your award since I don't have your address (and don't want your address).
     
  11. MrChips

    Moderator

    Oct 2, 2009
    12,429
    3,360
    The big black thing on the right is a stand off. But what the heck are those three light blue things?
     
  12. #12

    Expert

    Nov 30, 2010
    16,261
    6,768
    In 1971, I had what we called, "green dot" rectifiers in my truck stock. They were obviously manufactured with axial leads. Those "black dot" devices look like radial leads, severely bent. I also think they could be rectifiers but question why a manufacturer would bend a radial lead device into submission when axial lead rectifiers were available 7 years before these parts were installed.
     
  13. #12

    Expert

    Nov 30, 2010
    16,261
    6,768
    The blue things with holes are an early form of plastic transistor package that resembles a small TO-220.
     
  14. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    5,435
    1,305
    Hmm, it's a lowish power device running from 24vAC and a 2 diode rectifier. It has a 4017 ring counter IC and an unknown IC with at least 3 transistors in a space-critical layout, not heat critical so they don't drive big loads.

    The 4017 runs up to 10 things in sequence, they were used mainly in things like light chasers and lighting effects. Also they were used in things like electronic organs for arpeggio (note sequencing) effects.

    Of the two I would pick some type of lighting flashing controller.
     
  15. #12

    Expert

    Nov 30, 2010
    16,261
    6,768
    It's beginning to look like a, "drive by" thread.
    (Bonsaimaster1 dropped off a question and kept on going.)
    We might never find out what it is.
     
    Last edited: Mar 1, 2013
  16. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    5,435
    1,305
    Well it's the little mysteries that make life interesting! :)
     
  17. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
    6,357
    718
    I think The RB is onto the purpose, a sequencer of sorts.

    I remember seeing those odd green transistors in another circuit, I forget the name, TO-220AB or something, but that pale green color sears a scar in your mind.
     
  18. bonsaimaster1

    Thread Starter New Member

    Feb 8, 2013
    10
    1
    Thanks everyone for replying I just tried a axial leaded varieties for the board and it didn't work and I tried a few diodes none are working I think I need different voltages in both varistors an diodes, if anyone has other thought to what they are please reply and FYI the board plugs into a Japanese pachinko machine which controls the tulips to open and lights with sound.
     
  19. bonsaimaster1

    Thread Starter New Member

    Feb 8, 2013
    10
    1
    Sorry I meant axial leaded varistors in my last reply.
     
  20. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
    6,357
    718
    What does the circuit do?

    Can you post a photo of the back of the board as well as a larger image of the front?

    What do the items measure out of circuit as? Short/open/diode test, cap test, etc?
     
Loading...