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Identify smd zener diode

Discussion in 'General Electronics Discussion' started by Jotto, Nov 7, 2012.

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  1. Jotto

    Jotto

    120
    0
    Aug 24, 2012
    band one red (thick band) at very end of diode seems to designate the cathode.
    band two yellow 4?
    band three green 5?

    I have looked at different sites concerning the code chart, all say that not all manufactures use the same coding system. If someone knows a good site for this, please let me know.

    Thanks Jim
     
    Last edited: Nov 7, 2012
  2. Harald Kapp

    Harald Kapp Moderator Moderator

    10,053
    2,144
    Nov 17, 2011
    The thick band at the end of the diode usually is the cathode (not anode).
    As for the color code I can't help, sorry.

    If the diode is still o.k., you can at least try to measure the zener voltage using a power supply (+ to cathode!), a series resistor and an ammeter in series. Increase the voltage until a current of at least 1mA flows. Then measure the zener voltage.
     
  3. Jotto

    Jotto

    120
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    Aug 24, 2012
    No, can't do that because both are shorted from damage.

    Its just a power supply, so I will remove one later and just measure the voltage. Two mosfets shorted out and took out the zeners.

    Thanks for correcting my brain fart, to much going here these days.
     
  4. Harald Kapp

    Harald Kapp Moderator Moderator

    10,053
    2,144
    Nov 17, 2011
    Is there any inscription on the PCB that could help identify the diodes?
     
  5. Jotto

    Jotto

    120
    0
    Aug 24, 2012
    Unit is made by Wintec in Isreal, manufacture can't release schematic because of proprietary to the other manufacture. We have to make our own schematics or just troubleshoot by knowledge of the equipment. They don't want you to work on any of it.

    Vendor came out yesterday to work on one of their machines and were replacing the power supply I am working on. So I got that for free, the problem wasn't the power supply but the tech not taking the time to do a visual before replacing parts.

    I tested the power supply and realized there was nothing wrong with it, but called later concerning the machine an I went out and found that a cable was not properly seated. So I got a power supply for free.

    I work on so many power supplies, WinTec, 3Y, Condor, Setec. If they were $100.00 or less I wouldn't even touch them, but they are a bit more. Once I determine the value of the zener I will add it to the original post.

    Thanks for your assistance.

    Jim
     
  6. CocaCola

    CocaCola

    3,635
    5
    Apr 7, 2012
    Generic cop out excuse that annoys me to no end... If a 'competitor' was actually interested in reverse engineering their circuit it's trivial easy to do so... At the end of day they don't want people actually repairing the devices because then they wouldn't be able to sell replacement parts at huge markups...

    My Rant for the day...
     
  7. Jotto

    Jotto

    120
    0
    Aug 24, 2012
    Here its a joke, they buy a unit for the machine. Lets say a touch screen controller from 3M, they get a 10 year warranty, we get 6 months. Then if you wish to replace it from the manufacture charges 3 times what you can buy it for from the original vendor.

    To let you know I work at a casino. Hey its not hard work and they feed me too.

    We do go to the OEM if we can. Sometimes we can buy direct and other times we can't. Now some I can buy the part, but not the complete unit. Sometimes it the other way around.
     
  8. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,396
    2,777
    Jan 21, 2010
    Sounds like you will have multiple units like this.

    The easy way is to find a working one and compare the faulty one to that.

    We've had a few threads on SMD zener voltages. One of them had some useful links to the "standard" used by one manufacturer.
     
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