Voltage regulator repair

Discussion in 'General Electronics Chat' started by duckyde, Sep 2, 2009.

  1. duckyde

    Thread Starter New Member

    Sep 2, 2009
    Hello all,

    I'm a newbie member with perhaps an unusual problem and very basic circuit knowledge. I am attempting to repair a voltage regulator for my Russian motorcycle which uses a generator rather than an alternator. The system itself is 12 volt and like a car is designed to be regulated around 14.5 volts. The regulator consists of a circuit board with various components soldered to it and enclosed in a simple metal case. I found one diode which visually seems bad (it has a burn mark on the side) and using an ohm meter it measures the same resistance in both directions. Printed on the diode is:


    My first question is do these mean anything to anyone, or does anyone know of a US-Russian cross reference (as ridiculous as that may sound). Secondly, does anyone know of a Russian Electronic spec sheet or some way I can figure out some specs for these components?

    Buying spare parts for this bike is a bit of a hassle and is why I'm trying to fix this one. Thanks in advance!
  2. bertus


    Apr 5, 2008

    Can you post a photo, so we can see the size of the diode?
    Diodes are there in many sizes and specs.

  3. StayatHomeElectronics

    Well-Known Member

    Sep 25, 2008
    What is the resistance it is measuring?
  4. billbehen

    Active Member

    May 10, 2006
    Since the voltage you're regulating is like 15Votls max then maybe a 60Volt part would work? As for amps, i agree that size and general apprearance would guide you so far a total power rating. Maybe take it to RadioShack to compare physical size. A 60 Hz rectifier might not be fast enough so look for a more electronics type. Schottkys are very fast, but maybe not so rugged.... Also, when an active component goes, sometimes other parts fail too, so check around on the board for other damage!
  5. duckyde

    Thread Starter New Member

    Sep 2, 2009
    Bertus -

    I'm going to try and post a couple of the pictures I took. I tried using a scale to give size and proportion and so the scale itself is in decimal inch. The diode is mounted on the board near the top in the picture. To the left and right of the white wires are two small holes for the diode.

    StayathomeElectronics - the resistance measures 79.0 ohms in both directions

    billbehen - I considered a 60volt piece but it seemed like overkill. I'm assuming that means 60 volts max rather than a mean value? In my searches I was looking for some more along the lines of 20volts or 12-14 if it was a mean value.
  6. bertus


    Apr 5, 2008
  7. kkazem

    Active Member

    Jul 23, 2009
    Since you're measuring the correct resistance on the part, there is nothing wrong with it. Look to the active devices, like the TO-220 semiconductor. That could be a bipolar transistor, a MOSFET, or an IC 3-terminal regulator. Your best chance is to get a schematic and/or parts list from the manufacturer. Other than that, you're better off building a new one from a 3-terminal adjustable regulator that you set to 13.8 VDC to 14.5V. You can use an LM317 type, which is self protecting for overcurrent and overtemperature. But depending on the output current needed, you may need to heat-sink it or possibly use a higher current part. See the Linear Technology online catalog of voltage regulators.

    Gooh luck,
    Kamran Kazem