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Urgently need a scematic

Discussion in 'Electronic Repair' started by [email protected], Apr 10, 2005.

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  1. Guest

    .... for a Trace 2624 inverter (old black box model). Here on Great
    Barrier Island we have no grid power, so the inverter is essential.
    Its' fan malfunctioned and the unit suffered a meltdown. Whilst I could
    replace all the FETs and any other obviously fried components I'd
    really like to know what waveforms should be where before I hook it
    back up to the battery bank and possibly see all my work and a couple
    of dozen new components go up in smoke again. The Trace people (never
    big on support) don't want to know, as the unit is about 12 years old.
    Even if I could just get it going again as a charger it would be
    useful. I'll happily pay money for a photocopy or a decent scan if
    somebody out there has a service manual. It is a 230v model, but I
    imagine the only major difference from a 110v model is the transformer.
  2. James Sweet

    James Sweet Guest

    If you can't get a schematic from the manufacture then it quite likely is
    simply not available anywhere. Replace the fried components and test the
    rest of the transistors and diodes with a multimeter, then apply a current
    limited power source. When I repair inverters I usually run them off either
    a 3A bench supply or an old computer supply capable of 10A on the 12V line
    depending on the size of the inverter. That's usually enough to power up one
    with no load or a small nightlight bulb for testing but not enough to blow
    up a dozen FET's in the blink of an eye as the hundreds of amps available
    from a battery will.
  3. Guest

    I would suggest asking the solar energy people, but it appears that
    someone has already asked there. Unless, of course, two separate
    installations in NZ managed to blow up a Trace 2624 at the same time.
    If it's one of the square DC fans that are common in computers, you can
    get a lot of these now that have a tachometer lead that provides pulses
    when the blade is turning. You'll have to come up with a circuit to
    monitor the pulses and sound a buzzer (if someone is around to hear it),
    shut off power (unattended), etc. A simpler way might be a thermostat in series with a buzzer or
    relay coil.
    How about this... Disconnect the main transformer from everything,
    and apply line voltage to the output side. Measure the voltages on
    the windings on the low-voltage side. Replace the burned parts.
    Measure the resistance of the input terminals (both ways) to see if
    it's really low... if it is, recheck the repair work. If not, hook
    a small light bulb (or series string of light bulbs to get the right
    voltage) to the output of the inverter... where the low-voltage winding
    of the transformer would usually be. (The bright filament of an 1157
    12 V car tail light bulb, or the only filament of an 1156, is about 27
    W. Most car headlights are 50 to 60 W.) Then, hook up the battery bank
    through a relatively small fuse (1 A, 5 A, etc), or use a light bulb
    instead of a fuse -
    .. In your case you'll put the bulb in the DC input line from the
    batteries. Give it a try - if the fuse blows, or the bulb in the DC
    input lead comes on brightly, there's still a problem. If the bulb(s)
    on the output light up at about the right brightness, you're on the
    right track. You can either load it up with more bulbs on the output
    and test again, or go ahead and hook up the transformer.

    One flaw in this theory is that I believe some of these inverters
    have a feedback winding on the transformer to correct the frequency
    of the oscillator. The light bulb load won't provide this feedback,
    and the oscillator may not start.

    There is a schematic for a very simple inverter here:

    One thing I do in cases like this is that if one transistor is blown,
    and it's not screamingly expensive, I order three of them as
    replacements. That way, if I was wrong at first, I get two more
    guesses before I have to sit down and really think about it. :)
    If I guess right, I have spares for a future failure (if it blew once,
    it'll blow again) or for some other project.

    Good luck!

    Matt Roberds
  4. Bill Jeffrey

    Bill Jeffrey Guest

    Have you inquired at the solar energy forum sponsored by Northern
    Arizona Wind and Sun? Several knowledgable people on the forum.

    Bill Jeffrey
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