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Urgently need a scematic

.... 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.
 
J

James Sweet

Jan 1, 1970
0
... 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.

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.
 
... for a Trace 2624 inverter (old black box model).

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.
Its' fan malfunctioned and the unit suffered a meltdown.

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
http://dkc3.digikey.com/PDF/T051/1132.pdf in series with a buzzer or
relay coil.
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.

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 - http://repairfaq.cis.upenn.edu/sam/tshoot.htm#tshslt
.. 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:
http://repairfaq.cis.upenn.edu/sam/samschem.htm#schbp1

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
 
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