Re: (ET) wiring diag help needed...

["Ralph G Vogan" <ralphgv CenturyTel net>]

Dave,  There must be two parts to this problem.  A negitive wire contacting
the tractor, or mower frame, and a positive wire doing the same thing.  
Also
the power must be flowing through the AllTrax, or a short inside of it.

 1.  Take the AllTrax off and check it with an ohm-meter to see if there is
a short between any of the contacts on it and it's mounting plate.  Check
with Steve, but I think the mounting plate should be isolated from any
wiring points.  If it's shorted that could have been a part of the problem.

 2.  You can operate the PTO contactor by hand, with the power off, and see
if all four contact points make and brake, to check if any of them have
welded together.  If they are ok then that wasn't the problem.  If any are
welded together that could be part of the problem, or a result from another
problem (see 3).

 3.   If you had sparks on the mower deck, then unplug it and check for a
short between any of the prongs on it's plug and the frame of the deck.  
The
deck frame should be isolated from all the wiring.  If it is shorted it IS 
a
part of the problem.

4.  Check the 12 volts to the frame to see if it will light a small 12 volt
bulb.  If it lights then check the wire between the back battery box + and
the front battery box negitive post.  That wire carries negitive 12 volts 
in
respect to the front two batteries.  It can short to the frame or the motor
v belt pulley.  Inspect it carefully.  If the bulb will not light and the
voltage disappears when it is connected then it is just a small leakage
voltage and not a problem.

 5.  Another place there could be a short is in the drive motor it'self.
Disconnect the drive motor wires and check each one to see if it is shorted
to the frame.  Again the frame should be isolated from all wiring.

Let me know what you find.

Ralph V
ralphgv centurytel net

----- Original Message ----- 
From: "Dave & Deb" <daveb drizzle com>
To: <ralphgv CenturyTel net>
Sent: Wednesday, July 28, 2004 6:25 PM
Subject: Re: (ET) wiring diag help needed...


 Ralph,

    I had a chance to look at my e-trac with the smoked alltrax controller
last wkend.  I discovered I had 36v going to the frame!  something has
grounded.  I visually checked all the wires for bare spots.  Didn't find
any.  I started removing wires from components one by one.  When I had the
controller completely disconnected the voltage to the frame dropped to 12v.
I don't know at this point if the "ground fault" caused the controller to
get smoked or if the smoking controller caused the ground fault.  I did
check out the PTO wiring per your explanation (thanks) and it looked fine 
to
me.  could it be that the PTO contactor is faulty, that is could it "short"
the motors in such a way that the motors when switching to generators sent 
a
spike back through the main disconnect thence to the controller and smoked
it?

 I know I need a course in Elect 101 but I can't wait till fall quarter! 
:^)
any comments greatly appreciated,

 Dave