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RE: (ET) Still working on my ET problems

At 09:56 PM 6/4/03 , Roy Vanderhoef wrote:


Ok let me recap the problem, how it got started and the current
symptoms.

First I bought the tractor last year and put new batteries in it.  I
used it once and ran great, set the charger and it hummed away and after
12 ish hours I turned it off as un plugged it, I was surprised to note
the charger dial did not rotate, but with lack of experience just
figured that is how it worked. The next time I used it barley cut my 1/4
acre and was running way low on the charge available, and pushing high
in the draw. Recharged again, same thing with the charger not rotating,
dose hum and draws enough current through the cord that it gets warm.
The disconnect switch on the left side must be on while charging. If the charger works at all, the capacitor may be bad. An open one will give a low charge voltage. 



This time when I used the tractor it did not cut half of the lawn before
it died, smelled something burning, and the break popped.  After a
little it came back on but all I had was 1-3 forward and all reveres
gears.  So I came to you all for help.  Figured out that my charger was
not charging.  Charged batteries up over 3 days with regular 12V
charger.  Still no top speed rangers but at least I can cut the grass.
:-)

When I got a chance to look in to it, I found a mouse nest behind the
access panel, and that the resistor card had two of the circuit fried.
Ah, the old mouse nest trick. This has happened to half the tractors out there, it seems. They chew through some wires to get there, so look real close for open or shorted wires. 



One of the resistors was scorched and desolider, and the VDR-1 surge
suppressor printed on the board was fried, missing a section.  I have
resoliderd the resistor and replaced the printed circuit with a wire
jumper.

Now all of my forward speeds work, and the reveres works speraticly, as
described before.



Could well be chewed wires.



I have taking closer reading of the voltage between 6 and 11 and find
that there is no voltage in neutral, forward speed 1 or reveres speed
one, then in forward speeds 2 through 6 and reveres speeds 2 and 3 there
is about 33 volts.  I also measured the voltage between 10 and 49 on the
reveres relay and found 28 ish volts between them  when Reveres is
selected and it drops slightly as you select the reveres speeds.  Also
measured the voltage on the other relay and found the same voltage in
Reveres 3 and in forward 4-6.  That is this relay is activated when you
select either reveres 3 or forward 4 through 6.
The #11 wire wanders around the tractor. Check where it goes from the speed control to the resistor board, it may be open, see above note on mice. 



Another thing I noticed that might not be normal, with the transmition
in neutral, when I select any forward speed the usage meter shows almost
no usage, but when I select reveres 1 the usage meter jumps to low
yellow, and low red with Reveres 2 and pegs red with reveres 3.  If the
motor stars it will drop back to low yellow, if I back off to reveres 2
or 1 it still stay in the yellow.
Maybe the normally closed contact on the FW relay (wire 11 to 13). The ribbon resistors in the armature are giving the different currents. Looks like no field current. It seems you are getting field at some times, true? If so the wires from the surge suppressor to the motor are ok. 


Once again getting reveres to actually spin the motor is hit or miss.
As I was just checking it again, I was able to just select R1 and get
the motor to spin once or twice with out having to push to R3 then back
down.  Also if reveres will not start the motor, it seams like that
selecting forward once or twice then selecting reveres allows me to
POSSIBLY get reveres to start the motor.

One more thing that has happened a few times, as I backed out of the
forward gears back to neutral the motor is still engaged, and I have to
move the control up a little then back down.
The common failure mode of the speed controls is the nubs of the microswitches wear down and fail to operate at the right time, or at all. Worth replacing them all. Not a hard job. 
...
> When you manually actuate the relay (with the power off) you should see the top leafs move a little as the middle ones move down, then see the bottom ones move a little when the middle ones get to them. 

Not following you on this,  are you referring to the reveres relay and
actually moving it with my finger with power off or are you talking now
about the speed selector lever??
Playing with the relay itself. If you aren't getting good contact pressure on any contact, the best thing is to replace the relay. But it is possible to get most old ones to work by bending the "springs" a little as I described. By the way, there is a tab on the "back" to adjust the position of the center arm when un-activated. 


> Both relays are always have the middle contact in contact with the back
contacts, I can physically move them, but don't really notice a brushing
action.


It's a very small movement.


By the way one of the back contacts on the reveres relay appears to have
been shorts with a very top of it burnt off, but the little pad area is
there, and the corresponding center contact appears to have a solder
blob on it.  Despite this however it appears to make good contact.
The burn was probably caused by a mis-alligned relay. As you can see from the schematic, the wiper (center arm) moves from +36 v in one position, to ground in the other. If it contacts both at once, ZAP! Best to replace the relay. 



> This action causes a wiping effect and is intended
to keep pressure on the electrical contact, and also keep the contacts
clean. If not, you can carefully push near the attachment end to make it
so. The contacts are silver, so shouldn't be filed


Oops to late I already figured perhaps all they needed was a little
cleaning and toke an old Yankee try and lightly brushed them with a file



Paul and Sue Abendroth
pabendro gemair com
our permanent address is pabendroth dma org