FA00023 R 1
PARTS-SERVICE
JANUARY 9, 1997
W45XT, W/B/C60-SOXT
GRAM
T5XI
Correct Page 3
SUBJECT: DIRECTIONAL POTENTIOMETER ASSEMBLY 2308319
A new direction potentiometer and switch assembly has been released to make several
improvements over the present design used on the W45XT, W/B/C60-80XT and the TSXT.
The new assembly is directly interchangeable with the old switch, both mechanically and
electrically, and requires only a few minutes to install
In comparmg the two assemblies, the single most important design change is
the potentiometer. The new potentiometer differs &om the previous one in that it is bi-
directional as opposed to uni-directional. In other words, for the forward direction, the
potentiometer rotates clockwise and for reverse the potentiometer rotates counterclockwise.
The potentiometer resistance is the shape of a bell curve with a normal midpomt resistance of
3,300 ohms. From the factory, the potentiometer will be adjusted to the midpoint, or the high
point of the bell shaped resistance curve. Due to the tolerance of the potentiometer, it is
recommended that the neutral setting be based upon the midpoint, or the high point.
The potentiometer mounting has been incorporated into the bracket to minimize the number
of parts in the switch assembly as well as to control the location of the potentiometer relative
to the pivot shaft. The mounting hole has also changed from a slot to a punched hole to
better locate the potentiometer in the switch assembly. These two ohanges together ensure
that the proper gear mesh is maintaned.
The gears used to drive the potentiometer are made from anodized aluminum rather than
composite materials. The larger drive gear is pinned with a roll pin to the pivot shaft and the
smaller gear is fastened to the potentiometer shaft with two set screws.
Page three is a copy of the prelimmary parts page for the new switch assembly. The parts
denoted with an asterisk are items which are not to be serviced separately. These items are a
subassembly which requires significant effort to disassemble. Any attempt to remove or
replace the roll pin may damage the pivot shaft bushings and compromise the alignment.
Therefore, it is necessary to replace the entire assembly when these parts are needed.
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FA0023
All of the components of the previous assembly, with the exception of the forward/reverse
switch P/N 2309240 and insulators P/N 374160, will be canceled to use the new assembly.
Page two has the potentiometer adjustments and gear orientation for future reference should
the potentiometer need changing. Pay particular attention to the position of the set screws.
They must be located correctly to prevent gears from binding.
POTENTIOMETER ADJUSTMENT
NEUTRAL >3300 Ohms
FULL ROTATlON FORWARD < 100 Ohms
FULL ROTATlON REVERSE < 100 Ohms
ADJUST THE POTENTlOMETER USING THE SLOT IN THE SHAFT END.
ROTATE THE SHAFT CLOCKWISE/COUNTER-CLOCKWiSE TO THE FOLLOWING
SPECS
GEAR ORIENTATION
INSTALL 2306975, SPUR GEAR, ONTO POTENTIOMETER SHAFT SUCH THAT
THE SET SCREWS ARE ORIENTED SYMMETRICALLY ABOUT THE
GEAR AS PICTORALLY SHOWN.
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* NOT SERVICED SEPARATELY
Item Qnty. Part Number Description
1 1 2308319 Direction/Accelerator Switch Assembly
2 2 2302033 Potentiometer
3 1 2306975 Gear
4 1 2311041 Spacer Plate
5 3 374160 Insulator
6 2 2309240 Switch
7 1 2311820 Nut Plate
8 1 2302220 Standoff
9 1 220436 Screw, #4-40 x 1 1/4
10 1 220418 Screw, #4-40 x 3/8