Alamo Machete T 7740 User Manual

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MACHETE

TECHNICAL INFORMATION BULLETIN No. 041398

Alamo Industrial ™ Technical Services Department

1502 East Walnut

Seguin, Texas 78155

830-372-2708

Models:

All Machete Boom , MB21 & MB24

All Slope Mowers

Date:

Apr. 13, 1998

Bulletin No:

041398

Eleminate Erratic Boom movement:

(which utilize the joystick operated proportional valve system)

Procedures to eliminate erratic boom operation caused by microwave interference from

customer installed two-way radios.

There have been some scattered reports in regards to erratic or unexpected movement of one

or more of the proportionally controlled boom functions of the joystick control system during the
operation of the customer installed two-way radios.

Specifically, the Swing , Lift or Dipper functions may operate at a speed of one foot of movement

every 10 to 20 seconds, depending on the function and direction, when the radio microphone is keyed.

Research and experiments with machines in the field has revealed that this phenomenon is the

reception of the signal transmitted by the radio passing through the variable controls of the boom control
system. Specifically, the wire harness of the control system acts much like a receiving antenna and
receives the radio signal which sends a false signal through harness.

Elimination of the interference may be obtained with the use of at least of three possible options:

Remove the radio from the tractor completely.

Install a reflecting plate under the Antenna. A reflecting plate is simply a thin, flat piece of metal

which provides the proper amount of impedance to essentialy reflect the signal emanating down from
the antenna and prevent interference with the valve electronics and tractor functions. Since the
installation requires a fairly large (at least 36" square) area, the specially designed reflecting or "ground
plane tape" can be used in place of the metal sheet for easier installation. this tape is available at most
electronics or radio equipment sources.

Utilize a ground plane antenna. These specially designed antenna utilize the standard central

radial element and at least two other radials set at 45° angles to the central one. These radials must
be cut to specific lengths depending on the frequency of the system. Only a professional radio installer
or retailer should be consulted in regard to the avaialbility and proper installation of these antenna.

The installation, operation, and resulting effects to the tractor or any attachment due to the

addition of a radio system to any machine is the responsibility of the machine owner and the radio
installer. Only trained, profesional radio installers should be utilized.

This document does not authorize the repair or replacement of parts under warranty