Maintenance And Troubleshooting Of 5P9698 Calibrator{0600, 0650} Caterpillar

The 5P9698 Calibrator (1) is a self-contained (one unit), battery operated calibration oscillator. The position of the calibrator, or temperature, has no effect on calibrator operation. The 5P9698 Calibrator is easier to use and the cost is less than a signal generator with a digital frequency readout.

The calibrator can give seven different output frequencies. In addition to calibration of Caterpillar diagnostic equipment, these seven output frequencies make possible the calibration of many other instruments.

NOTE: Modifications must be made to some early 5P9698 Calibrators. On units that do not have a "C" stamped on the front after the serial number at location (X), modifications must be made to the unit. If the unit has a "C", no modifications are needed. If the modifications are to be made, obtain a 1000 ohm (1K ohm) 10%, 1/4 Watt carbon resistor at an electronic supply store. See page 9 for the procedure to make the modifications.

On the front of the calibrator is an output selector switch (2), that has eight positions; a battery meter (3) that shows the condition of the battery (meter needle must be in the white area when the selector switch is at one of the output frequency positions); two adapters (4) for use with the 1P5500 Phototach Group or the 5P3600 Hydraulic Flow Meter; and a three foot lead (5), with phone plug.

Maintenance Instructions

Checks Before Calibration

Before calibration of the 5P9698 Calibrator, always check the condition of the battery. Look at the BATTERY METER to check battery condition. An indication of a weak or dead battery will be when the meter needle stops in the red zone.

To install a new battery, remove the four screws (1) and front panel (2). Check the contacts of the battery holder, and the inside of the calibrator for any corrosion. Clean as necessary. At installation of the battery, always check for correct polarity.

Circuit Description

The 5P9698 Calibrator is a very stable crystal controlled oscillator. Transistors Q1 and Q2, and their associated resistors and capacitors, form an oscillator stage oscillating at 409.6 kHz. Trimmer capacitor C4 adjusts the crystal frequency.

Integrated circuit, IC1, is a 14 stage ripple carry binary counter. It divides the crystal frequency to provide outputs of 25, 50, 100, 200, 400, 800 and 1600 Hz. Test point one (TP1), provides a one-half crystal frequency output that is "buffered" by IC1 to prevent test equipment from loading the oscillator stage, during testing and calibration.

Output stage Q3 is an emitter follower providing 1 volt, P-P output with a nominal 600 ohm source impedance. This signal is AC coupled through C5 to the output lead.

Calibration Of 5P9698 Calibrator

Connect a 6 digit frequency counter, known to be accurate, to TP1. (TP1 is the solid wire, approximately 1/2" (12.7) long, extended out of the printed circuit board near trimmer C4.) The outer foil around the printed circuit board is circuit common. Adjust trimmer capacitor C4, until the reading on the frequency counter is 204810 ± 3 Hz.

Oscilloscope Wave Forms For Troubleshooting The Calibrator

Oscillograms are all taken at setting of 1 millisecond sweep time, and 5 volts/cm with the centerline as ground zero.

(1) IC1 - Pin 10.

(2) IC1 - Pin 9.

(3) IC1 - Pin 13.

5P9698 Calibrator Schematic And Parts List

NOTE: Parts and repair service are available from Flo-Tech, Inc. For repair service, return

Specifications

Modifications To Early Calibrator Groups

(1) Check your calibrator; if there is a "C" stamped on the front cover after the serial number at location (X), no modifications are needed. If there is no "C", make the modifications that follow.

(2) Remove panel (1) from 5P9698 Calibrator (2). Locate resistor (R6) as shown. Use a small soldering iron to heat each lead wire until the solder melts; then use needle nose pliers or a 5P1720 Oil Seal Pick to lift the part out of the printed circuit board. Install a new 1K ohm (1000 ohm) 1/4 watt carbon resistor in the location where resistor (R6) was removed. Use a letter "C" stamp to mark the front panel after the serial number at location (X). Use caution to prevent damage to the electric circuitry. Install the panel in the case.

NOTE: The calibrator can be sent to the address shown on page 7 for the above modifications. Indicate to the repair center that change "C" must be made to the calibrator. A fee will be charged for the modifications.