Tenma 72-9280 Operating Manual
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Tenma 72-9280 Operating Manual

Tenma 72-9280 Operating Manual

Automotive digital multimeter
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72-9280
P/N:110401102827

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Summary of Contents for Tenma 72-9280

  • Page 1 72-9280 P/N:110401102827...

  • Page 2: Table Of Contents

    72-9280: OPERATING MANUAL Contents Overview ..............................4 Unpacking Inspection...........................4 Safety Information..........................5 Rules For Safe Operation ......................5 Automotive Servicing Safety Guide..................7 International Electrical Symbols......................11 The Meter Structure (see figure 1).......................12 Rotary Switch ...........................13 AC or DC Voltage Measurement....................13 millvoltage Measurement......................13 Resistance Measurement......................13 Functional Buttons (see figure 2) .....................14...
  • Page 3 72-9280: OPERATING MANUAL DC millvoltage Testing ......................20 AC/DC Current Testing ......................22 Resistance Testing........................23 Continuity Testing ........................25 Diode Testing ..........................27 Capacitance Testing .......................30 Frequency Testing ........................31 Dwell Testing...........................34 Hold............................37 Range............................38 Max/Min...........................38 Data Outputting ........................38 Display backlight ........................39 The BLUE button........................39 Automatic power off ........................39 Diagnosis of Automotive Troubles ......................39...
  • Page 4 72-9280: OPERATING MANUAL Accuracy Specifications ........................70 Maintenance ............................77 General Service ........................77 Replacing the Fuses .......................77 Replacing the Battery......................78...

  • Page 5: Overview

    To avoid electric shock or personal injury, read the “Safety Information” and “Rules for Safe Operation” carefully before using the Meter. Automotive Digital Multimeter Model 72-9280 (hereafter referred to as “the Meter”) is a 4000 counts, 3-3/4 digits manual ranging meter. The meter uses large scale of integrated circuit with integrated A/D converter as its core.

  • Page 6: Safety Information

    72-9280: OPERATING MANUAL Test Lead 1 pair Alligator Clip 1 pair RS232C interface cable 1 piece CD-ROM 1 piece 9V Battery 1 piece In the event you find any missing or damage, please contact your dealer immediately. Safety Information This Meter complies with standards IEC61010: in pollution degree 2, overvoltage category (CATIII 1000V, CAT 600V) and double insulation.
  • Page 7 72-9280: OPERATING MANUAL Before using the meter, inspect the body casing; do not use the meter if it is damaged or the case (or part of the case) is removed; look for cracks or missing plastic or missing parts. Examine the insulation around the connectors.

  • Page 8: Automotive Servicing Safety Guide

    72-9280: OPERATING MANUAL Replace the battery as soon as the battery indicator appears. With a low battery, the meter might produce false readings that can lead to electric shock and personal injury. The internal circuit of the meter shall not be altered or tampered with, as it will likely damage the meter and possibly cause electrical shock.
  • Page 9 72-9280: OPERATING MANUAL around the components and wiring of the air bags, or any actions that will deploy an air bag, which can result in personal injury and damage. Note that the air bag will also be active for a few minutes after the ignition is off (or even when the automotive battery is cut off), which is driven by a safety power reserve.
  • Page 10 72-9280: OPERATING MANUAL Do not smoke, light a match, burn a candle, or otherwise have any type of open flame near the automobile. Take extra caution when working near ignition coils, ignition leads, and spark plug sockets because these components are provided with high voltages when the automobile is operating.
  • Page 11 72-9280: OPERATING MANUAL there is any doubt in the situation, contact a professional and certified mechanic immediately before any attempt to fix, alter, or further test the vehicle. Before the diagnosis of any trouble, visually inspect all of the components of the vehicle, including the exterior, interior, under the carriage, and under the hood.

  • Page 12: International Electrical Symbols

    72-9280: OPERATING MANUAL connected, sometimes these parts strictly require a complete connection. Check circuit connections: any pin corrosion, bend or damage, inappropriate connection position or damaged electrode lead. International Electrical Symbols AC (Alternating Current) DC (Direct Current) Ground AC or DC...

  • Page 13: The Meter Structure (See Figure 1)

    72-9280: OPERATING MANUAL Warning. Refer to the Operating Manual. Conforms to Standards of European Union. The Meter Structure (see figure 1) (Figure 1) LCD display Functional buttons...

  • Page 14: Rotary Switch

    72-9280: OPERATING MANUAL SELECT button Power button Rotary Switch Input Terminals Rotary Switch Below table indicated for information about the rotary switch positions. Rotary Switch Function Position AC or DC Voltage Measurement Millivoltage Measurement Resistance Measurement Capacitance measurement Continuity Test...

  • Page 15: Functional Buttons (See Figure 2)

    72-9280: OPERATING MANUAL Current measurement, unit: mA Current measurement, unit: A Automotive engine tach testing (Displayed Reading x 10), Unit: rpm RPM x 10 Automotive ignition dwell testing, Unit: degree DWELL Functional Buttons (see figure 2) Below table indicated for information about the functional button operations.
  • Page 16 72-9280: OPERATING MANUAL HOLD/ Press HOLD once to enter hold mode. Press HOLD again to exit hold mode and the present value is shown. Press and hold for 2 seconds to turn the display backlight on or off. MAX/MIN Start recording of maximum and minimum values.

  • Page 17: Display Symbols (See Figure 3)

    72-9280: OPERATING MANUAL Display Symbols (see figure 3) Figure 3 Data output is in progress. Low Battery Warning: To avoid false readings, which could lead to possible electric shock or personal injury, replace the battery as soon as the battery indicator appears.
  • Page 18 72-9280: OPERATING MANUAL Maximum or Minimum reading displayed 4CYL, 6CYL, or 8CYL displayed Test of continuity Indicates for DC voltage or current Indicates for AC voltage or current Indicates for dangers Data hold is active The meter is in Auto range mode...

  • Page 19: Measurement Operation

    72-9280: OPERATING MANUAL Test of RPM Indicates for units Measurement Operation AC/DC Voltage Testing Warning To avoid injury or damage to the meter from electric shock, please do not attempt to measure voltages higher than 1000V, although readings may be obtained. Please take extra care when measuring high voltages to avoid electric shock.
  • Page 20 72-9280: OPERATING MANUAL Note If the value of voltage to be measured is unknown, use the maximum measurement position (1000V) and reduce the range step by step until a satisfactory reading is obtained. Please take extra care when measuring high voltages to avoid electric shock.

  • Page 21: Dc Millvoltage Testing

    72-9280: OPERATING MANUAL (Figure 4) DC Millivoltage Testing Warning To avoid injury to you or damages to the Meter from electric shock, please do not attempt to measure voltages higher than the range although readings may be obtained. When AC voltage measurement has been completed, disconnect the connection between the...
  • Page 22 72-9280: OPERATING MANUAL To measure DC millvoltage, connect the Meter as follows: Insert the red test lead into the V terminal and the black test lead into the COM terminal. 2. Set the rotary switch to an appropriate measurement position in mV 3.

  • Page 23: Ac/Dc Current Testing

    72-9280: OPERATING MANUAL AC/DC Current Testing Warning Before connecting the Meter in serial to the tested in-circuit, disconnect in-circuit power. If the fuse burns out during measurement, the Meter may be damaged or the operator himself may be hurt. Use proper terminals, function, and range for the measurement. When the testing leads are connected to the current terminals, do not parallel them across any circuit otherwise it will burn the fuse or damage to the Meter.

  • Page 24: Resistance Testing

    72-9280: OPERATING MANUAL and interval time between 2 measurement greater than 15 minutes. (Figure 6) Resistance Testing Warning To avoid damages to the Meter or to the devices under test, disconnect circuit power and discharge all the high-voltage capacitors before measuring resistance.
  • Page 25 72-9280: OPERATING MANUAL To measure resistance, connect the Meter as follows: Insert the red test lead into the terminal and the black test lead into the COM terminal. Set the rotary switch to an appropriate measurement position in range then press blue button to select resistance measurement mode.

  • Page 26: Continuity Testing

    72-9280: OPERATING MANUAL (Figure 7) Continuity Testing Warning To avoid possible damage to the Meter and to the device under test, disconnect circuit power and discharge all high-voltage capacitors before testing diodes and continuity. To avoid injury to yourself, never attempt to input an effective voltage over 60V in DC or 30V in...
  • Page 27 72-9280: OPERATING MANUAL To test for continuity, connect the Meter as below: Insert the red test lead into the terminal and the black test lead into the COM terminal. Set the rotary switch to , then press blue button to select continuity mode.

  • Page 28: Diode Testing

    72-9280: OPERATING MANUAL (Figure 8) Diode Testing Warning To avoid possible damage to the Meter and to the device under test, disconnect circuit power and discharge all high-voltage capacitors before testing diodes and continuity. To avoid injury to yourself, never attempt to input an effective voltage over 60V in DC or 30V in...
  • Page 29 72-9280: OPERATING MANUAL To test a diode out of a circuit, connect the Meter as follows: Insert the red test lead into the terminal and the black test lead into the COM terminal. Set the rotary switch to For forward voltage drop readings on any semiconductor component, place the red test lead on the component’s anode and place the black test lead on the component’s cathode.
  • Page 30 72-9280: OPERATING MANUAL The LCD will display “OL” indicating open-circuit or wrong polarity connection. When diode testing has been completed, disconnect the connection between the testing leads and the circuit under test. (Figure 9)

  • Page 31: Capacitance Testing

    72-9280: OPERATING MANUAL Capacitance Testing Warning To avoid damage to the Meter or to the equipment under test, disconnect circuit power and discharge all high-voltage capacitors before measuring capacitance. To measure capacitance, connect the Meter as follows: Insert the red test lead into the terminal and the black test lead into the COM terminal.

  • Page 32: Frequency Testing

    72-9280: OPERATING MANUAL (Figure10) Frequency Testing To measure frequency, connect the Meter as follows: 1. nsert the red test lead into the Hz terminal and the black test lead into the COM terminal. 2. Under AC/DC voltage, DC millivoltage or AC/DC current measurement, press Hz button to select frequency measurement mode, the measured value shows on the display.
  • Page 33 72-9280: OPERATING MANUAL Note Refer to accuracy specifications for maximum ranges When frequency measurement has been completed, disconnect the connection between the testing leads and the circuit under test, and remove the testing leads from the input terminals of the...
  • Page 34 72-9280: OPERATING MANUAL (Figure 11)

  • Page 35: Dwell Testing

    72-9280: OPERATING MANUAL Dwell Testing (Figure 13)
  • Page 36 72-9280: OPERATING MANUAL In the past, it was very important to test the dwell of the cut-off switch of an ignition system. The dwell testing measures the duration which the cut-off switch remains off when the cam is turning. Today’s automobiles are ignited electronically, and it is no longer necessary to adjust the ignition dwell.
  • Page 37 72-9280: OPERATING MANUAL press BLUE button to select RPM X10 measurement mode. Insert the red test lead into the RPM terminal and the black one into the COM terminal. Select an appropriate number of cylinders. Connect the ends to be tested as illustrated.

  • Page 38: Hold

    72-9280: OPERATING MANUAL (Figure 14) Hold The Hold mode is applicable to all measurement functions: Press HOLD to enter Hold mode and save the present reading...

  • Page 39: Range

    72-9280: OPERATING MANUAL Press HOLD again to exit Hold mode In Hold mode, is displayed while holding the reading Range Press RANGE to enter the manual ranging mode (the Meter will beep) Press RANGE to step through the ranges available for the selected function (the Meter will beep again) Press and hold RANGE for over 2 seconds to return to auto ranging.

  • Page 40: Display Backlight

    72-9280: OPERATING MANUAL Display backlight Press and hold HOLD button for over 2 seconds to turn on or turn off the display backlight. The BLUE button This button is used for selecting the required measurement function when there is more than one function at one position of the rotary switch.

  • Page 41: Switch Testing

    72-9280: OPERATING MANUAL Set the rotary switch to Insert the red test lead into the terminal and the black one into the COM terminal. Short circuit the red and black test lead probes, when the reading of the meter should be displayed between 0.2...

  • Page 42: Starting/Charging System Testing

    72-9280: OPERATING MANUAL The same as in Items 1 to 3 of Fuse Testing. Connect the red and black test lead probes in parallel to the two ends of a solenoid or relay. The impedance of most of solenoids or relay coils is less than 200 .

  • Page 43: Battery Power Consumption (Engine Off)

    72-9280: OPERATING MANUAL Load-Free Battery Testing Before testing the starting/charging system, test the battery to see if it is fully charged. Set the rotary switch to DCV. Insert the red test lead into the V terminal and the black one into the COM terminal.
  • Page 44 72-9280: OPERATING MANUAL consumption of the battery, which may finally lead to the exhaustion of the battery. Turn off and close the ignition key and all its accessories. Make sure that the bus, engine louver and cabin lights have been turned off and closed.

  • Page 45: Trigger Voltage Battery Load Testing

    72-9280: OPERATING MANUAL Trigger Voltage Battery Load Testing Upon the start of the engine, test the battery to see if it can offer an adequate voltage. Set the rotary switch to DCV. Insert the red test lead into the V terminal and the black one into the COM terminal.
  • Page 46 72-9280: OPERATING MANUAL 9.4 V 10.0 C (50 F) 9.3 V 4.4 C (40 F) 9.1V -1.1 C (30 F) 8.9 V -6.7 C (20 F) 8.7 V -12.2 C (10 F) 8.5 V -17.8 C (0 F) Voltage Drop Testing Test the voltage drops caused by the switch, cable, solenoid or connector.
  • Page 47 72-9280: OPERATING MANUAL test lead into the COM terminal. Refer to the LOSS typical trigger voltage circuit. (See figure 15) Test the voltage between any of the following pairs of points respectively: 1&2, 2&3, 4&5, 5&6, 6&7, 7&8, 8&9, 8&10...
  • Page 48 72-9280: OPERATING MANUAL Compare the readings of the tested voltages against the example table. If the voltage is on the high side, check the components and connectors to see if there is anything wrong. If anything wrong is found, complete necessary servicing.
  • Page 49 72-9280: OPERATING MANUAL Turn on the lamps, windshield wipers, fans and so on to increase the loads of the electronic systems with the voltage readings being no less than 13.0 V. If the readings in Steps 3, 4, and 5 are normal, the charging system is also normal. If the...
  • Page 50 72-9280: OPERATING MANUAL (Figure 16) Warning: The reading of the testing becomes the actual tested resistance only after the reduction of the short-circuit values of the test leads. primary resistance generally between 0.3 and 2.0 .
  • Page 51 72-9280: OPERATING MANUAL Make sure the unit is set to auto ranging and test the primary coil of the ignition coil. Connect the red test lead probe to the secondary outlet and the black one to the primary “-” pole. Refer to the appropriate automotive manuals for details.
  • Page 52 72-9280: OPERATING MANUAL Ignition System High-Voltage Damper Testing (Figure 17) Move the connectors of the ignition system from the engine. Refer to the ignition system movement procedure in various kinds of automotive manuals for the details. Warning: Some of Chrysler’s products use a spark plug high voltage damper with “positive lock” end electrodes, which can only be moved out of the distributor board.
  • Page 53 72-9280: OPERATING MANUAL details. Set the rotary switch to the . Insert the red test lead into the terminal and the black one into the COM terminal. Connect the red and black test lead probes in parallel to the two ends of the high-voltage damper and observe the reading.
  • Page 54 72-9280: OPERATING MANUAL When the tach and dwell are tested in the computer of the automobile, a Hall sensor is used. The Hall sensor is normally used in the ignition system to detect the position of the camshaft so that the computer of the automobile can set the optimal time for the ignition and the opening of the fuel injector.
  • Page 55 72-9280: OPERATING MANUAL Magnetic Resistance Sensor (Figure 19) The functions of a magnetic resistance sensor is similar to those of a Hall sensor and the testing methods of both sensors are also similar. Their normal resistance is generally in a range of 150...
  • Page 56 72-9280: OPERATING MANUAL RPM Testing (Figure 20) Set the rotary switch to RPMx10 and select the number of cylinders in the automobile to be tested. Insert the red test lead into the terminal and the black one into the COM terminal.
  • Page 57 72-9280: OPERATING MANUAL manuals for the detailed position); or the negative pole of the ignition coil if the automobile is equipped with a distributor board (Refer to the appropriate service manuals for the detailed position). The normal starting rotation speed of an engine is about 50 RPM to 275 RPM. Refer the detailed position to the servicing handbooks of various kinds of automotive manuals because this value relates to the then temperature, engine size, battery size, etc..
  • Page 58 72-9280: OPERATING MANUAL When the automobile is operating in a short fuel state or in a long fuel state, the dwell of the meter should be displayed between 10 and 50 . Fuel Injector Resistance Testing (Figure 21) The testing method is similar to that of the resistance of an ignition coil.
  • Page 59 72-9280: OPERATING MANUAL manuals for the detailed position.) Connect the red and black test lead probes to the two ends of the injector. The general normal resistance is less than or equal to 10 . Engine Sensor Testing (Figure 22)
  • Page 60 72-9280: OPERATING MANUAL To adapt to the provisions for low injection and fuel saving in the early 1980’s,the computer-controlled regulators were installed in the automobile and the sensors provided the computer with required data.The Meter is an effective tool for the detection of the operation of a sensor.
  • Page 61 72-9280: OPERATING MANUAL If the sensor has a 2- or 4-lead outlet, the ground terminal is its special wiring. Connect the red test lead probe of the meter to the signal terminal (i.e. hot end) of the sensor. If the sensor has more than 3 leads, what is used in the automobile is a heated oxygen sensor, which has 2 hot ends.
  • Page 62 72-9280: OPERATING MANUAL The TITANIA sensor has a resistance of about 4 k . Warning: In testing, the readings will vary with the heating temperature. Be extremely cautious when working with the heating devices and open flame. Allow appropriate time to cool before further testing.
  • Page 63 72-9280: OPERATING MANUAL (Figure 23) Testing Procedure: The same as in the resistance testing method. When the general temperature of a sensor rises, its resistance will drop. The thermal resistance of the temperature sensor of the automotive engine is generally less than 300...
  • Page 64 72-9280: OPERATING MANUAL Position Sensor (Figure 24) The position sensor is an electrometer or variable resistance. It is used for the computer monitoring of the position and direction of a mechanical device. The typical position sensors include throttle, exhaust recalculating EGR, blade air flow and other sensors.
  • Page 65 72-9280: OPERATING MANUAL Connect the red and black test lead probes respectively to the signal test terminal and ground terminal. Refer to various automotive servicing manuals for its position and the resistance to be tested. Absolute Pressure (MAP) and Baro Sensor...
  • Page 66 72-9280: OPERATING MANUAL Absolute Pressure (MAP) and Baro Sensor (Figure 25)
  • Page 67 72-9280: OPERATING MANUAL The MAP sensor is used to change a pressure signal into a DC voltage or frequency one. All GM, Chrysler, Honda and Toyota use DC voltage type MAP sensors, while Ford uses frequency type MAP sensors. Refer to relevant manuals for other automotive manufacturers.
  • Page 68 72-9280: OPERATING MANUAL Warning: RPM =Frequency *120/ the number of cylinders. Mass Air Flow (MAF) Sensor Figure 26...
  • Page 69 72-9280: OPERATING MANUAL The sensor converts the air flow into a DC voltage, low frequency or high frequency signal. The Meter can only be used to test a DC voltage or low frequency signal. Testing Procedure: Connect the DC voltage type MAF sensor in the DC voltage testing method and set the rotary switch to DCV.

  • Page 70: General Specifications

    72-9280: OPERATING MANUAL General Specifications Maximum Voltage between any Terminals and grounding: Refer to the different range input protection voltage. Fuse Protection of A mA terminal: 1A, H 240V, fast type, 6x25mm Fuse Protection of A terminal: 10A,H 240V, fast type, 6x25mm Maximum Display: 4000;...
  • Page 71 72-9280: OPERATING MANUAL IEC61010: CATIII 1000V, CAT 600V overvoltage and double insulation standard. Certification: Accuracy Specifications Accuracy: (a% Reading + Digits), guarantee for 1 year. Operating Temperature: 18 C to 28 C. Relative Humidity: No more than 75% RH. DC Voltage...
  • Page 72 72-9280: OPERATING MANUAL Overload Protection: 1000V DC or AC Displays effective value of sine wave (mean value response)(10%~100% of the range) DC millvoltage Range Resolution Accuracy Overload Protection 40mV 0.01 mV 500AC (0.8%+3) 400mV 0.1 mV Note: Input impedance: Around 4000M .
  • Page 73 72-9280: OPERATING MANUAL AC Current Range Resolution Accuracy Accuracy 40Hz ~ 400Hz 400Hz ~ 1kHz 400 A 0.1 A (1.2%+10) (1.2%+5) 4000 A 40mA 10 A (1.5%+5) (1.5%+10) 400mA 100 A (2%+5) (2%+10) 10mA Note: Fuse Protection of A mA terminal: 1A, H 240V, fast type, 6x25mm...
  • Page 74 72-9280: OPERATING MANUAL Resistance Range Resolution Accuracy Overload Protection (1%+5) 500Vp 400k (1.5%+5) Capacitance Range Resolution Accuracy Overload Protection 10nF 10pF 100nF 100pF 500Vp 1000nF (3%+5) 10 F 10nF 100 F 100nF Frequency Range Accuracy 10Hz~1MHz (0.1%+4)
  • Page 75 72-9280: OPERATING MANUAL Overload Protection: the same as AC/DC voltage, DC millvoltage, AC/DC Current, and RPM mode. Input Amplitude: a 1) AC/DC voltage mode, When 40Hz ~ 1KHz: a range x 10% (except 1000V range) a 400V (1000V range) When 10Hz ~40Hz or 1k Hz ~1MHz: for reference only.
  • Page 76 72-9280: OPERATING MANUAL Continuity Testing Range Resolution Overload Protection 500Vp Note: Open circuit voltage approximate 3V. The buzzer does not sound when the resistance value is >30 . The circuit is disconnected. The buzzer sounds continuously when the resistance value is 30 .
  • Page 77 72-9280: OPERATING MANUAL Tach (Rotation Speed) Testing Range Resolution Accuracy Overload Protection 4CYL 500 Vp 6CYL 10 RPM (3%+5) 8CYL Note: Input Scope: 10V in forward impulse; Bandwidth 0.5mS Maximum Tach: 10000 RPM, Tach = Displayed Reading x 10.

  • Page 78: Maintenance

    72-9280: OPERATING MANUAL Maintenance This section provides basic maintenance information including battery and fuse replacement instruction. Warning Do not attempt to repair or service your meter unless you are qualified to do so and have the relevant calibration, performance test, and service information.

  • Page 79: Replacing The Battery

    72-9280: OPERATING MANUAL fuses ONLY in accordance with the following procedure. To replace the Meter’s fused: Turn the Meter off and remove all connections from the terminals. Remove the holster from the Meter. Remove the 3 screws from the case bottom, and separate the case top from the case bottom.
  • Page 80 72-9280: OPERATING MANUAL To replace the Meter’s battery: Turn the Meter power off and remove all connections from the terminals. Take the Meter out from the holster. Remove the screw from the battery compartment and open the battery compartment. Take out the battery and replace with a new 9V battery.
  • Page 81 72-9280: OPERATING MANUAL Copyright 2011 Tenma All rights reserved. Manufacturer: Tenma Test Equipment 405 S. Pioneer Blvd Springboro, OH 45066 www.tenma.com...

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