Troubleshooting | Agilent Technologies U1251A specs

5 Maintenance

Troubleshooting

WA R N I N G

To avoid electrical shock, do not perform any service unless you are qualified to do so.

	If the instrument fails to operate, check the battery and the
	test leads. Replace them if necessary. And if the instrument
	still does not function, check the operating procedures in
	this manual. When servicing, use only specified replacement
	parts. Table 5- 5 below will assist you to identify some basic
	problems and their solutions.
Table 5-5Basic troubleshooting procedures

Malfunction	Troubleshooting procedure
No LCD display after power ON	• Check the battery. Charge or replace it.

No beeper tone	• Check the setup mode to verify if the beeper is set to OFF. Then select the
	desired driving frequency.

Fail on current measurement	• Check the fuse.

No charging indication [1]	• Check 440 mA fuse.
	• Check the external adaptor to verify if the output is DC 24 V and the adaptor is
	plugged into the charging terminals completely.
	• Line power voltage (100V~240 VAC 50 Hz/ 60 Hz).

Battery life very short after full	• Check if the correct rechargeable battery is used.
charge/Battery not able to charge	• Try to charge and discharge for 2 or 3 cycles in order to maintain the battery’s
after pro-long storage period	highest capacity.
	• NOTE: The performance of the rechargeable battery may degrade with time.

Fail on Remote control	• Check that the optical side of the cable is connected to the meter and the text
	side of the cover is up.
	• Check the baud rate, parity, Data bit, Stop bit (default is 9600, n, 8, 1)
	• Driver install for IR-USB.

Notes for basic troubleshooting procedures table:

1Never turn the rotary switch of the multimeter from the OFF position when it is charging.

108	Agilent U1251A/U1252A User’s and Service Guide

Image 128

Agilent Technologies U1251A manual 5Basic troubleshooting procedures, Malfunction Troubleshooting procedure

Contents

Agilent U1251A U1252A Handheld Digital Multimeter U T I O N WA R N I N G Safety Symbols Safety Information WA R N I N G Never measure voltage when current measurement is selected Meter, and follow the correct polarity Regulatory Markings Product Category Affixed product label is as shown below This Guide… Declaration of Conformity DoC Contents Setting Percentage % Scale Readout Overload alert Returning to Default Factory Settings Agilent Technologies calibration servicesAdjustment is recommended Calibration interval Adjustments Consideration Valid adjustment input valuesAdjustment procedure Calibration errors 161 III Xviii List of Figures Reset setup List of Tables 159 Getting Started Introducing the U12521A/U1252A Handheld Digital Multimeter Introducing the U12521A/U1252A Handheld Digital Multimeter Check the shipment Adjusting the tilt-stand IR-USB cable To PC host Tilt-stand at 3Tilt-stand at hanging position Display Keypad Rotary switch Terminal Connectors Front panel at a glance IR communication port Tilt-stand Battery access coverRear panel at a glance Rotary switch at a glance 7U1252A keypad 2Keypad desciption and functions Button Sets to Auto Range mode Display at a glance 3General display symbols LCD symbol Description 4Priamry display symbols 5Secondary display symbols KHz Range Counts/segments Used for the function 6Analog bar range and counts2500 Diode Ω, nS Selecting display with the Hz button 7Selecting display with the Hz button Frequency Hz Duty cycle % Frequency HzHz Frequency counter press Frequency Hz Pulse width ms Duty cycle % Hz Frequency counter press Frequency Hz 100 Selecting display with the Dual button 8Selecting display with the Dual buttonBy pressing For U1251A AC a Rotary switch position Function Primary display Selection display with the Shift buttonHz AC coupling 9Selecting display with the Shift button 9Selecting display with the Shift button For U1252A DC mV Temp Rotary switch position Input terminals Overload protection Terminals at a glance Making Measurements Understanding The Measurement Instructions No.Instructions Understanding The Measurement Instructions1Numerical steps descriptions Measuring AC voltage Red Lead Black Lead Measuring DC voltage 2Measuring DC voltage Press If necessary to ensure Measuring CurrentΜA & mA measurement Black Lead Red Lead 3Measuring μA and mA current 2Percentage scale and measurement range Percentage scale of 4 mA to 20 mAPress 4Measuring scale of 4-20 mA Ampere measurement 5A ampere current measurement Frequency Counter 6Measuring frequency Measuring Resistance, Conductance and Testing Continuity Audible continuity 8Audible continuity, conductance, and resistance test 3Audible continuity measurement range Measurement range Beeper sound threshold 9Conductance measurement Testing Diodes 10Measuring forward bias of diode 11Measuring reverse bias of diode Measuring Capacitance Means the capacitor is charging Discharging 12Capacitance measurements Measuring Temperature 14Connecting the probe with adapter into the multimeter Making Measurements 15Surface temperature measurement Input warning Alerts and Warning During MeasurementOverload alert Charge terminal alert 17Charge terminal alert Functions and Features Dynamic Recording Press to restart the dynamic recording 1Dynamic recording mode operation 2Data hold mode operation Data Hold Trigger Hold Refresh Hold Press to return Null Relative 4Null relative mode operation Decibel Display Reference for other voltage measurements 5dBm/dBV display mode operation Press Pres s Ms Peak Hold If the reading is OL, pressTo re-start the peak-recording measurement If you need to re-start the peak recording, press 61 ms peak hold mode operation Data Logging Manual logging Full Log Interval logging Are filled, Full is indicated on the secondary display 9Interval Automatic logging mode operation Reviewing logged data 10Log review mode operation Square Wave Output for U1252A Frequency Hz 11Frequency adjustment for square wave output Press 13Duty cycle adjustment for Square Wave Remote Communication Connect To PC Features and Functions Changing The Default Setting Setting Data Bit Selecting Setup Mode Display Description 1Available setting options in Setup modeMenu Item Available setting options Swaps display to C Setting Data Hold/Refresh Hold Mode 1Data hold/Refersh hold setup Setting Data Logging Mode Press PressPress Setting Thermocouple Types U1252A only 3Thermocouple type setup Setting Reference Impedance for dBm Measurement 4Reference impedance for dBm measurement setup Setting Minimum Frequency Measurement 5Minimum frequency setup Setting Temperature Unit 6Temperature unit setup Setting Auto Power Saving Mode 7Auto power saving setup Setting Percentage % Scale Readout % scale readout setup Setting Beep Frequency 9Beep frequency setup Setting Backlight Timer 10Backlit timer setup Setting Baud Rate 11Baud rate setup remote control Setting Parity Check 12Parity check setup Setting Data Bit 13Data bit setup for remote control Setting Echo Mode 14Echo mode setup for remote control Setting Print Mode 15Print mode setup for remote control Returning to Default Factory Settings Press Press Maintenance Introduction General maintenanceBattery replacement Nominal voltage List of compatible batteries for the Agilent U1251AList of of compatible batteries for the Agilent U1252A Multimeter is to be unused for long periods of time Charging the batteryStorage considerations U T I O N 2Battery capacity display as trickle Condition Battery voltage Proportional percentage 2Error messages Error Error message 4Charging mode Agilent U1251A/U1252A User’s and Service Guide 103 6Battery charging procedure Fuse checking procedure Figure above Replacing the fuse 3Measurement readings for fuse checking Fuse Agilent part number Rating Size Type 4Fuse specificationsFuse Malfunction Troubleshooting procedure Troubleshooting5Basic troubleshooting procedures Replaceable Parts To order replaceable parts 110 Agilent U1251A/U1252A User’s and Service Guide Current terminal test Closed- case electronic calibrationBacklit test Closed-case electronic calibration Agilent Technologies calibration servicesCalibration Overview Adjustment is recommended Calibration interval Application Recommended equipment Recommended Test Equipment1Recommended Test Equipment Backlit test Testing the displayBasic Operating Test Setup Current terminal test Charge terminal alert test Test Considerations Calibration Security Performance Verification Tests Doing the performance verification tests Step Test Function Range Error from nominal 1 year2Performance verification test steps U1251A ± 20 mV ± 17.5 mV 500 ± 200 mV 1000 ± 800 mV Agilent U1251A/U1252A User’s and Service Guide 123 ± 75 μV ± 350 mW 33250A Output Step Test Function Range 5520A Output Square Wave Use 53131A Output Use 34410A Agilent U1251A/U1252A User’s and Service Guide 127 Unsecuring the instrument for calibration To Unsecure the Instrument from the Front Panel Agilent U1251A/U1252A User’s and Service Guide 129 Tory default code using the front panel Calibration process Using the front panel for adjustments Selecting the Adjustment Mode Calibration memory for the present function Adjustments ConsiderationProblem and repeat the procedure Function Range Valid Amplitude Input Values Valid adjustment input values3Valid adjustment input values Adjustment procedure Simultaneously to exit the adjustment mode 136 Agilent U1251A/U1252A User’s and Service Guide 4Adjustment table Step Test Function Cal Range Input Cal Item U1251A U1252A 138 Agilent U1251A/U1252A User’s and Service Guide Agilent U1251A/U1252A User’s and Service Guide 139 Open Agilent U1251A/U1252A User’s and Service Guide 141 Your instrument was calibrated before it left the factory Finishing the adjustmentTo read the calibration count Calibration errors Number Recommended Accuracy Requirements 144 Agilent U1251A/U1252A User’s and Service Guide Frequency Sensitivity Specifications Frequency Counter Specifications for U1252A Product Characteristics Power Supply Agilent U1251A/U1252A User’s and Service Guide 147 Calibration Cycle Measurement Category Measurement category definition Specification Assumptions Electrical Specifications DC SpecificationsFunction Range Resolution Burden Voltage U1251A U1252A Accuracy Maximum open voltage + 4.2 AC Specifications Frequency Function Range Resolution Function Range Resolution 45 Hz KHz 10 kHz 20 kHz Function Range ResolutionFrequency 20 Hz 45 Hz KHz 10 kHz Frequency Hz 45 Hz Frequency 30 Hz 45 Hz KHz 7U1252A true RMS ac+dc current specificationsFunction Range Resolution 45 Hz KHz 10 kHz Capacitance Specifications Temperature Specifications8Capacitance specifications 9Temperature specifications Frequency Specifications Duty Cycle and Pulse Width Specifications10Frequency specifications 11Duty cycle and pulse width specifications Frequency Sensitivity Specifications Minimum sensitivity RMS sine waveModel Number U1251A U1252A 100 kHz Input Range Peak Hold SpecificationsSignal Width Accuracy For DC mV/voltage/current Frequency Counter Specifications for U1252A 15Frequency counter divide by 1 specifications16Frequency counter divide by 100 4 specifications Sensitivity Min. Input Frequency Output Range Accuracy 17Square wave output specificationsSquare Wave Output for U1252A Operating Specifications Display update rate approximate18Display update rate approximate Realtime clock. Only ONE sample per second can be logged Input impedance 19Input Impedance 164 Agilent U1251A/U1252A User’s and Service Guide Contact us