Polar Instruments T1000A User manual

Polar Instruments Ltd.
Garenne Park
Rue de la Cache
St. Sampson
Guernsey
Channel Islands
GY2 4AF
England
Fax: [phone]
MAN 148-9603
T1000A
OPERATOR
MANUAL

T1000A FAULT LOCATOR OPERATOR MANUAL
WARRANTY
For a period of one year from its date of purchase new and undamaged from Polar
Instruments Ltd, POLAR INSTRUMENTS LTD or its authorized distributors will, without
charge, repair or replace at its option, this product if found to be defective in materials
or workmanship, and if returned to POLAR INSTRUMENTS LTD or its authorized
distributors transport prepaid. This warranty is expressly conditioned upon the product
having been used only in normal usage and service in accordance with instructions of
POLAR INSTRUMENTS LTD and not having been altered in any way or subject to
misuse, negligence or damage, and not having been repaired or attempted to be
repaired by any other than POLAR INSTRUMENTS LTD or its authorized distributors.
EXCEPT FOR THE FOREGOING EXPRESS WARRANTY OF REPAIR OR
REPLACEMENT POLAR INSTRUMENTS LTD MAKES NO WARRANTY OF ANY
KIND, INCLUDING BUT NOT LIMITED TO, ANY EXPRESS OR IMPLIED WARRANTY
OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE, AND
POLAR INSTRUMENTS LTD SHALL NOT BE LIABLE FOR ANY DAMAGES,
WHETHER DIRECT OR NOT OR OTHERWISE, BEYOND REPAIR OR REPLACING
THIS PRODUCT.
Copyright Polar Instruments Ltd. 1995
DECLARATIONS

T1000A OPERATOR MANUAL
ii
ELECTROMAGNETIC COMPATIBILITY
European Community Directive Conformance Statement
This product is in conformity with the protection requirements of EC Council Directive
89/336/EEC on the approximation of the laws of the Member States relating to
electromagnetic compatibility.
A declaration of conformity with the requirements of the Directive has been signed by
POLAR INSTRUMENTS (UK) LTD
11 College Place
London Road
Southampton
England
SO1 2FE
This product satisfies EN50081-1:92 and EN 50082-1:92

SAFETY
iii
SAFETY
WARNING
The LIVE and NEUTRAL lines on this unit are BOTH fused.
This unit contains no user-serviceable parts. When the unit is connected to its supply,
the opening of covers or removal of panels is likely to expose dangerous voltages. To
maintain operator safety, do not operate the unit unless the enclosure is complete and
securely assembled.
GROUNDING
This unit must be earthed (grounded); do not operate the instrument with the safety
earth disconnected. Ensure the instrument is connected to an outlet with an effective
protective conductor terminal (earth). Do not negate this protective action by using an
extension cord without a protective conductor.
Note: This instrument is fitted with 3-wire grounding type plug designed to fit only into a
grounding type power outlet. If a special local plug must be fitted to the power cord
ensure this operation is performed by a skilled electronics technician and that the
protective ground connection is maintained. The plug that is cut off from the power cord
must be safely disposed of.
Power cord color codes are as follows:
Europe
brown live
blue neutral
green/yellow earth (ground)
United States
black live
white neutral
green ground

T1000A OPERATOR MANUAL
iv
POWER SUPPLY
Check that the indicated line voltage setting corresponds with the local mains power
supply. See the rear panel for line voltage settings.
To change the line voltage settings refer the instrument to a skilled electronics
technician. Instructions for changing the line voltage settings are contained in the
T1000A Service Manual published by Polar Instruments.
T1000A OPERATION
This manual contains instructions and warnings which must be observed
by the user to ensure safe operation. Operating this instrument in ways
other than detailed in this manual may impair the protection provided by
the instrument and may result in the instrument becoming unsafe. Retain
these instructions for later use.
The T1000A is designed for use indoors in an electrical workshop environment at a
stable work station comprising a bench or similar work surface.
Use only the accessories (e.g. test probes and clips) provided by Polar Instruments.
The T1000A must be maintained and repaired by a skilled electronics technician in
accordance with the manufacturer’s instructions.
If it is likely that the protection has been impaired the instrument must be made
inoperative, secured against unintended operation and referred to qualified service
personnel. Protection may be impaired if, for example, the instrument:
•Shows signs of physical damage
•Fails to operate normally when the operating instructions are followed
•Has been stored for prolonged periods under unfavourable conditions
•Has been subjected to excessive transport stresses
•Has been exposed to rain or water or been subject to liquid spills
CAUTION
Electrical Isolation
Always disconnect the board under test from the local mains supply (including ground)
before using this instrument.
SPECIFICATIONS

SPECIFICATIONS
v
ASA Test Ranges Open Circuit Voltage Short Circuit Current
Junction 1V 500µA
Logic 10V 5mA
Low 10V 150mA
Med 20V 1mA
Hi-Cap (1Hz fixed) 10V 150mA
Low-Cap (2kHz fixed) 10V 20µA
ASA Test Frequencies
Low 95Hz
Medium 500Hz
High 2kHz
Curve Tracing
Collector drive Peak Voltage Peak Current
10V 10mA maximum
10V 100mA maximum
+/– selectable
Base Step Generator
Number of steps 8
Step amplitude 1V/step or 1mA/step (selectable)
Amplitude adjustable (0 – 100%)
Polarity (selectable)
Display Outputs to drive oscilloscope in X-Y mode
(100mV/div)
Power supply Detachable power cord
ENVIRONMENTAL OPERATING CONDITIONS
The instrument is designed for indoor use only under the following environmental
conditions:
Altitude Up to 2000m
Temperature +5°C to +40°C ambient
Relative humidity RH 80% maximum at 31°C — derate
linearly to 50% at 40°C
Mains borne transients As defined by Installation Category II
(Overvoltage Category II) in IEC664
Pollution Degree 2 (IEC664)
Power Requirements

T1000A OPERATOR MANUAL
vi
230V ± 10%, 115V ± 10% or 100V ± 10% at 50/60Hz, 20VA.
Physical characteristics (excluding accessories)
Dimensions 300 mm (11.8 in.) wide
120 mm (4.7 in.) high
275 mm (10.8 in.) deep
Weight 2 kg (4.4 lb.)
ACCESSORIES
Standard Accessories
Oscilloscope cable assembly ACC150
Probe set MMP159
Test clip set ACC110(Red)
ACC111(Black)
Operator manual MAN148
SYMBOLS
CAUTION To prevent damage to this product and to ensure its safe use
observe the specifications given in this manual when connecting to
terminals marked with this symbol.
COM This terminal is internally connected to earth (ground).

SPECIFICATIONS
vii
GUIDE TO THE MANUAL
INTRODUCTION An overview of the Polar T1000A fault locator
and its applications.
GENERAL DESCRIPTION A description of the principles of operation and
front and rear panels.
INSTALLATION AND SET UP Connecting the T1000A to a power supply.
ASA DEVICE TESTING Information about the different ways in which
the ASA facilities of the T1000A can be used
and how to test devices.
ASA SEMICONDUCTOR TESTING Describes methods of testing signal diodes,
zener diodes, LEDs and transistors in circuit.
THE CURVE TRACER Testing three terminal devices using the
T1000A curve tracer
SIMPLE MAINTENANCE Details of maintenance and cleaning
procedures.

T1000A OPERATOR MANUAL
viii
CONTENTS
DECLARATIONS............................................................................................................. i
ELECTROMAGNETIC COMPATIBILITY......................................................................ii
European Community Directive Conformance Statement.........................................ii
SAFETY......................................................................................................................... iii
WARNING...................................................................................................................iii
GROUNDING ..............................................................................................................iii
POWER SUPPLY........................................................................................................iv
T1000A OPERATION..................................................................................................iv
CAUTION.....................................................................................................................iv
Electrical Isolation..............................................................................................iv
SPECIFICATIONS..........................................................................................................iv
ENVIRONMENTAL OPERATING CONDITIONS .........................................................v
ACCESSORIES...........................................................................................................vi
Standard Accessories...............................................................................................vi
SYMBOLS ...................................................................................................................vi
SECTION 1 – INTRODUCTION................................................................................... 1-1
THE T1000A FAULT LOCATOR.............................................................................. 1-1
1-1 Introduction to the T1000A.............................................................................. 1-1
1-2 Areas of application......................................................................................... 1-1
1-3 Analog Signature Analysis...............................................................................1-1
1-4 The T1000A transistor curve tracer.................................................................1-2
SECTION 2 – GENERAL DESCRIPTION................................................................... 2-1
PRINCIPLES OF OPERATION ................................................................................2-1
2-1 Controls, connectors and probes .................................................................... 2-1
The T1000A front panel..................................................................................2-1
CURVE TRACE section...............................................................................2-1
ASA section................................................................................................. 2-1
The T1000A rear panel...................................................................................2-1
2-2 Producing signatures....................................................................................... 2-2
2-3 Four-quadrant signatures................................................................................2-2
2-4 The T1000A equivalent circuit......................................................................... 2-3
2-5 Producing transistor curves............................................................................. 2-4
Bipolar junction transistors.............................................................................. 2-4
Field effect transistors..................................................................................... 2-4

CONTENTS
ix
SECTION 3 – INSTALLATION AND SET-UP............................................................. 3-1
PREPARATION FOR USE....................................................................................... 3-1
3-1 Unpacking ....................................................................................................... 3-1
3-2 Connecting the T1000A to a power supply ..................................................... 3-1
3-3 Connecting the T1000A to an oscilloscope..................................................... 3-2
3-4 Connecting the test cables.............................................................................. 3-3
Single Channel Applications ........................................................................... 3-3
Dual Channel (Comparison) Applications....................................................... 3-3
SECTION 4 – ASA DEVICE TESTING........................................................................ 4-1
TESTING COMPONENTS ....................................................................................... 4-1
4-1 ASA techniques............................................................................................... 4-2
Troubleshooting without documentation ......................................................... 4-2
Typical faults................................................................................................... 4-3
4-2 Testing resistors.............................................................................................. 4-4
4-3 Testing capacitors........................................................................................... 4-6
Choosing capacitor testing ranges.................................................................. 4-7
Leakage current in capacitors......................................................................... 4-8
Capacitors in circuit......................................................................................... 4-9
4-4 Inductors ....................................................................................................... 4-10
Signatures of inductors................................................................................. 4-10
SECTION 5 – ASA SEMICONDUCTOR TESTING..................................................... 5-1
USING ASA TO TEST SEMICONDUCTORS........................................................... 5-1
5-1 Diodes, LEDs and Zeners............................................................................... 5-1
5-2 Testing transistors in circuit............................................................................. 5-3
Identifying Transistor Terminals...................................................................... 5-3
5-3 Field Effect Transistors (FETs)........................................................................ 5-5
Junction FETs (JFETs) ................................................................................... 5-5
Metal-Oxide Semiconductor FETs (MOSFETs).............................................. 5-5
5-4 Integrated Circuits........................................................................................... 5-5
5-5 Testing Devices in Circuit.............................................................................. 5-10
Circuit Example............................................................................................. 5-10
5-6 Testing Bus-connected devices .................................................................... 5-13
SECTION 6 – THE CURVE TRACER.......................................................................... 6-1
TESTING TRANSISTORS WITH THE CURVE TRACER........................................ 6-1
6-1 Bipolar junction transistors.............................................................................. 6-1
6-2 Field Effect Transistors (FETs)........................................................................ 6-4
Junction field effect transistors........................................................................ 6-4
Testing Junction FETs with the CURVE TRACER....................................... 6-4
Metal-oxide field effect transistors................................................................... 6-5
Testing MOSFETs with the CURVE TRACER............................................. 6-5

T1000A OPERATOR MANUAL
x
SECTION 7 – SIMPLE MAINTENANCE AND CLEANING ......................................... 7-1
Fault diagnosis ......................................................................................................7-1
Cleaning ................................................................................................................7-1
Technical Support..................................................................................................7-1
USER GUIDE (FRENCH)
USER GUIDE (GERMAN)
USER GUIDE (ITALIAN)

1-1
SECTION 1 – INTRODUCTION
THE T1000A FAULT LOCATOR
1-1 Introduction to the T1000A
The T1000A Fault Locator and Curve Tracer provides a fast and efficient means of
testing components, either in isolation or in circuit.
All testing is done with power disconnected from the circuit, so there is no risk to the
user and components under test cannot be damaged.
In addition to its Analog Signature Analysis (ASA) ranges the T1000A provides basic
curve tracing facilities.
Two channels, A and B, enable the characteristics of both a reference and a faulty
component or circuit to be compared. Faults in complex circuits can thus be
diagnosed without a high degree of technical skill or detailed knowledge of the circuit
functions—this facility will be found particularly useful when documentation is not
available.
The T1000A incorporates no final display circuitry—its outputs are connected to an
oscilloscope operating in X-Y mode.
1-2 Areas of application
The T1000A is an ideal instrument for a wide range of applications:
•Field Service – fault finding.
•Manufacturing – goods inwards testing and troubleshooting.
•Repair – rapid diagnostics.
•Education– examination of device characteristics.
1-3 Analog Signature Analysis
The T1000A Fault Locator and Curve Tracer tests components by applying a
current-limited alternating (AC) drive voltage across the component and monitoring
the resultant current flow to display impedance signatures. Signatures for different
types of components have distinctly different shapes that can be easily
distinguished.

T1000A OPERATOR MANUAL
1-2
1-4 The T1000A transistor curve tracer
The T1000A CURVE TRACER applies a varying potential difference across the
collector-emitter terminals of a transistor under test while applying incrementing
voltage or current steps to the base of the transistor. The resulting display is the
classic “family of curves”, allowing the technician to verify the operation of the
transistor under test.
The inclusion of two channels in the T1000A allows the user to compare the
behaviour of two devices simultaneously. Viewing two sets of curves on the screen
enables transistor matching to be easily accomplished.
The T1000A circuitry allows the operator to select voltage or current drive of both
polarities so the curve tracer is suitable for both NPN and PNP bipolar junction and
n-channel and p-channel field effect transistors.

2-1
SECTION 2 – GENERAL DESCRIPTION
PRINCIPLES OF OPERATION
2-1 Controls, connectors and probes
The T1000A front panel
CURVE TRACE section
Channel A and B transistor test sockets — arranged to accommodate bipolar junction
and field effect transistors. Two channels are included to allow device comparison.
Step polarity/drive controls — use the polarity and drive controls to select voltage or
current drive of appropriate polarity when testing bipolar or field effect transistors.
Step Amplitude control — use the Step Amplitude control to control the conduction of
the transistor under test.
ASA section
Voltage range and frequency switches — use the voltage range and frequency
switches to select appropriate drive voltages and frequencies during signature analysis.
Channel A and B probes — probe across devices (between Channel A and COM or
Channel B and COM) to observe device signatures.
COM (common return) connector — connect the COM test clip to the ground of the
board (or boards) under test.
Channel A position controls — use the Channel A position controls to move the
channel A trace vertically and horizontally with respect to the Channel B trace.
The T1000A rear panel
The IEC power connector, power ON/OFF switch, X and Y signature outputs are
mounted on the rear of the instrument.
The X and Y signature outputs supply the X and Y components of the analog signature
to the X and Y oscilloscope inputs via the supplied BNC cables.

T1000A OPERATOR MANUAL
2-2
2-2 Producing signatures
The T1000A applies an alternating voltage to a component or circuit and displays the
resulting current versus voltage display on an oscilloscope CRT screen.
The voltage applied across the component is displayed horizontally, the current through
the component is displayed vertically, so the resulting V/I graph represents the
resistance, or impedance, of the component. This is defined as the Impedance
Signature of the device.
The T1000A generates voltages of both polarities, i.e. applies both positive and
negative voltages to a component, causing current to flow in both directions. The result
is a four quadrant graph (see Figure 2-1).
Figure 2-1 The T1000A CRT Display
2-3 Four-quadrant signatures
Impedance signatures are graphs of current against voltage, plotted on a scale which
has its origin at the centre of the CRT display screen.
As the voltage applied to the component is driven positive and negative, positive
voltages and currents are displayed in the upper right quadrant on the CRT, negative
voltages and currents are displayed in the lower left quadrant.
The graticule marked on the CRT face is usually graduated so approximate current and
voltage measurements can be made.
1st Quadrant2nd Quadrant
3rd Quadrant 4th Quadrant
+V
+I
-V
-I
Horizontal (Voltage) Axis
Vertical (Current) Axis

GENERAL DESCRIPTION
2-3
It is usually not necessary, however, to calculate actual current values in a component
to verify its correct operation. When fault finding on an electrical circuit, the technician
is frequently looking for components that have failed completely. Often, a brief glance
at the signature of a suspect device will be sufficient to show whether it is good or
defective.
2-4 The T1000A equivalent circuit
The T1000A can be represented by a voltage source, VS, in series with an internal (or
source) impedance, ZS, and the component under test by a simple impedance, ZL
(Figure 2-2).
Figure 2-2 T1000A equivalent circuit
The T1000A contains circuits which measure the voltage across, and the current
through, the component to be tested and outputs a display on an attached
oscilloscope.
The voltage, VL, across the impedance, ZL, will depend on the value of the component
under test and controls the horizontal deflection of the display.
Current through the component under test will cause a voltage to be developed across
the T1000A internal impedance, ZS. This voltage controls the amount of vertical
deflection on the display.
A high value impedance in the component under test (that is, high compared with the
value of ZS)will result in low circuit current (and therefore a low voltage across ZS)with
most of the T1000A source voltage, VS,appearing across ZL, producing a signature
with a shallow slope.
A low value impedance will result in high circuit current and most of the source voltage
developed across ZS; the result is a steeply sloping signature.
Vs
Zs
ZL
A
VL

T1000A OPERATOR MANUAL
2-4
Figure 2-3 shows the signatures of two resistors, measured on the same voltage range,
superimposed. Component B has a greater resistance then component A.
Figure 2-3 T1000A oscilloscope display showing two impedance signatures
2-5 Producing transistor curves
The T1000A CURVE TRACE section incorporates front panel sockets and circuitry for
testing a wide range of semiconductor devices.
Bipolar junction transistors
The CURVE TRACE waveform generating circuitry tests transistors by producing the
familiar “family of curves”. Positive or negative collector-emitter drive voltages and base
steps are selectable via the front panel to accommodate both NPN and PNP
transistors.
Base current step amplitude may also be varied from the front panel, allowing the
T1000A to test a wide range of transistors from small signal devices to power
transistors.
The front panel transistor sockets are arranged for convenient insertion of different
case styles.
Two curve trace channels are provided to allow for comparison testing and device
matching. This will be especially useful if the device type is unknown.
Field effect transistors
The T1000A allows the operator to specify gate-source voltage drive steps of both
polarities so the curve tracer is suitable for both n-channel and p-channel field effect
transistors.
AB

3-1
SECTION 3 – INSTALLATION AND SET-UP
PREPARATION FOR USE
3-1 Unpacking
The instrument is shipped in a sturdy transit pack. Open the pack carefully and remove
the instrument and its accessories.
If the instrument is damaged in any way contact the local distributor or supplier.
Retain the pack for possible future use.
The T1000A pack should contain:
T1000A
Power cord
Pair of probes (red and black)
Pair of test clips (red and black)
Operator manual
Note: If the instrument has been shipped or stored in a cold environment, allow the
instrument to reach the temperature of its new location before applying power.
3-2 Connecting the T1000A to a power supply
Refer to the voltage label on the rear panel of the instrument and make sure that
the marked rating is suitable for the local mains power supply.
If the rating on the label is not suitable for the local power supply refer the instrument to
a skilled electronics technician. Instructions for changing the line voltage settings are
contained in the T1000A Service Manual.
Note: If a special local plug must be fitted to the power cord ensure this operation is
performed by a skilled electronics technician and that the protective ground connection
is maintained. The plug that is cut off from the power cord must be safely disposed of.

T1000A OPERATOR MANUAL
3-2
Power cord color codes are as follows:
Europe
brown live
blue neutral
green/yellow earth (ground)
United States
black live
white neutral
green ground
3-3 Connecting the T1000A to an oscilloscope
1. Switch on the oscilloscope.
If the oscilloscope trace in Y-T mode is not perfectly horizontal, adjust its Trace
Rotation control until the trace is parallel to the X axis. If the instrument is moved to a
new location readjustment of the Trace Rotation control may be necessary.
2. Set the oscilloscope to X-Y mode.
3. Set the oscilloscope input coupling switches to DC coupled and the X and
Y sensitivity to 100mV/division.
4. Adjust the CRT beam intensity for a visible spot; use the vertical and
horizontal position controls to locate the spot at the screen centre.
Caution: The oscilloscope CRT phosphor could be burnt if the intensity is
set too high and the same display is left on the screen for several hours.
5. Connect the X and Y outputs on the T1000A to the X and Y inputs on the
oscilloscope via the BNC cables provided.
6. Connect the power cord to the T1000A and to the power supply and
switch on (the power switch is located at the rear of the instrument).
7. Select the LOGIC RANGE and LOW FREQUENCY from the T1000A
ASA section.
The oscilloscope should display the T1000A channel A and B outputs (two horizontal
traces) about the screen centre. Rotate the A POSITION horizontal and vertical controls
and ensure that one trace on the oscilloscope screen, the T1000A’s channel A output,
moves correctly vertically and horizontally with respect to the channel B trace. Adjust
the oscilloscope X and Y position controls to centre the traces about the screen centre.
The oscilloscope should require no further adjustment (apart from minor intensity
adjustments).