Polar Instruments T1500A User manual

Polar Instruments Ltd.
Garenne Park
St. Sampson
Guernsey
Channel Islands
GY2 4AF
ENGLAND
Fax: [phone]
MAN159–9604
T1500A
SERVICE
MANUAL

T1500A SERVICE 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. 1996

DECLARATIONS
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

T1500A SERVICE MANUAL
ii
SAFETY
WARNING The service instructions contained in this manual
are for use by qualified electronic service personnel only.
WARNING
The LIVE and NEUTRAL lines on this unit are BOTH fused.
When the unit is connected to its supply, the opening of covers or removal of panels is
likely to expose dangerous voltages.
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
POWER SUPPLY
Check that the indicated line voltage setting corresponds with the local mains power
supply. See the rear panel for line voltage settings. Instruments with a serial number
prefixed with a letter (e.g. A1234) are configured for 90 – 110 Volts only.

SAFETY
iii
Changing the line voltage settings on this instrument must only be performed by a
skilled electronics technician. Instructions for changing the line voltage settings are
contained in Section 5.
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 unit 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 instrument 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.
Static Sensitive Devices
This unit contains Static Sensitive Devices. Static discharge can damage some
electronic components. Care must be taken when handling these components. Observe
appropriate precautions to avoid damage.

T1500A SERVICE MANUAL
iv
SPECIFICATIONS
ASA Test Ranges Open Circuit Voltage Short Circuit Current
Junction 1V 500µA
Logic 10V 5mA
Low 10V 150mA
Med 20V 1mA
High 40V 1mA
Hi-Cap (1Hz fixed) 10V 150mA
Low-Cap (2kHz fixed) 10V 20µA
ASA Test Frequencies
Low 95Hz
Medium 500Hz
High 2kHz
Display Internal CRT
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
230V ± 10%, 115V ± 10% or 100V ± 10% at 50/60Hz, 40VA.
Fuses
230V 160mA T
115V 315mA T
Channel A and B Output Fuses
160mA Fast

SPECIFICATIONS
v
Physical characteristics (excluding accessories)
Dimensions 300 mm (11.8 in.) wide
110 mm (4.4 in.) high
260 mm (10.3 in.) deep
Weight 1.5 kg (3.3 lb.)
SYMBOLS
REFER TO MANUAL These sockets are for connecting only Polar Instruments
probes and connectors for use as described in the
Operator Manual. 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).
ACCESSORIES
Standard Accessories
Probe set MMP159
Test clip set ACC110 (Red)
ACC111 (Black)
Operator manual MAN151

T1500A SERVICE MANUAL
vi
CONTENTS
DECLARATIONS............................................................................................................. i
ELECTROMAGNETIC COMPATIBILITY.......................................................................i
European Community Directive Conformance Statement..........................................i
SAFETY..........................................................................................................................ii
WARNING....................................................................................................................ii
GROUNDING ...............................................................................................................ii
POWER SUPPLY.........................................................................................................ii
OPERATION................................................................................................................iii
CAUTION.....................................................................................................................iii
Electrical Isolation.....................................................................................................iii
Static Sensitive Devices ...........................................................................................iii
SPECIFICATIONS..........................................................................................................iv
ENVIRONMENTAL OPERATING CONDITIONS ........................................................iv
Fuses........................................................................................................................iv
Channel A and B Output Fuses................................................................................iv
Physical characteristics (excluding accessories).......................................................v
SYMBOLS ....................................................................................................................v
ACCESSORIES............................................................................................................v
Standard Accessories................................................................................................v
SECTION 1 – PERFORMANCE CHECK .................................................................... 1-1
MAINTENANCE AND CALIBRATION OF INSTRUMENTS ..................................... 1-1
Performance Check............................................................................................... 1-1
Adjustment Procedure........................................................................................... 1-1
Recommendations for Routine Maintenance ........................................................1-1
PERFORMANCE CHECK ........................................................................................ 1-2
Procedure.............................................................................................................. 1-2
SECTION 2 – CALIBRATION...................................................................................... 2-1
CALIBRATION PROCEDURE.................................................................................. 2-1
Equipment required............................................................................................... 2-1
Calibration procedure............................................................................................ 2-1
SECTION 3 – CIRCUIT DESCRIPTION......................................................................3-1
T1500A CIRCUIT DESCRIPTION............................................................................3-1
Sine generator....................................................................................................... 3-1
Sine drivers............................................................................................................ 3-1
Switching...............................................................................................................3-2
Amplifier ................................................................................................................ 3-3

CONTENTS
vii
CRT....................................................................................................................... 3-3
Power supplies...................................................................................................... 3-3
High voltage supply............................................................................................ 3-3
Low voltage supplies.......................................................................................... 3-4
X and Y-plate drivers............................................................................................. 3-4
SECTION 4 – DISMANTLING INSTRUCTIONS ......................................................... 4-1
DISMANTLING THE T1500A ................................................................................... 4-1
SECTION 5 – LINE VOLTAGE AND FUSE CHANGING............................................ 5-1
LINE VOLTAGE SELECTION AND FUSE CHANGING........................................... 5-1
Changing the line voltage...................................................................................... 5-1
Fuse Replacement. ............................................................................................... 5-1
SECTION 6 – FAULT DIAGNOSIS ............................................................................. 6-1
TROUBLESHOOTING HINTS.................................................................................. 6-1
SECTION 7 – MAINTENANCE AND CLEANING........................................................ 7-1
Cleaning................................................................................................................ 7-1
Technical Support ................................................................................................. 7-1
Instrument repair................................................................................................... 7-1
SECTION 8 – REPLACEMENT PARTS...................................................................... 8-1
CRT BOARD PARTS................................................................................................ 8-2
MAIN BOARD/PANEL PARTS................................................................................. 8-2
MECHANICAL PARTS............................................................................................. 8-6
SECTION 9 – SCHEMATIC DIAGRAMS..................................................................... 9-1