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PFL780 Polar Instruments Ltd. Garenne Park SERVICE St. Sampson Guernsey MANUAL Channel Islands http://www.polar.co.uk Fax: +44 (01) 481 252476 Email: mail@polar.co.uk MAN 161–9803...
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Copyright Polar Instruments Ltd. 1997 Microsoft and MS-DOS are registered trademarks of Microsoft Corporation IBM is the registered trademark of International Business Machines Corporation.
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PFL780 FAULT LOCATOR SERVICE MANUAL POLAR INSTRUMENTS LTD. HARDWARE WARRANTY Product Warranty. Product hardware is warranted to be free from defects in material and workmanship during the Warranty Period (as defined below). Product hardware is warranted to conform substantially to Polar’s then current (as of the date of Polar’s product shipment) published user documentation during the Warranty Period.
DECLARATIONS European Community Directive Conformance Statement Refer to the Operator Manual to determine conformance with European Community Directives.
PFL780 SERVICE MANUAL 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 later units 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.
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.
SPECIFICATIONS 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...
PFL780 SERVICE MANUAL 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.
SECTION 1 – PERFORMANCE CHECK MAINTENANCE AND CALIBRATION OF INSTRUMENTS For most of Polar Instruments’ products there are two maintenance procedures — the Performance Check and the Calibration. Some instruments may have a single (combined) procedure. Performance Check The Performance Check (or Checkout Procedure) is used to verify the basic functions of the instrument.
Note: Close any active windows to return to the root menu for access to UTILITIES. The PC can now report the status of all the systems within the PFL780 unless there is a failure of the RS232 link, which would be reported should communication not be established.
Note: a true RMS DVM may give a slightly different reading. Testing the PFL780 clips, cables and relays If it is desired to test clips and cables and the relays of the PFL780 it will be necessary to build a simple test fixture.
SECTION 2 – CALIBRATION CALIBRATION PROCEDURE WARNING: Hazardous voltages are exposed on the PCB when the cover is removed. This procedure should only be performed by a technically qualified person aware of the hazards and taking all reasonable care. Equipment required Accurate (0.5% or better at 10V DC) DVM Procedure 1.
Refer to the CPU I/O schematic I/O ports Communication between the CPU and the rest of the PFL780 is by memory mapped ports and a small number of devices connected directly on the data bus. Output ports U1,2,3,4 and U9 provide the route for control signals into the circuits of the main board while U5 and U17 are input ports.
PFL780 SERVICE MANUAL EAROM U10 is the EAROM which is a serially driven non-volatile device operating much slower than normal bus speed and with all its signal and control lines driven by port U9. The serial output goes to input port U5.
CIRCUIT DESCRIPTION The differential current out of the DAC is converted to a voltage sine wave of 5V pk-pk symmetrical about ground by op-amps U47A and B. A capacitor filter is included between the two amp stages to smooth any steps from the waveform;...
PFL780 SERVICE MANUAL INPUT AMPLIFIER Refer to the Input Amplifier schematics Programmable gain amplifier The A and B signal bus connects to the input of the programmable gain signal amplifier U920. Rf for the input op-amp is selected by U57 and Ri is 1M in all except JUNCTION range when relay K9 switches in a 110k resistor in parallel to reduce Ri to 100K.
CIRCUIT DESCRIPTION operation and +5 V provides an OFF state. The status outputs of U58 on pins 19 and 20 connect to an input port. Analog stores The DAC incorporates a latch and outputs the decoded voltage immediately the new data is written into it by the processor.
The cooling fan has its own regulated supply, U108. The 5V supply for the logic and processor of the PFL780 is generated by a switch mode regulator U103 from the +15V line. Note that C102 is a high quality low series resistance electrolytic capacitor. The 5V from the switcher supplies only the User output and the digital test circuits directly driving the user’s...
CIRCUIT DESCRIPTION U3 decodes the high side driver address to take its selected output high. This will turn on one of the open collector devices in the array U1, supplying base current to the driver PNP transistor which will lift its collector to nearly 15V.
PFL780 SERVICE MANUAL Driver control buffers/latches The data bus from the main board, together with control signals and some address lines connect to the Scanner/ICFT board through the 40-way cable. The data bus is buffered by U54 and U55 but also connects to the 6 input ports from the comparators, one of which is shown.
CIRCUIT DESCRIPTION Schematic ICT Page 1 covers output drivers DS0 – DS15 (drivers DS16 – DS31, DS32 – DS47 are shown on schematics ICT Page 2 and ICT Page 3). Note that the output DS0 corresponds to pin 1 of a 40 pin IC, up to DS39 which corresponds to pin 40.
2 minutes after power is removed until internal capacitors discharge. Note: the PFL780 covers are attached to the main body of the instrument by safety ground cables. To disconnect the safety ground cables detach the push-on connector from the tab bolted to the cover.
PFL780 SERVICE MANUAL CAUTION — Do not try to remove the main board from the chassis until the above procedure is completed. It is very unlikely this would ever be necessary. Re-assembly Re-assembly is the reverse of the above. Ensure the safety ground cables are replaced as the covers are fitted.
SECTION 5 – LINE VOLTAGE AND FUSE CHANGING WARNING: There are hazardous voltages inside the instrument when connected to its power supply. REMOVE THE POWER CORD before touching any part of the line input circuit. Note that high voltages may continue to be present for 2 minutes after power is removed until internal capacitors discharge.
PFL780 SERVICE MANUAL Replacing fuses Line Fuse 1. If a line fuse failure is suspected, disconnect the power cord. Early instruments: Locate the line fuse on the rear of the instrument, remove and test. If faulty, dismantle the instrument as described in section 4.
SECTION 6 – FAULT DIAGNOSIS WARNING: Hazardous voltages are exposed on the PCB when the cover is removed. These procedures should only be performed by a technically qualified person aware of the hazards and taking all reasonable care. SYSTEM DIAGNOSTICS If the “System OK”...
PFL780 SERVICE MANUAL Instrument diagnostics If the PC cannot be used then it is possible to perform some basic diagnostics on the instrument itself. WARNING: DANGEROUS VOLTAGES EXIST ON THE BOARD. Remove the top cover and turn the power on.
If it becomes necessary to repair the instrument, in the first instance contact the Polar Instruments distributor in your country. In case of difficulty contact Polar Instruments Ltd. at the address at the front of this manual. Do not send the instrument until shipping instructions have been received from the...
Note: Parts marked with an asterisk (*) have been subject to modification in later instruments. Safety critical parts (listed in bold type) must be replaced with parts obtained from Polar Instruments Ltd or your Polar Instruments distributor to ensure continued safe operation.
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PORT 0007 I/P Leakage On a bus U16B 74HC373 Guard Hi 74HC32 74HC75 U22A 74HC04 PORTWR2 0.01uF 74HC374 PORTWR7 SW12 T-Series and Toneohm 220uF 100K LM386 SPEAKER Fault Finding 220uF Schematic 2 15-Feb-95 Hairline Short Large Land Bridge Polar Instruments...
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+15V U63C R242 C116 -15V 220uF 10K 1% TL084 R236 THRESH2 U922 R250 LM759 C118 10K 0.1% 0.1uF C117 R249 R251 -15V 220uF Polar Intruments Ltd Garenne Park, St. Sampsons Guernsey, Channel Islands Inst. Title PFL780 A to D Converter...
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0.1uF U31B 74HC74 74AC32 U14D U31A 74AC32 R-IN U31D 74AC32 RESET RESET 74AC32 U33F NOT FITTED 7705 .1uF 10uF 74HC04 62256 74HC74 U30B Polar Intruments Ltd Garenne Park, St. Sampsons Guernsey, Channel Islands Inst. Title PFL780 CPU S/No 11378 up...
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0.1uF U31B 74HC74 74AC32 U14D U31A 74AC32 RESET R-IN U31D NOT FITTED 74AC32 74AC32 RESET U33F 7705 .1uF 10uF 74HC04 62256 WATCHDOG Polar Intruments Ltd Garenne Park, St. Sampsons Guernsey, Channel Islands Inst. Title PFL780 CPU up to S/No 11377...
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