Audiolab 8000AV Original Service Manual in

introduction No part of this document may be reproduced or transmitted in any form or by any means, electronic or mechanical, for any purpose, without the express written permission of International Audio Group Limited (IAG). This manual is for the exclusive use of I AG, its approved distributors and approved UK service agents. No part of this manual shall be transferred to a third party without the written permission of I AG. It is the responsibility of the user to ensure that all the information contained in this manual is current. Notification for new issues of this manual and minor updates will be given via the I AG web-site or on request. This manual has been prepared with the greatest care, it is intended for information only and no liability shall be accepted for errors or changes to specification. For further service information, parts lists and updates, please contact our web-site. © 2005 International Audio Group Limited. All rights reserved. Notification for new issues of this service manual will be given via the Audiolab web site:- issue number :- 2005/001/8000P GRP00003.0 01 1 issue date :- September 04 2005 2 25 5. .0 01 1. .1 19 99 99 9

index 1.0 safety and servicing notes 1.1 Safety precautions ....................................................................................1 1.2 Electrostatic discharge precautions .............................................................1 1.3 Soldering.................................................................................................1 2.0 front and rear panel layouts 2.1 Front panel controls ..................................................................................3 2.2 Rear panel connections .............................................................................3 3.0 Pages 4 and 5 DELETED 4.0 functional tests 4.1 Test equipment required ............................................................................6 4.2 Functional test procedure ...........................................................................7 5.0 performance tests 5.1 Test equipment required ..........................................................................12 5.2 Performance test procedure .....................................................................13 6.0 test points 6.1 Functional and performance test points .....................................................17 7.0 circuit schematics 7.1 Master schematic diagram (SCH279M-01-06.................... .......................18 7.2 Power amplifier left channel schematic (SCH27901-03-07) .........................19 7.3 Power amplifier right channel schematic (SCH27901-02-07) .......................20 7.4 Power supplies protect and mute schematic (SCH27901-01-03) ..................21 8.0 printed circuit board layout 8.1 Printed circuit board layout (top view) .......................................................22 8.2 Printed circuit board layout (bottom view) ..................................................23 9.0 technical data 9.1 8000P Technical specifications ................................................................24 9.2 International standards ............................................................................25

1 1.0 safety and servicing notes 1.1 Safety precautions 1. This unit is Class II, which means that it is not connected to the protective earth system. All live voltages are insulated from the case by double insulation. 2. Do not attempt to service unless qualified to do so. 3. Disconnect unit from AC power supply before removing cover. 4. Components marked with the symbol on the circuit schematic are safety critical and must only be replaced with an identical component, or an alternative approved by the manufacturer. 5. Switch unit off, and disconnect from supply before making and breaking any connections. 6. Do not adjust any controls unless instructed to do so in this manual. 1.2 Electrostatic discharge precautions Electrostatic discharge (ESD) is due to charges produced by insulating materials rubbing together. Humans collect electrostatic charge through normal activities when clothes rub together and when walking on carpet. This charge may be discharged suddenly when you touch a conductor. If the conductor is connected to a sensitive electronic circuit, you may damage the components. It is also possible to reduce the life of components without causing any obvious damage. To prevent ESD damage, it is necessary to follow these guidelines. 1. Prepare work area. Place an ESD protective mat on the bench, strapped to the protective earth circuit. 2. Prepare yourself. Put on an ESD protective wrist band, strapped to the protective earth circuit, or to the ESD protective mat. 3. Keep all PCBs removed from unit in ESD protective bags. 4. Keep all replacement electronic components, PCBs and stock items in ESD protective bags or boxes. 5. Be particularly careful with components marked with the following symbol: 1.3 Soldering How to de-solder components Components should be removed, wherever possible, using a de-soldering tool. Be careful not to damage tracks and pads by applying too much pressure. How to make good solder joints 1. Ensure surfaces are clean. 2. Keep soldering iron clean and wetted with solder. Use an appropriate bit. Do not leave soldering iron on when not in use.

2 1.0 safety and servicing notes 3. Apply soldering iron to both component lead and pad before applying solder. Make sure that the soldering iron is applied long enough for the solder to wet properly, but do not apply for too long or component damage may occur. 4. Allow a small gap between component body and pad. Solder must not reach the base of the component. How to detect acceptable joints 1. Solder joints should have from a shiny to satin lustre and a generally smooth appearance. 2. Solder should have wetted both the component lead and pad. 3. There should be a concave meniscus between the objects being soldered. The angle of solder to pad should be less than 90° unless the solder joint extends over the edge of the pad. 4. Solder should fill the component pad and wet component lead around the full circumference (360°). How to detect unacceptable joints 1. Poor wetting produces a bead of solder. The fillet will be convex instead of concave, and there will not be a feather edge. 2. On double-sided PCBs, solder should wet all round plated-through hole, on both sides of the PCB. Cleaning up after soldering 1. Flux is very corrosive. Remove with IPA (propan-2-ol) before completing the job. 2. Remove any solder balls and splashes from the unit. 3. Check all new solder joints and ensure all PCBs are clean before replacing covers. 4. After replacing covers, clean the case and any display windows with a damp cloth. Do not use any organic solvents. If scratched, replace display windows. Trim Line

6 4.0 functional tests These notes are provided to assist you in servicing the amplifier. The circuit schematics are marked with typical voltage levels, which may assist in defining the cause of any problem. 4.1 Test equipment required Equipment Digital Multimeter Dual Tracking DC Power Supply Various Leads Specification Accuracy better than 0.5% in V and mV ranges Output: ±32 V DC 2 A Positive terminal of negative supply must be connected to negative terminal of the positive supply unless internally linked V mA V mA -ve +ve Select Tracking 0 V +32 V -32 V Black = -ve Red = +ve Green = 0 V -ve +ve Figure 4.1 - Functional test set-up for left channel

7 4.0 functional tests V mA V mA -ve +ve Select Tracking 0 V +32 V -32 V Black = -ve Red = +ve Green = 0 V -ve +ve Figure 4.2 - Functional test set-up for right channel No 4.2.1. 4.2.2. 4.2.3. 4.2.4. Action Disconnect all cables from amplifier Check voltage setting Check fuse type Check fuse resistance Test Equipment Multimeter set to W Details Read ratings label on rear of amplifier. Open fuse holder in power socket on rear panel. Rated supply Fuse Type 230 V AC T4.0A L250V 115 V AC T5.0A 125V 100 V AC T6.3A 125V Fuse and spare fuse should be low resistance. 4.2 Functional test procedure For test point (TP) references, see section 6.0 Test Points.

8 4.0 functional tests 4.2 Functional test procedure For test point (TP) references, see section 6.0 Test Points. No 4.2.5. 4.2.6. 4.2.7. 4.2.8. 4.2.9. 4.2.10. 4.2.11. Action Set up power supply Remove cover Connect supplies to left channel as shown in Figure 4.1 Apply DC voltage to amplifier left channel Measure left channel supply rails Measure amplifier left channel offset Measure offset of left channel protection circuit Test Equipment Dual tracking DC power supply Dual tracking DC power supply Dual tracking DC power supply Multimeter set to V DC Multimeter set to mV DC Multimeter set to mV DC Details Set output voltage to ±32 V, current limited to 500 mA. With supplies off, connect • positive output of supply to positive terminal of positive rail capacitor • negative output of supply to negative terminal of negative rail capacitor • common (0 V) output of supply to common connection between two capacitors CAUTION: Do not connect with the wrong polarity. Check output of supplies is ±32 V and switch output on. Current output of each supply (+ve and -ve) should be <100 mA. If higher, turn RV101 (TP 9) and RV201 (TP 10) fully anticlockwise. Continue with test procedure if current output of each supply is 40 mA ±5 mA. If not, switch off and investigate. Measure voltage across D110 (TP 1+ and TP 1-) and D111 (TP 2+ and TP 2-) . Voltage should be 32 V ±0.25 V. Connect negative probe to 0 V (TP 0). Connect positive probe to R149 (TP 5) . Voltage should be <5 mV. Connect positive probe to junction of Q105 and R158 (TP 7). Voltage should be <5 mV.

9 4.0 functional tests No 4.2.12. 4.2.13. 4.2.14. 4.2.15. 4.2.16. 4.2.17. 4.2.18. Action Connect supplies to right channel as shown in Figure 4.2 Apply DC voltage to amplifier right channel Measure right channel supply rails Measure amplifier right channel offset Measure offset of right channel protection circuit Disconnect DC power supplies Fix any faults Test Equipment Dual tracking DC power supply Dual tracking DC power supply Multimeter set to V DC Multimeter set to mV DC Multimeter set to mV DC Details With supplies off, connect • positive output of supply to positive terminal of positive rail capacitor • negative output of supply to negative terminal of negative rail capacitor • common (0 V) output of supply to common connection between two capacitors CAUTION: Do not connect with the wrong polarity. Check output of supplies is ±32 V and switch output on. Current output of each supply (+ve and -ve) should be <100 mA. If higher, turn RV101 (TP 9) and RV201 (TP 10) fully anticlockwise. Continue with test procedure if current output of each supply is 40 mA ±5 mA. If not, switch off and investigate. Measure voltage across D210 (TP 3+ and TP 3-) and D211 (TP 4+ and TP 4-) . Voltage should be 32 V ±0.25 V. Connect negative probe to 0 V (TP 0). Connect positive probe to R249 (TP 6) . Voltage should be <5 mV. Connect positive probe to junction of Q205 and R258 (TP 8). Voltage should be <5 mV. If any faults have been detected, repair and return to the beginning of this test procedure. 4.2 Functional test procedure For test point (TP) references, see section 6.0 Test Points.

Audiolab 8000AV Original Service Manual in

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