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PRO-SVR_LEGACY    

 

 

Page 10 of 11 

Fuses

EXTRA PRECAUTIONS SHOULD BE TAKEN WHEN REPAIRING, MODIFYING, OR
TROUBLESHOOTING IN THE POWER SUPPLY AREA. UNIT MUST BE DISCONNECT
FROM MAIN SOURCE AND CAPACITORS MUST BE DISCHARGED USING A 100W 
INCANDESCENT BULB. 

 WHEN REPLACING FUSES, PLEASE MAKE SURE THAT THE FUSE HOLDERS ARE 
HOLDING THE FUSES VERY TIGHTLY. A LOOSE FUSE HOLDER CAN TRANSLATE INTO 
DISTORTION ON TOP OF THE SIGNAL. 

Main fuses: 
For 100 – 120v units: 5A slo-blo, Classe part number MDL-5A 
For 220 – 240v units: 4A slo-blo, Classe part number MDL-4A 
The main fuse is located at the back of the unit, on the rear panel. 

Voltage Change

EXTRA PRECAUTIONS SHOULD BE TAKEN WHEN REPAIRING, MODIFYING, OR
TROUBLESHOOTING IN THE POWER SUPPLY AREA. UNIT MUST BE DISCONNECT
FROM MAIN SOURCE AND CAPACITORS MUST BE DISCHARGED USING A 100W 
INCANDESCENT BULB. 

To convert from 120VAC to 220 VAC. 

1. Remove ONE of the wires of group 1 going to the power switch (see fig. 1 for details). 
2. Cut group 2 and separate all the wires at the junction where they joined the single wire going to the 

AC receptacle at the rear of the amplifier. 

3. With an ohmmeter, test for continuity between one of the wires removed from group 1 and each wire 

of group 2. 

4. Cut off and insulate the wire of group 2 which is continuous with the wire of group 1. 
5. Test for continuity between the same wire of group 1 and both wires of group 3 or both wires of group 

4 (do not separate the wires of each group). 

6. Whichever group is continuous with the wire from group 1 should be joined to the wire going to the AC 

receptacle at the rear of the amplifier (formely attached to group 2) Solder and insulate carefully. 

7. Reinsulate the non-continuous group and leave it as it was. 
8. Join together the wires from group 1 (the same wires you first removed and have tested with) to the 

non-continuous wire of group 2 (previously tested). Solder and insulate carefully. 

9. Replace the power switch with a 250v one. 
10. Remove the varistor, and replace with a 250v one 
11. Test the amplifier with a autotransformer. 

Содержание DR-8

Страница 1: ...PRO SVR_LEGACY Page 1 of 11 Date August 27 2007 Model Number DR 8 Class Audio Inc Subject Service manual Class Audio Inc 5070 Fran ois Cusson Lachine Qu bec Canada H8T1B3 www classeaudio com...

Страница 2: ...ent 8 Calibrations and Adjustments 9 Fuses 10 Voltage Change 10 Schematics 12 The contents of this document as well as the files associated with it contain confidential information that is proprietary...

Страница 3: ...t parts please contact your nearest service center always quoting the unit serial number North America Phone 978 664 2870 E mail classe bwgroupusa com Europe Phone 44 0 1903 221 700 E mail classe bwgr...

Страница 4: ...PRO SVR_LEGACY Page 4 of 11 Block diagrams...

Страница 5: ...o the troubleshooting guide 6 Slowly raise voltage until you hear relays click this point is around 55Vac Recheck every supply 7 If one or more supply are not within specifications return to the troub...

Страница 6: ...to make sure the unit is OFF before manipulating the connections When a high DC offset is present at the output the protection circuit opens both output relays even if the condition is only present o...

Страница 7: ...Check connexions Check output relays Check power supply circuits positive rail negative rail Mosfet supply Check output transistors Unit turn into protection Check for smoked and or burned components...

Страница 8: ...e Blown output transistors should be replaced by kits not individually These kits contains matched transistors for both rails of one channel When replacing blown output transistors you must also repla...

Страница 9: ...ot R16 to get a 14mV reading 5 Let the amplifier warm up for a 24 hours period with signal and load 6 Remove signal and load and reconnect the multimeter setted to mV scale to one of the emitter resis...

Страница 10: ...power switch see fig 1 for details 2 Cut group 2 and separate all the wires at the junction where they joined the single wire going to the AC receptacle at the rear of the amplifier 3 With an ohmmete...

Страница 11: ...PRO SVR_LEGACY Page 11 of 11 Voltage Change Fig 1 120v AC wiring Fig 2 220v AC wiring...

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