Fuses; Voltage Change - Classe Audio DR-8 Service Manual

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.
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