Classe Audio CAP-80 User manual

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Date: August 22, 2007
Model Number: CAP-80 / CAP-101
Classé Audio Inc. Subject: Service manual
Classé Audio, Inc. 5070 François Cusson Lachine, Québec Canada H8T1B3, www.classeaudio.com

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Table of Contents
Introduction 3
Important Notes on Servicing 3
Ordering Replacement Parts 3
Block Diagrams 4
Start up Procedure 5
Protection Modes and Indicators 6
Troubleshooting Guide 7
Output Transistors Testing and Replacement 8
Calibrations and Adjustments 9
Parts List 10
Updates 11
Fuses 12
Voltage Change 13
IR Interface Information 14
Schematics 15

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Introduction
Please read this manual carefully before commencing servicing!
Only qualified and authorized personnel should attempt to service this product.
The lightning flash with arrowhead symbol, within an equilateral triangle, is intended
to alert the user to the presence of uninsulated dangerous voltage within the
product’s enclosure that may be of sufficient magnitude to constitute a risk of electric
shock to persons.
The exclamation point within an equilateral triangle is intended to alert the user to
the presence of important operating and maintenance (servicing) instructions.
Classé has a global product support network. For product assistance or to order replacement parts please
contact your nearest service center always quoting the unit serial number.
North America
Phone: [phone] E-mail: [email protected]
Europe
Phone: [phone] E-mail: [email protected]
Asia
Phone: [phone] E-mail: [email protected]
Rest of the World
Phone: [phone] E-mail: [email protected]
Important Notes on Servicing
1. ALWAYS observe ESD precautions when handling electronic modules or PCBAs.
2. NEVER exchange boards with a different revision number, unless authorized by Classé.
3. ALWAYS use Classé original replacement parts. The use of generic parts may void the warranty of
the unit.
Ordering Replacement Parts
There may be a delay in processing incomplete requests. Please be sure to include all required information.
Remember to quote the serial number of the unit on all replacement part orders and the Classé order number
when returning defective parts for credit.

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Block diagrams

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Start Up Procedure
When receiving a unit, an assiduous visual inspection must be performed. Do not connect the unit without
analysing the symptoms reported by the customer and the results of the inspection.
Using the troubleshooting guide, find the problem and proceed to the repair. Once this step is done, follow
these steps, known as the start-up procedure, to ensure that everything in the unit is in working condition.
1. Proceed with a post repair visual inspection. Take the time to check if every wire is reconnected
properly, every screw is bolted on, no soldering and/or metal residues lying in the unit, every fuse has
been replaced, etc.
2. Turn the bias trimpots, counter clockwise until a click is heard.
3. Since there is no soft-start sequence of the CAP-80 / CAP-101, it is impossible to use a bypass to
perform a slow start up.
4. Connect Main supply, and turn on the unit.
5. If one or more supply are not within specifications, return to the troubleshooting guide.
6. If every supply is within specifications, report to calibration and adjusments to adjust bias and DC
offset. Note that bias can be adjusted to 14mV, and the following tests can be performed before the
unit is send to the burn-in bench for a 24 hours warm-up.
7. Connect the unit to a load, and to a source using single ended inputs.
8. Perform a test with a 200Hz, a 2kHz and a 20kHz tone, both sinus wave and square wave. Check the
output with a oscilloscope, on 4 ohms and 8 ohms loads. Take special cares about oscillation and phase
correlation between channels.
9. Connect the unit to a small speaker, and short the input. Check for any noise.
10. Put the unit on a burn-in bench, and let it sit for 24 hours, then readjust bias. Let the unit on the burn-
in bench for another 72 hours.
11. Redo steps 7 to 11 before shipping to the customer.

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Protection Modes and Indicators
The front LED display shows the status of the amplifier. When starting up normally, the CAP80 / CAP101 will
show a countdown from 20 to 0. However, there is no protection on the CAP80 / CAP101. The CAP80 /
CAP101 is equipped with four rail protection fuses. In the event that one or more of these fuses would blow,
the technician will first need to identify and cure the cause of failure (please report to troubleshooting guide).
When the cause has been identified, disconnect the unit from the system including the AC power. Remove the
top cover and look for damaged or burned components. If no other components than the fuses appear to be
damaged, the technician can then replace the broken fuses with the same value and rating (please report to
fuses section). The rail fuses are located on the main board. When replacing fuses, please make sure that the
fuse holder are holding the fuses very tightly. A loose fuse holder can translate into distortion on top of the
signal.

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Troubleshooting Guide
Symptom Possible cause
Unit won’t turn on Check connections;
Check fuses;
Check soft-start circuit;
Check relays;
Check power supply circuits (positive rail, negative rail, Mosfet
supply).
Smoked and/or burned
components
Check for short between components and ground;
Check output transistors;
Check output relays;
Check power supply circuits (positive rail, negative rail, Mosfet
supply).
Blown fuses Check for short between fuse and ground;
Check power supply circuits (positive rail, negative rail, Mosfet
supply).
No output 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;
Check power supply circuits (positive rail, negative rail, Mosfet
supply);
Check source and load;
Check protection circuit;
Check sensor wires between sensor PCB and control PCB;
Check outputs transistors and Mosfet drivers.
Excessive buzz and/or hum Check electrical lines;
Check for a ground loop in the system.
Oscillation Check source;
Check capacitors on main board;
Check 4.7ƻresistor.
Intermittent signal Check connections;
Replace shield wires.

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Output Transistors Testing and Replacement
PLEASE NOTE THAT THESE TESTS ARE ONLY EFFECTIVE ON BIPOLAR TRANSISTORS.
DO NOT PERFORM THESE TESTS ON MOSFET DEVICES, AS THEY ARE LIKELY TO
BECOME SHORT DURING THE TEST.
You should check all pin combinaisons, as there is a chance that only one side of the transistor is short. When
replacing outputs transistors, the technician should first disconnect both outputs and main board to check if
the blown outputs were caused by a faulty component on the amplifier’s base. 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 replace positive and negative Mosfet drivers and bias
transistor. Carefully inspect 4.7ƻresistor and 10ƻsoft start resistor, and replace if necessary. Replace any
burnt component or board.
Pins : 1 Base
2 Collector
3 Emitter
You should have these results, if the transistor is good.
2SC3263 (NPN)
Positive lead Negative lead Result
B C Conductive
B E Conductive
C B Infinite
C E Infinite
E B Infinite
E C Infinite
2SA1294 (PNP)
Positive lead Negative lead Result
B C Infinite
B E Infinite
C B Conductive
C E Infinite
E B Conductive
E C Infinite

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Calibrations and Adjustments
Bias adjustment:
Note: Bias adjustment should be made without any load connected to the amplifier’s output, and no signal
connected to the amplifier’s input.
1. Since it is impossible to connect a multimeter to both emitter’s resistors in order to measure and adjust
bias without disassembling the heatsink from the chassis, we provided a test point to ease the bias
procedure. It is located near the bias trimpot.
2. Connect the positive probe of a millivoltmeter to the test point and the negative probe to the positive
speaker post of the channel to be adjusted.
3. Turn trimpots counterclockwise until it reaches 0ƻ. A click should be heard.
4. Turn on amplifier, and let it warm up for 15 minutes on idle.
5. Adjust trimpot to get a 14mV reading.
6. Let the amplifier warm up for a 24 hours period with signal and load.
7. Remove signal and load, and reconnect the multimeter.
8. Readjust to 20mV.
DC offset:
Note: DC offset adjustment should be made without any load connected to the amplifier’s output, and no
signal connected to the amplifier’s input.
On these units, DC offset can’t be adjusted. Measure DC offset using a voltmeter connected to the output
posts, scale setted to mV. DC offset should be less than 10mV.

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Parts List
This is not a detailed part list. It is a list of major chassis parts and PCBs. If you need to order a specific part,
please contact Classe Audio with the part location, PCB number, and model and serial number of the unit.
If you need a complete PCB, please replace the (x) in the Classe part number with the revision number printed
on the board.
Parts Description Classe part number
B151X Complete PCB, input B151XR(x)
B152X Complete PCB, supply B152XR(x)
B153X Complete PCB, display B153XR(x)
B154X Complete PCB, main B154XR(x)