Classe Audio CAM-350 Service manual

Classé Audio Inc.

Date:

Model Number:

Subject:

August 16, 2007

CAM-350

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 12

IR Interface Information 13

Schematics 14

The contents of this document as well as the files associated with it contain confidential information that is proprietary to Classé Audio

Incorporated and are intended solely for the purpose of servicing product. No part of its contents may be used, copied, disclosed, or conveyed to any party in any manner whatsoever without prior written permission from Classé Audio Incorporated.

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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: (978) 664-2870 E-mail: [email protected]

Europe

Phone: 44 (0) 1903 221 700 E-mail: [email protected]

Asia

Phone: (852) 2790 8903 E-mail: [email protected]

Rest of the World

Phone: (514) 636-6384 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. Connect the unit to a variable transformer, setted to 0Vac.

3. Turn the bias trimpot (RV1) counter clockwise until a click is heard.

4. Connect the bypass wire to the variable transformer. This bypass is a power cord, modified on the female side in order to bypass the soft start sequence. It is connected to the line tab on voltage selector PCB.

5. Slowly raise the voltage to 10Vac, and check positive and negative rails and pre-driver supply. Check fuses.

6. If one or more supply are not within specifications, return to the troubleshooting guide.

7. Slowly raise voltage until you hear relays click, this point is around 55Vac. Recheck every supply.

8. If one or more supply are not within specifications, return to the troubleshooting guide.

9. Raise voltage to 120Vac. Recheck every supply

10. If every supply is within specifications, unplug the unit and bypass from the variable transformer.

Reconnect only the unit.

11. 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.

12. Connect the unit to a load, and to a source using balanced inputs and single ended inputs, independently.

13. 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.

14. Connect the unit to a small speaker, and short the input. Check for any noise. Perform this step with single ended inputs and balanced inputs, independently.

15. Put the unit on a burn-in bench, and let it sit for 24 hours, then readjust bias. Let the unit on the burnin bench for another 72 hours.

16. Redo steps 11 to 14 before shipping to the customer.

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Protection Modes and Indicators

The front LED shows the status of the amplifier. When starting up normally, the CAM350 will show a

FLASHING RED LED for about 15 seconds and if all is normal, the LED will go SOLID RED. If there is a fault, the LED will go to a FLASHING GREEN LED. The CAM350 is equipped with four Mosfet 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 Mosfet fuses are located on the control 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

Unit won’t turn on

Smoked and/or burned components

Blown fuses

No output

Unit turn into protection

Excessive buzz and/or hum

Intermittent signal

Check connections;

Check fuses;

Check soft-start circuit;

Check relays;

Check power supply circuits (positive rail, negative rail, Mosfet supply).

Check for short between components and ground;

Check output transistors;

Check output relays;

Check power supply circuits (positive rail, negative rail, Mosfet supply).

Check for short between fuse and ground;

Check power supply circuits (positive rail, negative rail, Mosfet supply).

Check connexions;

Check output relays;

Check power supply circuits (positive rail, negative rail, Mosfet supply);

Check output transistors.

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.

Check electrical lines;

Check for a ground loop in the system.

Check capacitors on main board;

Check 4.7ƻ resistor.

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 4.7ƻ resistor and 10ƻ soft start resistor, and replace if necessary. Replace any burnt component or board.

Pins : 1 Base

You should have these results, if the transistor is good.

2SC3264 (NPN)

Positive lead Negative lead Result

C B Infinite

C E Infinite

E B Infinite

E C Infinite

2SA1295 (PNP)

Positive lead Negative lead Result

B C Infinite

B E Infinite

C E Infinite

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. On positive heatsink, connect a multimeter to R111 leads and set the multimeter to mV scale.

2. Turn trimpot R104 counterclockwise until it reaches 0ƻ. A click should be heard.

3. Turn on amplifier, and let it warm up for 15 minutes on idle.

4. Adjust trimpot R104 to get a 10mV reading.

5. Repeat procedure with negative heatsink.

6. Let the amplifier warm up for a 24 hours period with signal and load.

7. Remove signal and load, and reconnect the multimeter, setted to mV scale, to R112 leads.

8. Readjust R104 to get a 12mV reading.

9. Repeat procedure with negative heatsink.

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 number

B1DAX Complete PCB, power switch B1DAXR(x)

B1D1X

B02AX

Complete PCB, heatsink

Complete PCB, amplifier

B1D1XR(x)

B02AXR(x)

B1B3XR(x)

B1B1XR(x)

B016XR(x) B016X

B258X

B019X

B01GX

B1B2X

Complete PCB, AC

Complete PCB, input

Complete PCB, sensor

Complete PCB, filter

Complete PCB, supply

B258XR(x)

B019XR(x)

B01GXR(x)

B1B2XR(x)

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Updates

1. On board B1D1X (both PCBs), replace R104 with Classe part number 3299X-1-202.

2. On board B1D1X (both PCBs), replace D101 and D103 with Classe part number 1N5333B.

3. On board B1B3X, replace P011XR02 to 040AR3, and drop rail voltage sensor from 500mV to 250mV.

4. Add a jumper from GND post on B1B1X PCB to relay GND on B1B3X PCB.

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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: 10A slo-blo, Classe part number MDA-10A

For 220 – 240v units: 4A slo-blo, Classe part number MD

The main fuse is located at the back of the unit, on the rear panel.

Control board fuse: 0.50A, Classe part number 225.500

The control board fuse is located on top of the supply board (B1B2X)

Mosfet fuses: 0.75A, Classe part number 225.750

The Mosfet fuses are located on top of the supply board (B1B2X)

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.

1. Set the primary wires of the main transformer as described below.

2. Replace the varistor, according to new line voltage, following Classe’s recommendations. If varistor is not available, remove old varistor and leave it empty.

3. Set the jumpers accordingly on the auxiliary transformer located at the back of the unit on the top main board on the left-hand side of the auxiliary transformer (see tables below)

Primary wires, main transformer

100VAC Grey Yellow

120VAC Blue Black

Blue

Grey

Black

Yellow

Orange

Orange

White -

White - or

- 130

- 130

220VAC - Yellow Grey Black - White Orange 250

240VAC - Black Yellow - White Orange 250

Mains Position 1

Jumpers, auxiliary transformer

Position 2 Position 3 Position 4 Position 5

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IR Interface Information

Press and hold: AMP +

AMP +

AMP +

AMP +

AMP +

AMP +

LINE 1 =

LINE 2 =

LINE 3 =

BAL 1 =

BAL 2 =

BAL 3 =

Turns on Amplifier # 1

Turns on Amplifier # 2

Turns on Amplifier # 3

Turns on Amplifier # 4

Turns on Amplifier # 5

Turns on Amplifier # 6

J3 J2 J1 J0 ADDRESS

X X X X 0

X X X Out 1

X X Out X 2

X X Out 3

X Out X X 4

X Out X Out 5

X Out Out X 0

X Out Ot Out

Out X X X

0

0

Out X X Out 1

Out X Out X 2

Out X Out Out 3

Out Out X X 4

Out Out X Out

Out Out Out X

Out Out Out Out

5

0

0

RC Button Auto ON Note

Amp1 No QC

Amp2 No

Amp3 No

Amp4 No

Amp5 No

Amp6

Amp1

Amp1

DC

DC

DC

DC

DC

DC

DC

DC

No

No

Yes

No

No

No

No

No

No

No

Yes

On with AC

On with AC

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