Use the product only as specified. Review the following safety precautions to avoid injury and prevent damage to this product or any products connected to it. Carefully read all instructions. Retain these instructions for future reference.

This product shall be used in accordance with local and national codes.

For correct and safe operation of the product, it is essential that you follow generally accepted safety procedures in addition to the safety precautions specified in this manual.

The product is designed to be used by trained personnel only.

Only qualified personnel who are aware of the hazards involved should remove the cover for repair, maintenance, or adjustment.

Before use, always check the product with a known source to be sure it is operating correctly.

This product is not intended for detection of hazardous voltages.

Use personal protective equipment to prevent shock and arc blast injury where hazardous live conductors are exposed.

While using this product, you may need to access other parts of a larger system. Read the safety sections of the other component manuals for warnings and cautions related to operating the system.

When incorporating this equipment into a system, the safety of that system is the responsibility of the assembler of the system.

Before connecting probes or test leads, connect the power cord from the power connector to a properly grounded power outlet.

Keep fingers behind the protective barrier, protective finger guard, or tactile indicator on the probes. Remove all probes, test leads and accessories that are not in use.

Use only correct Measurement Category (CAT), voltage, temperature, altitude, and amperage rated probes, test leads, and adapters for any measurement.

Beware of high voltages

Understand the voltage ratings for the probe you are using and do not exceed those ratings. Two ratings are important to know and understand:

• The maximum measurement voltage from the probe tip to the probe reference lead.
• The maximum floating voltage from the probe reference lead to earth ground.

These two voltage ratings depend on the probe and your application. Refer to the Specifications section of the manual for more information.

WARNING:To prevent electrical shock, do not exceed the maximum measurement or maximum floating voltage for the oscilloscope input BNC connector, probe tip, or probe reference lead.

The Service safety summary section contains additional information required to safely perform service on the product. Only qualified personnel should perform service procedures. Read this Service safety summary and the General safety summary before performing any service procedures.

These terms may appear in this manual:

WARNING:Warning statements identify conditions or practices that could result in injury or loss of life.

CAUTION:Caution statements identify conditions or practices that could result in damage to this product or other property.

These terms may appear on the product:

• DANGER indicates an injury hazard immediately accessible as you read the marking.
• WARNING indicates an injury hazard not immediately accessible as you read the marking.
• CAUTION indicates a hazard to property including the product.

When this symbol is marked on the product, be sure to consult the manual to find out the nature of the potential hazards and any actions which have to be taken to avoid them. (This symbol may also be used to refer the user to ratings in the manual.)

The following symbols(s) may appear on the product.

CAUTION: Refer to Manual

Protective Ground (Earth) Terminal

Chassis Ground

Standby

Functional Earth Terminal

This manual contains information that is necessary to service the MSO44 and MSO46 instruments.

Check for a specific product designation in the header at the top of the page, in a heading, table or figure title, or within text. Material that does not have any specific product designation applies to all products in the manual.

For information on installing, operating, and networking the instrument, refer to the online help or user manual that was provided with your oscilloscope. You can also find the manual at tek.com, by searching for your product.

The Power Supply board converts AC line voltage to +12 V to power for all internal circuits.

The processor board contains the following functions:

Processor system

The processor system contains a microprocessor that controls the entire instrument. The processor system also contains the flash memory for the operating system, system RAM, and interfaces to I/O ports and the acquisition system.

Rear panel I/O ports

The processor board contains USB ports, an Ethernet port (LAN), a HDMI Video port, the USB-TMC port, an AUX OUT BNC connector, an EXT REF IN BNC connector, and the AFG Out generator BNC connector.

Other functions

The processor board also houses the AFG generator, USB-TMC controller and USB host hub.

The Main board contain the following functions:

Acquisition system

The Acquisition system begins with the analog signal path and ends with a digitized signal in memory. The signal enters a channel input, and then passes through an attenuator and preamplifier. The analog signal from each preamplifier goes through a digitizer, and then into acquisition memory. The analog signal from each preamplifier is also distributed to a trigger circuit.

Analog Front-end

All of the analog and digital inputs are routed to the analog Front-end circuitry. The analog channels are amplified and attenuated through the front-end circuitry, and are output to the acquisition ASICs. The digital channels simply pass through the front-end circuitry to the acquisition ASICs.

Power converter

The Carrier interface assembly converts the +12 V power to all voltages used for the analog and digital circuitry throughout the system. Standby power is used to keep portions of the system powered at all times that AC power is connected to the instrument.

Other functions

The Main board interfaces to the Power supply and various cooling fans.

The Front Panel board contains digital logic that reads the front-panel buttons and controls and sends this information to the processor system on the Processor board. The Front Panel board also generates the probe compensation output signal, provides USB ports on the front panel and houses the main power switch. The front panel routes the digital front-end signals from the probe directly to the main board.

Before servicing this product, read the General Safety Summary and the Service Safety Summary at the front of the manual, as well as the following ESD information.

CAUTION:Electrostatic discharge (ESD) can damage any semiconductor component in this instrument.

When performing any service that requires internal access to the instrument, adhere to the following precautions to avoid damaging internal modules and their components due to electrostatic discharge:

1. Minimize handling of static-sensitive circuit boards and components.
2. Transport and store static-sensitive modules in their static protected containers or on a metal rail. Label any package that contains static-sensitive boards.
3. Discharge the static voltage from your body by wearing a grounded antistatic wrist strap while handling these modules.
4. Service static-sensitive modules only at a static-free work station.
5. Do not allow any items capable of generating or holding a static charge on the work station surface.
6. Handle circuit boards by the edges when possible.
7. Do not slide the circuit boards over any surface.
8. Avoid handling circuit boards in areas that have a floor or work-surface covering capable of generating a static charge.

Adjustment and calibration must be performed by a Tektronix Service Center.

Go to tek.com to find information on contacting Tektronix Service Support.

This section describes how to inspect for dirt and damage. It also describes how to clean the exterior and interior of the instrument.

Inspection and cleaning are done as preventive maintenance. Preventive maintenance, when done regularly, may prevent instrument malfunction and enhance its reliability.

Preventive maintenance consists of visually inspecting and cleaning the instrument and using general care when operating it.

How often to perform maintenance depends on the severity of the environment in which the instrument is used. A proper time to perform preventive maintenance is just before instrument adjustment.

This section contains procedures for removal and installation of replaceable modules in the instrument. Refer to the Replaceable parts section for lists and exploded views of replaceable modules.

Any module inside of the chassis that does not have a remove and replace procedure requires that the entire instrument be returned to Tektronix Service Center for service.

WARNING:Before performing this or any other procedure in this manual, read the safety summaries found at the beginning of this manual. Also, to prevent possible injury to service personnel or damage to the instrument components, read Preventing ESD. Before performing any procedure in this subsection, disconnect the power cord from the line voltage source. Failure to do so could cause serious injury or death.

Note:Read the cleaning procedure before disassembling the instrument for cleaning.

This section contains information and procedures designed to help you isolate faults to a module.

CAUTION:Before performing this or any other procedure in this manual, read the General Safety Summary and Service Safety Summary found at the beginning of this manual. To prevent possible injury to service personnel or damage to electrical components, please read information on Preventing ESD.

This section requires that service personnel have the appropriate skills to work on this instrument, including PC troubleshooting and Microsoft Windows operating system skills. Details of PC and Windows operation and service are not in this manual.

For assistance, contact your local Tektronix Service Center.