Agilent Technologies 66000A User manual

SERVICE GUIDE
for Agilent 66000A
MPS Mainframe
Serial Numbers:
Agilent Model 66000A: 3522A01561 thru 03295
US35220101 and up
Agilent Part No. 66000-90003 Printed in USA
Microfiche Part No. 66000-90004 Update: June, 2000

2
CERTIFICATION
Agilent Technologies certifies that this product met its published specifications at time of shipment from the factory. Agilent
Technologies further certifies that its calibration measurements are traceable to the United States National Bureau of
Standards, to the extent allowed by the Bureau's calibration facility, and to the calibration facilities of other International
Standards Organization members.
WARRANTY
This Agilent Technologies hardware product is warranted against defects in material and workmanship for a period of three
years from date of delivery. Agilent Technologies software and firmware products, which are designated by Agilent
Technologies for use with a hardware product and when properly installed on that hardware product, are warranted not to
fail to execute their programming instructions due to defects in material and workmanship for a period of 90 days from date
of delivery. During the warranty period Agilent Technologies will, at its option, either repair or replace products which
prove to be defective. Agilent Technologies does not warrant that the operation of the software, firmware, or hardware shall
be uninterrupted or error free.
For warranty service, with the exception of warranty options, this product must be returned to a service facility designated
by Agilent Technologies. Customer shall prepay shipping charges by (and shall pay all duty and taxes) for products
returned to Agilent Technologies for warranty service. Except for products returned to Customer from another country,
Agilent Technologies shall pay for return of products to Customer.
Warranty services outside the country of initial purchase are included in Agilent Technologies’ product price, only if
Customer pays Agilent Technologies international prices (defined as destination local currency price, or U.S. or Geneva
Export price).
If Agilent Technologies is unable, within a reasonable time to repair or replace any product to condition as warranted, the
Customer shall be entitled to a refund of the purchase price upon return of the product to Agilent Technologies.
LIMITATION OF WARRANTY
The foregoing warranty shall not apply to defects resulting from improper or inadequate maintenance by the Customer,
Customer-supplied software or interfacing, unauthorized modification or misuse, operation outside of the environmental
specifications for the product, or improper site preparation and maintenance. NO OTHER WARRANTY IS EXPRESSED
OR IMPLIED. AGILENT TECHNOLOGIES, INC. SPECIFICALLY DISCLAIMS THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
EXCLUSIVE REMEDIES
THE REMEDIES PROVIDED HEREIN ARE THE CUSTOMER'S SOLE AND EXCLUSIVE REMEDIES. AGILENT
TECHNOLOGIES SHALL NOT BE LIABLE FOR ANY DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR
CONSEQUENTIAL DAMAGES, WHETHER BASED ON CONTRACT, TORT, OR ANY OTHER LEGAL THEORY.
ASSISTANCE
The above statements apply only to the standard product warranty. Warranty options, extended support contracts, product
maintenance agreements and customer assistance agreements are also available. Contact your nearest Agilent
Technologies. Sales and Service office for further information on Agilent Technologies' full line of Support Programs.

3
SAFETY SUMMARY
The following general safety precautions must be observed during all phases of operation of this mainframe.
Failure to comply with these precautions or with specific warnings elsewhere in this guide violates safety
standards of design, manufacture, and intended use of the mainframe. Agilent Technologies assumes no liability
for the user's failure to comply with these requirements.
GROUND THE MAINFRAME.
This product is a Safety Class 1 instrument (provided with a protective earth terminal). To minimize shock hazard, the
mainframe must be connected to an electrical ground. The mainframe must be connected to the ac power supply mains
through a three-conductor power cable, with the third wire firmly connected to an electrical ground (safety ground) at the
power outlet. Any interruption of the protective (grounding) conductor or disconnection of the protective earth terminal will
cause a potential shock hazard that could result in personal injury.
DO NOT EXCEED INPUT RATINGS.
This mainframe is equipped with a power line filter to reduce electromagnetic interference and must be connected to a
properly grounded receptacle to minimize electric shock hazard. Operation at line voltages or frequencies in excess of those
stated on the line rating label may cause leakage currents in excess of 5.0 mA peak.
DO NOT OPERATE IN AN EXPLOSIVE ATMOSPHERE.
Do not operate the mainframe in the presence of flammable gases or fumes.
BEFORE APPLYING POWER.
Verify that the power cord is correctly connected to the mainframe.
SAFETY SYMBOLS.
Instruction manual symbol: the product will be marked with this symbol when it is necessary for the user to
refer to the instruction manual (refer to Table of Contents) .
Indicates hazardous voltages.
Indicate earth (ground) terminal.
The WARNING sign denotes a hazard. It calls attention to a procedure, practice, or the like, which, if not
correctly performed or adhered to, could result in personal injury. Do not proceed beyond a WARNING
sign until the indicated conditions are fully understood and met.
The CAUTION sign denotes a hazard. It calls attention to an operating procedure, or the like, which, if
not correctly performed or adhered to, could result in damage to or destruction of part or all of the
product. Do not proceed beyond a CAUTION sign until the indicated conditions are fully understood and
met.
Mainframes that appear damaged or defective should be made inoperative and secured against unintended operation until
they can be repaired by qualified service personnel.
.

4
Printing History
The current edition of this guide is indicated below. Reprints of this guide containing minor corrections and updates may
have the same printing date. New editions are identified by a new printing date and, in some cases, by a new part number.
A new edition incorporates all new or corrected material since the previous edition. Changes to the guide occurring
between editions are covered by change sheets shipped with this guide. Also, if the serial number prefix of your mainframe
is higher than those listed on the title page of this guide, then it may or may not include a change sheet. That is because
even though the higher serial prefix indicates a design change, that change may not affect the content of the guide.
Edition 1 . . . November, 1992
Updated June, 2000
Copyright 1992, 2000 Agilent Technologies, Inc.
This document contains proprietary information protected by copyright. All rights are reserved. No part of this document
may be photocopied, reproduced, or translated into another language without prior consent of Agilent Technologies. The
information contained in this document is subject to change without notice.

5
Table of Contents
Overview..................................................................................................................................................................................7
About This Manual...............................................................................................................................................................7
Related Documents...........................................................................................................................................................8
Revisions and Updates..........................................................................................................................................................8
Manual..............................................................................................................................................................................8
Firmware...........................................................................................................................................................................8
Safety Considerations ...........................................................................................................................................................8
Electrostatic Discharge .........................................................................................................................................................9
Service Tools and Equipment...............................................................................................................................................9
Verification............................................................................................................................................................................11
Preliminary Checkout .........................................................................................................................................................11
POWER-ON Checkout.......................................................................................................................................................12
Selftest Sequence............................................................................................................................................................12
In Case of Trouble..........................................................................................................................................................12
Output Checkout.................................................................................................................................................................14
In Case of Trouble..........................................................................................................................................................14
Problem Not Identified .......................................................................................................................................................14
Disassembly ...........................................................................................................................................................................15
Disassembly Procedures .....................................................................................................................................................15
Removing the Modules and Module Connectors............................................................................................................15
Removing the Cover .......................................................................................................................................................15
Removing the Front Frame .............................................................................................................................................15
Removing the Front Bezels and Keyboard Plug .............................................................................................................16
Removing the Rear Subchassis.......................................................................................................................................16
Removing the Pc Boards.................................................................................................................................................16
Reassembly Procedures ......................................................................................................................................................17
Installing the Pc Boards..................................................................................................................................................17
Assembling the Rear Subchassis.....................................................................................................................................18
Assembling the Keyboard Plug and Front Bezels...........................................................................................................18
Assembling the Front Frame...........................................................................................................................................18
Assembling the Cover.....................................................................................................................................................19
Troubleshooting....................................................................................................................................................................21
Troubleshooting Sequence..................................................................................................................................................21
Accessing the Flowcharts....................................................................................................................................................21
If You Experienced a Selftest Failure.............................................................................................................................21
If You Experienced Other Problems With the Mainframe..............................................................................................22
Troubleshooting Flowcharts ...............................................................................................................................................22
Replacement Parts................................................................................................................................................................33
Diagrams................................................................................................................................................................................39
Test Point and Component Location Diagram....................................................................................................................39
Main Board Schematics......................................................................................................................................................39
Sheet 1 Circuit Functions................................................................................................................................................39

6
Sheet 2 Circuit Functions................................................................................................................................................39
Sheet 3 Circuit Functions................................................................................................................................................40
Backplane Board Schematic...............................................................................................................................................40
Exploded View Diagram.....................................................................................................................................................40
Schematic Notes .................................................................................................................................................................41
Manual Backdating ..............................................................................................................................................................49
Index ......................................................................................................................................................................................51

Overview 7
1
Overview
About This Manual
This manual is a complete guide for servicing the Agilent 66000A Modular Power System (MPS) Mainframe.
Troubleshooting information for the Agilent 661xxA MPS Power Modules is provided in the module service manual (see
"Related Documents"), which should be used with this manual.
Note Troubleshooting the Agilent 66000A MPS Mainframe requires the use of one working Agilent 661xxA
MPS Power Module.
This manual is organized into the following major sections:
•Overview discusses safety and equipment considerations to be aware of when troubleshooting. It also lists the tools and
equipment required for troubleshooting.
•Verification consists of a series of tests that are used to help isolate a fault. It includes the selftest sequence that runs
automatically at power-on and verifies the integrity of the microprocessor, the GPIB and serial interfaces, and the
memory.
•Disassembly procedures are used to disassemble the instrument for repair.
•Troubleshooting procedures systematically verify selected circuits to isolate the cause of a problem. Suggestions for
remedying the problem are also provided. Troubleshooting procedures are provided for the following circuits:
§Bias Supplies.
§Microprocessor.
§RAM and ROM Memory.
§GPIB and Serial Interfaces.
§Discrete Fault Indicator/Remote Inhibit (DFI/RI) Circuitry.
§Trigger Circuits.
§Power Module Communication.
§Keyboard Accessory Port.
•Replacement Parts lists part numbers for electrical components and miscellaneous chassis parts.
•Schematics and component location diagrams are provided as an aid in troubleshooting and repair.

Overview
8
Related Documents
The following documents are related to this manual:
Manual
Part Number Description
Agilent 66000A MPS Mainframe Installation
Guide
66000-90001
Provides product specifications, installation, and connection information.
Agilent Series 661xxA MPS Power Modules
User's Guide
5959-3386
Describes the operation of the MPS Power Modules.
Agilent Series 661xxA MPS Power Modules
Programming Guide
5959-3362
Describes SCPI programming commands, status reporting.
Agilent Series 661xxA MPS Power Modules
Service Manual
5959-3364
Provides replaceable-parts lists, circuit diagrams, and verification procedures for the
Agilent Series 661xxA MPS Power Modules.
Revisions and Updates
Manual
Agilent Technologies instruments are identified by a two-part, ten-character serial number, such as 3138A-00101. The first
five characters (e.g. 3138A) are the serial prefix, which is the same for all identically made instruments. The last five digits
(e.g. 00101) are a unique serial number assigned to each instrument. If a significant design change is made, the prefix
changes but the last five numbers continue in sequence.
This manual applies to Agilent 66000A MPS Mainframes with the same serial prefixes and serial numbers equal to or
higher than the ones shown on the title page. If the prefix number on your mainframe is higher than the one on the title page,
then the mainframe was made after publication of the manual and may have hardware and/or firmware differences not
covered in the manual. If there are such differences, they are documented in one or more "Manual Changes" sheets sent with
the manual.
Firmware
This manual applies to mainframes that run on software revisions A.00.01 through A.00.05. The mainframe ROM chip has a
label that specifies the firmware revision.
Safety Considerations
The Agilent 66000A MPS Mainframe is a Safety Class 1 instrument that has a protective earth terminal. Refer to the Safety
Summary page at the beginning of this manual for general safety procedures and the meaning of safety symbols appearing in
the manual and on the mainframe.

Overview 9
Electrostatic Discharge
The Modular Power System has components that can be damaged by ESD (electrostatic discharge).
Failure to observe standard anti-static practices can result in serious degradation of performance even
when complete failure does not occur.
When working on the Modular Power System, observe all anti-static work practices. This includes, but is not limited to:
•Working at a static-free station, such as a table covered with static-dissipative laminate or with a conductive table mat
(Agilent P/N 9300-0797).
•Using a conductive wrist strap (Agilent P/N 9300-0969 or 9300-0970).
•Grounding all metal equipment at the station to a single, common ground.
•Connecting low-impedance test equipment to static sensitive components only when those components have power
applied to them.
•Removing power from the Modular Power System before removing or installing printed circuit boards.
Service Tools and Equipment
The following tools are required to repair the Agilent 66000A MPS Mainframe:
•T15 and T25 TORX drivers.
•10mm and 7mm HEX NUT drivers.
•#2 POZI driver.
•Slot-head screwdrivers - small and medium.
•DIP component removal tool.
•Soldering iron and solder.
•De-solder removal tool.
•Needle-nose pliers.
•Anti-static work mat and wrist strap.
The following equipment is required to troubleshoot the Agilent 66000A MPS Mainframe:
Table 1-1. Service Test Equipment
Instrument Required Critical Specifications Recommended Model Use1
Power Cords (see Figure 1-1) Option #831 P/N 8120-5573 V,T
Option #833 P/N 8120-5568
Option #834 P/N 8120-5566
Option #841 P/N 8120-5572
Option #843 P/N 8120-5571
Option #845 P/N 8120-5570
Option #846 P/N 8120-5565
Option #847 P/N 8120-5567
Option #848 P/N 8120-5569
Test Cable BNC (male) to BNC (male) P/N 8120-1838 V,T
Mini-Grapper clip leads Wire Size: 24 AWG P/N 8120-3326 or 8120-3327 V,T
DFI RI connector Type: Terminal Block 4-pos.
(supplied with mainframe) P/N 1252-1488 V,T

Overview
10
Table 1-1. Service Test Equipment (continued)
Instrument Required Critical Specifications Recommended Model Use1
MPS Power Module Agilent 661xxA Series V,T
DMM Agilent 34401A or equivalent T
Logic Probe Agilent 545A or equivalent T
Oscilloscope Bandwidth: 100 MHz Agilent 54504A or equivalent T
MPS Keyboard2Agilent 66001A V
Isolation transformer T
1 V = Verification; T = Troubleshooting.
2 Use of the keyboard is recommended for displaying selftest error messages.
Figure 1-1. Power Cords

Verification 11
2
Verification
Operation verification of the Agilent 66000A MPS Mainframe consists of performing the procedure that is located in this
section. This procedure verifies that the mainframe is performing properly without testing all specified parameters. The tests
include a preliminary checkout, power-on selftest, and module communication.
Preliminary Checkout
1. Make sure that the front power switch is off (0).
2. Look at the "Line Rating" chart on the rear of the mainframe.
a. Verify the modules are set to the appropriate line voltage setting. Line selector switches are located on the bottom
of the modules.
Note At least one module is required to verify the operation of the mainframe.
b. Remove the fuse and verify that the fuse is as specified on the label.
c. Install the module(s).
3. Make sure that the power cord is connected to the terminal block in accordance with the prevailing color code.
Connection of this instrument to an ac power source should be done only by qualified personnel.
Power Cord Wire Color Codes
Label UL/CSA Cords Harmonized Cordage
Line "L" Black Brown
Neutral "N" White Blue
Ground Green or Green with Yellow stripe Green with Yellow stripe
4. Make sure that there is no load connected to the output connector by removing the output connector assembly.
5. Verify that the GPIB address switch is set to the desired address (0 - 31).

12 Verification
POWER-ON Checkout
1. Connect the instrument to the power source and turn the front power switch to ON (1).
2. Listen to confirm the modules' fans are on.
The power supply undergoes a selftest when you turn it on. The power-on selftest sequence tests the microprocessor, GPIB
interface, and serial communications.
Selftest Sequence
3. All display digits and annunciators on the keyboard briefly turn on.
4. All front panel LEDs and annunciators on the modules briefly turn on.
5. The keyboard briefly displays the message:
6. The keyboard then displays the state of the addressed module.
Note The information displayed on the keyboard assumes:
•At least one power module is installed,
•Factory default state still stored in location 0,
•Frame mode switch on the back of the mainframe is set to MAIN,
•GPIB address of the mainframe is set to 5,
•Module configuration switches set to factory default states (all OPEN).
In Case of Trouble
Note In case of a module failure, the front panel will display an Error Code -Uxx. Refer to the Agilent Series
661xxA Service Manual for information on troubleshooting the dc power modules.
A problem exists in the mainframe when one of these conditions is observed during selftest:

Verification 13
Table 2-1. Problem Symptoms
Symptoms Probable Cause Troubleshooting Procedure1
Keyboard and modules remain turned off
(fans not ON) Input Line Voltage, check fuse F8 Bias Troubleshooting
Module fans turn ON, front displays
remain blank (Turned OFF) No bias voltages, check fuses F1 & F2 Bias Troubleshooting
Modules remain OFF, keyboard displays
blinking cursor ¦Primary Microprocessor (U44) defective, check fuse F1 ROM & Microprocessor Troubleshooting
Keyboard displays
Self-test Failed, ROM Checksum Test ROM (U51) defective ROM & Microprocessor
Troubleshooting
Keyboard displays
Self-test Failed, Internal RAM Test Primary Microprocessor (U44)
defective ROM & Microprocessor Troubleshooting
Keyboard displays
Self-test Failed, External RAM Test RAM (U52) defective ROM & Microprocessor
Troubleshooting
Keyboard displays
Self-test Failed, GPIB Test GPIB Controller (U17) defective Overall Troubleshooting
Keyboard displays
Self-test Failed, Serial Comm Test DUART (U91) defective Overall Troubleshooting
Keyboard displays
NO MODULES INSTALLED Backplane power-up or
communication defective Overall Troubleshooting2
Keyboard displays
MODULE NOT FUNCTIONING Module defective or backplane
communication defective Overall Troubleshooting
1Refer to Chapter 4 of this manual for detailed troubleshooting procedures.
2Assumes that at least one module has been installed and is connected to the mainframe backplane.

14 Verification
Output Checkout
1. Make sure that there is no load connected to the output connector by removing the output connector assembly.
2. Check the basic voltage functions and module communications as shown in following table:
Action Keyboard Display Explanation
Press *RST Resets the Modular Power System
Press :OUTP ON Enables the output
Press :CURR 1 Sets the output current to 1 A
Press :VOLT 5 Sets the output voltage to 5 V
3. The keyboard display should now be in meter mode indicating the voltage and status of the dc power module:
Disable the output prior to connecting a load.
Press
In Case of Trouble
If the keyboard and module displays do not read the correct voltage, check the operation of the module. Refer to the
"Performance Measurement" section of the Agilent Series 66lxxA Power Modules Service Manual.
Problem Not Identified
If after performing the checkout procedures you were unable to isolate the problem, refer to the "Overall Troubleshooting"
procedure in Chapter 4. The overall troubleshooting procedure will verify whether the mainframe is at fault and will isolate
the problem to a functional block.

Disassembly 15
3
Disassembly
This chapter provides disassembly and reassembly instructions for the Agilent 66000A MPS Mainframe. Refer to Chapter 6
for an exploded view diagram of the mainframe. Major mechanical components are identified with "MP" designations and
are referenced in this section. Refer to Chapter 5 for the component descriptions. Refer to Chapter 1 for the tools required to
disassemble and reassemble the unit.
Disassembly Procedures
SHOCK HAZARD To avoid the possibility of personal injury, remove the mainframe from operation
before removing the top cover. Turn off ac power and disconnect the line cord, GPIB cable, and load leads
before attempting any disassembly.
When servicing the Main assembly and Backplane assembly, ac line voltages are present on the Main board
and backplane connectors.
Most of the attaching hardware is metric. Use of other types of fasteners will damage threaded inserts.
Removing the Modules and Module Connectors
Before you can disassemble the mainframe, you must first remove all of the power supply modules as well as the module
connectors on the back of the mainframe.
1. Use the slot-head screwdriver and release the pull tab at the front of each module.
2. Pull all of the modules out of the mainframe.
3. Use the Pozi driver and disconnect all of the module connectors from the back of the mainframe.
Removing the Cover
1. Use the T25 driver and remove the four screws that attach the handles (MP22) to the chassis .
2. Slide the cover (MP6) back, spread the sides slightly, and lift the cover up.
3. Lift the top tray (MP3) out of the chassis.
Removing the Front Frame
The cover must be removed from the unit before you can remove the front frame.

16 Disassembly
1. Use the T15 driver and remove the four screws that attach the front frame (MP18) to the chassis.
2. Slide the front frame forward about two inches.
3. Carefully unplug the cable (MP23) from the keyboard plug.
Removing the Front Bezels and Keyboard Plug
The front frame must be removed from the chassis before you can remove the bezel pieces (MP11-12).
Note The keyboard plug (A3) can only be removed from the front frame after the bottom bezel (MP11) has
been removed.
1. Insert the slot-head screwdriver into the notch at the bottom of each side bezel (MP12) to remove the bezels.
2. While applying upward pressure with the screwdriver to clear the latch, pull the side bezel away from the frame. When
the latch clears the bottom bezel (MP11), the side bezel will come right out.
3. Repeat this procedure for the other side bezel.
4. When the side bezels have been removed, simply grasp the top (MP10) or bottom bezel (MP11) at either end and pull
the bezels away from the frame. The bezels will snap out of the front frame.
5. Use the T15 driver to remove the two screws that attach the keyboard plug (A3).
Removing the Rear Subchassis
The cover must be removed from the unit before you can remove the rear subchassis (MP4).
1. Use the T15 driver and remove the six screws (three on each side) that attach the rear subchassis (MP4) to the chassis.
2. Slide the subchassis backward about three inches.
3. Carefully unplug the keyboard cable assembly (MP23) from the subchassis.
4. Grasp the on/off pushrod (MP13) firmly and unsnap it from the switch located inside the subchassis. Pull the pushrod
straight back from the subchassis to unsnap it.
5. Remove the rear subchassis from the chassis.
Removing the PC Boards
The rear subchassis must be removed from the unit before you can remove the pc boards (A1, A2).
Observe all standard anti-static procedures when removing the pc boards from the subchassis (see
Chapter 1).

Disassembly 17
1. Use the Pozi driver and remove the line cord from the unit. Note the color code and location of each wire on the
terminal block before removing the cord.
2. Use the T15 driver and remove the four screws (two on the front and two on the back) that attach the backplane cover
(MP5) to the subchassis (MP4).
3. Pull the bottom edge of the cover out slightly so that it clears the alignment pins and lift the cover straight up.
4. Grasp the Backplane board (A2) firmly and lift it straight out of its plug-in sockets.
5. Check to make sure that the FLT/INH connector is unplugged from the back of the unit.
6. Use the 7mm hex driver and remove the two nuts that connect the GPIB connector to the rear panel.
7. Use the 10mm hex driver and remove the nut that connects the ground wire to the rear panel.
8. Use the T15 driver and remove the three screws that attach the Main board (A1) to the subchassis (MP4).
9. Carefully lift up the pc board and remove it from the subchassis.
Reassembly Procedures
Most of the attaching hardware is metric. Use of other types of fasteners will damage threaded inserts.
Installing the PC Boards
1. Align the connectors on the Main board (A1) with the cutouts in the rear panel and carefully install the board in the
subchassis (MP4).
2. Make sure the Main board is fully inserted in the notches along the edge of the subchassis.
3. Use the T15 driver and install the three screws that attach the Main board to the subchassis .
4. Use the 7mm hex driver and install the two flat washers, split washers, and nuts that fasten the GPIB connector to the
rear panel.
5. Install the Backplane board (A2) into the connectors on the Main board.
6. Connect the ground hardware to the chassis in the following order:
a. lock washer.
b. ground wire.
c. lock washer.
d. nut.
7. Use the 10mm hex driver and tighten the grounding nut.
8. Align the slots in the backplane cover (MP5) with the notches on the Backplane board (A2) and snap the cover into
place. Use the slot-head screwdriver to align the board in the slots.

18 Disassembly
9. Make sure that the pins on the bottom of the cover are in their holes and that the cover is flush against the subchassis.
10. Use the T15 driver and install the four screws (two on the front and two on the back) that attach the backplane cover to
the subchassis.
Assembling the Rear Subchassis
1. Slide the rear subchassis (MP4) under the sides of the chassis but don't push it all the way in yet; leave about two inches
of space.
2. Connect the keyboard cable (MP23) to the connector inside the subchassis.
3. Make sure that the on/off pushrod (MP13) and the chassis pins line up with the openings on the rear subchassis and
slide the subchassis into place.
4. Use the T15 driver and install the six screws (three on each side) that attach the rear subchassis to the chassis. Don't
tighten the screws until all six have been started.
5. Push the on/off pushrod (MP13) in from the front panel in until it snaps twice. The pushrod must snap twice to indicate
that it is firmly connected to the switch inside the subchassis .
Assembling the Keyboard Plug and Front Bezels
1. Use the T15 driver to install the two screws that attach the keyboard plug (A3) in the second and third hole on the
bottom right corner of the front frame (MP18) when viewed from the front. The bottom of the frame is thicker than the
top.
2. Align the pins on the top and bottom bezels (MP10, MP11) with the corresponding holes on the frame and snap the
bezels into place.
3. Check along the edges of the top and bottom bezels to make sure that they are snapped all the way into place.
4. Install the side bezels (MP 12) by inserting the top corner of each bezel first, then push the bottom corner toward the
side of the frame until it snaps into place.
Assembling the Front Frame
1. Position the front frame (MP18) close to the front of the chassis. Insert the on/off pushrod (MP13) into its opening and
connect the keyboard cable (MP23) to keyboard plug (A3).
2. Insert the sides of the chassis between the front frame (MP18) and the side bezels (MP12). Push the front frame onto
the chassis as far it will go.
3. Use the T15 driver and install the four screws that attach the front frame to the chassis.
4. Look through the slots in the bottom tray and check that the keyboard cable (MP23) is positioned in the cable clamp. If
not, insert the slot-head screwdriver through the slots in the bottom tray and slide the cable into the cable clamp. Don't
force the tiewrap under the cable clamp; position the tiewrap in front of the cable clamp.

Disassembly 19
Assembling the Cover
1. Place the top tray (MP3) on the chassis with the vents toward the front of the unit.
2. Spread the sides of the cover (MP6) and slide it onto the chassis so that it fits into the slot behind the front panel
assembly. Check that the cover is flush against the rear panel.
3. Use the T25 driver and install the four screws that attach the handles and the cover to the chassis.
4. Reattach the line cord if it has been removed from the unit using the Pozi driver. If necessary, refer to the Mainframe
Installation Guide for more information.