HP E840 A Series Troubleshooting guide

Contents
HP E8401A, E8403A User and Service Manual
Edition 1
Contents 1
HEWLETT-PACKARD WARRANTY STATEMENT ..............................................3
Safety Symbols.............................................................................................................4
WARNINGS.................................................................................................................4
Declaration of Conformity............................................................................................5
Reader Comment Sheet ................................................................................................7
Chapter 1
Getting Started ...............................................................................................................9
Product Overview .........................................................................................................9
Preparing Your VXI System for Use..........................................................................10
AC Power Requirements .....................................................................................10
Positioning the Mainframe for Adequate Cooling ..............................................10
Connecting the
Mainframe to a Permanent Earth Ground ...........................................................11
Installing VXI Instruments .........................................................................................12
Installing C-Size Instruments ..............................................................................13
Installing A- and B-Size Instruments ..................................................................14
Front Panel Features ...................................................................................................15
Diagnostic Connector .................................................................................................16
+5VC (pin 6) .......................................................................................................17
+12VC (pin 7) .....................................................................................................17
+5V STDBY (pins 8, 21) ....................................................................................17
SYSRESET* (pin 10) ..........................................................................................17
ACFAIL* (pin 23) ...............................................................................................17
Using the Remote Power-On Pins .......................................................................18
Disabling the On/Stdby Switch ...........................................................................19
Mainframe Options and Accessories..........................................................................21
Chapter 2
Rack Mounting and Option Installation ...................................................................23
Chapter Overview.......................................................................................................23
Rack Mounting the HP E840xA Mainframe ..............................................................23
Parts List ..............................................................................................................24
Rack Mounting the HP E840xA using Support Rails .........................................25
Procedure .............................................................................................................25
Rack Mounting the HP E840xA Using Rack Slide Rails ...................................29
Procedure .............................................................................................................29
Installing the Cable Tray.............................................................................................34
Parts List ..............................................................................................................34
Procedure .............................................................................................................34
Installing the Tinted Acrylic Door (Option 915)........................................................36
Parts List ..............................................................................................................36
Installing the Intermodule Chassis Shields.................................................................38
Parts List ..............................................................................................................38

2 Contents
Procedure .............................................................................................................38
Installing the Backplane Connector Shields...............................................................40
Parts List ..............................................................................................................40
Procedure .............................................................................................................40
HP E840xA Air Filter Kit...........................................................................................42
Chapter 3
Servicing Your Mainframe .........................................................................................43
Chapter Overview.......................................................................................................43
Problem Isolation........................................................................................................43
No Power Line Fuse ............................................................................................43
Isolating Problems ...............................................................................................44
Replacing Assemblies.................................................................................................44
Removing the Rear Panel from the Mainframe ..................................................45
Removing the Mainframe Cover .........................................................................46
Replacing the Basic Monitor Board ....................................................................47
Replacing the HP E8401A Power Supply ...........................................................48
Replacing the HP E8403A Power Supply ...........................................................49
Replacing the Impeller ........................................................................................50
Replacement Power Cords..........................................................................................51
Appendix A
HP E8401A, E8403A Product Specifications ............................................................53
Product Descriptions...................................................................................................53
General Specifications .........................................................................................53
Mechanical Specifications ...................................................................................53
Output Power Specifications ......................................................................................54
Total Available and Usable Power ......................................................................54
Peak and Dynamic Current .................................................................................54
Output Voltage Specifications ............................................................................55
Input Power Requirements..........................................................................................55
Cooling Specifications................................................................................................56
Cooling Specification Charts ..............................................................................56
Acoustical Noise Specifications .................................................................................58
Backplane Specifications............................................................................................58
Basic Monitor Specifications......................................................................................58
Environmental Specifications.....................................................................................59

3
HEWLETT-PACKARD WARRANTY STATEMENT
HP PRODUCT: HP E8401A, E8403A C-Size VXI Mainframes DURATION OF WARRANTY: 3 years
1. HP warrants HP hardware, accessories and supplies against defects in materials and workmanship for the period specified above. If
HP receives notice of such defects during the warranty period, HP will, at its option, either repair or replace products which prove to be
defective. Replacement products may be either new or like-new.
2. HP warrants that HP software will not fail to execute its programming instructions, for the period specified above, due to defects in
material and workmanship when properly installed and used. If HP receives notice of such defects during the warranty period, HP will
replace software media which does not execute its programming instructions due to such defects.
3. HP does not warrant that the operation of HP products will be interrupted or error free. If HP is unable, within a reasonable time, to
repair or replace any product to a condition as warranted, customer will be entitled to a refund of the purchase price upon prompt return
of the product.
4. HP products may contain remanufactured parts equivalent to new in performance or may have been subject to incidental use.
5. The warranty period begins on the date of delivery or on the date of installation if installed by HP. If customer schedules or delays HP
installation more than 30 days after delivery, warranty begins on the 31st day from delivery.
6. Warranty does not apply to defects resultingfrom (a) improper or inadequate maintenance or calibration, (b) software, interfacing, parts
or supplies not supplied by HP, (c) unauthorized modification or misuse, (d) operation outside of the published environmental
specifications for the product, or (e) improper site preparation or maintenance.
7. TO THE EXTENT ALLOWED BY LOCAL LAW, THE ABOVE WARRANTIES ARE EXCLUSIVE AND NO OTHER
WARRANTY OR CONDITION, WHETHER WRITTEN OR ORAL, IS EXPRESSED OR IMPLIED AND HP SPECIFICALLY
DISCLAIMS ANY IMPLIED WARRANTY OR CONDITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY, AND
FITNESS FOR A PARTICULAR PURPOSE.
8. HP will be liable for damage to tangible property per incident up to the greater of $300,000 or the actual amount paid for the product
that is the subject of the claim, and for damages for bodily injury or death, to the extent that all such damages are determined by a court
of competent jurisdiction to have been directly caused by a defective HP product.
9. TO THE EXTENT ALLOWED BY LOCAL LAW, THE REMEDIES IN THIS WARRANTY STATEMENT ARE CUSTOMER’S
SOLE AND EXLUSIVE REMEDIES. EXCEPT AS INDICATED ABOVE, IN NO EVENT WILL HP OR ITS SUPPLIERS BE
LIABLE FOR LOSS OF DATA OR FOR DIRECT, SPECIAL, INCIDENTAL, CONSEQUENTIAL (INCLUDING LOST PROFIT OR
DATA), OR OTHER DAMAGE, WHETHER BASED IN CONTRACT, TORT, OR OTHERWISE.
FOR CONSUMER TRANSACTIONS IN AUSTRALIA AND NEW ZEALAND: THE WARRANTY TERMS CONTAINED IN THIS
STATEMENT, EXCEPT TO THE EXTENT LAWFULLY PERMITTED, DO NOT EXCLUDE, RESTRICT OR MODIFY AND ARE
IN ADDITION TO THE MANDATORY STATUTORY RIGHTS APPLICABLE TO THE SALE OF THIS PRODUCT TO YOU.
U.S. Government Restricted Rights
The Software and Documentation have been developed entirely at private expense. They are delivered and licensed as "commercial
computer software" as defined in DFARS 252.227- 7013 (Oct 1988), DFARS 252.211-7015 (May 1991) or DFARS 252.227-7014 (Jun
1995), as a "commercial item" as defined in FAR 2.101(a), or as "Restricted computer software" as defined in FAR 52.227-19 (Jun
1987)(or any equivalent agency regulation or contract clause), whichever is applicable. You have only those rights provided for such
Software and Documentation by the applicable FAR or DFARS clause or the HP standard software agreement for the product involved.
HP E8401A, E8403A C-Size VXI Mainframes User/Service Manual
Edition 1
Copyright © 1998 Hewlett-Packard Company. All Rights Reserved.

4
Safety Symbols
Instruction manual symbol affixed to
product. Indicates that the user must refer to
the manual for specific WARNING or
CAUTION information to avoid personal
injury or damage to the product.
Alternating current (AC)
Instruction manual symbol affixed to
product. Indicates that the user must refer to
the manual for specific WARNING or
CAUTION information to avoid personal
injury or damage to the product.
Indicates the field wiring terminal that must
be connected to earth ground before
operating the equipment — protects against
electrical shock in case of fault.
Direct current (DC).
Indicates hazardous voltages.
or Frameorchassisgroundterminal—typically
connects to the equipment's metal frame.
WARNING Calls attention to a procedure, practice, or
condition that could cause bodily injury or
death.
CAUTION Calls attention to a procedure, practice, or
conditionthatcouldpossiblycausedamageto
equipment or permanent loss of data.
WARNINGS
The following general safety precautions must be observed during all phases of operation, service, and repair of this product. Failure to
comply with these precautions or with specific warnings elsewhere in this manual violates safety standards of design, manufacture, and
intended use of the product. Hewlett-Packard Company assumes no liability for the customer's failure to comply with these requirements.
Ground the equipment: For Safety Class 1 equipment (equipment having a protective earth terminal), an uninterruptible safety earth
ground must be provided from the mains power source to the product input wiring terminals or supplied power cable.
DO NOT operate the product in an explosive atmosphere or in the presence of flammable gases or fumes.
For continued protection against fire, replace the line fuse(s) only with fuse(s) of the same voltage and current rating and type. DO NOT
use repaired fuses or short-circuited fuse holders.
Keep away from live circuits: Operating personnel must not remove equipment covers or shields. Procedures involving the removal of
covers or shields are for use by service-trained personnel only. Under certain conditions, dangerous voltages may exist even with the
equipment switched off. To avoid dangerous electrical shock, DO NOT perform procedures involving cover orshield removal unless you
are qualified to do so.
DO NOT operate damaged equipment: Whenever it is possible that the safety protection features built into this product have been
impaired, either through physical damage, excessive moisture, or any other reason, REMOVE POWER and do not use the product until
safe operation can be verified by service-trained personnel. If necessary, return the product toa Hewlett-Packard Sales and Service Office
for service and repair to ensure that safety features are maintained.
DO NOT service or adjust alone: Do not attempt internal service or adjustment unless another person, capable of rendering first aid and
resuscitation, is present.
DO NOT substitute parts or modify equipment: Because of the danger of introducing additional hazards, do not install substitute parts
or perform any unauthorized modification to the product. Return the product to a Hewlett-Packard Sales and Service Office for service
and repair to ensure that safety features are maintained.
Documentation History
All Editions and Updates of this manual and their creation date are listed below. The first Edition of the manual is Edition 1. The Edition
number increments by 1 whenever the manual is revised. Updates, which are issued between Editions, contain replacement pages to
correct or add additional information to the current Edition of the manual. Whenever a new Edition is created, it will contain all of the
Update information for the previous Edition. Each new Edition or Update also includes a revised copy of this documentation history page.
Edition 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . May, 1998

5
European contact: Your local Hewlett-Packard Sales and Service Office or Hewlett-Packard GmbH, Depart-
ment HQ-TRE, Herrenberger Straße 130, D-71034 Böblingen, Germany (FAX [phone])
Declaration of Conformity
according to ISO/IEC Guide 22 and EN 45014
Manufacturer’s Name: Hewlett-Packard Company
Loveland Manufacturing Center
declares that the product:
Product Name: HP E8401A, E8403A C-Size VXI Mainframes
Model Numbers: HP E8401A, E8403A
Product Options: All
conforms to the following Product Specifications (preliminary):
Safety: IEC 1010-1 (1990) including Amendment 2 (1996)/EN 61010-1 (1993)
CSA C22.2 #1010.1 (1992)
UL 3111-1 (1994)
EMC: CISPR 11:1990/EN55011 (1991): Group 1 Class A
EN50082-1:1992
IEC61000-4-2: 1995 4kV CD, 8kV AD
IEC61000-4-3: 1995 3V/m
IEC61000-4-4: 1995 1kV Power Line, 0.5kV Signal Lines
ENV50141: 1993/prEN50082-1 (1995): 3Vrms
EN61000-4-5: 1995 1kV CM, 0.5kV DM
EN61000-4-8: 1993/prEN50082-1 (1995): 3 A/m
EN61000-4-11: 1994/prEN50082-1 (1995): 30%, 10ms; 60%, 100ms
Supplementary Information: The product herewith complies with the requirements of the Low Voltage Directive
73/23/EEC and the EMC Directive 89/336/EEC and carries the "CE" mark accordingly.
May 6, 1998
Jim White, Quality Manager

6
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HP E8401A, E8403A, VXI Mainframes User and Service Manual
Edition 1
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Getting Started 9Chapter 1
Chapter 1
Getting Started
This chapter contains general information on the operating features of the
HP E8401A and E8403A C-Size VXI mainframes. The following tablelists
the differences between these two mainframes:
Unless otherwise specifically noted, descriptions in this manual relate to
both VXI mainframes. The designation HP E840xA refers to both VXI
mainframes.
Product Overview
The HP E840xA VXI mainframes are designed in full compliance with
VXIbus specification revision 1.4, VXIplug&play specification VPP-8, and
VMEbus system specification revision C.1. Additional features of the HP
E840xA mainframes include:
•Mainframe monitoring for verification of:
n backplane voltage conditions
n mainframe temperatures
n fan and impeller operation
•State of the art cooling technology:
n quiet, variable speed power supply fan and backplane impeller
n increased static pressure
n all fans operate at either full speed or in variable speed mode.
•Front Panel Diagnostic Connector for:
n power supply voltage measurements
n power supply and backplane temperature measurements
n power supply fan and backplane impeller verification
•Easy maintenance:
n easy rear panel access to power supply and cooling impeller
(either bench or rack mount operation).
n optional air filter kit is available for harsh environments.
Power Supply
(0 °C to 55 °C)
500 W 1000 W
Basic
Monitor
HP E8401A Mainframe ää
HP E8403A Mainframe ää

10 Getting Started Chapter 1
Preparing Your VXI System for Use
The HP E840xA mainframes are shipped from the factory ready to use. This
section describes important mainframe installation procedures.
AC Power
Requirements The HP E840xA mainframes can be operated at line voltages of
90 VAC to 264 VAC, and line frequencies of 47 Hz to 66 Hz. The
mainframe can also operate at 360 Hz to 440 Hz with line voltages of
90 VAC to 132 VAC.
The mainframes ship with a power cord and with a fuse installed in the
power supply. The fuse is suitable for all line voltages, but is not accessible.
Appendix A contains complete input power specifications.
WARNING The power cord is the only way to disconnect the mainframe
from AC power and, therefore, it must be accessible to the
operator at all times. When the HP E840xA mainframes are
mounted in a system cabinet, the power cord need not be
accessible since the cabinet must have its own disconnect
device.
Positioning the
Mainframe for
Adequate Cooling
VXI instruments are cooled by air drawn through the back of the mainframe
and exhausted out the sides. The power supply is cooled by air drawn from
the right side (facing the mainframe) and exhausted out the left side. When
placing the mainframe on a work bench or if the mainframe is rack mounted,
provideat least a one inch clearance at the backand sides to allow for proper
air flow.
Air filters are not necessary on these mainframes. However, an optional air
filter kit (mainframe option 938 or HP E8401-80938) is available for use in
harsh environments. The airflow is restrictedless than 10% with the air filter
installed. Refer to “HP E840xA Air Filter Kit” on page 42 for installation
information.

Getting Started 11Chapter 1
Connecting the
Mainframe to a
Permanent Earth
Ground
The mainframe must be connected to a permanent earth ground for line
frequencies greater than 66 Hz. This connection is made on the back of the
mainframe:
1. Connect a 16 AWG (1.3 mm or larger) wire to the PEM nut shown in
Figure 1-1. The wire must be green with a yellow stripe, or bare (no
insulation). Use a m4 x 10 screw, grounding lug, and toothed washers
(or toothed lug) as shown in the Figure.
2. Attach the other end of the wire to a permanent earth ground using
toothed washers or a toothed lug.
WARNING For protection from electrical shock when operating at
frequencies greater than 66 Hz, connect the chassis ground
terminal to permanent earth ground.
AVERTISSEMENT Risque de Choch èlectrique. Si la frèquence du secteur est
supèrieure à 66 Hz, relier la borne de masse du chassis à une
prise de terre fixe.
Figure 1-1. Connecting an HP E840xA Mainframe to a Permanent Earth Ground
(HP E8403 shown, HP E8401 is similar)

12 Getting Started Chapter 1
Installing VXI Instruments
The HP E840xA mainframes have 13 slots labeled 0 through 12. Any VXI
instrument can be installed in any slot; however, slot 0 is reserved for
devices capable of providing the system’s slot 0 functionality. This
functionality includes:
•locating instruments installed in the mainframe
•managing (arbitrating) data flow across the backplane
•providing the system clock (SYSCLK - 16 MHz)
Examples of these devices are the HP E1406 Command Module and
embedded controllers such as the HP E623x series VXI Pentium PCs, the
HP RADEPC7B PC, and the HP E1497/E1498 V743 controllers.
Multiple instruments which combine to create a virtual instrument (e.g. a
scanning multimeter), and instruments which access the backplane local bus
should be installed in adjacent slots.
1. To prevent damage to the VXI instruments, install the instruments
when power is not applied to the mainframe.
2. Insert the instrument into the mainframe by aligning the instrument
with the card guides inside the mainframe. Slowly push the
instrument into the slot until it seats in the backplane connectors. The
front panel of the instrument should be even with the front edges of
the mainframe.
3. Tighten the retaining screws on the top and bottom of the module.
WARNING All instruments within the VXI mainframe are grounded through
the mainframe chassis. During installation, tighten the
instrument’s retaining screws to secure the instrument to the
mainframe and to make the ground connection.

Getting Started 13Chapter 1
Installing C-Size
Instruments Figure 1-2 shows the installation of C-Size instruments.
WARNING All instruments within the VXI mainframe are grounded through
the mainframe chassis. During installation, tighten the
instrument’s retaining screws to secure the instrument to the
mainframe and to make the ground connection.
Figure 1-2. Installing C-Size Instruments in the HP E840xA Mainframe
seat the module by
pushing in the
extraction levers
slide the module
into the mainframe
until it plugs into the
backplane connectors
retaining
screws
extraction
levers

14 Getting Started Chapter 1
Installing A- and
B-Size Instruments Figure 1-3 shows the installation of A- and B-size instruments.
•HP E1403B A/B-size Module Carrier extends the P1 connector on
the VXIbus backplane and mounts the (A/B-size) modules flush with
C-size modules. This carrier is recommended for Hewlett-Packard
B-size, slave-only devices which have the P1 connector.
•HP E1407A A/B Module Carrier extends the P1and P2 connectors
on the VXIbus backplane. This carrier is recommended for B-Size,
slave-only devices which have the P1/P2 connectors.
WARNING All instruments within the VXI mainframe are grounded through
the mainframe chassis. During installation, tighten the
instrument’s retaining screws to secure the instrument to the
mainframe and to make the ground connection.
Figure 1-3. Installing A- and B-Size Instruments in the HP E840xA Mainframe

Getting Started 15Chapter 1
Front Panel Features
Figure 1-4. HP E8401A and E8403A Basic Monitoring Front Panel
Section Indicator / Switch Description

Power
On Indicator
Standby Indicator
Green - the mainframe is turned on.
Amber - the mainframe is in standby mode; no power is applied to the VXI modules.
ô
Supply
Voltages Indicator
Temp Indicator
Green - all voltages on the VXI backplane are within ±8% of the VXI specification.
Flashing Amber - one or more voltages is out of specification. The backplane voltages
and allowed variations are listed below:
Voltage Allowed Variation Diagnostic Pin
+5V +4.875V to +5.125V 1
+12V +11.64V to +12.6V 14
-12V -12.6V to -11.64V 2
+24V +23.28V to +25.2V 15
-24V -25.2V to -23.28V 3
-5.2V -5.46V to -5.044V 16
-2V -2.1V to -1.9V 4
Green - the power supply temperature is acceptable.
Flashing Amber - the power supply is approaching thermal shutdown. The power supply
temperature can be measured on pin 11 of the Diagnostic connector.
í
Fans
Fan Switch
Fans Indicator
Full - the power supply and mainframe cooling fans are operating at full speed.
Var(iable) - the power supply and mainframe cooling fans are providing adequate cooling
(default setting). Fan speed is a function of the power supply temperature and the
reference temperature (Diagnostic connector pin 12). The reference temperature is a
function of ambient temperature and load.
Green - the power supply and mainframe cooling fans are operating.
Flashing Amber - the power supply fan or the mainframe cooling fan is not operating. Fan
operation can be checked using pin 13 of the Diagnostic connector.
÷
Backplane
Activity Indicator
SYSFAIL Indicator
Reset Switch
Green - there is communication between instruments across the backplane. Off - there is
no communication between instruments on the backplane.
Flashing Amber - one or more instruments has asserted its SYSFAIL line due to a
power-on initialization failure, self-test failure, or hardware failure. SYSFAIL is asserted
momentarily at power on and during a system reset.
Pressing the reset button asserts the SYSRESET* line on the VXI backplane. When
asserted (low), this line resets the VXI system; all VXI instruments are rest to their
power-on state.
û
Diagnostic
Connector
Refer to “Diagnostic Connector” on page 16.

16 Getting Started Chapter 1
Diagnostic Connector
The 25-pin Sub-D diagnostic connector provides access to backplane
voltages, power supply and backplane temperatures, and output signals. The
pins are described in Table 1-1.
Table 1-1. Diagnostic Connector Pin Descriptions
Pin # Function Description
1 +5 VM +5V backplane voltage monitor (high impedance). (+4.875 Vdc to +5.125 Vdc)
2 -12 VM -12V backplane voltage monitor (high impedance). (-12.6 Vdc to -11.64 Vdc)
3 -24 VM -24V backplane voltage monitor (high impedance). (-25.2 Vdc to -23.28 Vdc)
4 -2 VM -2V backplane voltage monitor (high impedance). (-2.1 Vdc to -1.9 Vdc)
5 Rem On Remote power on. See “Using the Remote Power-on Pins.”
6 +5 VC +5 VDC source output (1A maximum).
7 +12 VC +12 VDC source output (1A maximum).
8 +5 V Stdby Input for +5V STDBY (1A maximum for pins 8 and 21 combined).
9 GND Chassis ground.
10 SysReset * TTL low-true input signal causes system reset, output indicates system reset.
11 PS Temp Output voltage proportional to power supply temperature (0 VDC at 0 °C, with a rise of
10 mV per degree centigrade).
12 Ref Temp Output voltage proportional to backplane temperature (0 VDC at 0 °C, with a rise of 10 mV
per degree centigrade). A function of the ambient temperature and load.
At no load, Tref ~ 2 °C + ambient. At full load and high fan speed,
Tref ~ 14 °C + ambient. At full load and low fan speed, Tref ~ 20 °C + ambient.
13 Fans OK * TTL low-true output voltage indicates power supply and backplane cooling fans are
operating.
14 +12 VM +12V backplane voltage monitor (high impedance). (+11.64 Vdc to +12.6 Vdc)
15 +24 VM +24V backplane voltage monitor (high impedance). (+23.28 Vdc to +25.2 Vdc)
16 -5.2 VM -5.2V backplane voltage monitor (high impedance). (-5.46 Vdc to -5.044 Vdc)
17 GND Chassis ground.
18 REM Rtn Remote power switch return. See “Using the Remote Power-On Pins.”.
19 V OK * TTL low-true output voltage indicating the +5V, ± 12V, ± 24V, -5.2V, and -2V power supply
voltages are within ± 8% of its allowed variation.
20 GND Chassis ground.
21 +5 V Stdby Input for +5V STDBY (1A maximum for pins 8 and 21 combined).
22 GND Chassis ground.
23 ACFAIL * TTL low-true output asserted by the mainframe power monitor at power down or whenever
a loss of power is detected.
24 GND Chassis ground.
25 RSV Reserved.
1
14
15
2
3
4
5
16
17
6
7
8910
11
181920
2122
23
12
13
24
25

Getting Started 17Chapter 1
+5VC
(pin 6) The +5 volt output allows you to power external TTL circuits if required.
The maximum current allowed from this supply is 1.0A
+12VC
(pin 7) The +12 volt output allows you to power external circuits, charge a battery,
or power relays if required. The maximum current allowed from this supply
is 1.0A
+5V STDBY
(pins 8, 21) This provides an input to the mainframe backplane for a +5V DC standby
power source. This may be from a separate battery or power supply. The
maximum current allowed is 1A total (pins 8 and 21 wired in parallel). It can
be used to power timers and other circuits when the mainframe is instandby
mode.
SYSRESET*
(pin 10) This pin provides an extension of the VXI backplane SYSRESET* signal
line. It can be used to monitor for SYSRESET* or to send a SYSRESET*
tot hebackplane. Shorting this line to ground asserts the SYSRESET* signal
to the system. If you use an extension cable from the Diagnostic Connector,
make certain that you do not violate the VXI backplane electrical
specifications (i.e. keep the cable as short as possible, buffer the signal line,
etc.).
ACFAIL*
(pin 23) This pin lets you monitor the ACFAIL* signal from the VXI backplane. If
you useanextension cable from theDiagnostic Connector, make certainthat
you do not violate the VXI backplane electrical specifications (i.e. keep the
cable as short as possible, buffer the signal line, etc.).

18 Getting Started Chapter 1
Using the Remote
Power-On Pins Theremotepower-onpins(pins5and18)of the DiagnosticConnectorallow
you to turn the mainframe on and off without using the front panel On/Stdby
switch. With the On/Stdby switch in the Stdby (off) position, connecting pin
5 to pin 18 on the diagnostic connector turns the mainframe on.
Disconnecting pin 5 from pin 18 turns the mainframe off.
Note Pin 18 is ground in the HP E8401 and E8403 mainframes. Therefore,
you only need to ground pin 5 to turn the mainframe on.
Figure 1-5. Remote Standby Switch Wiring.
0Ω
Resistor

Getting Started 19Chapter 1
Disabling the
On/Stdby Switch The front panel On/Stdby switch is disabled by removing surface mount 0Ω
resistor located on the front monitor board (see Figure 1-6). The resistor is
labeled: REM PWR JUMPER.
Caution After removing the 0Ωresistor, heat damage may prevent the
resistor from being re-installed to re-enable the On/Stdby
switch.
To access the basic monitor board and resistor:
1. Turn off the mainframe and remove the power cord.
2. Remove the rear panel. Refer to “Removing the Rear Panel from the
Mainframe” on page 45 for instructions.
3. Remove the mainframe cover by removing the 10 (five on each side)
m3x6 flat head torx screws.
Figure 1-6. Disabling the On/Stdby Switch
Location of 0Ωresistor

20 Getting Started Chapter 1
4. Remove the 0Ω resistor by heating both sides simultaneously with
soldering irons. Separate the resistor from the board by gently
pressing the tips of the soldering irons together.
5. Save the resistor in order to re-enable the On/Stdby switch. Again,
heat damage may prevent the resistor from being re-installed.
6. Replace the mainframe cover and rear panel. Make certain that all ten
mainframe cover screws and all 14 rear panel screws are secured.