DEC VR315, VR325 Service Manual

VR315andVR325MonochromeMonitors
ServiceGuide

Order Number EK-VR315-SV-002

Digital Equipment Corporation

Second Edition, February 1991

The information in this document is subject to change without notice and should not
be construed as a commitment by Digital Equipment Corporation. Digital Equipment
Corporation assumes no responsibility for any errors that may appear in this document.

The software described in this document is furnished under a license and may be used or
copied only in accordance with the terms of such license.

No responsibility is assumed for the use or reliability of software on equipment that is not
supplied by Digital Equipment Corporation or its affiliated companies.

Restricted Rights: Use, duplication, or disclosure by the U. S. Government is subject to
restrictions as set forth in subparagraph ( c) ( 1) ( ii) of the Rights in Technical Data and
Computer Software clause at DFARS 252.227–7013.

Copyright © Digital Equipment Corporation 1991
All Rights Reserved.

Printed in U.S.A.

The following are trademarks of Digital Equipment Corporation:
DEC DIBOL UNIBUS

DEC/CMS EduSystem VAX
DEC/MMS IAS VAXcluster
DECnet MASSBUS VMS
DECsystem–10 PDP VT
DECSYSTEM–20 PDT
DECUS RSTS
DECwriter RSX

dt

This document was prepared and published by Educational Services Development and
Publishing, Digital Equipment Corporation.

Contents

About This Manual vii

1 Overview

1.1 Product Description ................................ 1–1

1.1.1 Model Variations ................................ 1–2

1.2 Tools and Equipment ............................... 1–2

1.3 Recommended Spare Parts List ....................... 1–3

2 Troubleshooting

2.1 Before You Start. . . ................................ 2–1

2.2 Troubleshooting Procedures . . ........................ 2–2

2.3 Troubleshooting Tables.............................. 2–2

3 Removing and Replacing FRUs

3.1 Introduction ...................................... 3–1

3.1.1 Removing the External Cables ...................... 3–2

3.1.2 Removing the Rear Cover . ........................ 3–3

3.1.3 Removing the Top Cover . . ........................ 3–4

3.2 Field Replaceable Units (FRUs)....................... 3–5

3.2.1 Interconnect Cable ............................... 3–6

3.2.2 Power Supply Module ............................ 3–8

3.2.3 Discharging the CRT and Removing the Anode Cap ..... 3–10

3.2.4 Deflection Module ............................... 3–12

3.2.5 Video Casting Assembly . . . ........................ 3–16

3.2.6 CRT/Chassis Assembly............................ 3–20

3.3 CRT Disposal (Trained Service Personnel Only) . . . ....... 3–21

3.4 Tilt-Swivel Base . . ................................ 3–24

iii

iv Contents

4 Aligning the Video Monitor

4.1 Introduction ...................................... 4–1

4.1.1 Before You Start . ................................ 4–1

4.1.2 Check LEDs and Heater Filament................... 4–4

4.1.3 Displaying Screen Tests . . . ........................ 4–4

4.2 Monitor Adjustments ............................... 4–5

4.3 Deflection Adjustments ............................. 4–6

4.3.1 Raster Adjustment ............................... 4–6

4.3.2 Anode Voltage Adjustment . ........................ 4–6

4.3.3 Height and Width Adjustments ..................... 4–6

4.4 Using the Radiance Meter . . . ........................ 4–8

4.5 Cutoff Adjustment . ................................ 4–10

4.6 GAIN Adjustment . ................................ 4–11

A VR315 and VR325 Documentation

Figures

1–1 Monochrome Monitor ............................... 1–1

3–1 Removing Cables from the Monitor .................... 3–2

3–2 Rear Cover Removal ............................... 3–3

3–3 Top Cover Removal ................................ 3–4

3–4 Field Replaceable Units ............................. 3–5

3–5 Disconnecting the Interconnect Cable . . . ............... 3–7

3–6 Removing the On/Off Switch Cable from the Power Supply . . 3–8

3–7 Removing the Power Supply . ........................ 3–9

3–8 Discharging the CRT and Removing the Anode Cap ....... 3–11

3–9 Loosening the Captive Screw . ........................ 3–13

3–10 Disconnecting Cables from the Deflection Module . . ....... 3–14

3–11 Removing the Deflection Module ...................... 3–15

3–12 Removing Cables from the Video Casting ............... 3–17

3–13 Removing the CRT Socket Connector ................... 3–18

3–14 Removing the Video Casting . ........................ 3–19

3–15 Crushing the Evacuation Point ....................... 3–23

3–16 Tilt-Swivel Base . . ................................ 3–25

4–1 User Controls and Indicator . . ........................ 4–3

Contents v

4–2 Circle-Crosshatch Pattern . . . ........................ 4–4

4–3 Using the Metric Measuring Tape ..................... 4–5

4–4 Internal Controls . . ................................ 4–7

4–5 Radiance Meter . . . ................................ 4–9

4–6 Using the Radiance Meter . . . ........................ 4–10

4–7 GAIN, G2, and FOCUS (G4) Adjustments .............. 4–11

Tables

1–1 Tools and Equipment ............................... 1–2

1–2 Recommended Spare Parts. . . ........................ 1–3

2–1 Blank Screen, No Video or Raster ..................... 2–3

2–2 Blank Screen, No Video, but Raster is Present ........... 2–5

2–3 Poor Display Quality ............................... 2–6

4–1 Monitor Controls and Indicators ...................... 4–2

AboutThisManual

VR315 and VR325 Video Monitors

This guide describes how to service the VR315 and VR325 monochrome
monitors in the field.

Manual Organization

This manual is organized as follows:

• Chapter 1 provides a general overview of the product and includes a
list of spare parts.

• Chapter 2 describes the troubleshooting procedures.

• Chapter 3 provides the removing and replacing procedures for the
Field Replaceable Units (FRUs).

• Chapter 4 describes the alignment procedures.

• Appendix A describes related documentation.

Conventions

Convention Meaning

Caution Provides information to prevent damage to the equipment.
Warning Provides information that relates to personal safety.
Note Provides general information.
PN Refers to a part number.

!

monitor Refers to the VR315 and VR325 monochrome monitors.

This type of number in text refers to an item in an illustration.

vii

1

Overview

1.1 Product Description

The monochrome monitor (Figure 1–1) has a direct viewed antiglare
screen with an auto-ranging power supply for worldwide operation. Its
built-in tilt-swivel base lets the user adjust the screen for viewing comfort.
When connected to a host system, the monitor displays information sent
by the host.

Figure 1–1 Monochrome Monitor

MA-0299-90.DG

1–1

1–2 Overview

1.1.1 Model Variations

The monitor is available in the following models:

Model Applicable Area

VR315-DA Northern hemisphere
VR315-D4 Southern hemisphere
VR325-DA Northern hemisphere
VR325-D4 Southern hemisphere

1.2 Tools and Equipment

Table 1–1 lists the tools and equipment you will need to service the
monitor:

Table 1–1 Tools and Equipment

Tools and Equipment Part Number

Terminal technician tool kit 29-27340-01
Static protection kit 29-26246-00
Anode discharge tool 29-24717-00
Metric measuring tape 29-25342-00
Safety goggles 29-16141-00
Gloves 29-16146-00

Overview 1–3

1.3 Recommended Spare Parts List

Table 1–2 lists the recommended spare parts for the monitor.

Table 1–2 Recommended Spare Parts

VR315 Part

Spare Part

Power supply 54-19629-02 54-19629-03
Deflection module 54-19826-01 54-19826-02
Video casting assembly 70-27073-01 70-27073-01
Module interconnect cable 70-27000-02 70-27000-02
CRT/chassis assembly

Northern Hemisphere 70-27477-01 70-27481-03
Southern Hemisphere 70-27477-02 70-27481-04

Number

VR325 Part
Number

2

Troubleshooting

This chapter describes how to troubleshoot a monitor problem through
fault isolation.

2.1 Before You Start

The following information will help you troubleshoot the monitor easily
and effectively:

WARNING

If you smell burning components, press the monitor power switch
off and disconnect the power cord.

• If you are going to service a display quality type of problem, tell the
customer to warm the monitor up for at least 20 minutes, if possible,
before you arrive and begin the troubleshooting procedures.

• Magnetic fields affect monitor performance and can give a false
indication of a monitor failure. Place the monitor away from any
electromagnetic devices such as printers and terminals, or away from
large magnetized objects such as filing cabinets and steel beams in
walls.

NOTE

Any time you replace a video casting assembly, deflection module,
or power supply module, perform all the necessary adjustments.
Refer to Chapter 3.

2–1

2–2 Troubleshooting

2.2 Troubleshooting Procedures

These procedures assume that only one assembly has failed or only one
problem exists. Always troubleshoot the most obvious symptom first;
however, one symptom may indicate multiple failures. Problems may
come from either the host system or the monitor.

Troubleshoot the monitor as follows:

1. Ask the operator to describe the problem. The operator often is the
most knowledgeable.

2. Identify the problem. The screen display often indicates which
problem is occurring.

3. Isolate the problem. Refer to the troubleshooting tables (Section 2.3)
to find the suggested solutions.

4. Display the host system alignment test patterns to make sure that
no other problem exists. Refer to the host system service guide for
displaying test patterns.

2.3 Troubleshooting Tables

The troubleshooting tables list the possible cause in order of probability.
This troubleshooting information applies to three types of video problems
that the monitor may exhibit:

• A blank screen, without video or raster (Table 2–1)

• A blank screen, without video, but raster present (Table 2–2)

• Poor display quality (Table 2–3)

Use the troubleshooting tables as follows:

1. Note the symptom of the problem.

2. Check the Symptom column for a match.

3. Check the conditions in the Possible Cause column in the order given.

4. Perform the action in the Suggested Solution column in the order
given.

Troubleshooting 2–3

Table 2–1 Blank Screen, No Video or Raster

Symptom Possible Cause Suggested Solution

Blank screen, no video
or raster. Power to
the monitor is on (the
power switch is in) but
the power indicator
light is off.

No video or raster, but
the power indicator is
on.

The power cord is
not connected to
the power source or
monitor.

Low or no power at
wall outlet.

Power supply
module is faulty.

Deflection module
is faulty.

Video module is
faulty.

Brightness or
contrast is set
incorrectly.

Power to the host
system is not on.

Host signal cable is
disconnected.

Connect the power cord to the
power source or monitor.

Use another wall outlet. If
the problem continues, call the
facilities person.

Replace the power supply
module (Section 3.2.2).

Replace the deflection module
(Section 3.2.4).

Replace the video casting
assembly (Section 3.2.5).

Adjust the brightness and
contrast controls.

Turn power to the host system
on.

Connect the signal cable to the
monitor and host.

2–4 Troubleshooting

Table 2–1 (Cont.) Blank Screen, No Video or Raster

Symptom Possible Cause Suggested Solution

No video or raster, but
the power indicator
and LED on the
deflection module are
on.

No video or raster, but
the power indicator
LED is on; the
deflection module
LED is off.

Deflection module
is faulty.

Video casting
assembly is faulty.

CRT/chassis
assembly is faulty.

Internal cabling is
loose or faulty.

G2 Bias is set
incorrectly.

Signal cable is
faulty.

Deflection module
is faulty.

Deflection module
is faulty.

Replace the deflection module
(Section 3.2.4).

Replace the video casting
assembly (Section 3.2.5).

Replace the CRT/chassis
assembly (Section 3.2.6)
only after trying the previous
solutions.

Check all cabling going to
the deflection module and
the video casting assembly,
including the CRT socket
connector. If necessary, secure
the cables.

Correct the G2 adjustment.
(Section 4.5).

Replace the signal cable.
Refer to the host system
documentation.

Replace the deflection module
(Section 3.2.4).

Replace the deflection module
(Section 3.2.4).

Troubleshooting 2–5

Table 2–2 Blank Screen, No Video, but Raster is Present

Symptom Possible Cause Suggested Solution

Raster can be
displayed by
adjusting the
brightness control,
but no video or
cursor can be seen
even when the
contrast control is
at maximum.

The Host system
CRT screen saver
feature is activated.

Internal cabling is
loose or faulty.

The host system
is not supplying
video signals to the
monitor.

Host system is
faulty.

Video casting
assembly is faulty.

Deflection module is
faulty.

Faulty CRT/chassis
assembly

Press any key to reactivate the
display.

Check all the cables to the
deflection module and the
video casting assembly.

Connect the monitor to a
known working host system (if
available) to verify the problem
before replacing any monitor
modules.

Repair the host system.

Replace the video casting
assembly (Section 3.2.5).

Replace the deflection module
(Section 3.2.4).

Replace the CRT/chassis
assembly (Section 3.2.6)
only after trying the previous
solutions.

2–6 Troubleshooting

NOTE

Make sure the monitor has warmed up for at least 20 minutes
before you use Table 2–3.

Table 2–3 Poor Display Quality

Symptom Possible Cause Suggested Solution

Poor geometry,
centering, height,
width, and/or
linearity.

Poor light output
(using the all-white
diagnostic pattern).
The Display is not
bright enough.

Controls on top of the
monitor are out of
adjustment.

Local magnetic fields. Remove any electro-

Monitor is out of
adjustment.

Deflection module is
faulty.

CRT/chassis assembly
is faulty.

The brightness or
contrast control is set
incorrectly.

Host system is not
supplying correct
signal levels.

GAIN and Cutoff
adjustments may be
incorrect.

Video casting
assembly is faulty.

Deflection module is
faulty.

See section 4.1.

mechanical devices from
the vicinity of the monitor, or
move the monitor to another
location.

Perform the alignment
procedure. Refer to Chapter

4.
Replace the deflection module

(Section 3.2.4).
Replace the CRT/chassis

assembly (Section 3.2.6) only
after trying the previous
solutions.

Adjust the brightness and
contrast controls.

Repair the host system.

Perform the GAIN
adjustment (Section 4.6)
and the Cutoff adjustment
(Section 4.5).

Replace the video casting
assembly (Section 3.2.5).

Replace the deflection module
(Section 3.2.4).

Troubleshooting 2–7

Table 2–3 (Cont.) Poor Display Quality

Symptom Possible Cause Suggested Solution

CRT is worn out. Replace the CRT/chassis

Display is too bright. Brightness control is

Vertical lines are not
straight.

Video noise (Display
has intermittent
flashing or changes
in brightness.)

Focus is not sharp. Adjustment is

set incorrectly.
Video casting

assembly is faulty.
Deflection module is

faulty.
Local magnetic fields

are present.

Deflection module is
faulty.

Faulty CRT/chassis
assembly

The signal cable is
loose or faulty.

Video casting
assembly is faulty.

Deflection module is
faulty.

Power supply module
is faulty.

Host system is faulty. Repair the host system.

incorrect.
Deflection module is

faulty.

assembly (Section 3.2.6) only
after trying the previous
solutions.

Set the brightness control to
the optimum range.

Replace the video casting
assembly (Section 3.2.5).

Replace the deflection module
(Section 3.2.4).

Remove any electro­mechanical devices from
the vicinity of the monitor, or
move the monitor.

Replace the deflection module
(Section 3.2.4).

Replace the CRT/chassis
assembly (Section 3.2.6) only
after trying the previous
solutions.

Reseat the connectors or
replace the signal cable.

Replace the video casting
assembly (Section 3.2.5).

Replace the deflection module
(Section 3.2.4).

Replace the power supply
module (Section 3.2.2).

Perform the FOCUS
adjustment (Section 4.5).

Replace the deflection module
(Section 3.2.4).

2–8 Troubleshooting

Table 2–3 (Cont.) Poor Display Quality

Symptom Possible Cause Suggested Solution

Video casting
assembly is faulty.

CRT/chassis assembly
is faulty.

Replace the video casting
assembly (Section 3.2.5).

Replace the CRT/chassis
assembly (Section 3.2.6) only
after trying the previous
solutions.

3

RemovingandReplacingFRUs

3.1 Introduction

This chapter describes how to remove and replace the monitor field
replaceable units (FRUs).

The monitor consists of a small number of removable FRUs that are easily
accessed and removed from the rear of the monitor. No special tools are
needed, and self-retaining hardware is used.

The procedures describe how to remove the FRUs. To install each FRU,
do the reverse of the removal procedure.

WARNING

Turn power to the monitor off before performing any of these
procedures.

NOTE

Before removing any FRUs, you must remove the rear cover and
the top cover.

3–1

3–2 Removing and Replacing FRUs

3.1.1 Removing the External Cables

Remove the external cables (Figure 3–1) as follows:

1. Make sure the power switch is off (out).

2. Unplug the power cord from the power source (wall outlet or host
system) first, then from the monitor.

3. Remove the signal cable from the rear of the monitor.

NOTE

Push the connector in and rotate it to the left until the signal
cable is released from the connector.

Power Cord

Power Source
From Host System

Figure 3–1 Removing Cables from the Monitor

MA-0225-90.DG

Removing and Replacing FRUs 3–3

3.1.2 Removing the Rear Cover

Remove the rear cover as follows:

1. Remove the external cables (Section 3.1.1).

2. Use a Phillips screwdriver to remove the four screws that hold the
rear cover to the enclosure (Figure 3–2).

3. Remove the rear cover by pulling the cover towards you.

Figure 3–2 Rear Cover Removal

MA-0226-90.DG

3–4 Removing and Replacing FRUs

3.1.3 Removing the Top Cover

Remove the top cover as follows:

1. Remove the rear cover (Section 3.1.2).

2. Tilt the top cover up and slide it toward the rear of the monitor.
(Figure 3–3).

Top
Cover

Figure 3–3 Top Cover Removal

MA-0227-90.DG

Removing and Replacing FRUs 3–5

3.2 Field Replaceable Units (FRUs)

The monitor FRUs are shown in Figure 3–4.
When replacing any FRU, tilt the monitor from the back to the front to

allow easier access to the modules.

WARNING

Turn the power off before disconnecting or replacing any FRU.

CRT Chassis
Assembly

Deflection
Module

Figure 3–4 Field Replaceable Units

Interconnect
Cable

Video Casting
Assembly

Power
Supply

MA-0228-90.DG

3–6 Removing and Replacing FRUs

3.2.1 Interconnect Cable

Remove the interconnect cable as follows:

1. Remove the rear cover (Section 3.1.2).

2. Remove the top cover (Section 3.1.3).

3. Disconnect the interconnect cable in the following order (Figure 3–5).

FRU Connector Interconnect Cable Plug

Power supply (right) J1 P1
Video casting (center) J2 P2
Deflection module (left) J3 P3

!
"
#

Removing and Replacing FRUs 3–7

CAUTION

When replacing the interconnect cable, verify that the pull tab
(labeled P2) is above the cable connector on the deflection module.
You can damage the monitor if this cable is replaced incorrectly.

Figure 3–5 Disconnecting the Interconnect Cable

2

3

Interconnect

Cable

MA-0229-90.DG

1

3–8 Removing and Replacing FRUs

3.2.2 Power Supply Module

Remove the power supply module as follows:

1. Remove the rear cover (Section 3.1.2).

2. Remove the top cover (Section 3.1.3).

3. Remove the interconnect cable (Section 3.2.1).

4. Disconnect the 3-wire, 5-pin On/Off switch cable (P4) from the
connector (J4) at the top of the power supply by pressing the tab
on top of the connector (Figure 3–6).

3-Wire, 5-Pin,
On/Off Switch

Cable

Power
Supply

Figure 3–6 Removing the On/Off Switch Cable from the Power Supply

MA-0230-90.DG

Removing and Replacing FRUs 3–9

5. Loosen the captive screw that holds the power supply to the chassis
(Figure 3–7).

6. Slide the power supply module out of the card guides.

Power
Supply

Figure 3–7 Removing the Power Supply

MA-0231-90.DG

3–10 Removing and Replacing FRUs

3.2.3 Discharging the CRT and Removing the Anode Cap

Discharging the CRT is a process that drains to ground any leftover
voltages that remain in the extra-high tension (EHT) cable after power is
removed. Discharge the CRT as follows:

1. Remove the rear cover (Section 3.1.2).

2. Remove the top cover (Section 3.1.3).

3. Remove the interconnect cable (Section 3.2.1).

4. Remove the power supply module (Section 3.2.2).

WARNING

The following steps expose you to the CRT anode which may
store a high voltage.

5. Attach the clip end of the anode discharge tool (PN 29-24717-00) to a
chassis ground point near the CRT anode.

WARNING

Keep your free hand away from any part of the monitor during
the anode discharge process.

6. Using one hand, carefully slip the anode discharge tool under the CRT
anode connector cup until it touches the connector prongs. Maintain
contact for at least 10 seconds.

NOTE

Be careful when you use the anode discharge tool. Do not tap
the CRT. Avoid scratching or marring the CRT glass when you
insert or remove the tool.

7. Remove the CRT anode cap from the CRT, as shown in Figure 3–8.

Removing and Replacing FRUs 3–11

A. Push in the direction
of the arrow.

B. When one barb is free
push in the opposite
direction (see arrows)
to remove anode cap.

,

MA-0232-90.DG

Figure 3–8 Discharging the CRT and Removing the Anode Cap

3–12 Removing and Replacing FRUs

3.2.4 Deflection Module

Remove the deflection module as follows:

CAUTION

Use a static protection kit (PN 29-26246-00) when handling the
deflection module.

1. Remove the rear cover (Section 3.1.2).

2. Remove the top cover (Section 3.1.3).

3. Remove the power supply module (Section 3.2.2).

4. Discharge the CRT and remove the anode cap (Section 3.2.3).

WARNING

You must complete the discharge procedure for the CRT
(Section 3.2.3) before removing the deflection module.

5. Remove the interconnect cable (Section 3.2.1).

6. Loosen the captive screw that holds the deflection module to the
chassis (Figure 3–9).

7. Remove the 2-wire, 3-pin G2 and Focus cable (P7) from the connector
(J7) at the top of the video casting assembly by pressing on the sides
of the connector and pulling. You may need a small screwdriver to
assist in releasing the tabs.

Deflection
Module

Removing and Replacing FRUs 3–13

2-Wire, 3-Pin
Cable

Video
Casting
Assembly

Figure 3–9 Loosening the Captive Screw

6-Wire, 8-Pin

Brightness/

Contrast
Cable

MA-0233-90.DG

3–14 Removing and Replacing FRUs

9. Disconnect the 9-wire, 9-pin raster control cable (P6) from the
connector (J6)!at the top of the deflection module by pressing
the tab on top of the connector.

10. Disconnect the multicolored, 6-wire, 9-pin CRT/yoke cable (P11) from
the connector (J11)"on the deflection module by pressing the tabs
on the connector (Figure 3–10).

9-Wire, 9-Pin,
Raster Control
Cable

1

6-Wire, 9-Pin,

6-Wire, 9-Pin,
CRT/Yoke Cable

CRT/Yoke Cable

2

2

Figure 3–10 Disconnecting Cables from the Deflection Module

MA-0234-90.DG

Removing and Replacing FRUs 3–15

11. Slide the deflection module out of the card guides (Figure 3–11).

Card
Guide

Deflection
Module

Figure 3–11 Removing the Deflection Module

MA-0235-90.DG

3–16 Removing and Replacing FRUs

3.2.5 Video Casting Assembly

Remove the video casting assembly as follows:

1. Remove the rear cover (Section 3.1.2).

2. Remove the top cover (Section 3.1.3).

3. Remove the interconnect cable (Section 3.2.1).

4. Remove the 2-wire, 3-pin cable (P4) from the connector (J4) at the top
of the video casting assembly (Figure 3–12) by pressing on the sides of
the connector and pulling. You may need a small screwdriver to assist
in releasing the tabs.

5. Disconnect the 6-wire, 8-pin brightness/contrast cable (P5) from the
connector (J5) at the bottom of the video casting assembly by pressing
the top center tab on the connector. Place the cable out of the way
behind the video casting.

2-Wire, 3-Pin
Cable

Removing and Replacing FRUs 3–17

6-Wire, 8-Pin
Brightness/
Contrast
Cable

MA-0236-90.DG

Figure 3–12 Removing Cables from the Video Casting

6. Gently push the CRT socket connector off the socket pins
(Figure 3–13).

CAUTION

When you install the video casting assembly, carefully push
the CRT socket connector onto the CRT neck. Use care not to
bend the pins during this procedure.

3–18 Removing and Replacing FRUs

CRT
Socket
Connector

Socket
Pins

Figure 3–13 Removing the CRT Socket Connector

7. Loosen the captive screw at the top of the video casting (Figure 3–14).

8. Gently pull the top of the video casting assembly towards you and lift
it out of the chassis.

MA-0238-90.DG

Removing and Replacing FRUs 3–19

Video Casting
Assembly

Figure 3–14 Removing the Video Casting

MA-0237-90.DG

3–20 Removing and Replacing FRUs

3.2.6 CRT/Chassis Assembly

To disassemble the CRT/chassis assembly:

1. Remove the rear cover (Section 3.1.2).

2. Remove the top cover (Section 3.1.3).

3. Remove the interconnect cable (Section 3.2.1)

4. Remove the power supply module (Section 3.2.2)

5. Discharge the CRT and remove the anode cap (Section 3.2.3).

WARNING

You must discharge the CRT and remove the anode cap
(Section 3.2.3) before removing the deflection module.

6. Remove the deflection module (Section 3.2.4)

7. Remove the video casting assembly (Section 3.2.5)

NOTE

After removing the above FRUs, the remaining part is the
CRT/chassis assembly.

Removing and Replacing FRUs 3–21

3.3 CRT Disposal (Trained Service Personnel Only)

This section describes how to safely dispose of the monitor cathode-ray
tube (CRT). CRTs are glass vacuum tubes. Because air pressure outside
the tube is greater than air pressure inside, there is always the possibility
of accidental implosion.

WARNING

You must handle CRTs very carefully to avoid accidental
implosion and shattering glass. Use the following guidelines
and disposal procedure to remove and dispose of a CRT. These
guidelines and procedure are Digital policy for all CRTs with
more than three inches in diameter.

NOTE

This procedure supersedes all other tech tips about replacing
and disposing of CRTs. This procedure is for Digital personnel
only, and is not intended for use by OEM and self-maintenance
customers.

Location

Work in areas where risks and exposure are limited to trained Digital
personnel. Only Digital personnel should be in the area during CRT
removal and replacement.

Handling a CRT

• Never handle the CRT by the neck. Always use two hands and hold
the CRT by the sides near the face of the tube.

• Keep the CRT away from your body during handling.

• Do not let the neck strike anything.

• Do not rest the CRT on its neck.

• Do not let the CRT touch any tools, such as screwdrivers and soldering
irons.

Stocking and Storage

All CRTs must be kept in a closed container or mounted in the device
cabinetry.

CRT Disposal

Use the following procedure to safely dispose of CRTs. Always perform
this procedure at a Digital facility.

3–22 Removing and Replacing FRUs

WARNING

Do not dispose of any CRT until it is rendered inoperative and
safe to dispose.

Never perform the following disposal procedure at the customer
site. Return the defective CRT to the local Digital facility for
disposal.

At the Digital facility you must:

• Clear the area of nonessential personnel.

• Have a second person in the area in case of an emergency.

• Wear safety goggles (PN 29-16141-00).

• Wear gloves (PN 29-16146-00).

• Use pliers.

WARNING

To avoid injury to your eyes or hands, always wear goggles
and gloves when you work with a CRT. Never handle pieces of
phosphor-coated glass without wearing protective gloves.

Before you perform the following procedure, remove the FRUs listed in
Section 3.2.6.

1. Place the old CRT/chassis assembly and the original packing material
in the container from which you removed the new CRT/chassis
assembly.

2. Using pliers, slowly crush, but do not snap, the evacuation point
(Figure 3–15). Do not move or disturb the CRT until the hissing
sound of in-rushing air stops.

CAUTION

Use care not to break the unprotected glass area of the CRT
neck that surrounds the evacuation point.

NOTE

The evacuation point is a protrusion that extends from
the circular area defined by the CRT neck pins. The glass
protrusion is sometimes encased in a protective plastic cap,
and more force is required to crush it.

Removing and Replacing FRUs 3–23

Figure 3–15 Crushing the Evacuation Point

3. Seal the carton with packing tape and dispose of it in the Digital site’s
trash receptacle.

NOTE

The safe "gassing" of the CRT is necessary to prevent liability and
safety problems that may arise from accidental CRT implosion.

MA-X0667-88

3–24 Removing and Replacing FRUs

3.4 Tilt-Swivel Base

Helpful Hint: During normal use, the tilt-swivel base should not come
off the unit. There is a retainer plug in the center of the swivel retainer
(74-39791-01) to hold the base on. If the tilt-swivel base should come off
and the retainer teeth are not broken, you do not have to take the monitor
apart. Use the following procedure to put the tilt-swivel base back on the
monitor.

1. Place the monitor screen-side down on a soft pad.

2. Align the tilt-swivel base with the wider part downward toward the
screen (Figure 3–16).

3. Place a curved tool, like a long Allen wrench, through the center of
the swivel retainer inside the base.

4. While pressing on the base with one hand, pull the swivel retainer
toward the base until the retainer teeth click into position.

5. Install a retainer plug (74-41176-01) in the retainer to keep the teeth
apart.

Removing and Replacing FRUs 3–25

Teeth of
Swivel
Clamp

Monitor
Base

Monitor
(Bottom
View)

Figure 3–16 Tilt-Swivel Base

MA-0239-90.DG

4

AligningtheVideoMonitor

4.1 Introduction

This chapter describes how to align the monitor display. You do not have
to perform every adjustment procedure each time you align the monitor;
however, you should check all adjustments in the order shown.

The success of one adjustment may depend on the accuracy of the
preceding adjustments with the exception of the FOCUS and G2
adjustments. If a setting is already correct, you can skip that adjustment
and go on to the next one.

Use Section 4.1.1 to set up the monitor for adjustments. You must use
the screen alignment test patterns to make all adjustments. Refer to your
host system documentation to set up test patterns.

4.1.1 Before You Start

NOTE

If a customer calls with a display quality type of problem, ask the
customer to leave the monitor on until you arrive. Then, after
removing the rear cover, only a 5 minute warm-up is needed.

Clean the Monitor

Use a soft tissue or cloth and a non-abrasive, nonflammable glass cleaner,
or use Digital’s video screen cleaner (PN VT3XX-SC).

Set up the Monitor

Before you perform adjustments, set up the monitor as follows:

1. Place the monitor on a nonconductive surface.

2. Remove the rear cover (Section 3.1.2).

3. Remove the top cover (Section 3.1.3).

4. Reconnect the video cable.

4–1

4–2 Aligning the Video Monitor

5. Reconnect the power cord.

6. Press the power switch to on. Wait for a video display to appear on
the screen.

7. Verify that the user controls on the top of the monitor are in the
center position of the thumbwheels. The user adjustments are listed
in Table 4–1 and shown in Figure 4–1.

8. Rotate the monitor so the adjustments on the deflection board are on
the right and the screen to view the test pattern is on the left. When
performing the geometry adjustments, the monitor should be facing
east, if possible.

Table 4–1 Monitor Controls and Indicators

Item Control/Indicator Function

!

"
#
$
%

&

'

1

The VR315 has a degauss icon on the bezel because this bezel was planned for use with
a companion color product. The VR315 and VR325 monochrome monitors do not have or
need a degauss switch.

Power switch/
indicator

Contrast Adjusts the video display intensity.
Brightness Adjusts the video background intensity.
Rotation Rotates the video display area.
Horizontal centering Adjusts the horizontal position of the active

Vertical centering Adjusts the vertical position of the active

Degauss switch Not installed

Turns the power on and off. When the power
is on, the switch is lit up. For extended
monitor life, switch the power off when not
in use.

area with respect to the bezel.

area with respect to the bezel.

1

.

Aligning the Video Monitor 4–3

4

1

2

3

7

5

6

Figure 4–1 User Controls and Indicator

MA-1295-89.DG

4–4 Aligning the Video Monitor

4.1.2 Check LEDs and Heater Filament

Visually check the monitor to ensure that the following components are
ON:

• LED on the power switch

• LED on the deflection module

• CRT heater filament

4.1.3 Displaying Screen Tests

The procedures in this chapter refer to a circle-crosshatch alignment test
pattern (Figure 4–2) and an all-white test pattern. Display them on the
screen as needed by using procedures for your host system.

Refer to the host system service guide for accessing these diagnostic
screen patterns.

Figure 4–2 Circle-Crosshatch Pattern

MA-X0889-88

Aligning the Video Monitor 4–5

4.2 Monitor Adjustments

Let the monitor warm up for at least 20 minutes before performing any
adjustments. The warm-up time ensures that the circuitry is at a stable
temperature before you do any adjustments.

NOTE

In the following steps, use a metric measuring tape (PN 29-25342)
to measure the dimensions of the screen display. To avoid
scratching the screen with the tape’s metal clip, start the
measurement at 10 cm. See Figure 4–3.

10 119

199 mm

VR315 - 236 mm

VR325 - 265 mm

Figure 4–3 Using the Metric Measuring Tape

MA-0301-90.DG

LJ-00545-TI0

4–6 Aligning the Video Monitor

4.3 Deflection Adjustments

4.3.1 Raster Adjustment

1. Set the user controls (Figure 4–1) on the top and the bottom of the

monitor in the center position of the thumbwheels.

2. Adjust the Contrast control just until the raster displays.

3. Adjust the G2 potentiometer to its centered position (Figure 4–4).

4. Adjust VLIN potentiometer to its centered position.

5. Using a hex-head driver, set HLIN for the maximum width of the

raster, then reduce the raster size by about 5 mm.

4.3.2 Anode Voltage Adjustment

The anode voltage affects the overall display size, both the height and the
width of the display. Only the center region of the potentiometer affects
the display size. Adjust the anode voltage as follows:

1. Mark the position on the ANODE potentiometer where the display

size is maximized and minimized, by turning it in one direction and
then the other.

2. Set the ANODE potentiometer to the half-way point between where

the display size was at a maximum and at a minimum.

4.3.3 Height and Width Adjustments

Check and adjust linearity as follows:

1. Display the circle-crosshatch pattern (Figure 4–2).

2. Set the Brightness control on the bottom of the monitor to display the

raster.

3. Set the HPHASE potentiometer so that video display is centered in

the raster.

4. Using a Phillips screwdriver, adjust HCEN to center the display in

the bezel.

5. Using a hex-head driver, set WIDTH so that the right half of the

display is the correct width.

6. Using a hex-head driver, set HLIN so that the left half of the display

is correct.

Aligning the Video Monitor 4–7

7. Repeat step 4 until the correct size, centering, and linearity is

obtained. Then continue with step 8.

Width

HLin

HLin

HCen

GainGain

G2

Focus (G4)

Anode

HPhase

VCen
VLin

Height

VHold

Figure 4–4 Internal Controls

8. Adjust VCEN (Figure 4–4) so that the display is centered in the bezel.

9. Set HEIGHT so that the center to the bottom half of the dimension is

correct.

10. Adjust VLIN so that the center rectangles are the same size as the

bottom and top rectangles.

MA-0471-90.dg

4–8 Aligning the Video Monitor

4.4 Using the Radiance Meter

Use the radiance meter as follows:

1. Remove the cap from the radiance meter sensor head and connect the

occluder to the radiance meter (Figure 4–5).

CAUTION

Avoid excessive force when tightening the occluder or you may
damage the radiance meter. Do not touch the exposed filter
after the protective cap is removed.

2. Connect the ac line adapter to the radiance meter and plug the

adapter into a wall outlet.

NOTE

Ensure that your radiance meter is in calibration.

3. Turn the power switch to on.

NOTE

Do not use the POWER ON W/BACKLIGHT position when you
are using the radiance meter with batteries.

4. Set the range switch to the second position from the top (1.999).

Aligning the Video Monitor 4–9

Occluder

Sensor
Head

Power
Switch

Range
Switch

AC Adapter

AC Adapter
Connector

MA-X0665-88A

Figure 4–5 Radiance Meter

5. Place the occluder firmly against the center of the screen (Figure 4–6).

Take a red china pencil to draw an arc or circle around the occluder.

NOTE

You must take all meter readings with the meter centered in
this arc or circle.

4–10 Aligning the Video Monitor

MA-0302-90.DG

Figure 4–6 Using the Radiance Meter

4.5 Cutoff Adjustment

To adjust G2 control, use the radiance meter on the screen (Figure 4–6).
Check and adjust G2 (Figure 4–7) as follows:

1. Set the Brightness to minimum and Contrast controls to maximum.

2. Set G2 using the raster pattern so that the maximum background

luminance is 0.010.

3. Display the Circle/Crosshatch pattern and set FOCUS (G4) for best

overall sharpness.

Aligning the Video Monitor 4–11

4.6 GAIN Adjustment

1. Set the Contrast control to maximum and Brightness control for

background extinction.

2. Set GAIN using the All-White pattern to obtain 0.283 luminance at

the screen center.

G2

G4

Gain

Figure 4–7 GAIN, G2, and FOCUS (G4) Adjustments

MA-0300-90.DG

A

VR315andVR325Documentation

You can order the following VR315 and VR325 documents, some of which
are available in several languages, from Digital. Contact your sales
representative for availability and more information.

Installing and Using the VR315 and VR325 Monochrome Monitors

EK-VR315-IN-002

This guide provides users with the information needed to install, operate,
and maintain the VR315 and VR325 monitors. The manual also describes
all controls and indicators.

VR315/VR325 Monochrome Monitor IPB

EK-VR315-IP-002

This document provides a detailed parts breakdown of the VR315 and
VR325 field replaceable parts. The documents do not contain part
numbers for components on the printed circuit modules. However,
these components are listed in the Field Maintenance Print Set, ordered
separately.

VR315 Field Maintenance Print Set

MP-03013-01

This document provides a complete set of electrical and mechanical
schematic diagrams for the VR315 monitor.

VR325 Field Maintenance Print Set

MP-03013-02

This document provides a complete set of electrical and mechanical
schematic diagrams for the VR325 monitor.

A–1