Qume QVT 101 Operating manual

WARNING
The ROM resident software incorporated in
thi s product is protected by copyri ght and
may not be copied or duplicated without the
written authorization of Qume Corporation.
Reorder Number 35057
April 1985
© 1985 Qume Corporation, Printed in U. S. A.
OocuMinder, LetterPro, MicroDrive, Multistrike,· PHD, ProFeeder, Q, QPW,
Quickload, Qume, QumeTrak, QVT, Sprint, SprintFeed, Stockpak, SuperStrike, The
Qume Connection, TriGimbal, Twintellect, TwinTrack, Wedge, and WideTrack are
trademarks of Qume Corporation. .
Qum Corporation nBkes no representation or warranties of artY kind Wlatsoever with respect to
the contents hereof and specifically disclaims aflY ill1llied warranties of nerchantibility or
fitness for
aflY particular purpose. Qure Corporation shall not be liable for errors contained
herein or for incidental or consE!(JJential dcmges in connection with the fumishing, perfonnance,
or use of this I1Bterial. Qure Corporation reserves the ri91t to revise this publication fran
tine to tine
and to make changes in the content hereof without obligation to notify aflY person of
such revi sion or changes.
Contents of this publication ~ be preliminary and/or l18y be changed at artY tine without notice
and shall not be regarded as a warran1'¥.· .
2350 Qum Drive, san Jose, Califomia 95131, TWX 910-338-0232, Phone (.4()3) 942-4(0)
,..

PREFACE
The
QVT-10l
Maintenance
Guide
has
been
designed
to
allow maintenance personnel
to service the
QVT-10l
m Terminal
by
quickly
isolating
a
fault
and
taking cor-
rective
action in a
minimum
amount
of time.
It
is
assumed
that
all
service
personnel
who
may
use
this
guide
have
rudimentary
knowledge
of video display
terminals
and
related maintenance
practices.
i
I
I
1
I~
'1
I
I
'~,

The QVT-10l Maintenance Guide 1s divided into the following sections:
• Section
1: Troubleshooting -for isolating a fault to a subassembly.
• Section 2: Subassellbly Raoval
and Replacf!llent -procedures for
removing and replacing a defected subassembly.
• Section 2: Alignlent -procedures for performing
any necessary video
alignment
after replacing a subassembly.
• Section 3: Parts -information for identification of replaceable
parts
and recommended spares.
• Section 4: Circuits
and Diagraas -reference material.
ASSOCIATED PUBLICATIONS
For general User Information:
QVT-10l Operator Manual ••••...•••.••.••••••.••••• ~ ••••••Reorder Number 35073
if

TABLE OF CONTENTS
Page No.
SECTION 1: TROUBLESHOOTING ...•••.
. ....••............. 1-1
INTRODUCTION ••••••••••••••••••••••••••••••••••••••
. .•••••.•..••••••.•• 1-1
TROUBLESHOOTI NG TECHN I QUE. .••.•.••.••.•.••••.•.••..•••••..••••.••.•••••••• 1-1
TROUBLESHOOTI NG FLOWCHARTS •••••••••••••••••••••••••••••••••••••••••••••••• 1-1
Tools and Equipment Required •••••••••••••••••••••••••••••••••••••••••••• 1-1
Fault Isolation Flowchart #1 ••••••••••••••••••••••••.••••••••••.•••••••• 1-3
Fault Isolation Flowchart
#2 ••••.••..••••••••••.•••••••••.••.•••..•••••• 1-4
Fault Isolation Flowchart
#3· •••••••••••••••••••••••••••••••••••••••••••• 1-6
Fault Isolation Flowchart
#4 •••••.•••••••••••••••••••••••••..•.••••••••• 1-7
Fault Isolation Flowchart #S •••••••••••••••••••••••••••••••••••••••••••• 1-B
ERROR CODES SUMMARy •••••••••••••••••••••••••••••••••••••••••••••••••••••• 1-10
SECTION 2:
SUBASSEMBLY REMOVAL AND REPLACEMENT •••.•.•.•••.••••....•.••..• 2-1
INTRODUCTION •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 2-1
SAFETY SUMMARy •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 2-1
REQUIRED· TOOLS •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 2-1
Lower Monitor Area •••••••••••••••••••••••••••••••••••••••••••••••••••••• 2-1
Upper
Monitor Area •••••••••••••••••••••••••••••••••••••••••••••••••••••• 2-2
COVER SETS •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 2-2
Keyboard -
Top Cover •••••••••••••••••••••••••••••••••••••••••••••••••••• 2-2
Keyboard - Bottom Cover (Keyboard PCB and Coiled Keyboard Cable) •••••••• 2-3
Key Caps ••••••••••••••• ,. •••••••••••••••••••••••••••••••••••••••••••••••• 2-6
Monitor Back Cover •••••••••••••••••••••••••••••••••••••••••••••••••••• 2-7
Monitor - Bottom Cover •••••.••..•••••.•.••••.••••••••.••••...•.•••••••.• 2-9
LOWER MONITOR AREA SUBASSEMBLIES ••••••••••••••••••••••••••••••••••••••••• 2-11
Power/Log;c PCB •••••••••••••••••••••••.••••••••.•••••••••••••••••.•••.• 2-13
Transformer ..•....••...•..••.....••••••............•.....••......•..... 2-14
Power On/Off Switch ••••••••.•••••.••••.••••••••••.••••• · .•••...•••.•.••• 2-15
Fuse Hol der •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 2-15
Battery .••.........••..•.........•••....•••••...•..•.•••....•...•.•••.. 2-17
Brightness Control ..•••••••.•.•••.••••••••.•••••••••.••••.••••••..•.••. 2-19
UPPER MONITOR AREA SUBASSEMBLIES •.••••••••••••••.•••••••••••••••••••••••. 2-21
Video PCB •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 2-22
Discharging the CRT High-Voltage Circuit •••••••••.•••••••.••••••••.•••• 2-23
CRT •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 2-23
SECTION 3:
Al.1 GNl£NT •••••••••• •••• ••• ••••••••• ••••••••••••••••••• •••• 3-1
I NTRODUCT I ON •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 3-1
TOOLS AND EQUIPMENT REQUIRED ••••••.••..••••••••••••••••••••••.••••••.••••. 3-1
ALIGNMENT CONDITIONS •••••••••••••••••••••••••••••••••••••••••••••••••••••• 3-2
VIDEO ALIGNMENT PROCEDURES •••••.•.••••.••••••••••••••••••••••••••.•••••••• 3-4
Horizontal Display Width (Line Width) ••••••••••••••••••••••••••••••••••• 3-S
Vertical Display Height ••••••••••••••••••••••••••••••••••.•••••.••••••••• 3-6
Horizontal Linearity (Uniform Character Width) •••••••••••••••••••••••••• 3-7
Vertical Linearity
(Uniform Character Height) ••••••••••••••••••••••••••• 3-7
Sri ghtness ..•..•• ~ .•.•••••.••..••••••.•••••.•.•.••••••••••.•....•.••.•..•. 3-7
Focus. : ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 3-8
Display Centering (Raster Position) ••••••••••••••••••••••••••••••••••••• 3-B
;;i

TABLE OF CONTENTS (Cont.)
Page No.
~ECTION 4: PARTS •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 4-1
ReCOMMENDED SPARE PARTS ••••••••••••••••••••••••••••••••••••••••••••••••••• 4-2
'\
SECTION 5: CIRCUITS AND DIAGRAMS •.••••••••••••••••••••••••••••••••••••••••• S-1
5-1 QVT-101 Functional Block Diagram •••••••••••••••••••••••••••••••••••• S-3
S-2 QVT-101 Interconnect Wiring Diagram ••••••••••••••••••••••••••••••••• S-S
5-3 QVT-101 Keyboard Schematic Diagram •••••••••••••••••••••••••••••••••• S-7
5-4 QVT-101 Video PCB Schematic Diagram ••••••••••••••••••••••••••••••••• S-9
5-5 QVT-101 Power/Logic PCB Schematic Diagram (8 sheets) ••••••••••••••• S-11
Figure
2-1
2-2
2-3
2-4
2-S
2-6
2-7
2-8
2-9
2-10
3-1
3-2
4-1a
4-1b
4-2
Table
1-1
4-1a
4-1b
4-2
4-3
iv
LIST OF ILLUSTRATIONS
Page No.
Keyboard Top Cover Removed •••••••••••••••••••••••••••••••••••••••••• 2-4
Keyboard PCB Removal and Replacement •••••••••••••••••••••••••••••••• 2-S
Keycap Removal and Replacement •••••••••••••••••••••••••••••••••••••• 2-6
Monitor Back Cover Removal and Replacement •••••••••••••••••••••••••• 2-8
Monitor
Bottom Cover Removal and Replacement ••••••••••••••••••••••• 2-10
Lower Monitor Area ••••••••••••••••••••••••••••••••••••••••••••••••• 2-12
Power On/Off Switch and Fuse Holder Removal and Replacement •••••••• 2-16
Battery Removal and Replacement •••••••••••••••••••••••••••••••••••• 2-18
Brightness Control
Removal and Replacement ••••••••••••••••••••••••• 2-20
Upper Moni~or Area ••••••••••••••••••••••••••••••••••••••••••••••••• 2-21
The "H" Test Pattern •••••••••••••••••••••••••••••••••••••••••••••••• 3-3
Location of Video Alignment Components •••••••••••••••••••••••••••••• 3-4
QVT-lOl Upper Monitor Area (Exploded View) •••••••••••••••••••••••••• 4-3
QVT-I0l Lower Monitor Area (Exploded View) •••••••••••••••••••••••••• 4-7
QVT-lOl Power/Logic PCB (Exploded View) •••••••••••••••••••••••••••• 4-13
LIST OF TABLES
Page No.
Error Codes Summary •••••••••••••••••••••••••••••••••••••••••••••••• 1-10
QVT-101 Upper Monitor Area Parts •••••••••••••••••••••••••••••••••••• 4-S
QVT-lOl Lower Monitor Area Parts •••••••••••••••••••••••••••••••••••• 4-9
QVT-lOl Power/Logic PCB Parts •••••••••••••••••••••••••••••••••••••• 4-1S
Recommended Spare Parts •••••••••••••••••••••••••••••••••••••••••••• 4-16

..
SECTION 1
TROUBLESHOOTING
INTRODUCTION
This section provides a troubleshooting method for isolating most QVT-101
failures to an easily replaced subassembly, by systematically advancing
through a series of troubleshooting flowcharts.
TROUBLESHOOTING TECHNIQUE
Effective troubleshooting technique should always begin with a thorough visual
inspection.
Look for obvious things that may adversely effect the performance
of the terminal, such as:
• Is the
AC power source supplying adequate power,
• Is the brightness potentiometer properly adjusted,
•
Are all connectors making good contact,
• Is there a compatibility
problem between the terminal and the host?
TROUBLESHOOTING FLOWCHARTS
When using the following troubleshooting flowcharts, always begin with Fault
Isolation Flowchart # 1.
Although each flowchart is more or less tailored to
troubleshoot a general area,
it should be noted that they have been purpose-
fully arranged to quickly
isolate a fault to a replaceable subassembly. It is
not recommended that the flowcharts be used out of sequence.
Refer to the Circuits
and Diagrams Section for more specfic information as
necessary.
Tools and Equipment Required
• 0825 Loopback Connector,
• Phillips Screwdriver,
• Multimeter,
•
High Voltage Probe,
• Interconnect
Wiring Diagram and Schematics (refer to Section 5) •
1-1

TROUBLESHOOTI NG
Fault Isolation Flowchart f 1
Power on unit.
Doeslunit display an error code? ---YES---> Proceed to Table 1-1 Error Codes
Summary at end of this section.
-NO
Perform Self-Test (press ESC/shift V keys).
Doe.l unit
perform Self-Test? ---NO---> Proceed to Flowchart # 2.
-YES
Exit Self-Test,
enter
Local mode.
Press each key on
keyboard.
I
Are characters
displayed
as keys
are pressed? ---NO---> Proceed to Flowchart # 3.
-YES
Exit Local mode, enter On Line
mode &Full Duplex mode. Install
loopback connector to EIA port.
Press
each key on keyboard.
I
Are characters
displayed as
keys
are pressed? ---NO---> Defective Power/Logic PCB. Replace Power/Logic
PCB (refer to Section 2).
-YES
Connect printer to AUX port.
Exit
On Line mode &enter
Local mode. Print.
I
1-3
1
1
J
I

TROUBLESHOOT! NG
Fault Isolation Flowchart' 1 (Cont)
Is screen
data printed? ---NO---> Defective
Power/Logic PCB. Replace Power/Logic
. PCB (refer to Section 2)
-YES
Unit checks OK.
Fault Isolation Flowchart # 2
From Flowchart # 1.
Is A! line fuse good ?---NO---> Replace bad fuse. Continue.
-YES
Does fuse fail again at power on1 --NO---> Return. Begin Flowchart # 1.
veril~Y::eratlon of ON/OFF switch.
Is switch defective? ---NO---> Return. Begin Flowchart # 1.
-YES
Replace switch (refer to Section 2). Continue.
Doeslfuse fail again at power on? --NO---> Return.
-YES
Begin Flowchart # 1.
Replace fuse. Disconnect P5 to isolate power transformer. Measure
transformer output and verify voltage (23 volts AC + 10').
I -
Is voltage present? ---NO---> Power transformer is defective. Replace
power transformer (refer to Section 2).
-YES
Power transformer checks OK. Power off unit and reconnect power transformer
connector
P5 on Power/Logic PCB. Disconnect P19 and the keyboard telephone
jack
from the Power/Logic PCB. Power on unit.
I
1-4

TROUBLESHOOTING
Fault Isolation Flowchart # 2 (Cont)
Does fuse fail again at
power on? --NO---> Power/Logic PCB checks OK. Keyboard or Video PCB is
defective. Continue.
-YES
Replace fuse. Connect keyboard telephone jack to the Power/Logic PCB.
Power on unit.
Doeslfuse fail
again at power on?
-YES
--NO---> Keyboard checks OK. Video PCB is shorted.
Replace Video PCB (refer to Section 2).
Return to Flowchart * 1.
Keyboard or coiled keyboard cable is defective.
Return to Flowchart *1.
1-5

TROUBLESHOOTING
Fault Isolation Flowchart' 3
From Flowchart *1.
Is +12 Vdc and GND present at Pll
on Keyboard PCB (pin 1, GND/pin 2, +12 Vdc) ---NO---> Coiled keyboard cable
is defective. Replace
coiled keyboard cable
(refer to Section 2).
-YES
Is 1 Vdc + 1V present at test pOint K1 on
Power/LogfC PCB? ---NO---> Power/Logic PCB is defective. Replace Power/Logic
PCB (refer to Section 2).
-YES
Depress each key on keyboard for a minimum
of 2 seconds each and observe for an AC RMS
voltage at test point K1 on Power/Logic PCB.
Does1thfs voltage fncrease to appro •• 200 mVac RMS whfle
each key is pressed? ---NO------> Keyboard is defective. Replace keyboard·
1
assembly (Refer to Section 2).
-YES
Is t e correct character displayed. ------NO------> Proceed to Flowchart *4.
-YES
Unit checks OK. Proceed to System Test.

TROUBLESHOOTING
Fault Isolation Flowchart # 4
From Flowchart # 3.
Chec! the following voltages on the Power/Logic PCB:
U1
U1
Pin 12 +5 Vdc
Pin 1 Gnd
US
US
Pin 1 -12 Vdc
Pin 14 +12 Vdc
Are a
1
::
E
:Oltages present?
--NO---> Oefective power supply circuit. Repair.
Veri y proper operation of
the brightness control. Rotate
control fully
CCW, then fully
CWo Observe a 300 mVdc voltage
chanre between pins 1 and 2 of P7.
Does voltage change by approx.
300 mVdc? ---NO---> Brightness control is defective. Replace brightness
control
(refer to Section 2).
-YES
Blank screen (Shift-Home/Clear). At P19,
pin 5 observe for an AC RMS voltage. Display
self-test (ESC V). At P19, pin 5 observe for
an AC RMS voltage.
Did !Oltage increase to approximately
400 mVac RMS when self-test was
displayed? ---NO---> Power/Logic PCB is defective. Replace Power /Logic PCB
(refer to Section 2).
-YES
Proceed to Flowchart # 5.
1-7

Fault Isolation Flowchart I 5
From Flowchart # 4.
DiSpLy "H" Test Pattern (Setup-Zero).
I
ChecR voltages on Video PCB, P1:
0-102 Anode +12 Vdc
0-104 Anode GND
TROUBLESHOOTING
Are voltages present? ---NO---> Defective power supply circuit. Repair
-YES
With brightness control
fully
CW, check at junction of R551
. and R553 for approx. 400 mVac RMS.
I
Is approx. 400 mVac RMS present? ---NO---> Defective power supply circuit.
Repair.
-YES
With a high voltage probe, I
check the CRT anode cap ( WARNING: HIGH VOLTAGE
for approx. 13 kVdc. I
Is tlere approximately 13 kVdc present at the CRT
anode cap? ----NO----> Video PCB defective. Replace Video PCB (refer to
Section 2).
-YES
ChecR the following voltages on the Video PCB (tolerance + 25%):
1-8

TROUBLESHOOTING
P3, Pin 2
P3, Pin 1
P4, Pin 2
P4, Pi n 1
G1 -28 Vdc
CAUTION
Take precautions when handling the CRT. DO
NOT scratch or strike the CRT or subject it
to unusual pressure. The CRT contains a
high vacuum and breakage of the tube may
result in injury from flying glass.
Hazardous voltages are present in the
general area of the
f1yback transformer
lead
and the CRT anode cap. Exercise
caution to avoid
electrical shock when
performing any video alignment procedure.
Remember that the terminal is powered ON.
0.3 Vac RMS
1.3 Vac RMS
10 Vac RMS
25 Vac RMS
G2
0154 cathode
G4
Q503 Col.
550 Vdc
45 Vdc
175 Vdc
12 Vdc
Are all voltages present? ---NO---> Video PCB defective. Replace Video PCB
(refer to Secti on 2).
-YES
CRT defective. Replace CRT (refer to Section 2).
1-9

TROUBLESHOOTING
ERROR CODES SUMMARY
As part of the terminal's power on sequence, it performs an internal self-
test, and signals that it has successfully completed this test by sounding the
audible alarm.
However, if a non-fatal error is detected, an error code will
be displayed'on the screen. For example, if the letter "0" is displayed, this
signifies that a fault has been isolated to the Power/Logic PCB (i.e. IC
Ul8). The following table lists all possible error codes.
Table 1-1. Error Codes Su .... ry
ERROR CODE CORRECTIVE ACTION
A Replace UlO, or the Power/Logic PCB.
B Replace U8, U9, or the Power/Logic PCB.
C Replace U8, U9, UlO, or the Power/Logic PCB.
o Replace Ul8, or the Power/Logic PCB.
E Replace UlO and U18, or the Power/Logic PCB.
F Replace U8, U9 and U18, or the Power/Logie PCB.
G Replace U8, U9, U10 and U18, or the Power/Logic PCB.
H Replace the keyboard.
I
Replace U10, or the Power/Logic PCB, and the keyboard.
J Replace U8 and U9, or the Power/Logic PCB, and the keyboard.
K
Replace U8, U9 and UlO, or the Power/Logic PCB, and the keyboard.
L
Replace U18, or the Power/Logic PCB and the keyboard.
M Replace U10 and U18, or the Power/Logic PCB and the keyboard.
N
Replace U8, U9 and U18, or the Power/Logic PCB and the keyboard.
o Replace U8, U9, UlO and U18, or the Power/Logic PCB and the
keyboard.
Note: U8, U9, UlO and U18 are located on the Power/Logic PCB.
1-10

SUBASSEMBLY REMOVAl AND REPLACEMENT
INTRODUCTION
This section describes how to remove and replace the major subassemblies of
the
QVT -101 Before begi nni ng, place the Power On/Off swi tch in the OFF
position and disconnect the power cord from the power source. Thoroughly read
each procedure before attempting any subassembly removal and replacement.
SAFETY SUtl4ARY
Always remember that the terminal modules contain extremely high voltages. If
proper precautions are not taken, contact with these voltages can result in
injury.
Observe the following precautions.
•
•
•
Unless otherwise instructed by procedures in this manual, always turn
off the terminal power with the rocker-type power switch on the rear of
the_
mon; tor base and unplug the power cord from the monitor before
removing the cover or attempting subassembly removal or adjustment.
Always read the removal and replacement instructions carefully before
attempting the
removal of any subassembly. -
Take special precautions when working with the CRT. Do not scratch or
strike the CRT, or subject it to unusual pressure. The CRT contains a
high vacuum; breaking the CRT may cause injury from flying glass or
high voltages. As a precaution wear eye protection when working with
the
CRT.
REQUIRED TOOLS
The tools required for removal and replacement of subassemblies are listed
below_
•
•
•
Phillips screwdriver, medium (No.2 tip)
Soldering
equipment
Keycap extraction tool (Qume Part Number 84873-01)
lower Monitor Area
The lower monitor area contains the Power/logic PCB and the line transformer,
and brightness control.
CAUTION
Hazardous voltages are exposed in the general
area of the
AC input circuit, line trans-
former,
and power supply. Before performing
any service in the lower monitor area, power
OFF the terminal and disconnect the power
cord.
2-1

SUBASSEMBLY REMOVAL AND REPLACEMENT
Upper Monitor Area
The upper monitor area contains the CRT and the video PCB.
COVER SETS
CAUTION
Take special care when working in the general
area of the
CRT. Do not scratch or strike
the CRT or subject it to unusual pressure.
The CRT contains a high vacuum and breakage
of the tube
may resul tin injury from flyi ng
glass. As a further precaution wear suitable
clothing
and eye protection.
A hazardous residual voltage
may be present
on the CRT at the flyback transformer anode
cap. Always discharge the CRT anode to
ground before performi ng any mai ntenance in
the
upper moni tor area (refer to Step 2 of
the
Video PCB Removal and Replacement
procedure) .
The paragraphs below descri be the removal and replacement of the cover sets
for the keyboard and monitor. This procedure prefaces the removal and
replacement of the other QVT-lOl subassemblies.
Keyboard - Top Cover
The top cover of the keyboard is secured from the underside of the keyboard
assembly by six screws.
REMOVAL
1. Disconnect the keyboard cable from the monitor.
2. Place the
keyboard upside down on a level surface and remove the six
screws.
Lift the bottom cover with keyboard PCB away from the top cover.
REPLACEMENT
To replace the top cover, repeat removal instruction in reverse order.
2-2

SUBASSEMBLY REMOVAL AND REPLACEMENT
Keyboard - Bottom Cover (Keyboard PCB and Coiled Keyboard Cable)
To remove and replace the bottom keyboard cover, it is also necessary to
remove and replace the keyboard PCB and the keyboard cable.
REMOVAL
1. Remove the top cover from the keyboard assembly. Refer to the Keyboard
Top Cover Removal and Replacement procedure.
2.
Remove the six screws that secure the keyboard PCB to the bottom cover.
However, the two screws with tabs, located at bottom center of keyboard,
do not have to be removed, just loosen each tab/screw and move holddown
tab to one side. See Figure 2-1.
3.
Li ft the keyboard PCB up and 1 ay ;t over the back edge of the bottom
cover. See Figure 2-2.
4. Disconnect the coiled
keyboard cable from the keyboard PCB and remove the
cable
from its retainers on the inside of the bottom cover. Be careful
not to
damage the cable by overstressing its applying excessive force to
its terminations. Remove the keyboard cable, keyboard PCB, and bottom
cover.
2-3

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Removal
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2-5