Qume QVT 101 PLUS Operating manual

.- .
.-.

WARNING
The ROM resident software incorporated in
this product is protected by copyright and
may not be copied or duplicated without the
written authorization of Qume Corporation.
Reorder Number 35087
May 1986
Copyright 1986 Qume Corporation, Printed in U.S.A.
DocuMinder,
LetterPro, MicroDrive, Multistrike, PHD, ProFeeder, QPW, Quickload,
SprintFeed, Stockpak, SuperStrike, The Qume Connection, TriGimbal, and Wedge are
trademarks of Qume Corporation. Q, QVT, QUME, QumeTrak, SPRINT,
TWINTELLECT, TwinTrack, and WideTrack are registered trademarks of Qume
Corporation.
QUME CORPORATION MAKES NO REPRESENTATION OR WARRANTIES OF ANY
KIND WHATSOEVER WITH RESPECT TO THE CONTENTS HEREOF AND
SPECIFICALLY DISCLAIMS ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR
FITNESS FOR ANY PARTICULAR PURPOSE. Qume Corporation shall not be liable'
for errors contained herein or for incidental or consequential damages in connection
with the furnishing, performance, or use of this material. Qume Corporation
reserves the right to revise this publication from time to time and to make changes
in
the content hereof without obligation to notify any person of such revision or
changes.
Contents of this publication may be preliminary and/or may be changed at any time
without notice and shall not be regarded as a warranty.
500 Yosemite Drive, Milpitas, California 95035, TWX 910-338-0232, Phone [phone]
(
I
.,,-- .-
~- -

PREFACE
The QVT 101 PLUS'" Mai ntenance Gui de has been desi gned to a" ow mai ntenancp
personnel
to service the QVT 101 PLUS'" Terminals by quickly isolating a fault
to the assembly level and taking corrective action in a minimum amount Of
time. It is assumed that all service personnel who may use this guiciE: have
rudimentary knowledge of video display terminals and related maintenance
pract ices.

The QVT 101 PLUS· Maintenance Guide is divided into the following sections:
•Section 1: Troubleshooting for
isolating a fault to asubassembly.
•Section
2: Subassembly Removal and Replacement procedures for
removing and replacing adefective subassembly.
•Section
3: Alignment procedures for performing any necessary video
alignment
after replacing asubassembly.
•Section 4: Parts information
for identification of replaceable parts
and recommended spare parts.
•Section 5: Circuits and Diagrams reference material.
• Appendix A: Current Loop/RS-422 procedures for installing aCurrent
Loop board or an RS-422 board.
ASSOCIATED PUBLICATIONS
For general User Information:
QVT 101 PLUS· Setup Guide ••••••••••••••••••••••••••••••• Reorder Number 35143
QVT 101 PLUS· Technical Reference Manual •••••••••••••••• Reorder Number 35153
QVT 101 PLUS· Quick Reference Card •••••••••••••••••••••• Reorder Number 35108
;;

TABLE OF CONTENTS
Page No.
SECTION 1: TROUBLESHOOTING •••••••••••••••••••••••••••••••••••••••••••••••
INTRODUCTION ••••••••••••••••••••••••••••••••••••••••••••••••••
TROUBLESHOOTING TECHNIQUE •••••••••••••••••••••••••••••••••••••
TROUBLESHOOTING FLOWCHARTS ••••••••••••••••••••••••••••••••••••
Tools and Equipment Required •••••••••••••••••••••••••••••••
Rear Connector Pin Designations ••••••••••••••••••••••••••••
Fault Isolation Flowchart 11 •••••••••••••••••••••••••••••••
Fault Isolation Flowchart 12 •••••••••••••••••••••••••••••••
Fault Isolation Flowchart 13 •••••••••••••••••••••••••••••••
Fault Isolation Flowchart 14 •••••••••••••••••••••••••••••••
Fault Isolation Flowchart IS •••••••••••••••••••.•••••••••••
SELF-DIAGNOSTICS ••••••••••••••••••••••••••••••••••••••••••••••
SECTION 2: SUBASS~M8LY REMOVAL AND REPLACEMENT •••••••••••••••.•••••••••.•
INTROD :TION •••••••••••••••••••••••••••••••••••••••••• ••••••••
SAFETY SUMMARy ••••••••••••••••••••••••••••••••••••••••• •••••••
REQUIRED TOOLS ••••••••••••••••••••••••••••••• •••••••••••••••••
UPPER MONITOR ASSEMBLy •••••••••••••••••••••••••••••••• ••••••••
Removing and Replacing the Back Cover ••••••••••••••••••••••
Discharging the CRT High-Voltage Circuit •••••••••••••••••••
Removing and Replacing the Video/Power Supply PCB Assembly
Removing and Replacing the CRT and Yoke Assembly •••••••••••
Removing and Replacing the Front Bezel •••••••••••••••••••••
Removing and Replacing the Green LED On/Off Light ••••••••••
Removing and Replacing the Transformer •••••••••••••••••••••
LOWER MONITOR ASSEMBLy ••••••••••••••••••••••••••••• •••••••••••
Removing and Replacing the Bottom Cover ••••••••••••••••••••
Removing and Replacing the Logic Board •••••••••••••••••••••
Removing and Replacing the RAM Back-Up Battery •••••••••••••
Removing and Replacing the Brightness Control Assembly •••••
Removing and Replacing the Power Switch/Fuse/ ••••••••••••••
Filter Assembly
Removing and Replacing the Keyboard Connector Assembly •••••
KEYBOARD ASSEMBLy •••••••••••••••••••••••••••• •••••••••••••••••
Disassembling and Reassembling the Keyboard Assembly •••••••
Replacing the Coiled Cable Assembly ••••••••••••••••••••••••
Removing and Replacing Keyboard Keycaps ••••••••••••••••••••
SECTION 3: ALIGNMENT •••••••••••••••••••••••••• •••••••••••••••••••• •••••••
INTRODUCTION •••••••••••••••••••••••••••••• •••••••••••• ••••••••
TOOLS AND EQUIPMENT REQUIRED ••••••••••••••••••••••••••••••••••
ALIGNMENT CONDITIONS •••••••••••••••••••••••••••••••• ••••••••••
VIDEO ALIGNMENT PROCEDURES •••••••••••••••••••••• ••••••••••••••
Horizontal Display Width (Line Width) ••••••••••••••••••••••
Vertical Display Height •••••••••••••••••••••••••• ••••••••••
Brightness •••••••••••••••••••••••••••••• •••••••••••••• •••••
F OC us ••••••••••••••••••••••••••••••• ••••• ••••••••••••••••••
Display Centering (Raster Position).: ••••••••••••••••••••• •
1-1
1-1
1-1
1-1
1-1
1-2
1-7
1-8
1-10
1-11
1-12
1-13
2-1
2-1
2-1
2-1
2-2
2-3
2-4
2-6
2-8
2-12
2-12
2-13
2-14
2-14
2-15
2-17
2-17
2-19
2-20
2-21
2-21
2-22
2-23
3-1
3-1
3-1
3-2
3-4
3-5
3-6
3-7
3-8
0-
3-7
.-
.. - ~--
; i ;

TABLE OF CONTENTS (Cont.)
Page No.
SECTION 4: PARTS •••••••••••••••••••••••••••••••••••••••••••••••••••••••• 4-1
INTRODUCTION •••••••••••••••••••••••••••••••••••••••••••••••••• 4-1
RECOMMENDED SPARE PARTS ••••••••••••••••••••••••••••••••••••••• 4-1
EXPLODED VIEW DRAWINGS •••••••••••••••••••••••••••••••••••••••• 4-3
SECTION 5: CIRCUITS AND DIAGRAMS ••••••••••••••••••••••••••••••••••••••••• 5-1
APPENDIX A:INSTALLATION OF CURRENT LOOP OR RS-422 BOARD •••••••••••••••••• A-I
LIST OF ILLUSTRATIONS
F; gure
Page No.
1-1
2-1
2-2
2-3
2-4
2-5
2-6
2-7
2-8
2-9
2-10
2-11
2-12
2-13
2-14
2-15
2-16
2-17
2-18
2-19
2-20
3-1
3-2
4-1
4-2
4-3
5-1
5-2
5-3
5-4
5-5
5-6
5-7
A-I
iv
QVT 101 PLUS ~~ar Connector Panel •••••••••••••••••••••••••••••••••
QVT 101 PLUS Upper Monitor Assembly ••••••••••••••••••••••••••••••••
Removal of Back Cover ••••••••••••••••••••••••••••••••••••••••••• ~ ••
Discharging
the CRT High-Voltage C;rcuit •••••••••••••••••••••••••••
D;sconnecting the CRT Anode Cap ••••••••••••••••••••••••••••••••••••
Removal of Video/Power Supply PCB Assembly •••••••••••••••••••••••••
Removal of CRT and Yoke Assembly ••••••••••••••••••••••••••••••••••
Removing the CRT and Yoke Assembly from the Main Chassis •••••••••••
Removing the CRT and Yoke Assembly from the Bezel ••••••••••••••••••
Locating and Installing the Ground Wire and Spring •••••••••••••••••
Removing the Green LED ON/Off Light •••••••••••••••••••••••••••••••
Replacing the Transformer ••••••••••••••••••••••••••••••••••••••••••
Removal of the Rear Connector Cables and Bottom Cover ••••••••••••••
Removal of the Logic Board •••••••••••••••••••••••••••••••••••••••••
Removal of the Keyboard Connector Assembly •••••••••••••••••••••••••
Removal of the Logic Board RAM Back up Battery •••••••••••••••••••••
Removing and Replacing the Brightness Control Assembly •••••••••••••
Keyboard Bottom Cover ••••••••••••••••••••••••••••••••••••••••••••••
Keyboard with Top Cover Removed ••••••••••••••••••••••••••••••••••••
Removal of Keyboard Keycaps ••••••••••••••••••••••••••••••••••••••••
Replacement of Keyboard Keycaps ••••••••••••••••••••••••••••••••••••
The ·'H
II
Test Pattern •••••••••••••••••••••••••••••••••••••••••••••••
Location of Video ALignment Components •••••••••••••••••••••••••••••
Upper Monitor Area (2 sheets) ••••••••••••••••••••••••••••••••••••••
Lower Monitor Area (2 sheets) ••••••••••••••••••••••••••••••••••••••
Keyboard Top Assembly ••••••••••••••••••••••••••••••••••••••••••••••
Functional Block Diagram •••••••••••••••••••••••••••••••••••••••••••
Overall Interconnect Diagram •••••••••••••••••••••••••••••••••••••••
Power Supply Control PCB Schematic ••••••••••••••••••••••••••••••••
Video/Power Supply PCB Schematic ••••••••••••••••••••••••••••••••••
Logic PCB Schematic (7 Sheets) •••••••••••••••••••••••••••••••••••••
Keyboard PCB Schematic ••••••••••••••••••••••••• : ••••••••••••••••••
RS-422 Current Loop Schematic ••••••••••••••••••••••••••••••••••••••
Installation of Current Loop or RS-422 Board •••••••••••••••••••••••
1-2
2-3
2-4
2-5
2-n
2-7
2-8
2-10
2-11
2-12
2-15
2-18
2-19
2-20
2-21
2-22
2-24
2-25
2-26
2-27
2-27
3-3
3-4
4-3
4-9
4-11
5-3
5-5
5-7
5-9
5-11
5-25
5-27
A-4

Table
LI ST OF TABLES
Page No.
1-1 AUXILIARY (EIA RS-232-C Interface DCE) Connector, J9............... 1-2
1-2 EIA (System Interface RS-232-C DTE) Connector, J8 •••••••••••••••••• 1-3
1-3
Power Troubleshooting.............................................. 1-4
1-4 Logic
Board Troubleshooting •••••••••••••••••••••••••••••••••••••••• 1-5
1-5
Keyboard Troubleshooting ••••••••••••••••••••••••••••••••••••••••••• 1-6
4-1 Recommended Spare Parts ••••••••••••••••••••••••••••••••.•.•••••••.• 4-1
4-1 QVT 101 PLUS Replaceable Parts List •••••••••••••••••••••••••••••••• 4-4
4-2
QVT 101 PLUS Keyboard Exploded Parts List •••••••••••••••••••••••••• 4-8
A-2 Current Loop and RS-422 Installation ••••••••••••••••••••••••••••••• A-2
v

SECTION 1
TROUBLESHOOTING
INTRODUCTION
This section provides atroubleshooting method for isolating most QVT 101 PLUS
terminal failures to an easily replaced subassembly, by systematically
advancing through a
series of troubleshooting flowcharts and checking the
results of the self-diagnostic test.
TROUBLESHOOTING TECHNIQUE
Effective troubleshooting technique should always begin with athorough visual
inspection. Loo~ for obvious things that may adversely effect the performance
of
the terminal, such as:
•Is
the bri htness control properly adjusted;
•Is the
AC line fuse OK;
•Is the AC power source supplying adequate power;
• 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 ageneral area, it should be noted that they have been purpose-
fully arranged to quickly isolate a fault to areplaceable 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
•
DB25 Loopback Connector
•
Phillips Screwdriver
•Multimeter
•
High Voltage Probe
•Extender,
PCB (Qume Part Number 302152-01)
•
Long Nose Pliers
•Terminal Extraction Tool (Qume Part Number 302156-01)
•Interconnect Wiring
Diagram and Schematics (refer to Section 5)
1-1
..
.'
..

TROUBLESHOOTING
Rear Connector Pin Designations
Tables 1-1
and 1-2 list the pin designations for the connectors on the rear
panel (see Figure 1-1 for
identification and location of connectors for the
QVT 101 PLUS Terminal). Tables 1-3 through 1-5 provide information for
troubleshooting
power. logic PCB and keyboard malfunctions.
POWER CORD
CONNECTION
AUX CONNECTOR EIA CONNECTOR
(PRINTER) (HOST COMPUTER)
Figure 1-1. QVT-I01 PLUS Rear Connector Panel
Table 1-1.
AUXILIARY (EIA RS-232-C Interface DCE) Connector. J9
Pin Number
Description
Si gna 1Direction
1Chassis
Ground
------------
2Receive
Data
To Terminal
3Transmit
Data
From Terminal
6
Data Set Ready
To Terminal
7Signal
Ground
------------
20
Data Terminal
Ready
To Terminal
1-2
..
.-

TROUBLESHOOTI NG
Table 1-2. EIA (System Interface RS-232-C OTE) Connector, J8
Current Loop, +Receive, -------------
or RS-422-A Receive -)
Current Loop, - Transmit,-------------
RS-422-A Transmit +)
Data Terminal Ready From Terminal
Current
Loop, -Receive, --------------
or RS-422-A Receive +)
Current Loop, + Transmit,--------------
or RS-422-A Transmit -)
*Optional
Pin Numher
1
2
3
4
5
6
7
8
12*
13*
20
24*
25*
Description
Chassis
Ground
Transmit Data
Receive Data
Request-to-Send
Clear-to-Send
Data Set Ready
Signal Ground
Data Carrier Detect
Signal Direction
From Terminal
To Terminal
From Terminal
To Termi na 1
To Terminal
To Terminal
NOTE: When the Current Loop/RS422-A option board is installed, Pins 12. 13,
24,
and 25 will become active when RS422/CL is selected in Setup. Pins 2 and
3 (RS232) will become inactive when RS422/CL is selected in Setup.
1-3

TROUBLESHOOTING
SYMPTOM
Table 1-3. Power Troubleshooting
PROBABLE CAUSE
REMEDY
No power to terminal
when power On/Off switch
switch
is On.
No raster on CRT
when brightness con-
trol is moved across
its entire range.
Brightness cannot
be
varied
1-4
1. Blown AC fuse (under the
terminal).
2. Defective Power Switch/
Fuse/Filter Assembly
3. Defective Video/Power
Supply PCB Assembly
4. Defective Power Supply
Control PCB
1. Defective Video/Power
Supply
PCB Assembly.
2. Defective
CRT
Brightness control assy.
problem
Replace fuse with
one of proper rating.
Perform continuity check on
the Power Switch and the
Filter Assy. If defective,
replace the assembly.
Refer
to Section 2.
Replace
Video/Power
Supply PCB Assembly. Refer
to Section 2.
Replace (see Section
2)
Replace the Video/
Power Supply PCB Assy.
Refer
to Section 2
Replace
CRT. Refer to
Section 2, Removing and
Replacing CRT.
Perform resistance check
across control. If de-
fective, replace bright-
ness control assy.
Refer
to Section 2,
Removing and Replacing
Brightness Control
Assembly.

TROUBLESHOOTING
Table 1-4. Logic Board Troubleshooting
SYMPTOM
Self-test fails.
(ESC V)
PROBABLE CAUSE
1. Weak or defective RAM
back -up battery.
2. Defective logic PCB
3. Check for loose
interconnect cables
4. Defective
Video/Power
Supply PCB Assembly.
REMEDY
Replace RAM back-up
battery on logic PCB.
Refer to Section 2,
Removing and Replacing RAM
Back-Up Battery.
Replace logic
PCR. Refer to
Section 2, Removing and
Replacing Logic Board.
If loose, tighten.
Check power supply
voltages.
If defective.
replace
Video/Power Supply
PCB Assembly. Refer to
Flowchart '5.
1-5

TROUBLESHOOTING
SYMPTOM
Table 1-5. Keyboard Troubleshooting
PROBABLE CAUSE
REMEDY
Incorrect character
shown on screen.
1-6
1. Faulty coiled keyboard
cable
2. Faulty connector/
receptacle assembly.
3. Defective microprocessor.
4. Defective keyboard
Perform continuity
check. Replace cable
if defective. Refer to
Section 2, Replacing the
Keyboard Coiled Cable.
Perform continuity
check. Refer
to Section 2,
Removing and Replacing
Keyboard Cable
Connector/Receptacle
Assembly.
Replace microprocessor.
Refer
to Section 2~
Removing and Replacing
Keyboard Microprocessor
(302080-001).
Replace keyboard.

TROUBLESHOOTING
Fault Isolation Flowchart '1
Power on unit.
I
Does unit display an error code? ---YES---> Proceed to Table 1-6, Error Codes
Summary at end of this Section.
-NO
Perform Self-Test (enter Setup Mode. Select Local Mode. Issue Escape V.
Does unit
perform self-test? ---NO---> Proceed to Flowchart 12.
-YES
Exit self-test (press Shift Break then Clear)
while in Local
mode.
Press each key on
keyboard.
Are characters
displayed as keys
are pressed? ---NO---> Proceed to Flowchart 13.
-YES
Exit Local mode, enter
full duplex mode. Install
loopback connector to EIA port.
Press each key on keyboard.
Are characters
displayed as keys
pressed? ---NO---> Logic
PCB defective. Replace Log;c
PCB (refer to Section 2).
-YES
Connect printer to AUX port.
Exit Full Duplex & enter
Local mode. Print.
I
1-7

TROUBLESHOOTING
Fault Isolation Flowchart II (Cont)
Is screen
data printed? ---NO--->
Logic PCB defective. Replace
Logic
PCB (refer to Section 2)
-YES
Unit checks OK.
Fault Isolation Flowchart 12
From Flowchart #1.
Is AC line fuse good ?---NO---> Replace bad fuse. Continue.
-YES
Does fuse fail at power on? ---NO---> Return. Begin Flowchart #1.
-YES
Verify operation of ON/OFF switch.
Is switch defective? ---NO---> Proceed
to Transformer Measurement
-YES
Replace Power Switch/Fuse/Filter Assembly (refer to Section 2). Continue.
Does fuse fail again at power on? ---NO---> Return. Begin Flowchart #1.
-YES
Replace fuse. Disconnect P3 on Power Supply Control PCB to isolate power transformer.
Measure transformer output on P3 and verify voltage (23 volts AC ~ 10~).
Is voltage present? ---NO---> Power transformer is defective.
Replace power transformer (refer to
Section 2).
-YES
1-8
(

TROUBLESHOOTING
Fault Isolation Flowchart 12 (Cont)
Power transformer checks OK. Power off and reconnect P3 on the Power Supply Control
PCB. Disconnect the keyboard connector from the Lower Monitor Assembly and
remove the Logic PCB Assembly.
I
Power On the unit
I
Does fuse fail again at
power on?-----------------NO---->Video/Power Supply PCB Assembly checks OK
I
YES
I
Power Supply Contro PCB or Video/Power Supply PCB Assembly is defective. Disconnect
the
Power Supply Co trol PCB
I
Replace fuse and Power On the terminal
I
Does fuse fail again?--->NO---->Power Supply Control PCB is OK.
Video/Power Supply PCB Assembly is defective. Remove
and replace the Video/Power Supply PCB.
Reconnect the Power Supply Control PCB and
install the Logic PCB.
Yes
I
Power Supply Control PCB is defective. Remove and Replace
I
Replace fuse. Does fuse blow?------NO--->Video/Power Supply Control PCB
and Logic PCB check OK.
I
YES
I
Logic PCB is defective. Remove and Replace. Reconnect Keyboard
I
Replace fuse. Power On unit.
Does fuse blow?------------->No--->Begin Flowchart *1
I
YES
I
Keyboard or Keyboard cable is defective.
Proceed to Flowchart ,3.
1-9

TROUBLESHOOTING
Fault Isolation Flowchart 13
From Flowchart '1.
Is +5 Vdc present between pin 1(Sig. GNO)
and pin 2 (+5 VOC) on the Keyboard PCB
(P1).
-YES
---NO---> Perform continuity check
on coiled keyboard cable.
If defective. replace
keyboard cable
(refer to
Section 2).
Is the correct character displayed? ---NO---> Proceed to Flowchart '4.
-YES
Unit checks OK. ProceeL to the System Test (Host)
1-10

·
L
TROUBLESHOOTING
Fault Isolation Flowchart 14
From Flowchart '3.
Check the following voltages (with respect to GND) on the Logic PCB edge Connector PI:
Pin 9
+SVDC
Pin 2 +SVDC
Pin 21 +12VDC
Pin 22 -12VDC
Pin 6 GNO
Are all voltages present? ---NO---> Defective Video/Power Supply PCB Assy. Replace.
-YES
Verify proper operation of
the brightness
control. Ro-
tate control full CCW, then
full CWo Observe a 3VDC
voltage change between pins 13
and 14 of P1 (Logic PCB 22 pin connector).
Does voltage change approx.
3VDC? ---NO---> Brightness control is defective. Replace Brightness
control
(refer to Section 2).
-YES
Blank screen (enter Clear). At P1,
pin 19 (Logic PCB) observe for an AC RMS voltage. Display
self-test (enter in Local Mode-Escape V.). At PI, pin 19
observe for an AC RMS voltage.
Did voltage increase approximately
SOOmVac RMS when self-test was
displayed? ---NO---> Logic PCB is defective. Replace Logic PCB
(refer to Section 2).
-YES
Proceed to Flowchart '5.
1-11

TROUBLESHOOTING
Fault Isolation Flowchart '5
From Flowchart 14.
Oi spl ay "w Test Pattern (enter Shift/Setup-0).
I
Check voltages on Video/Power Supply PCB Assembly.
0-104 Anode +12 Vdc
0-102 Anode GND
Are voltages present? ---NO---> Defective Video/Power Supply PCB Assembly. Replace.
-YES
With brightness control
full CW, check Video (P6 Pin 7)
for approximately
400 mVac RMS.
Is approx. 400 mVac RMS present? ---NO---> Defective Video/Power Supply PCB Assembly.
Replace.
-YES
I
< WARNING: HIGH VOLTAGE
I
With ahigh voltage probe,
check the CRT anode cap
for approx. 13 KVdc.
I
Is there approximately 13 KVdc present at CRT
anode cap? ---NO---> Video/Power Supply PCB Assembly defective.
Secti
on 2).
-YES
1-12
Replace (refer to

TROUBLESHOOTING
Fault Isolation Flowchart 15 (Cont.)
Check the following voltages on the Video/Power Supply PCB Assembly (tolerance ~ 25%):
voltages present? ---NO---> Video/Power Supply PCB Assembly defective.
Replace. (refer to Section 2).
P4
P4
P4
P4
G1
I
Are a 11
Pin l(Brown)
Pin
2(Red)
Pin 3( Ye 11 ow )
Pin 4(Blue)
-30
VOC
4.49 VAC RMS
27.0 VAC RMS
0.40 VAC RMS
1. 5 VAC RMS
G2
0154
G4
H
550 VOC
Cathode 45 VOC
175 VOC
12 VOC
-YES
CRT defective. Replace CRT (refer to Section 2).
SELF-DIAGNOSTICS
Each time the terminal is powered on, the terminal automatically performs a
self-test that checks the integrity of four critical areas: the Program ROM,
System RAM, Video RAM, and the Keyboard. Asuccessful self-test displays OK
in each tested area, and a failed self-test displays as ablinking NG (No
Good) as shown in Table 1-6.
Table 1-6. Error Codes Summary
Correct
Error
OK: No error detected
NG: No Good, error detected
.-
.-
1-13