Epson QX-10 User manual

TECHNICAL MANUAL
TROUBLESHOOTING
EPSON
08290002-0

TECHNICAL MANUAL
TROUBLESHOOTING
QX~O
This Technical Manual provides technical information on the structure, maintenance, and repairs of
the QX-10.
For the details of the operation, refer to the Technical Manual of QX-1 0 (Principles of Hardware Oper-
ation).
Major technical modifications, if made
in the future, will be notified through Service Bulletins, and the
Technical Manual should be revised accordingly. The.details
of the Manual are subject to change
withOl,!t notice.
All the information given in the Manual concerns the QX-1 0
to others.
All rights reserved. No part
of this publication may be reproduced, stored in a retrieval system, or trans-
mitted,
in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, with-
out the prior written permission by EPSON CORPORATION.
Copyright © 1983 by EPSON CORPORATION
Nagano, Japan

CONTENTS
CHAPTER 1 GENERAL
CHAPTER 2 DiSASSEMBLY
AND REASSEMBLY
CHAPTER 3 ADJUSTMENT AND MAINTENANCE
CHAPTER 4 REPAIRS
CHAPTER 5 TROUBLESHOOTING

CHAPTER 1
GENERAL
CONTENTS
1.1 Features........................................................................................................... 1-1
1.2 Hardware Configuration................................................................................ 1-1
1.2.1 General................................................................................................... 1-1
1.2.2 Hardware ............................................................................................... 1-1
1.3 Specifications .................................................................................................. 1-2
1.3.1 External Dimensions and Weight ......................................................... 1-2
1.3.2 Environmental Conditions .................................................................... 1-2

1.1 Features
The OX-1 0 is an all business computer system. It consists of a Z80A-compatible CPU, a memory of
256 KB maximum, two floppy disk drivers of double-sided, double-density, 5-1/4" disks, and a 12"
full-graphic CRT display with a resolution of 640 by 400 dots.
The standard configuration includes a programmable timer, Centronics-compatible
printer interface,
RS-232C interface, C-MOS RAM backed up by battery, clock and calendar, and separate keyboard. It
has five card slots which permit installation of optional cards as required.
Optional cards available include character generators
of varying fonts, IEEE-488 interface, optical fib-
er interface,
color CRT interface, and pulse transformer interface.
1.2 Hardware configuration
1.2.1 General
The OX-1 0 is composed of three units: the main system unit, the keyboard unit, and the monitor unit.
The main system unit,
the heart of the QX-10 system, includes the main circuit board, sub circuit
board, power supply, two 5-1/4" floppy disk drives developed by Epson, and five slots permitting in-
stallation
of optional cards.
The keyboard
unit is connected to the main system unit with a curled cord through which signals may
be transmitted in any direction.
The standard
monitor unit is a 12" high resolution green monitor capable of displaying bit images.
1.2.2 Hardware
Main system
CPU
Memory
Clock
Speaker
Interfaces
DMA
Interrupt levels
Counter/timer
FDD
Card slots
Monitor
Keyboard
.uPD780AC-1 (Z80A compatible, 4 MHz)
RAM :
256 KB (maximum on main board)
VIDEO RAM : 128 KB (maximum on CRT board)
C-MOS RAM : 2 KB (standard, backed up by battery)
EPROM : 2/4/8 K8 (for IPL)
C-MOS real-time clock (backed up by battery)
Permanent magnet speaker
Printer interface (Centronics-compatible)
RS-232C communications interface
7 channels
15
6 channels
5-1/4" FDD x 2
320 KB x 2 drives
48 TPI, double sided & double density
5
1 2" green monitor
640 x 400 dots
ASCII, HASCI
1-1

1.3 Specifications
1.3.1 External Dimensions and Weight
(1) External dimensions
Main system unit ca.
Green
monitor unit ca.
Keyboard
unit ca.
Optional card
(W)
50S
312
50S
(510)
2S0
(2) Weight: approx. 1Skg
1.3.2 Environmental Conditions
x
x
x
x
(1) Temperature .................... during operation
storage
(2) Humidity........................... during operation
storage
(3) Resistance
to shock ........ during operation
storage
(4) Resistance
to vibration.... during operation
storage
MainSY~
(0)
340
340
224
80
(H)
x 103 (mm)
x 270 (mm)
x
48 (mm)
(mm)
:
5°C to 40°C
: -30°C to 70°C
: 20 - 80% (no condensation)
:
10 - 90% (no condensation)
: max. 1
G, 1 msec
: max. 5
G, 1 msec
: max.
0.25 G, 5-50 Hz
: max. 3 G, 5-50Hz
Greeninitor unit
Fig 1-1 Hardware configuration of QX-10
1-2

Q10GMS
Board
,uP0765
(Channel A)
MPD7210
AC
Q10PS
(Channel B)
IN
board
JLPD8255
Fig 1-2 Block diagram of main component
1-3
U9h8
CRT
~
FOO (SO-321 )
Keyboard
RS-232C
Printer
(centronics type)
Open card

(A) Q10S SYM board
This is a main control board including CPU, compatible with Z80A, Z80A family LSI and main memory.
Name Model Q'ty Function
CPU .uPD780C 1
CPU (4MHz) compatible with Z80A.
DMA controller 8237A
2 Provided
with total of 7 channels for FDD, moni-
tor and options.
Interrupt controller 8259AC
2 Controls
the interrupt priority of total 15 levels
interrupt including PWD output keyboard inter-
rupt.
Interval timer
8253C 2 Controls
the boud rate of keyboard clock and
RS-232C.
Serial controller
7201C 1 Allocates channel a to the keyboard and B to
RS-232C, and controls serial data transfer with
CPU.
Printer controller
8255AC
1 Provided
with an 8-bit parallel port. Acts as an
interface
with printer conformable to Centronix.
Real time clock 46818P
1 Provided
with clock and calendar functions.
Floppy
disk controller
765AC
1 Interface
with FOO (SO-321 )
I/O selector LS154 1 Accesses each I/O point by decoding the 4-bit
low order address (A2 ,... A5) of CPU.
Main memory 416/4164
8 Dynamic RAM is used.
32
Provided with 4 banks maximum.
P-ROM
2716/32/
1 StoresIPL programs.
64
C-MOS RAM
449
1 Protects
the data on power failure. (Backed up by
an NiCd battery.)
Table 1-1 Primary configuration of Q1 0 SYM
1-4

Fig. 1-3
1 ,uPD780C (Z80A compatible CPU)
2 8237 A (Programmable DMA Controller)
3
8259AC (Programmable Interrupt Controller)
4
8253C (Programmable Interval Timer)
5 7201 C(Multi-protcol Serial Controller)
6
8255AC (Programmable peripheral Interface)
7 46818P (Real-time clock plus RAM)
8
765AC (Programmable Floppy Disk Controller)
9
LS 1 54 (I/O Selector)
10 416/4164 (D-RAM)
11 2716/32/04 (P-ROM for IPL)
12 449 (C-MOS RAM)
1-5

(B) Q10 GMS board includes graphic display controller
The board includes graphic display controller ,uPD7220 and V-RAM, and controls display of the green
monitor.
Name
Graphic display
controller
Video RAM
Character generator
Model Q'ty Function
7220 1 A display controller
with high speed drawing and
magnifying functions.
416/4164 16 Dynamic RAM is used.
2732/64
1
ROM storing display fonts to be sent to the dis-
play unit.
Table
1-2 Primary configuration of Q1 0 GMS
Fig.
1-4
1 7220 (Graphic Display Controller)
2 V-RAM
(16/64 k bit dynamic RAM)
3 P-ROM (Character Generator)
1-6

(e) Q10 PS board
This is a power supply unit for the OX-1 0 system and a switching regulator with a flyback transformer.
It accommodates to power supplies of 1 OOV and 200V levels by switching jumper wire J 1.
Specifications
(1) Input voltage:
(2) Frequency:
(3) Power cosumption:
(4) Input serge current:
(5) Leak current:
(6) Insulation strength:
(7) Insultation resistance~
(8) Output Voltage:
Output
voltage
+5
+12(C)
+12(F)
+12(L)
-12
100V-10% - 120V+10%
200V channel 220V - 10% '" 240V + 10%
50/60 Hz
Approx.75W
30A for 20 ms maximum
1 rnA maximum
1
OOV channel Can withstand 1 kV applied between AC power supply
and case
for 1 minute.
200V channel Can withstand 1.25 kV applied between AC power
supply and case for 1 minute.
10 M.Q for 500V DC minimum.
Limits ofoutput
Standard
USE
voltage current
5.0 '" 5.1 V
3.6A logic circuit
11.6
,.... 12.4 V O.9A green
monitor
11.4 - 12.6V
1.2A floppy disk drive
11 - 13V
a.45A
keyboard, RS-232C
-11 --13V a.a2A
D-RAM, RS-232C
Table 1-3
Fig. 1-5
1-7

(D) CRT display unit
Fig. 1-6 shows the standard green monitor unit of OX-1 O.
The CRT is characterized by high resolution of 640 x 400 dots and non-glare coating, preventing re-
flection.
Fig. 1-6
1 CRT
2 Anode cap
3 Deflection yoke
(DY)
4 Flyback transformer (FBT)
5 CRT drive unit (CDU)
1) Pin Definition
Pin No. Function
1 Video signal
2 Vertical synchronizing signal
3 Horizontal synchronizing signal
4 Power supply + 12V DC
5 Grounding (power supply, horizontal)
6 Grounding (video vertical)
7 Grounding (power supply, horizontal)
8 Frame grounding
Table 1-4
(E) Frame ground
(7) Ground (power, hor.)
(3) Horizontal sync
(5) Ground (power, hor.)
Fig- 1-7
1-8
(6) Ground (video, vert.)
(1) Video signal
(4) +12 VDC

2) Input Conditions
(1) Video signal:
(2) Video input impedance:
(3) Horizontal driving signal:
.
-------- 5.0V
-- .. ----- 4.0V
Fig 108
300 a min. 40 pF max.
TTL (positive)
--OV
l: 0 - 0,8 V H: 2.4 -5.5 V .
Full Bright
Half Bright
Dark
(4) Horizontal input impedance:
500amin.
(5) Vertical driving signal:
(6) Vertical input impedance:
3) Input signal timing
(a) Horizontal driving signal
19.3 kHz
Video signal
(b) Vertical driving signal
45.8 Hz
Video signal
(c) Video signal
TTL (positive)
l: 0 - 0.8 V
3.0 kamin.
H:2.4 - 5.5V
~nt-----\((~ ---In"'---_
I I »
-; t-- 1.44)AS
51.
84
.uS
13.44.u 38.40.u
Fig. 1 =9
____ ~Il~---- __ ~({~------~rl~------
--l I- 0.83 mS
1.09 mS
21.83 mS
20.74mS
Fig. 1-10
Fig. 1-11
1-9
Dot clock=16.667 MHz

(El Keyboard
The keyboard
of QX-1 0 is available in ASCII type and HASCI type, according to applications.
These two types are almost the same in hardware.
Keyboard data transfer is controlled by the
CPU ,uPD8049 used as a keyboard controller separately
from the main CPU.
Data transfer is made with the main system unit in the start-stop turning system at the rate of 1200
BPS.
Pin Definition
Pin No.
1
2
3
4
5
6
7
8
Fig
1-12
1 Keyboard controller (,uPD8049)
2 Key scan signal decoder (LS145)
Signal Direction Description
of Signal
OUT Received data
OUT Clock
(1200 BPS)
OUT +12 V
IN Transmitted data
-Ground
-Ground
-Ground
-Ground
Note: The direction
of signal is as viewed from the Q1 OSYM board
Table 1-5'
2
3
E 6
Fig. 1-13 Pin locations
1-10

(F) Floppy Disk Drive SO-321
Double sided, double density type of 5-1/4" floppy disk drive SO-321 has the features as described
below:
1) SO-321 produces an ultra
thin structure of 1/2 - 1/3 the convertional models.
2) In order
to miniaturize the circuit board and get high reliability, most of the control circuit is integrated
to two lSls.
Fig. 1-14
1 Head pad
2
VCM
3 Drive motor
4 Main
PCB
1-11

~ Specifications of 50-321
1. Memory capacity
(1) Unformatted
(2)
Fo~matted (1 6 sectors/track)
2. Recording density (side
1, trk 39)
3. Transmission speed
4. Track mean speed
waiting time
5. Access time
(1 ) Between tracks
(2) Between tracks maving average
(3)
Settling time
6. Motor starting time
7. Motor speed
8. Track density
9. Total number of tracks
10. Inner circumference track radius
11 .. Outer circumference track radius
12. Recording system
13. R/W head positioning
14. Main axis motor
15. Detectors
(1 ) Index hole
detector
(2) Track
No.OO detector
(3)
Wright protect detector
(4) Track address
detector
16.
Ambient conditions
(1 ) Temperature
(2) Relative
humidity
(3) Maximum
wet-bulb temperature
(4) Vibration
17.
Transportation and storage condition
(1 ) Temperature
(2) Relative
humidity
(3) Vibration
(4)
Impact
500 k byte (Double density recording)
328 k byte (Double density recording)
5876 BPI (Double density recording)
250 k bit/sec (Double density recording)
100 msec
15 msec
220 msec
15 msec
0.5 sec
:,300 rpm
1-12
48TPI
80
36.52 mm (trk 39, side 0)
55.03 mm (trk 00, side 1)
36.52 mm (trk 39, side 0)
34.40 mm (trk 39, side 1)
MFM
Voice coil motor
Outer rotor-type brushless transistor motor
Photoelectric conversion
Photoelectric conversion
Photoelectric conversion
Photoelectric conversion
4°C to 43°C
20% to 80% (no condensation)
29°C
0.6G,5 ,..,. 60 Hz
-40°C to 65"C
less than 95 % (no condensation)
less than 3G, 50 ,... 60 Hz
,less than 50 G

18. Power supply
(1 )
+12V(±5%-)
0.7 A (typ) (at reading/writing)
1.9 A (max) (at
motor starting)
(2)
+5V(±5%)
0.25 A (typ) (at reading/writing)
0.4 A (max) (at motor starting)
19. Power consumption : . 9.7 W (typ)
20. Reliability
(1 ) MTBF
1000 HOURS (POH)
(2)
MTIR
30 minutes
(3)
Soft error rate less than once every 1
09 bits
(4) Hard error rate less than once every
10
12 bits
(5) Seek error rate less than once every 1
06 seeks
21. Connectors
(1 ) Power supply
connector
AMP. PIN 1-480424-0 or equivalent
(2) Signal
connector
3 M PIN 3463-0001 or equivalent
1-13

CHAPTER 2
DISASSEMBLY ANDREASSEMBL Y
CONTENTS
2.1 Precautions for disassembly and reassembly ............................................ 2-1
2.2 Disassembly and reassembly of the main unit ........................................... 2-2
2.2.1 Optional cover and upper case......................................................... 2-2
2.2.2 Q1 OGMS board.................................................................................. 2-4
2.2.3 Q10SYM board................................................................................. 2-5
2.2.4 Q1 OPS board (Power supply unit)...................................................... 2-6
2.2.5 FDO (SO-321 ) unit ............................,............................................... 2-7
2.2.6 Power lamp ....................................................................................... 2-8
2.3 Disassembly and reassembly of CRT (green
monitor unit} .................................................................................................. ~. 2-9
2.3.1 Cover ................................................................................................. 2-9
2.3.2 CRT .................................................................................................. 2-10
2.3.3 Board (CRT drive unit)..................................................................... 2-11
2·.4 Disassembly and reassembly of the
keyboard unit ................................................................................................ 2-1 2
2.4.1 Cover ................................................................................................ 2-1 2
2.4.2 Replacement
of key switches and
LED lamps ....................................................................................... 2-1 3
2.5 SO-321 mechanism ..................................................................................... 2-14
2.5.1 Main board set ....................................................... 00 ....................... 2-14
2.5.2 Voice coil motor unit (VCM unit).................................................... 2-16
2.5.3 Sub-frame, collet set, collet lever
and pad arm ..........................................................................:.........
2-18
2.5.4 Front panel ...................................................................................... 2-20
2.5.5 Disk guide (L) unit, write protector set
and ejecttransmission level ........................................................... 2-21
2.5.6 Disk drive
motor and endless belt.................................................. 2-24
2.5.7 Disk guide (R), idler set and disk drive
pulley set......................................................................................... 2-26
2.5.8 Index detector A set........................................................................ 2-28
2.5.9 Index detector Bset........................................................................ 2-30
2.5.10 Eject lock lever set.......................................................................... 2-32

2.1 Precautions for disassembly and reassembly
Before disassembling or reassembling the QX-1 0, pay attention to the following.
1) Make sure the power switch is turned off.
Disconnect the AC cable from the AC inlet.
2) Disconnect the cables of the keyboard, CRT unit, etc. connected to the OX-1 O.
3) Power is charged in the electrolytic condenser in the power supply unit for a few minutes after
the power switch is turned off. So take care to avoid electric shock.
4) Take special care to keep the CRT unit away from cathode rays or the yoke coil.
If the anode cap is removed, it must be properly discharged with a resistor of about 10m inter-
posed between the cap and GND.
5) When a substrate using ICs such as a circuit board is handled, be sure to touch a grounded device
with your hands to discharge static electricity prior to handling.
6) Be sure to use the specified screws. (See Table 2-1 )
7) Do
not touch the contact surfaces of connectors with bare hands.
8)
When the Q 10 SYM substrate is removed or transported, disconnect the battery connector CN 12.
Abbreviations for screws and small parts
Abbrevia- Name Rough Sketch
tion
CS Cup screw
(@
~
CP
Cross-recessed pan head machine screw
@
~
CB
Cross-recessed head bind tapping screw
@
~
CPO
Cross-recessed head C.P.screw (with outside toothed lock washer) @
(J::EJ
CTB Cross-recessed head
bind tapping screw
@
~
CTC Cross-recessed head cup tapping screw
(@
dfm-
CTBR
Cro~s-recessed head Brajier head tapping screw
@
~
CO Cross-recessed head oval counter sunk screw
©
.~
HH Hexagon socket half-point set screw
@
~
PW
PI ane washer
@
~
SW
Sprinc -·;-,.3sher
©
~
-
OW
Outside toothed lock washer @ I
CW Conical toothed lock washer © D
HN Hexagon
nut
@ g
Table 2-1
2-1

2.2 Disassembly and reassembly of the main unit
2.2.1 Optional cover and upper case
Disassembly procedure
1. Remove two screws of the optional cover shown in
Fig. 2-1.
cs: M4 x 12 x 4
2. Remove the connector cap A between the option
cover and lowercase.
3. Remove
two screw hole caps located in the right
end of the upper case top with a (-) screwdriver.
4. Remove the thefour setscrews of the upper case
shown in
Fig. 2-3.
CS: M4 x 12 x 4
5. Remove the
two connectors shown in Fig.
2-4.(CN6 and CN7 on the Q1 0 SYM substrate)
2-2
Notes on disassembly
~~~~~r-OI:>ticmaJ cover
Fig. 2-1
• To replace connector cap A, first replace the op-
tional cover and ~hen insert the lowerpart of con-
nectorcap A into the groove of the lower case and
push the upper part.
Screw hole cap
Uppercase
Fig 2-2
Fig 2-3
Upper case
Q10 SYM BOARD
Fig. 2-4