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Epson LQ-1500 Service Manual

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L Q - 1 5 0 0

SERVICE MANUAL

®
EPSON
Printed on Recycled Paper

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Summary of Contents for Epson LQ-1500

  • Page 1: Service Manual

    L Q - 1 5 0 0 SERVICE MANUAL ® EPSON Printed on Recycled Paper...
  • Page 2 TABLE OF CONTENTS CHAPTER 1 GENERAL 1 . 1 P r o d u c t O v e r v i e w ..........................1.2 LQ-1500 Interface Overview ....................... Specifications ............................. Major Components ..........................CHAPTER 2 PRINCIPLES OF OPERATION General..
  • Page 3 CHAPTER 4 D I S A S S E M B L Y / A S S E M B L Y A N D A D J U S T M E N T 4.1 General..........................
  • Page 4 INTRODUCTION This technical manual describes the principle of mechanical and electrical operations, as well as the maintenance and repair procedures, of the EPSON LO-1500 Dot Matrix Printer. Chapters 4 through 6 of the manual deal with the fundamental troubleshoot- ing, maintenance and repair of the LO-1500.

  • Page 5: Product Overview.

    CHAPTER 1 GENERAL 1 .1 Product Overview................... 1.2 LQ-1500 Interface Overview ..............1.3 General Specifications ................1 - 4 1 .4 Major Components.................

  • Page 6: General Specifications

    1 .1 Product Overview The LO-1500 is a serial terminal printer, featuring 200 CPS, bi-directional printing (draft pica mode) with logical seeking capability, and 24 x 24 dot-matrix character formation. All interfaces for the LO-1500 which permit connection of the printer to various computers are optional. The interface circuit boards are cartridge type, which can be set snugly into the housing.
  • Page 7 @ Fanfold paper 101 mm to 406 mm 4 sheets max. (include original) Paper thickness and Weight Notes: 1. Jointing finish of copies should be point or line pasting. 2. Release the friction feed during the tractor feed operation. 3. Set the head adjusting lever as shown in above table. However, adjust the step setting within range +1 step, depending on print density.
  • Page 8 Table 1...

  • Page 9: Major Components

    1.4 Major Components The LQ-1500 consists, in a broad classification, of the following five major components (I ) Housing (2) Model-3660 printer mechanism (3) Control circuit boards (4) Interface circuit boards (5) Power supply circuit boards The housing of the LQ-1500 consists of an upper case and lower case. The lower case is designed to facilitate mounting of the following components.
  • Page 10 (1) Housing (Fig. 1 .1) Fig 1 .1 Upper and lower cases (2) Model-3660 printer mechanism (Fig. 1.2) The mechanism is an assembly of all the mechanical components including two stepper motors, a print head, a ribbon feeding mechanism, a carriage assembly, sensors, and a frame section. One stepper m o t o r o p e r a t e s t h e p r i n t h e a d c a r r i a g e , w h i l e t h e o t h e r w o r k s a s t h e p a p e r f e e d m o t o r .
  • Page 11 (4) Interface circuit boards (Fig. 1 .4) An interface circuit board exchanges data between the host computer and UXMCL circuit board. Fig. 1.4 Interface circuit board (5) Power supply circuit boards (Fig. 1.5) The power supply circuit of the LQ-1500, consists of two major components, the UXFIL and UXPS/ PSU 24E circuit boards.
  • Page 12 CHAPTER 2 PRINCIPLES OF OPERATlON ........... . 2-1 2.1 General ..........
  • Page 13 This chapter provides the descriptron of signals at the various connectors electrically interconnecting such major components as printer mechanism, control circuits, interface circuit, power supply circuit, and con- trol pannel of EPSON LO-1500 Terminal Printer, and explains the operating principles of the various me- chanism around the electric circuit of the printer.
  • Page 14 The CPU Z-80A provides overall control of the LQ-1500. In addition the LQ-1500 is supported by two slave CPUs: the 8042(8742), which controls the carriage motor; the 8041(8741), which controls the paper feed motor. Other major LSls include: 8255AC5 ,,._,_..,.,_.,.._._.._ Output port for head pin drive data 8259A _..._..__....
  • Page 15 2.3 Connector Pin Assignment 2.3.1 Connector on UXMCL circuit board 1) Table 2.1 CN1 pin assignment (a) Use ,,.,..,,..,.,..,...._.... Used for data exchange between the main circuit board and the interface circuit board (b) Number of pins ._,.,,..._.._...,,,,.._._.. Table 2.1 Pin assignment (CN1 of UXMCL) 2 - 3...
  • Page 16 Note: “Direction” refers to the direction of signal as viewed from the UXMCL circuit board...
  • Page 17 2) Table 2.2 CN2 pin assignment (a) Use ....Data exchange between the main circuit board UXMCL and the driver circuit board UXDRV. (b) Number of pins .._......
  • Page 18 2 - 6...
  • Page 19 3) Table 2.3 CN3 pin assignment (a) Use ..__....__..,,..._.._.. To supply power from the power supply board UXPS/PSU 24E to the main circuit board UXMCL. (b) Number of pins _,,.._.._.,,,.._._,,..r..__._ Table 2.3 Pin assignment (CN3 of UXMCL) Note: “Direction”...
  • Page 20 5) Table 2.5 CN5 pin assignment (a) Use ___...__..__..._.._.._._..._.__....Exchange of head/home position signals between the printer me- chanism Model-3660 and the main circuit board. (b) N u m b e r p i n s 4 Table 2.5 Pin assignment (CN5 of UXMCL) Note: “Direction”...
  • Page 21 Note: “Direction” refers to the direction of signal as viewed from the UXDRV circuit board.
  • Page 22 3) CN3 pin assignment Refer to Table 2.2. 4) Table 2.8 CN4 pin assignment e Exchange of carriage motor signals between the drive circuit board (a) U and the Model-3660 printer mechanism. (b) Number pins .._.... 18 Table 2.8 Pin assignment (CN4 of UXDRV) Note: “Direction”...
  • Page 23 5) Table 2.9 CN5 pin assignment (a) Use. .,.,.,,,..,..,..__...... Exchange of control signals between the drive circuit board and the Model-3660 printer mechanism for paper feed motor or paper hold release plunger. (b) Number of pins ,._._.._...__... Table 2.9 Pin assignment (CN5 of UXDRV) 6) Table 2.10 CN6 pin assignment (a) Use .._.._....
  • Page 24 2.3.3 Connector on UXPS/PSU 24E circuit board 1) CN1 pin assignment AC power is supplied from UXFIL circuit board 2) CN2 pin assignment Refer to 2.3.1 3) Table 2.3 3) CN3 pin assignment Refer to 2.3.2 1) Table 2.6 4) Table 2.12 CN4 pin assignment (a) Use ____..__...,,.,.,..._.._..._._..,..._._..._...,_._ To supply power from the UXPS/PSU 24E circuit board to the fan set UB.
  • Page 25 2.4 Electrical Circuits 2.4.1 Power circuit Overview The power supply circuit of the LQ-1500 consists of a fuse and filter circuit and power supply circuit. The output voltages are +5, +12 and -12V for logic circuits and +24V for printer drive. The power supply circuit, employs a switching power supply system in which the input voltage is directly rectified for use.
  • Page 26 Rectifying circuit and inrush current prevention circuit (100/120V version) Fig. 2.4 Rectifying circuit and inrush current prevention circuit In this power supply system, the AC input is directly rectified by the diode bridge DB1 and the output voltages are as shown above. An explosion-proof valve is provided in the upper part of the case of smoothing condenser Cl.
  • Page 27 In this circuit, transistors Ql and Q2 alternately supply current to the windings of transformer T3, produc- ing AC voltage as the output. 50/60 Hz input is frequency converted into 20 kHz through the action of pulse transformer T3. This circuit starts oscillating automatically at about 20 kHz by transformer T2. With the power supply on, R35 causes the base current to flow and either Q1 or Q2 turns on.
  • Page 28 +24V output circuit (100/120V version) Fig. 2.7 +24V output circuit The +24V output circuit is capable of supplying an average current of 6A. In this circuit, the pulse-width controlled voltage from VLT is rectified and smoothed. The output which is a pulse voltage, rectified by DB2 is smoothed by choke coil T4 and C2, so a continuous load current flows.
  • Page 29 Output cutoff circuit (100/120V version) Fig. 2.9 Output cutoff circuit The output cutoff circuit is activated when the PSC signal is input or 30V or more is output as a result of a malfunction. When the thyristor CY2 is kept on, Q13 turns on Q12 and stops the base current of Q3, so that power is not supplied to the control winding of VLT.
  • Page 30 The magnetic energy stored in transformer T5 during the ON period is discharged to the load side during the OFF period. When the magnetic energy is discharged, the counterelectromotive force in winding b is lost and Q4 starts turning on again. The output is stabilized by controlling the average current flowing to the winding c.
  • Page 31 [B] 220/24OV version circuit Noise filter circuit (220/24OV version) Fig. 2.12 Noise filter circuit has its own noise A switching regulator generates noise because of its circuit configuration. Each country regulations, the circuit configuration, Fig. 2.12, is adopted to meet VDE 0871 class B. Rectifying circuit, inrush current prevention circuit and converter circuit (220/24OV version) Fig.
  • Page 32 Power transformer circuit (220/24OV version) Fig. 2.14 Power transformer circuit The transformer T102, a variable leakage transformer, has a construction capable of output control. The pulse voltage input to the primary winding (terminals 1 and 4) is controlled by the DC current flowing at the control winding (terminals 5 and 8) and is output to the secondary winding (terminals 9 - 12).
  • Page 33 Fig.2.16 Switching regulator circuit This circuit is formed by a chopper circuit with a power supply of +24V. As shown in Fig.2.16. when transistor Tr301 turns ON, collector current ic flows, supplying current to the load. At the same time, magnetic energy being stored in choke coil L (See Ton, Fig.
  • Page 34 2.4.2 Reset circuit( Fig. 2.18) The reset signal is used to reset and start the CPU, causing It to initiate the routine which initializes the pro- cessor and associated circuitry. The reset signal is output only in the following cases: At power on: The signal is output for about 30 ms at the turning on of power.
  • Page 35 The home position sensor circuit detects signals defining when the printhead is in or out of the home posi- tion. The signal is read when the power switch is turned on or signal INIT is applied to the printer. This cir- cuit also operates at the instruction of carriage return.

  • Page 36: Sensor Circuit 2 - 2

    3) DTS sensor circuit (Fig.2.22) Fig. 2.22 DTS sensor circuit The DTS sensor circuit detects the print timing signal. This signal comes in three pulses in one period of MTS. As shown in Fig. 2.22, it operates the same way as the MTS sensor circuit. The timing of DTS signal is 287s in the draft mode and 840s in the letter quality (LQ) mode.
  • Page 37 Head temperature sensor circuit (Fig. 2.24) Overheating of the print head during heavy duty printing operation is prevented by the head temperature sensor circuit. Fig. 2.24 Head temperature sensor circuit The head temperature sensor circuit detects the temperature of the print head unit A fan, situated at home position circulates air, providing a cooling system.
  • Page 38 2.4.4 Carriage motor control circuit (Figs. 2.25.26) The control signal of the carriage motor is output from 8042 of the main circuit board. The signal is first received by the transistor array and then driven by the regulator IC STK6982 (IC2). The 2-2 phase carriage motor runs in combinations of phases A to D.
  • Page 39 Fig. 2.26 CR motor drive circuit 2 - 2 7...
  • Page 40 The phase changing signal for the carriage motor is output from P20 and P21 of CPU 8042. The control signal of phases A and B is inverted via the phase inverter, 1 1 C, and used as the control signal of phase C and phase D, respectively.
  • Page 41 (1) Motor bias voltage The bias voltage for the motor is of two kinds; one for operation use and the other for non-operation use. Table 2.15 Motor bias voltage (2) Carriage motor drive signal timing (a) Acceleration control and constant speed control For acceleration control and contant speed control, the following time settings (Table 2.16) are available in the printing speed (CR m o t o r speed) modes o f 1 163 pps, 7 6 9 pps, 5 9 2 pps and 3 9 7 pps: Table 2.16 Speed control table...
  • Page 42 Table 2.17 Data of decelerate time...
  • Page 43 Fig. 2.29 Deceleration and stop at home position (In case of 1163,769 pps)
  • Page 44 Fig. 2.30 Acceleration and printing control from position other than home position Fig. 2.31 Deceleration and stop at home position (In case of 1163, 769 pps)
  • Page 45 (c) Home Position Seek Movement of the carriage to home position at printer power on is called the home position (HP) seek. The CR motor speeds during the home position seek are all in the 1163 pps mode. The following flow chart exemplifies sequence of HP operational events.
  • Page 46 (d) Acceleration and printing control from home position: @ By the control of a) and b) of 12), the carriage is moved from left to right (column 1 to column 80). In this case, reading to recognize the HP signal is done only in the excitation condition memorized in v) of d).
  • Page 47 Fig. 2.34 LF motor drive circuit (1 ) Motor bias voltage The bias voltage for the motor is of two types. One for operation use and the other for non-operation use Table 2.20 Motor bias voltage (2) Paper feed step motor driven signal timing Fig.
  • Page 48 Fig. 2.35 Paper feed timing chart (In case of N pulse paper feed, N > 5)
  • Page 49 2.4.6 Head driver circuit (Fig. 2.36) (1 ) Solenoid driving control The head has 24 coils and +24V is always supplied to one end of each of the coils. To effect printing with the coils powered, it is necessary to switch on the driver transistors Q1 to Q24 and bring the voltage at one end of the relevant ils to the GND (Fig.
  • Page 50 (2) Counterelectromotive force absorbing circuit As the power supply to the solenoid is switched on and off at high speed, counterelectromotive force is produced in the coil. So that the driver transistor is not adversely affected, a diode and a diode array are provided to each driver transistor (points A, B), and a transistor, resistance, zener diode and electrolytic ca- pacitor (D19, Q27, R6, ZD3, C7) are provided for every 8 driver transisters by wired OR as shown in Fig.

  • Page 51: Auto Sheet Load Circuit 2 - 3

    (4) Driver circuit waveform Fig. 2.38 Driver current waveform 2.4.7 Auto sheet load circuit The auto sheet load circuit sets the paper when the sheet load switch is pressed. The operation consists of the control of the paper hold release lever and the control of the paper feed motor. Refer to 2.4.5 for the control of the paper feed motor.
  • Page 52 When the power switch is turned on, the head carriage, regardless of its position, returns to the left end, home position in an action of @ to 0. Upon receiving print data “EPSON” for a line, the printing is performed in an action of @ to @ with the head carriage moving to positior! @.

  • Page 53: Printer Mechanism

    2.5 Printer Mechanism (Model-3660) The Model-3660 printer mechanism features a 24-pin print head and incorporates all of the sophisticated technology of previously produced EPSON printers. Operation of the 24-pin print head is supported by the carnage components, including the timing belt, rib- bon driving gears, and the carnage motor;...
  • Page 54 1) HP (home position) sensor The HP sensor consists of an HP sensor board and a sensor plate located at the bottom of carriage. While the sensor plate intercepts the optical axis of the photocoupler, a HIGH signal is emitted (open collector output).
  • Page 55 Fig. 2.43 Carriage mechanism 2) Operation of print head unit (Fig. 2.44) The movement of a dot wire in printing a dot is as follows: @ W ith the current flowing through the head driving coil, the actuator plate is attracted to the iron core.
  • Page 56 Correspondence between dot wires and FPC terminals Fig. 2.45 Printhead connector 2 - 4 4...
  • Page 57 2.5.1.3 Paper feeding mechanism The paper feeding mechanism of the printer comprises two systems: a friction feed system to be used for cut sheet and a tractor feed system to be used for continuous business form 4 - 16 inches in width. Each of the two systems have functions such as ordinary feeding and quick feeding.
  • Page 58 2) Tractor feed system (for continuous business from 4 - 16 inches in width) The paper is held on sprocket wheels, some of the sprocket pins being engaged in holes in the paper. When the pulse motor rotates, the gears in the paper feeding gear train are driven in the directions o f a r r o w s , r e s p e c t i v e l y .
  • Page 59 3) Auto loading mechanism Set a cut sheet between the platen and the paper feeding lever. When the release solenoid is ener- gized, the solenoid shaft, sub paper holding lever and paper holding lever move in the direction of the arrow respectively to disengage the paper holding roller from the platen. At this point, the pulse motor (for paper feeding) is driven to feed the paper as specified.
  • Page 60 2.5.1.4 Ribbon feeding mechanism (Fig. 2.49) The ribbon unit consists of a cassette ribbon and a ribbon feeding mechanism. The ribbon feeding me- chanism is set at the bottom of the carriage. When the carriage moves to right or left, the ribbon driving pulley is turned by the ribbon driving wire wound around it so that the ribbon driving gear always turns counterclockwise in the next gear train.
  • Page 61 CHAPTER 3 OPTIONAL EQUIPMENT 3.1 Centronics Compatible Parallel interface ......... 3-1 3.1 .1 Overview..
  • Page 62 3.1 Centronics Compatible Parallel Interface Unit (Cat. No. 7171) 3.1 1 Overview W ith the IUPIF interface board, a centronics parallel data from a host computer can be output to and paint- ed dot by the EPSON LQ-1500 terminal printer. 3.1.2 Specification 3.1.2.1 Interface...
  • Page 63 International Character Selection Table 3.3 3.1.2.3 Pin assignment of interface connector le 3.1) A. CN1 : This connector communicates with CN1 of the UXMCL board. (Refer to Tab B. CN2: Future specification C. CN3: This connectorcommunicates with the host computer. (1) Number of pins..36 pins Table 3.4 Pin assignment (CN3 of IUPIF)
  • Page 64 3 . 3...
  • Page 65 1. The return side, i.e. a twisted pair return, is connected to the signal ground ground level. A twisted pair line must also be used for each signal for the interface and to connect the return side. To effectively pre- vent noise, shield this signal line cable and connect it to the enclosure grounds of the host computer and printer, separately.
  • Page 66 3.1.3.3 Handshaking of the parallel interface Fig. 3.1 Parallel interface timing 3 - 5...
  • Page 67 3.1.4 Block diagram Fig. 3.2 Block diagram Data is exchanged between the UXMCL and IUPIF boards through the 8255AC-5, a programmable peri- pheral interface. The data bus from the UXMCL board is connected to 8255AC-5 data pin D, - DT. Port B is connected to DIP switches DIP 1 and DIP 2.

  • Page 68: Circuit Diagram 3 - 2

    3.1.5 Circuit diagram 3 - 7...

  • Page 69: Component Layout

    Fig. 3.4 Component layout of IUPIF board...

  • Page 70: General

    The interface is a general-purpose, intelligent, serial interface which enables the data from different com- puters to be output to the EPSON LQ1500 terminal printer. Board components include a CPU, and a 2 K- byte buffer, which has flag control and X-ON/X-OFF control functions.
  • Page 71 (6) With X-ON/X-OFF control Table 3.7 Current Loop RS 232C Data X’fer When X-ON (1 1 H) signal is sent across When X-ON (1 1 H) signal is sent from pin Enabled No. 2 of interface connector. pin No. 17 and pin No. 24 of interface connector.
  • Page 72 3.2.2.2 Condition setting on the interface board (1) DIP switches setting The RS-232C/Current loop interface board is equiped with four DIP switches. The specifications of DIP 1 and DIP 2 are the same as those on the other interface boards. A.
  • Page 73 D. DIP 4 : Table 3.10 Setting of DIP 4 3 - 1 2...
  • Page 74 (1) Jumper wire connection TXD cannot be output unless CTS is ON (positive voltage) Note 1: Notes 2 and 3: RXD cannot be received unless both DSR and DCD are ON (positive voltage) Note 4: Jumpers 4 and 5 are used when current loop in the host computer is not connected to power supply.
  • Page 75 3.2.2.3 Pin assignment of interface connector A. CN1 : .This connector communicates CN1 of the UXMCL board Refer to 2.3.1. B. CN2: Future specification C. CN3: This connector communicates with the Host Computer. (1 ) Number of pins: 25 pin cannon type Table 3.13 Pin assignment (CN3 of IURS) Notes: 1.
  • Page 76 3.2.3 Operating principle 3.2.3.1 Data entry Serial data entry is performed under the preset conditions. (1) The serial data transferred from the host computer is input to CN3 pin 3 (RXD) or pin 25 (TTY RXD). (2) The data input to pin 3 (RXD) or pin 25 (TTY RXD) is entered in the CPU. Then, the data is converted from serial to parallel inside the CPU.
  • Page 77 (3) Flag set/reset, X-ON/X-OFF sequence Reverse Channel Control Fig. 3.6 Flag set and reset timings a) As shown in Fig. 3.6, the flag timing is set when 16 bytes remain in the buffer. At the same time, X-OFF is transmitted and the subsequent data input is prevented. However, even when the rest of buffer is for 16 bytes, data entry is possible until the buffe is completely full (total capacity, 2 K- bytes).
  • Page 78 (4) Bit rates and X-ON/X-OFF transmit timing Table 3.14 Bit rates and X-ON/X-OFF transmit timings At the above timing, X-ON/X-OFF is transmitted with an interval 80 times the width of one bit cell, i.e. for the data of 10 bits/character, X-ON/X-OFF is transmitted every 8 characters. In addition, when the state of X-ON/X-OFF shifts, the timing is as follows: Fig.
  • Page 79 3.2.3.3 Self-test Loopback or line monitor. The self- The printer self-test can be performed in either of two modes: testmode be selected by setting DIP switch pins 2-5 and 2-6 on the interface board. Refer to Table 3.15, for setting specifications. Table 3.13 Loopback/Line monitor (1) Loopback Mode: To enter the Loopback Mode, refer to Table 3.13, and set the DIP switches: then, turn the power on.
  • Page 80 3.2.4 Block diagram 3-19...
  • Page 81 3.2.5 Circuit diagram IURS CIRCUIT BOARD UNIT NO. Y49520300000 Fig. 3.9 IURS circuit board 3-20...
  • Page 82 Fig. 3.10 Component layout of IURS board...
  • Page 83 3.3 IEEE-488 Interface (Cat. No. 7165) 3.3.1 Introduction IEEE-488 Interface Unit incorporates a CPU and has a 2K-buffering function. This interface allows an IEEE-488 Computer or measuring instrument to produce printed output on an EPSON LQ-1500 dot matrix printer. 3.3.2 Specifications 3.3.2.1 Specification...
  • Page 84 3.3.2.2 Condition setting on the interface board The IEEE-488 interface board is provided with four DIP switches and four jumpers. Their respective func- tional settings are follows: Setting of DIP Switches A. DIP1 See 3.1.2.2 B. DIP2 See 3.1.2.2 C. DIP3 Address calculation formula: Table 3.16 Setting of DIP SW3 Example: The following example shows how to set printer address “6”.
  • Page 85 Setting of buffer-full recovery timing Buffer-full recovery timing is controlled by setting DIP switch 4, pins 3 and 4 (Table 3.18). Once the buffer is full, data entry will not be resumed until the buffer can again accommodate the number of bytes desig- nated by the switch setting.
  • Page 86 3.3.2.3 Pin assignment of interface connector A. CN 1 : Connected to UXMCL circuit board B. CN2: Future specification C. CN3: Connected to Host Computer 3-25...
  • Page 87 Fig. 3.13 IEEE-488 connector 3.3.3 IEEE-488 operational parameters 3.3.3.1 Handshaking Setting DIP switch pin No. 3-1 adjusts parameters for handshaking to either address (3-1 OFF) or listen only (3-1 ON) mode. (1) Address Operation Mode With DIP switch 3-1 OFF, data entry is enabled when a LOW attention (ATN) signal is emitted from the controller, and the printer is designated as listener.
  • Page 88 3.3.3.3 Self-test The printer self-test can be performed in one of two modes (1) Self-Print and (2) Bus Monitor. This self- test mode is selected prior to power up by setting DIP switch pins 4-7 and 4-8 on the IUIE interface board. The switches are read at initialization.
  • Page 89 (3) IEEE-488 handshake sequence Fig. 3.14 Timing chart of 3 wire handshaking Description of handshake timing 1) Listener waits for data. 2) Talker transmits data to data line. 3) Talker checks NRFD. DAV must be LOW NRFD HIGH. 4) Listener reads data with DAV LOW. NRFD is made LOW for data processing.
  • Page 90 3.3.5 Block diagram 3 - 2 9...
  • Page 91 When data is exchanged between the main board (UXMCL) and IUIE boards, the uPD781 1 controls data exchange as the centeral processor in the IUIE board. The data transferred from the IEEE-488 computer or measuring equipment is entered in pPD7811 and then stored in the 2 K-byte RAM. The stored data is en- tered in the buffer on the main board (UXMCL).
  • Page 92 3.3.6 Circuit diagram IUIE CIRCUIT BOARD UNIT N0.Y49520200000 Fig. 3.16 IUIE circuit board 3-31...
  • Page 93 Fig. 3.17 Component layout of IUIE...
  • Page 94 Double Bin Cut Sheet Feeder (# 8344) 3.4.1 Introduction The EPSON Cut Sheet Feeder #8334, 8344 makes a perfect companion to the LQ-1500 printer. Reliably and automatically feeding paper to the printer one sheet at a time, it greatly enhances the speed and effi- ciency of letter-quality document preparation.
  • Page 95 3.4.2 Specifications 1. Dimensions and Weight Double Bin Cut Sheet Single Bin Cut Sheet Feeder (# 8334) Feeder (# 8344) 350 mm Height 350 mm 306 mm 387 mm Depth 516 mm 516mm Width Weight 3.2 kg 4.4 kg 2. Form length (1) Minimum: 185 mm (7.25”) - bin 1 267 mm (10.5”) - bin 2...
  • Page 96 8. Paper specifications Use paper conforming to the specifications below to assure reliable operation of the cut sheet feeder. Paper which does not conform to the following specifications may be used; however, proper operation is not assured. Test such paper prior to regular use. Most paper is sensitive to temperature and humidity, and the performance of the paper used with the printer and cut sheet feeder can be adversely affected by these conditions.
  • Page 97 3.4.3 Principles of operation 3.4.3.1 General construction The cut sheet feeder is designed for paper feed from one or two paper feed bins. The construction of the cut sheet feeder can be broken down in 4 subassemblies: 0 Form Guide and Form Transport 0 Output Stacker 0 Drive Mechanism 0 Paper Feed bins...
  • Page 98 Both pick-up roller shafts and the eject roller shafts are driven by the printer platen. The platen motion is transmitted through the gear train to the cut sheet feeder. Two mechanical selection and feed units, one for each pick-up roller shaft, provide the selection of one feed bin and the insertion of a single sheet to the printer platen.
  • Page 99 3.4.3.4 Drive mechanism Fig. 3.19 Drive mechanism of the cut sheet feeder the platen shaft gear is transmitted through the idler gears to the eject roller shafts and the se- Rotation of feed units of the pick-up roller shafts. Refer to the function description of the selecti on and lection and feed unit.
  • Page 100 3.4.3.6 Construction and function of the selection and feed unit The purpose of the selection and feed unit is to select one pick-up roller shaft and transmit the platen motion to this shaft to insert a single sheet until it rests on the platen pinch rollers. The selection and feed unit is made up of a drive wheel assembly and a catch plate assembly.
  • Page 101 Selection Cycle: Assuming that all selection and feed units are in their home positions the execution of “n” line spaces in reverse direction and two line spaces in forward direction activates one of the se- lection and feed units. The selector latch of this unit will be engaged with the catch plate. When “n”= 8 Selection of Bin 1 (Red)* When “n”...
  • Page 102 One of the selection and feed units is selected. b) Selection and The corresponding pick-up roller shaft will rotate in reverse Insertion Cycle direction. 0 Platen motion is reversed. After “n” line spaces, the selector latch will drop to the inside cam of the catch plate .,. Bin 1 (Red one) is selected.
  • Page 103 3.4.4 Disassembly and assembly The following tools are required for disassembly and assembly of the cut sheet feeder # 8334/8344. Tools Screwdriver (+) # 2 Screwdriver (-) # 2 Pliers for electrical servicing Precautions Pay attention to the following points when disassembling and assembling the cut sheet feeder # 8334/8344.
  • Page 104 Removal of the basket Hold both ends of the basket and lift up until the basket is removed. Fig. 3.29 Removal of the basket Removal of the side cover The side cover is secured to the frame with pawls at three points, two on the top and one on the bot- tom.
  • Page 105 Removal of the feet Two feet are used to support the weight of the cut sheet feeder and cut sheets. They are simply inserted into the frame edges from the side. They can easily be removed by pulling them sideways. Fig.
  • Page 106 Remove the clamp on the back of the paper guide. Insert the screwdriver 9 into the notch on the clamp and force it upward until the clamp comes off. The leaf spring will also be removed. Note: The clamp is secured very tightly. First pry the clamp with the screwdriver tip to disengage the pawl and then, lift it up with the screwdriver blade.
  • Page 107 (3) Removing the brake lever, selection/feed unit, gear wheel and pickup roller. Remove the spring attached to the left side of the cut sheet feeder. Fig. 3.36 Removal of spring b) Removal of brake lever attached to the right side. Remove the spring located between the right and left brake levers.
  • Page 108 Remove the gear wheel. Fig. 3.39 Removal of gear wheel To remove the pickup e) Turn the pickup roller bearing counterclockwise to remove it. roller: first pull the pickup roller to the left and take out the right shaft; then, lift it out. Fig.
  • Page 109 (5) Removal of the output selector and eject roller shaft Remove the spring located between the output selector arms of the left and right sides and the frame. Remove the left and right output selector arms. Fig. 3.42 Removal of output selector arms Remove left and right screws securing profile 0, and remove the profile.
  • Page 110 (6) Removal of the printer adapter Removing the printer adapter (left side) Remove the three M4.2 x 19 screws securing the printer adapter and remove it. Screws Fig. 3.44 Removal of the printer adapter (left) b) Removing the printer adapter (right side) Remove the three M4.2 x 19 screws securing the right side of the printer adapter and remove it.
  • Page 111 (1) Mounting the output selector and eject roller shaft Before mounting the output selector, be sure that each of the separator’s film tabs is positioned correctly. Each double sided tab should be positioned so that the front profile is grasped between the two sides of the tab 0.
  • Page 112 Do not forget to insert a washer between the bin selector and frame. After the selectors are mounted, rotate the assembly one full turn clockwise and then counterclockwise to make sure that it rotates smoothly. If the unit rotation is not smooth, refer to section 3.4.5, Troubleshooting, Fault of selection and feed unit (Ref.
  • Page 113 3.4.5 Troubleshooting 3.4.5.1 General This chapter describes troubleshooting for the cut sheet feeder #8334/8344. All the operations of the cut sheet feeder are mechanical, and each part can be actually moved and checked visually. This makes troubleshooting very easy. Perform troubleshooting by referring to 3.3.4, “Disassembly and Assembly”. 3.4.5.2 Troubleshooting procedure The troubleshooting procedure following consists of a two part check of component functions.
  • Page 114 [Checking operation of the whole unit] Check operation by manual operation with the Cut Sheet Feeder mounted on the printer. 3-53...
  • Page 115 3 - 5 4...
  • Page 116 3 - 5 5...
  • Page 117 [Fault of selection and feed] 3 - 5 6...
  • Page 118 [Fault of paper guides1 3-57...
  • Page 119 [Fault of output selector] 3 - 5 8...
  • Page 120 [Other faults/Paper is fed at an angle] 3 - 5 9...
  • Page 121 3.4.6 Preventive maintenance 3.4.6.1 Introduction Due to its proven design all models of the cut sheet feeder family require a minimum of pre- ventive maintenance. To provide highly reliable, trouble-free operation of the cut sheet feeder the recommended preventive maintenance procedures should be performed approximately every 6 months of 1000 hours of use, whi- chever comes first.
  • Page 122 3.4.6.4 Cleaning procedure 0 Remove all paper dust from the feeder, using a vaccum cleaner with a small nozzle. 0 Brush all paper dust from the eject rollers. Ensure, that the paper deflector is not damaged or loose. 0 Check the surface of the eject rollers. If one or more of the rollers are damaged, the complete shaft must be replaced.

  • Page 124: Table Of Contents

    CHAPTER 4 DISASSEMBLY/ASSEMBLY AND ADJUSTMENT 4.1 General....................4.2 Tools and Measuring Instruments ............. 4-1 4.3 Disassembly and Assembly ..............4.3.1 Removal of upper case.............. Removing the circuit boards............. 4.3.2 4.3.3 Removal of Model-3660 printer mechanism ......4-6 4.3.4 Removal of fan set UB (head cooling fan).

  • Page 125: General

    4.1 General This chapter describes the method of disassembling the LQ-1500 Terminal Printer for replacement of ma- jor components. 4.2 Tools and Measuring Instruments The tools and measuring instruments contained in Tables 4.1 and 4.2 of this section must be prepared by the user prior to disassembling and troubleshooting the LQ-1500.

  • Page 126: Disassembly And Assembly

    Table 4.2 List of measuring instruments Lubricants and adhesive List The lubricants and adhesive which are indispensable for maintenance and repair are given below. 0: Available only from EPSON : Commercially available 4.3 Disassembly and Assembly The following explains the disassembly procedures of the main components. Unless otherwise speci- fied, each disassembled component can be reassembled by reversing the disassembly process.

  • Page 127: Removing The Circuit Boards

    The location of each printer component with the upper case detached is as shown in Fig. 4.2. Fig. 4.2 Location of each component 4.3.2 Removing the circuit boards The electric circuit boards in the LQ-1500, control the Model-3660 printer mechanism, and include the control circuit board (UXMCL), the driver circuit board (UXDRV), the power circuit board (UXPS or UXFIL) and an interface circuit board (IUPIF, IUIE or IURS).
  • Page 128 STEP 5 : Disconnect connector CN3 0 from the driver circuit board (UXDRV). STEP 6: Disconnect connector CN2 0 from the power circuit board (UXPS). STEP 7 : Remove 2 screws 0 securing the control circuit board (UXMCL). Disconnect the 9 hooks securing the control circuit board by hand, and remove it from the STEP 8: lower case.
  • Page 129 (3) Removal of power circuit board (UXPS or UXFIL) The power circuit board supplies DC voltage to the control circuit board and the driver circuit board. STEP 1: Remove the upper case. (See paragraph 4.3.1.) STEP 2: Disconnect the connectors from the power circuit board. 1.

  • Page 130: Removal Of Model-3660 Printer Mechanism

    4.3.3 Removal of Model-3660 printer mechanism The Model-3660 printer mechanism can be detached by removing the four connectors and four screws. Notes: When remounting the mechanism, be careful not to trap the control panel cable, paying atten- tion to routing. STEP 1: Remove the upper case.
  • Page 131 4.3.5 Removal, installation and adjustment of print head (1) Removal of print head Replace the print head in the following procedure: Notes: When replacing the print head, be sure to turn off the power. Remove the ribbon cassette from the print head. STEP 1: Manually the print head fully to the left.

  • Page 132: Adjustment 4 - 1

    (2) Installation and adjustment of print head STEP 1: Set the adjusting lever to the first step. Fig. 4.12 Adjusting lever STEP 2: Secure the print head by 2 screws. STEP 3: Connect 2 head cables to the connectors on Model-3660 in order from left to right. Caution: Unless head cables are securely connected, the assembly may not function.

  • Page 133: Removal Of Cpu And Rom

    STEP 5: Set the adjusting lever to the fifth step. STEP 6 : Hook the ribbon mask in the ribbon fixing pin, and set it to the original position. Fig. 4.14 Setting of ribbon mask Note: Incorrect setting of the ribbon mask may cause jammed ribbon or paper. STEP 7: Set the adjusting lever again according to the paper to be used.
  • Page 134 4.3.7 Adjustment of the print alignment (backlash) 1. Location of SW1 Dip switch 1 is located on the UXMCL circuit board as shown in Fig. 4.15; it is possible to set SW1 without removing other components. DIP switch SW1 Fig. 4.15 Location of SW1 2.
  • Page 135 3. Adjustment This ad- It is necessary to adjust the printing backlash when the print alignment on one line becomes bad. SW1. justment is performed by starting the test program of ROM with the operation of dip switch Please adjust step by step according to the following flow chart. 4-11...

  • Page 136: Adjustment

    4.4 Adjustment 4.4.1 MTS and DTS sensor board adjustment Adjust the MTS sensor board if sensor board has changed. Special Tools: Synchroscope Extension cables (2 types) Turn off the power. STEP 1: STEP 2: Remove the upper case. Remove the printer mechanism. STEP 3: Remove the UXDRV board.
  • Page 137 Securely tighten the setscrew if adjustment has completed. STEP 12: Adjust the phases of MTS and DTS signals. STEP 13: Scope set: MTS signal (One side of resistance R35 on the UXMCL Board) CH1: DTS signal (One side of resistance R34 on the UXMCL Board) CH2: TIME: 200 usec CHOP mode TRIG: CH1...

  • Page 138: Sensor Board Adjustment

    4.4.2 H.P. sensor board adjustment (Figs. 4.20,4.21) Disconnect the printer from the power source before making the adjustment. (Adjustment of the printing start position) Adjust the H.P. sensor board if sensor board has changed. STEP 1: Execute the MTS sensor board adjustment from STEP 1 through STEP 5 (Section 4.4.1). STEP 2: Set the printing paper, and print more than 7 or 8 lines.

  • Page 139: Backlash Of The Carriage Motor And Belt Driving Pulley

    Move and adjust the H.P. sensor board so that T3 reaches 300 to 600 us just before the STEP 7: adjustment is performed. Securely tighten the setscrew. STEP 8: Confirm that the sensor of the H.P. sensor board and sensor interseption plate of the car- STEP 9: riage do not contact with each other when the adjusting lever is set at the highest or lo- west level.

  • Page 140: Backlash Of The Paper Feed Motor And Paper Feeding Reduction Gear

    4.4.4 Backlash of the paper feed motor and paper feeding reduction gear (Fig. 4.25) If line spacing is unstable, adjust the backlash. STEP 1: Loosen the setscrews (CPO M3 x 6) of the line feed motor. Adjust the backlash between the motor pinion of the pulse motor and the paper feeding re- STEP 2: duction gear.
  • Page 141 CHAPTER 5 TROUBLESHOOTING 5.1 Entry of Troubleshooting ..............5.2 Check-out Procedure ................5.3 Unit Repair Flow Chart (UXMCL) ............5-18 5.4 Unit Repair Flow Chart (UXDRV)............5-33 5-40 5.5 Unit Repair Flow Chart (IUPIF) ............5-42 5.6 Unit Repair Flow Chart (UXPS)............

  • Page 142: Entry Of Troubleshooting

    5.1 Entry to Troubleshooting Troubleshooting is not an easy process since troubles can happen in various sections in various forms. The approach represented by the following three procedures, however, assures you of an easy entry to repair. 1. Check-out procedure (5.2) The check-out procedure provides entry to repair for troubles whose nature is not clear Use: enough.
  • Page 143 The user is recommended to keep the following replacement components: [Circuit boards] [Electric devices]...
  • Page 144 [Mechanical components] Model-3660 Y450590100 [Maintenance tool]...

  • Page 145: Check-Out Procedure

    5.2 Check-out Procedure (Repair by Unit Replacement) 5 - 4...
  • Page 146 5 - 5...
  • Page 147 5 - 6...
  • Page 149 < Carriage does not return to home position when power switch is turned on. >...
  • Page 150 <Carriage does not move. >...
  • Page 151 5-10...
  • Page 152 < Paper feeding motor does not stop. > <Control panel indication is faulty. > 5-11...
  • Page 153 <Switch on control panel can operate in the on-line state. > 5-12...
  • Page 154 < Sheet loading does not work properly. >...
  • Page 155 < Carriage does not move in Self Printing Test (1). > <“LF” and “FF” switches does not operate in off-line state. > 5 - 1 4...
  • Page 156 < Carriage does not move in Self-Printing Test (2). > 5 - 1 5...
  • Page 157 < Printing is faulty. > <Paper feeding is not made in Self Printing Test.> 5 - 1 6...
  • Page 158 < Operation is abnormal when connected with host computer. > 5-17...

  • Page 159: Unit Repair Flow Chart (Uxmcl)

    5.3 Unit Repair Flow Chart (UXMCL) 5-18...
  • Page 160 1. Printing Troubles 5-19...
  • Page 161 5-20...
  • Page 163 5-22...
  • Page 164 5 - 2 3...
  • Page 165 2. Carriage Troubles 5-24...
  • Page 166 5-25...
  • Page 167 5 - 2 6...
  • Page 168 5-27...
  • Page 169 5-28...
  • Page 170 3. Paper Feeding Troubles 5-29...
  • Page 171 5 - 3 0...
  • Page 172 5-31...
  • Page 173 4. Sheet Loading Problem 5-32...

  • Page 174: Unit Repair Flow Chart (Uxdrv)

    5.4 Unit Repair Flow Chat-t (UXDRV) 5-33...
  • Page 175 1. Printing Troubles 5 - 3 4...
  • Page 176 5-35...
  • Page 177 2. Carriage Troubles 5-36...
  • Page 178 3. Paper Feeding Troubles 5-37...
  • Page 179 5-38...
  • Page 180 4. Sheet Loading Troubles 5-39...

  • Page 181: Unit Repair Flow Chart (Iupif)

    5.5 Unit Repair Flow Chart (IUPIF) 5-40...
  • Page 182 5-41...

  • Page 183: Unit Repair Flow Chart (Uxps)

    5.6 Unit Repair Flow Chart (UXPS) 5 - 4 2...
  • Page 184 +24 voltage is not output. (The malfunction of the primary.) 5 - 4 3...
  • Page 185 The cause of Q1, Q2 malfunction If after repairing Q1 and Q2 the printer continues to malfunction when the power is switched on, check to see whether the converter, which connects the D.C power supply (10 to 30V) to A.C input oscillates inter- mittently.
  • Page 186 The voltage of +24 is low. Excessive voltage is output. 5 - 4 5...
  • Page 187 +5 is abnormal. 5-46...
  • Page 188 Vx is abnormal. 12 is abnormal. 5-47...
  • Page 189 CHAPTER 6 MAINTENANCE Maintenance ..................6.1.1 Cleaning ..................6.1.2 Inspection..................Lubrication..................... 6.2.1 Lubricants..................6.2.2 Lubrication requirement............6.2.3 Lubrication point................. 6.2.4 Adhesive application requirements......... 6-3 6.2.5 Adhesive application points............6-3 6.2.6 Lubricants and adhesives list........... 6-4...

  • Page 190: Maintenance

    6.1 Maintenance Proper maintenance is essential for the printer to keep its designed performance for the longest possible period, and to minimize the frequency of trouble. Carry out maintenance according to the following instructions. 6.1.1 Cleaning (1) Remove any dirt or stains using alcohol. Note: Never use thinner, trichloroethylene or ketone-based solvents, which might deteriorate plas- tic parts.

  • Page 191: Lubrication

    6.2 Lubrication Proper lubrication is essential for the printer to keep its designed performance for the longest pos- sible period, and to minimize the frequency of trouble. Carry out lubrication according to following instructions: 6.2.1 Lubricants The properties of lubricants used have a great influence on the performance and durability of the printer.

  • Page 192: Adhesive Application Requirements

    6.2.4 Adhesive application requirements This printer contains some screws and nuts secured by adhesive to prevent loosening due to vibra- tions. During disassembly/reassembly or parts replacement, apply adhesive to the required points according to the list below or “Lubrication and Adhesive Application Points Drawing”. The adhesive to be used for the printer is Neji Lock Green # 2.

  • Page 193: Lubricants And Adhesives List

    Note: Use of excessive quantity of adhesive may cause malfunction of adjacent parts due to flow of adhe- sive, so pay attention to application quantity. (See Fig. 6.1) Fig. 6.1 6.2.6 Lubricants and adhesives list The lubricants and adhesives which are indipensable for maintenance and repair are given below. (“) Commercially available. 0: Available only from EPSON.

  • Page 194: Chapter 7 Appendix

    CHAPTER 7 APPENDIX List of principal IC’s ..................Description of principal lC’s ............... Exploded diagram for LQ-1500 ..............7-35 Lubrication and adhesive application points drawing A......7-36 Lubrication and adhesive application points drawing B ......7-37 Lubrication and adhesive application points drawing C ......7-38 7-39 UXMCL circuit diagram ................
  • Page 195 List of Principal lC’s Table 7.1...
  • Page 196 Technical Data of Z-80A CPU 1. Architecture Configuration Fig. 7.1 shows a block diagram of the Z-80A architecture. An chip circuitry fun. Fig. 7.1 1 .1 CPU register group The Z-80A CPU has a 207-bit read/write memory which can be accessed at random by the program. Table 7.1 indicates the register array of this memory.
  • Page 197 Exclusive registers 1) Program counter (PC) The program counter holds 16 memory address bits for the instruction being currently executed. The CPU fetches the instruction from the memory address indicated by the program counter. This counter is automatically incremented when its own contents are transmitted to the address bus. In program jump, the increment does not work and a new value is set directly to the counter.
  • Page 198 General-purpose registers The CPU is provided with 2 sets of paired general-purpose registers, each of which can be used as an 8-bit register singly and each pair of which can be used as a 16-bit register pair. BC, DE and HL are gi- ven as the one set and, BC’, DE’...
  • Page 199 2. Pin Functions The Z-80 CPU is housed in a standard 40-pin DIP (dual in-line package). Its l/O pins are arranged as shown in Fig. 7-2. The following describes each pin function. Fig. 7.2 Pin configuration Tri-state, active HIGH Ao- AI form a 16-bit address bus.
  • Page 200 IORQ Tri-state, active LOW (I/O request) The I/O request signal is emitted when the effective I/O address for I/O’read or write is put on the low-order 8 bits of the address bus. This signal is also emitted together with signal M cycle, during an interrupt acknowledged, telling the I/O unit that the interruption response vector can be put on the data bus.
  • Page 201 Input, leading edge detection (Non-maskable in The non-maskable interrupt request has a priority order higher than that of the terrupt request) interrupt request (INT). Thus, when this signal enters before the rise of the last T cycle of the instruction being currently executed, it is accepted after comple- tion of this instruction.
  • Page 202 3. Timing In a combination of basic operations in the Z-80A CPU, the instruction is executed step by step. The basic operations include the following: Memory read/write, I/O unit read/write, Interrupt, Acknowledge Any instruction is executed in a combination of these basic operations. Any of these basic operations, performed with 3 to 6 clock pulses, can be prolonged to synchronize the CPU with an external unit in respect to operation speed.
  • Page 203 Clock pulse in the fetch cycle are used to refresh dynamic memory. (In the period of T4, as the fetched instruction is decoded and executed within the CPU, no other, operation to external units is made.) In the period of the memory refresh address is put on the 7 low-order bits of the address bus and signal RFSH becomes active.
  • Page 204 3.2 Memory read/wire Fig. 7.6 is the timing chart for the memory read/write cycle. The memory read/write cycle normally has the length of 3 T cycles, unless the wait signal emitted from the memory side is given. Signals MREQ and RD are used in the same way as in the fetch cycle. Fig.
  • Page 205 3.3 I/O cycle Fig. 7.8 indicates the read and write operations to I/O units. In this case, it should be noted that one wait state of Tw cycle is inserted automatically to compensate for the brief time required for the CPU to sample data after IORQ becomes active.
  • Page 206 3.4 Bus request/acknowledge cycle Fig. 7.10 is the timing chart in the bus request/acknowledge cycle. The CPU checks signal BUSRQ at the leading edge of the final clock pulse in each machine cycle. If signal BUSRQ is active, the CPU puts the address, data and tri-state control buses into HIGH impe- dance at the leading edge of the next clock pulse.
  • Page 207 * Wait state (signal pulse Tw) is inserted automatically. Fig. 7.11 The method of prolonging the acknowledge time by use of a programmable counter is shown in Fig. 7.12 and 7.13. Fig. 7.13 7-13...
  • Page 208 3.6 Non-maskable interruption response Fig. 7.14 is the timing chart in the non-maskable interrupt request/acknowledge cycle. Differently from signal INT, signal NMI is effective at the trailing edge, and its input can be performed at any timing of the instruction. However, to enter the acknowledge cycle after the current instruc- tion is completely executed, it is necessary to obtain the leading edge of signal NMI before the final T cycle of the instruction as a minimum requirement.
  • Page 209 Fig. 7.16 Pin configuration 7-15...
  • Page 210 (2) Block Diagram 8042 Fig. 7.17 Block diagram 7-16...
  • Page 211 (1) Features 8-bit microprocessor unit 0 Built-in 2-kbyte ROM (1 K byte ROM) 0 Built-in 128-byte RAM (64 byte RAM) 8-bit I/O port (2 sets) Two test input lines 0 Built-in 11 -bit program counter (10 BIT) 0 Built-in 8-bit timer/counter 0 Built-in clock generator 0 8-bit status register 0 Two data buffer registers...
  • Page 212 0 P20 to P27 (I/O port 2)..lnput/Output In addition to the ordinary functions of the I/O ports, there are the following functions: The lower four bits (P20 to P23) can also serve as the interface ports with the uPD8243 I/O expand- er.
  • Page 213 Programmable interrupt controller uPD8259AC 8-level priority controller 0 Extendible up to 64 levels Interrupt mode programmable Individual reuest mask CALL command code generation 0 N-channel MOS 0 I/O, TTL compatible 0 Single power supply, +5V Fig. 7.19 0 28-pin plastic DIP (D-28C) Names and functions of pins CS: Chip select WR: Write input...
  • Page 214 Programmable peripheral interface uPD8255AC-5 Compatible with uPD8085A microprocessor Controllable directly from CPU for setting and resetting each bit. TTL compatible 40-pin plastic DIP (D-40C) Compatible with Intel 8255A-5 4 MHz operation Powre supply, Vcc = +5V + 10% Fig. 7.20 Pin configuration Fig.
  • Page 215 uPD7811 (7810) Pin configuration PA7-0 : Port A MODEO.1 : Mode0.1 PB7-0 : Port B x 1 , x 2 : Crystal PC7-0 : Port C AN7-0 : Analog Input PD7-0 : Port D : Read Strobe PE7-0 : Port F : Write Strobe : Non-maskable Interrupt : Address Latch Enable...
  • Page 217 (1) Features of uPD7811 (7810) 0 Instruction ................. 158 kinds 0 Instruction cycle .
  • Page 218 Operation of 7811 Port F Table 7.3 0 7810 (a) By setting modes 0 and 1, assignment to the address bus (AB15 to 8) can be made in accor- dance with the size of memory to be provided externally. The remaining terminals can be used as input/output ports. See the following table.
  • Page 219 10) NMI (Non-maskable Interrupt)..lnput Non-maskable interrupt of the edge trigger (trailing edge) 1 1 ) INTI (Interrupt)..lnput Maskable interrupt input of the edge trigger (leading edge). It can also be used as the AC input zero cross detecting terminal. 12) AN7-0 (Analog Input)..lnput 8 analog inputs of A/D converter.
  • Page 220 (3) Memory timing Memory write is performed during T1 to T3. The Address and ALE signal timing is the same as for memory read. However, following address out- put, AD7 to 0 (PD7 to 0) are not disabled, and write data are output at AD7 to 0 from the beginig of T1 to the end of T3.
  • Page 221 Gate array uPB6101-009 0 Receiving signal I/F of Z-80 or Z-80A CPU, or Intel type peripheral LSI (8041 A, 8255A. 8259A, etc.) and controlling drum. 0 Operable at about 4 MHz with one wait state inserted to Z-80A CPU in OP code fetch only, and at about 2.5 MHz without no wait state.
  • Page 222 Programmable interval timer 8253-5 0 3 independent 16-bit counters 0 From DC to 2 MHz 0 Programmable count mode 0 Binary or BCD count 0 Single power supply, +5V 24-pin DIP 0 I/O, TTL compatible Fig. 7.28 Compatible with 8085A Names and functions of pins Do-D7: Data bus (8-bit)
  • Page 223 When the trigger input becomes lower than the trigger level, the flip-flop is set so that its output be- comes HIGH. When the threshold input becomes higher than the threshold level, the flip-flop is reset so that its out- put becomes LOW. When the reset input becomes LOW, the flip-flop is reset so that its output becomes LOW.
  • Page 224 Names and functions of pins P20 - Port 2 P23: Port 4 P40 - P43: Port 5 P50 - P53: Port 6 P 6 0 - P 6 3 : Port 7 P70 - P73: Chip select PROG: Program pulse The clock pulse used to obtain the timing of data output to CPU, or data or com- mand input from CPU, is entered to this pin.
  • Page 225 128K (16Kx8) EPROM 27128 0 16,324W x 8 configuration 0 Access time, 250 ns max. 0 Low-power standby mode 0 I/O, TTL compatible 0 N-channel MOS 0 Single power supply, +5V 0 28-pin ceramic DIP Names and functions of pins Ao-A13: Address Chip enable...
  • Page 226 Thick film IC STK6982 Names and functions of pins Power supply Common AB, common power supply line Ccd: Common CD, common power supply line COM: Common On - With Zener diodes connected to this pin, the voltages at pins can be clamped.
  • Page 227 Quad driver HA1 3007 Dielectric strength 5OV, max. output current 0.7 A 0 Low saturation voltage between collector and emitter 0 Input, TTL compatible Surge absorption diode against inductive load incorporated 0 Small input current Names and functions of pins OUT A - OUT D: output Input...
  • Page 228 Silicon transistor array uPA79C 0 Low output saturation voltage l High DC current amplification factor 0 Reverse bias protection diode incorporated in input side 0 Surge absorption diode incorporated in output side µ P A 7 9 C Fig. 7.43 ,uPA79C µPA79C is a transistor array in which a 7-circuit configuration with NPN silicon transistors, diodes and peripheral resistors is made into a monolithic IC.
  • Page 229 EXPLODED DIAGRAM FOR LQ-1500 (12OV VERSION) 7 - 3 5...
  • Page 231 7-37...
  • Page 232 7-38...
  • Page 237 UXPS CIRCUIT BOARD UNIT NO. Y45020300000 7-43...

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