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Service Manual
DOT MATRIX PRINTER
MODEL
CBM-710/720
Rev.1.00 Newly issued on Mar, 1989
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CONTENTS Chapter 1. Printer Disassembly and Assembly ....................................................................................... 1 1 How to Remove Upper Cover and Rear Cover ............................................................................................ 2 2 How to Remove The Printer Mechanism...................................................................................................... 3 3 How to Remove the Control Board ...........................................
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CBM-710/720 Service Manual Chapter 1 Printer Disassebly and Assembly 1
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CBM-710/720 Service Manual 1. How to the Upper Cover and Rear Cover 1) Unfasten 4 screws (M3 x 6) as shown in the figure and lift the upper cover upward, while disconnecting the connector. 2) Unfasten 4 screws (M3 x 6) at both sides and remove the rear cover. Upper Cover Connector Rear Cover 2
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CBM-710/720 Service Manual 2. How to Remove the Printer Mechanism • Remove the upper cover. • Unfasten 2 screws (M3 x 14) as shown in the figure. • Lift the printer mechanism in the arrow position for removal. Printer Mechanism 3. How to Remove the Control Board • Remove the rear cover. • Disconnect each connector. • Unfasten 4 pieces of board mounting screws for removal of the control board. Control Board 3
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CBM-710/720 Service Manual 4. How to Remove the Power Board and AC Power Unit 1) How to Remove the Power Board • Disconnect 2 connectors. • Unfasten 2 screws (M3 x 8) and 2 tapping screws (M3 x 8). • Remove the board, paying attention to the lead wire. 2) How to Remove the AC Power Unit • Unfasten 2 inlet set screws (M3 x 10) and an earth wire mounting screw (M4 x 6). • Unfasten 2 noise filter plate mounting screws (M3 x 6). • Unfasten 4 power transformer mounting screws (M4 x 6). • Disconnect t
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CBM-710/720 Service Manual 5. How to Remove the Auto Cutter Unit (720) • Remove the printer mechanism from the main body. • Remove 2 E3’s as shown in the figure. • Pull out the shaft in the arrow direction for removal of the auto cutter unit. (Note that 2 spacers come off at the same time). Auto Cutter Unit Spacer Printer Mechanism 6. How to Remove the Operation Panel Board and PE Sensor Board • Remove the upper cover and unfasten 2 tapping screws for removal of the operation panel board. • Remo
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CBM-710/720 Service Manual Chapter 2 Circuit Description 6
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CBM-710/720 Service Manual 1. Outline A block diagram of this printer is shown in Fig. 1-1. It consists of the control circuit centered around CPU, ROM, RAM and peripheral circuits, interface circuit for interfacing with each host computer, operator panel circuit for operating switch input and LED display, printer mechanism, auto cutter, and power circuit for furnishing power supply to each part. Fig. 1-1 Block Diagram 7
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CBM-710/720 Service Manual 2. CPU Peripheral Circuits 1) CPU and ROM/RAM The CPU M50734SP has a external memory type. Lower 8-bit address is fetched via the A0/D0 bus line by the 8-bit latch LS373. The 128-KB ROM and 64-KB RAM are used for performing the backup operation for power failure by the super capacitor. The ceramic oscillator is used as CPU clock and transmits 7.37 MHz. Fig. 2-1 CPU and ROM/RAM Circuit 2) Initial Resetting and Power Failure Interrupt Circuit The IC12 is an IC for genera
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CBM-710/720 Service Manual As can be seen in the timing chart, it detects that Vcc decreased up to about 4.5 V for power failure and generates the power failure interrupt signal and sends it to CPU. Upon receipt of the signal, CPU transmits the data in its buffer to RAM. This processing is done within about 200 μs. After about 1 ms, the reset signal is generated at IC12 and given to CPU, etc., causing all circuits to reset for prevention of explosive running. When the power supply is turned on,
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CBM-710/720 Service Manual 3. Printer Control Circuit 1) When L is output to the CPU port P31, the motor rotates and a timing pulse appears at the DP terminal of CN5. 2) After rotation of the motor, printing starts in timing at which the port P34 is changed into L from H by the home pulse of the printer. 3) In 9 ports of CPU output ports P20 to 27 and P30, the L pulse is output to the necessary port. Electricity is applied once to the DOT solenoid for two timing pulses and characters are printed
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CBM-710/720 Service Manual 4. Cutter Control Circuit Cutter Side X Y S Fig. 4-1 Cutter Control Circuit The cutter control circuit is as shown in Fig. 4-1. In the cutter side, M indicates the motor and S the home switch. The motor can make forward and reverse rotation by controlling X and Y inputs of the control circuit as shown in the table below. Normal Reverse Stop Stop X HL L H Y LH L H The timing chart is provided in Fig. 4-2. The rising of S when the motor makes forward rotation is the home
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CBM-710/720 Service Manual 5. Interface with Operation Panel As shown in Fig. 5-1, the operation panel circuit has the on-line switch and line feed switch. Each switch is connected to CPU input ports and each LED is connected through the driver to CPU output ports. Control circuit Operation Panel Circuit Vcc POWER LED1 R1 CPU ON-LINE LED2 P04 R2 ALARM LED3 P05 R3 SW1 ON-LINE P35 FEED SW2 P36 Fig. 5-1 Operation Panel Circuit 12
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CBM-710/720 Service Manual 6. Paper End Sensor Circuit Fig. 6-1 shows the paper end sensor circuit. The reflection type photo-interrupter is used as a sensor. When some paper is still left, the light reflected by paper strikes upon the photo-transistor; thus, the collector of the photo- transistor is L. When paper becomes short, no light is reflected, causing the collector to go H. As a result, the CPU input port P40 becomes H, going into the paper end state. Control Circuit Vcc CPU Paper End Se
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CBM-710/720 Service Manual 7. Parallel Interface Circuit This circuit conforms to the standard interface. Description will be made for each signal of interface connector as follows. Fig. 7-1 shows the data input and print timing chart and Fig. 7-2 the parallel interface circuit diagram. DATA (D1~D8) : 8-bit parallel signal (Positive logic) STB : Strobe signal for reading 8-bit data (Negative logic) RESET : Signal for resetting the printer (Negative logic) ACK : Data request signal to be output a
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CBM-710/720 Service Manual Fig. 7-2. Parallel Interface Circuit 15 Vcc IC10 R15 7406 33k CN3 RA5 CN2 16P 12-33kΩ IC137406 IC1 50734SP
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CBM-710/720 Service Manual 8. Serial Interface Circuit As the serial interface specification, RS-232C and 20 mA current loop can be switched by the slide switch. It can be switched by the user although fixed by setting at delivery time. 1) RS-232C By using MAX232C for data receiving (RD), data transmitting and BUSY (DTR), data is transmitted and received at level of RS-232C. The baud rates of 110 to 9600 bps can be selected by switching the DIP switch. 2) 20 mA Current Loop The photo coupler is
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CBM-710/720 Service Manual Fig. 8-1 Serial Interface Circuit Diagram 17
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CBM-710/720 Service Manual 9. RS422A Interface Circuit The RS422A interface circuit diagram is shown in Fig. 9-1. As can be seen in the figure, when TXD CONTROL is L, the line driver IC14 becomes enable, going into the ready-to-receive state. At this time, the line receiver IC15 becomes disable. When TXD CONTROL is H, IC14 becomes disable, while IC15 becomes enable, going into the ready-to-receive state. Communication is actually made through 2 lines although usually done through 4 lines (includ
