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:
I )
At power on: The signal is output for about 30 ms at the turning on of power.
2)
By interface signal: The signal is given while the INIT signal is output from the host computer.
Fig. 2.18 Reset circuit
The reset signal is output at power on when Vx (+5V) is applied to the power on reset circuit, consisting of
RM9, R3 and C4; it is passed on to IC 9B, pin 1, 8B and 8A, which
IS
the reset signal port initiator.
Time constant of the reset pulse is applied at R69 and C4.
This time constant is approximately 30 ms.
Upon the input of an INIT signal from the interface board, the interface reset (INIT) signal is input to: the
main CPU Z-80A; slave CPUs 8042 and 8041, PPI 8255AC-5; gate array uPB6101-009; and timer
NE555. The INIT signal is output only during the system reset or I/O reset of the host computer that con-
trols the LQ-1500.
If power is off the reset cannot be output.
2.4.3 Sensor circuit
Five sensor circuits (HP, MTS, DTS, PE and HOT1 and 2) monitor status of the printer mechanism and in-
form the Z80-A CPU as to the mechanism’s operational status at any given time.
1)
Home position sensor circuit (Fig.2.1 9)
Fig. 2.19 HP sensor circuit
Summary of Contents for LQ-1500
Page 1: ...L Q 1 5 0 0 SERVICE MANUAL EPSON a9Printed on Recycled Paper ...
Page 8: ...Table 1 1 3 ...
Page 16: ...Note Direction refers to the direction of signal as viewed from the UXMCL circuit board ...
Page 18: ...2 6 ...
Page 21: ...Note Direction refers to the direction of signal as viewed from the UXDRV circuit board 2 9 ...
Page 39: ...Fig 2 26 CR motor drive circuit 2 2 7 ...
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 48: ...Fig 2 35 Paper feed timing chart In case of N pulse paper feed N 5 ...
Page 56: ...3 Correspondence between dot wires and FPC terminals Fig 2 45 Printhead connector 2 4 4 ...
Page 64: ...3 3 ...
Page 66: ...3 1 3 3 Handshaking of the parallel interface Fig 3 1 Parallel interface timing 3 5 ...
Page 68: ...3 1 5 Circuit diagram 3 7 ...
Page 69: ...Fig 3 4 Component layout of IUPIF board ...
Page 73: ...D DIP 4 Table 3 10 Setting of DIP 4 3 12 ...
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 90: ...3 3 5 Block diagram m x 6 IA 3 29 ...
Page 93: ...Fig 3 17 Component layout of IUIE ...
Page 115: ...3 54 ...
Page 116: ...3 55 ...
Page 117: ... Fault of selection and feed 3 56 ...
Page 118: ... Fault of paper guides1 3 57 ...
Page 119: ... Fault of output selector 3 58 ...
Page 120: ... Other faults Paper is fed at an angle 3 59 ...
Page 123: ......
Page 144: ... Mechanical components Model 3660 Y450590100 Maintenance tool 5 3 ...
Page 145: ...5 2 Check out Procedure Repair by Unit Replacement 5 4 ...
Page 146: ...5 5 ...
Page 147: ...5 6 ...
Page 148: ...5 7 ...
Page 149: ... Carriage does not return to home position when power switch is turned on 5 8 ...
Page 150: ... Carriage does not move ...
Page 151: ...5 10 ...
Page 152: ... Control panel indication is faulty Paper feeding motor does not stop 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 156: ... Carriage does not move in Self Printing Test 2 5 15 ...
Page 157: ... Paper feeding is not made in Self Printing Test Printing is faulty 5 16 ...
Page 158: ... Operation is abnormal when connected with host computer 5 17 ...
Page 159: ...5 3 Unit Repair Flow Chart UXMCL 5 18 ...
Page 160: ...1 Printing Troubles 5 19 ...
Page 161: ...5 20 ...
Page 162: ... ...
Page 163: ...5 22 ...
Page 164: ...5 23 ...
Page 165: ...2 Carriage Troubles 5 24 ...
Page 166: ...5 25 ...
Page 167: ...5 26 ...
Page 168: ...5 27 ...
Page 169: ...5 28 ...
Page 170: ...3 Paper Feeding Troubles 5 29 ...
Page 171: ...5 30 ...
Page 172: ...5 31 ...
Page 173: ...4 Sheet Loading Problem 5 32 ...
Page 174: ...5 4 Unit Repair Flow Chat t UXDRV 5 33 ...
Page 175: ...1 Printing Troubles 5 34 ...
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: ...5 5 Unit Repair Flow Chart IUPIF 5 40 ...
Page 182: ...5 41 ...
Page 183: ...5 6 Unit Repair Flow Chart UXPS 5 4 2 ...
Page 184: ... 24 voltage is not output The malfunction of the primary 5 43 ...
Page 186: ...The voltage of 24 is low Excessive voltage is output 5 45 ...
Page 187: ... 5 is abnormal 5 46 ...
Page 188: ...Vx is abnormal 12 is abnormal 5 47 ...
Page 195: ...List of Principal lC s Table 7 1 7 1 ...
Page 209: ...Fig 7 16 Pin configuration 7 15 ...
Page 210: ... 2 Block Diagram 8042 Fig 7 17 Block diagram 7 16 ...
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Page 229: ...EXPLODED DIAGRAM FOR LQ 1500 12OV VERSION 7 35 ...
Page 230: ......
Page 231: ...7 37 ...
Page 232: ...7 38 ...
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Page 237: ...UXPS CIRCUIT BOARD UNIT NO Y45020300000 7 43 ...
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