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.
2. All interface condition are TTL based. The rise and fall times of each signal shall be less than 0.2
3. For details of the timing of each signal, refer to the timing chart.
4. Fata should be transferred to the printer after checking pulse ACKNLG or when signal BUSY
IS
LOW.
5. Signal AUTO FEED XT can be fixed to LOW when DIP switch SW2-3
IS
set ON.
6. When ACKNLG and STROBE are connected with the interface connector, DATA1 to 8 are set to an ap-
propriate character code (“1 ” at open against GND, “0” at short). A printing test including that for the in-
terface circuit can be executed without external equipment.
3.1.3 Operating principle
3.1.3.1 Data entry
As the interface board (IUPIF) is non-buffered, a 2 K-byte RAM on the main board (UXMCL) can serve as an
input (reception) buffer. This option is selectable via DIP switch setting on the interface board.
3.1.3.2 Buffer full/empty control
Table 3.5
Since signal BUSY is LOW until the 2 K-byte input buffer becomes full, the data from the host com-
puter is entered in the input buffer on the UXMCL board through 8255AC-5.
At the same time, developing the print pattern for one line starts for the 7 K-byte print buffer by Z-80A
CPU on board UXMCL. When the input buffer is partly empty, the data is entered, even during printing
or line feed. When the input buffer is full, the BUSY signal is HIGH, data entry is prohibited.
(2) When the input buffer
IS
invalid
The data is entered in through Interface 8255AC5 byte by byte. When 2 bytes of data are entered,
signal BUSY becomes HIGH to prohibit data entry.
At the same time that the data is entered in the buffer, a print pattern is developed for the print buffer
by Z-80A CPU on board UXMCL.
3-4
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 ...
Page 216: ......
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 234: ......
Page 235: ......
Page 236: ......
Page 237: ...UXPS CIRCUIT BOARD UNIT NO Y45020300000 7 43 ...
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