User manual EPSON LX300+

[. . . ] EPSON TERM NAL PR NTER LX-300 SERVICE MANUAL ( ) EPSON PRECAUTIONS Precautionary notations throughout the text are categorized relative to 1) personal injury and 2) damage to equipment. DANGER Signals a precaution which, if ignored, could result in serious or fatal personal injury. Great caution should be exercised in performing procedures preceded by DANGER Headings. WARNING Signals a precaution which, if ignored, could result in damage to equipment. The precautiomry measures itemized below should always be observed when performin grepair/ maintenance procedures. DANGER 1. ALWAYS DISCONNECT THE PRODUCT FROM BOTH THE POWER SOURCE AND PERIPHERAL DEVICES PERFORMING ANY MAINTENANCE OR REPAIR PROCEDURE. BASIC SAFETY MEASURES AS DICTATED FOR ALL ELECTRONICS TECHNICIANS IN THEIR LINE OF WORK. 3. WHEN PERFORMING TESTING AS DICTATED WITHIN THIS MANUAL, DO NOT 2. [. . . ] " SYSTEM IC (ICI) ( R84 PFA - ' 3 7 13s PFA PB- `3 R87 PFB nm7 ( {" `: MOTOR ASSY. , PI Q11 Q1 Q13 Q14 PF~ PFA Pm Pm R86 Ra5 `"O I ( <<-: * `L `1 VP Figure 2-18. Paper Feed Motor Driver Circuit Diagram 2. 3. 8 Printhead Driver Circuit Figure 2-19 shows the printhead driver arcuit block diagram. Print data, already expanded into image data, is split by the CPU block and transferred to the latch arcuit in the gate array block in the system IC (ICI). Port AN6 (pin 66) of ICI samples the voltage of the +35 VDC line via the A/D converter. By sampling the +35 VDC line voltage and dete rmining the length of the head drive signal, it is possible to maintain the energy supplied to the head at a constant level. If the voltage from the +35V line is HIGH, ICI shortens the output pulse. If the voltage from the +35 VDC line is LOW, ICI lengthens the output pulse. SYSTEM IC (ICI) I HD1 HD2 HD3 HD4 HDs HD6 HD7 HDs HD9 ;p~~ At& 68 Printhead 1 `~ RIO F14 D1 -c? Rll ~ Figure 2-19. Printhead Driver Circuit Diagram 2-16 Rev. A LX-300 Sanka Manual Opamting Principk 2. 3. 9 Interface Circuit Figure 2-20 shows the parallel interface circuit block diagram. Data from the host mmputer is latched within the system IC by a WOOSTROBE signal. The system IC outputs a BUSY signal automatically to stop the host computer from sending further data. The CPU block reads the data latched in the gate array block periodically without generating an interrupt. STSTEM IC PARALLEL l/F ICI --h y / / / / y / / / / / / / / / `ND7-0 "w. Parallel Interface Block Diagram Figure 2-21 shows the serial interface circuit block diagram. The serial interface conforms to EIA-232D. RXD is data received by the serial 1/0 of the CPU block from the host commter via driver/receiver IC2. Data is trans%tted to an irmut buffer in the svstem IC from the Cl% block. Printing starts when a CR code is received or whe~ the input but%r & filled. Driver/Reciver (IC2) TXD DTR RXD CTS SYSTEM IC (ICI) 365 Pm PB3 35` Pcl 6. Serial Interface Block Diagram Rev. A 2-17 Operating Principles 2. 3. 10 EEPROM Control Circuit LX#Xl Service Manual Figure 2-22 shows the EEPROM control arcuit block diagram. `The EEPROM (A5) contains such information as the top-of-form position. The EEPROM is non-volatile memory, so information is not lost if the printer is powered off. Since the EEPROM is a serial I/O-type device, the CPU +5V SYSTEM IC (ICI) PB7 PB5 PBO PB1 "-% (: converts 8-bit data into serial data. -+-h 9 7 2 3 ICT1 1 2 4 EEPROM (A5) Cs CK 3 DI 4 Do J Figure 2-22. EEPROM Control Circuit Diagram 2. 3. 11 CS Motor Assembly Circuit Figure 2-23 shows a block diagram of the CS motor assembly arcuit in the optioml color upgrade kit. [. . . ] Connector Pin Assignments - CN4 Pin 1 2 3 4 5 6 I/o I I I I Signal Name VP VP GND GND VL VL Function +35 VDC +35 VDC Signal ground Signal ground DC voltage for logic DC voltage for logic A-2 Rev. A Appandix LX-31M Service Manual Table A-5. Connector Pin Assignments - CN5 Pin 1 2 3 I/o 0 0 0 0 0 0 0 0 0 Signal Name HD 7 HD 1 Function Head data 7 Head data 1 4 5 6 7 8 9 10 11 12 / HD 5 HD 3 HDCOM HDCOM HDCOM HD 2 HD 9 HD 4 HD 8 HD 6 Head data 5 Head data 3 Common (VP) Common (VP) Common (VP) Head data 2 Head data 9 Head data 4 Head data 8 Head data 6 Table A-6. Connector Pin Assignments - CN6 Pin 1 I/o I Signal Name PE GND PE sensor Signal ground Function 2 ­ Table A-7. Connector Pin Assignments - CN7 Pin 1 2 I/o I Signal Name HP GND HP sensor Signal ground Funotion Table A-8. [. . . ]