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Service Manual

2. CCD signal processing circuit

CDS

CCD Signal Processor

CDS

CDS

PGA

PGA

PGA

CCD

MUX

ADC

R

G

B

Dout

The CCD signal processor includes all the necessary circuitry to perform three-

channel conditioning and sampling. The signal chain consists of three-channel

correlated double sampling (CDS) and programmable gain adjustment of the CCD

output (PGA) is a 16 bit analog to digital connector (ADC) quantizes the analog

signal.

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Summary of Contents for DocuMate 252

Page 1: ...Sheetfed Scanner Service Manual Version 1 0 ...

Page 2: ... 2 3 2 2 Main control circuit 3 3 3 2 3 Video circuit 3 4 3 2 4 LED and Push Button Module Circuit 3 6 3 2 5 Sensor input 3 7 3 2 6 Sub power supply circuit 3 8 3 2 7 Power supply 3 9 4 PROBLEM SOLVING 4 1 4 1 DIAGNOSTICS 4 1 4 1 1 Online diagnostics 4 1 4 1 2 Offline diagnostics 4 2 4 1 3 Diagnostic flowcharts 4 3 4 2 TROUBLESHOOTING 4 6 4 2 1 Flowcharts 4 6 4 2 2 Tables 4 9 5 DISASSEMBLY 5 1 5 1...

Page 3: ... 4 7 Removing the Main Control Board 5 12 5 4 8 Removing the Motor in Lower Optical Assembly 5 14 5 4 9 Removing the Inverter in the Lower Optical Assembly 5 15 5 4 10 Removing the Lower Optical Chassis 5 16 6 PARTS 6 1 6 1 SPARE PART DIAGRAM 6 1 iii ...

Page 4: ...semble the scanner make sure the power supply cord of theAV220 is disconnected from the power outlet Under any circumstance do not remove or install the connectors on the scanner with the power supply turned ON 2 Use caution not to drop small parts or screws inside the unit when disassembling and reassembling If left inside they might cause the malfunction of the unit 3 Do not pull the connector c...

Page 5: ...color R G B Image Type 256 shades of gray scale 64 shades of gray for halftones Line art binary Error diffusion 8 bit Color 24 bit Color ADF Scan Speed NONE Channel at 200dpi B W A4 size 25 pages per minute simplex mode 50 images per minute duplex mode Scan Area ADF minimum 3 5 x 2 88 x 50 mm ADF maximum 8 5 x 14 215 x 355 mm Paper Size ADF Max 8 5 x 14 Legal ADF single page min 3 5 x 2 ADF duplex...

Page 6: ...all in a humid or dusty place Use care not to scratch the glass surface of the scanner or the document holding pad with a clip or staple Do not use the wall socket with connecting devices which may generate noise for example air conditioner etc Use a suitable AC power source Place the scanner on a level surface 2 2 Unpacking Procedure Unpack the scanner according to the following procedure Remove ...

Page 7: ...2 3 1 6 4 5 1 Main Unit 2 Input Paper Tray 3 Output Paper Tray 4 USB Cable 5 Power Adapter 6 Power Cord Figure 2 1 Package Contents 2 2 ...

Page 8: ...talling the ADF Paper Tray 1 Attach the ADF Paper Tray to the clip joint of the scanner as indicated below When properly insert you will hear a snap in sound ADF Input Paper Tray Scanner Clip Joint Figure 2 2 Installing the ADF Paper Tray 2 3 ...

Page 9: ... Insert the right protrusion of the Output Paper Tray into the hole on the front of the scanner 3 Insert the left protrusion of the Output Paper Tray slightly into the hole on the front of the scanner Scanner Output Paper Tray Hole Output Paper Tray Protrusion Figure 2 3 Installing the Output Paper Tray 2 4 ...

Page 10: ...scanner Insert the other end to an appropriate power outlet Power Cable Figure 2 4 Installing the Power Cable 2 3 4 Turning on the Power After the power cable and the USB cable have all connected press the power switch to the I position to turn on the scanner To turn off the scanner please press the power switch to the O position Power Switch Figure 2 5 Turn on the scanner 2 5 ...

Page 11: ...with the text face down on the ADF Input Paper Tray Align the two sides of the document with the slide guides Please note that the ADF Input Paper Tray can hold up to 50 page document at a time Your Document Face Do n Paper Slider Figure 2 6 Place the document 2 6 ...

Page 12: ... 0 Controller Host Figure 3 1 Theory of Operation The reflected rays of your original as shown in the above Figure 3 1 pass through the lens and create an image on the CCD Charged Coupled Device Then according to the different light intensity perceived by the CCD the CCD will transfer these data into a series of analog signals to the main board where the signals are turned into digital signals The...

Page 13: ...3 2 Main control unit 3 2 1 System diagram Figure 3 2 System block diagram 3 2 ...

Page 14: ...256 BYTE internal RAM work area a 64 KB external RAM work area 2 timer counters 4 I O ports 2 external interrupts and 2 internal interrupts for 2 internal timer counters Address Maps ROM program area Internal RAM working area y External SRAM working area 0000 64KB Program FFFF 00 256 byte Internal Registers FF 0000 64 KB External Program FFFF 3 3 ...

Page 15: ... CCD cable Pin No Name Function 1 AG Analog Ground 2 VOR CCD Red Channel Output Signal 3 AG Analog Ground 4 VOG CCD Green Channel Output Signal 5 AG Analog Ground 6 VOB CCD Blue Channel Output Signal 7 AG Analog Ground 8 12VDC CCD Power Supply 9 SH CCD RGB Channel Shift Gate 10 PHI1 CCD Clock Phase 11 DG Digital Ground 12 PHI2 CCD Clock Phase 13 DG Digital Ground 14 RS CCD Reset Gate 15 DG Digital...

Page 16: ...The CCD signal processor includes all the necessary circuitry to perform three channel conditioning and sampling The signal chain consists of three channel correlated double sampling CDS and programmable gain adjustment of the CCD output PGA is a 16 bit analog to digital connector ADC quantizes the analog signal 3 5 ...

Page 17: ...n No Name Function 1 Ground Ground 2 Ground Ground 3 Button Scan 4 Button Cancel 5 Button Function select 6 LED G Ready status indicator 7 LED R Seven segment display 8 Seven 1 Seven segment display 9 Seven 2 Seven segment display 10 Seven 3 Seven segment display 11 Seven 4 Seven segment display Seven 5 12 Seven segment display 13 Seven 6 Seven segment display 14 Seven 7 Seven segment display Seve...

Page 18: ... paper position is detected by photo sensor The photo transistor transmission to the photo sensor receiver circuit is shown below Out Figure 3 3 Paper in out sensor The paper in out sensor is detected when the paper passes between the LED and the photo transistor B IR Sensor 5V 5V Figure 3 4 IR_Sensor _ OP DAC Out 3 7 ...

Page 19: ... the internal analog circuit Input is 24V and output is Vcc and 5Va The circuit configuration is shown below 24Vdc Vcc Switching 12V 5Va 24Vdc 12V Vcc 3 3V The sub power supply is used for A D and logic circuits Regulator Linear Regulator Linear Regulator Linear r Regulato 3 8 ...

Page 20: ...etails Table 3 1 The Power Adapter Type Characteristic Wall mount Input voltage range 100 240V Input current at the rated input output 2A type or less Input frequency 50 60Hz Max in rush current full load cold start 45A Output voltage 24Vdc Min load current 0 0A Max load current 2A Total power at full load 30W 3 9 ...

Page 21: ...anner has internal diagnostics to help you determine the cause of operational problems Some of the diagnostics function with the scanner online while others are part of a separate offline diagnostics feature 4 1 1 Online diagnostics Determine operational problems by observing the display panel Error Ready and Check LEDs With the scanner online and operating normally the Ready LED is on and the Err...

Page 22: ...ication ON No blinking OFF OK Ready OFF 1 Face down SDRAM failure OFF 2 Face up DRAM failure OFF 3 CPU DRAM failure OFF 4 Face down DC offset adjust failure OFF 5 Face up DC offset adjust failure OFF 6 Cover open error OFF 7 Face down light check failure OFF 8 Face up light check failure OFF 9 Paper jam OFF 0 USB disconnect Table 4 2 Offline diagnostics results For SRAM DRAM error refer to Main Co...

Page 23: ...gnostics indicate a group error Refer to Chapter 4 for parts replacement 4 1 3 1 Group 1 error flowchart CCFL assembly This flowchart applies when the Error LED shows number 7 and 8 Group 1 Error Yes No CCFL is on No End of test Yes CCFL is on Inverter error Replace lamp inverter circuit CCD error Replace optical assembly Replace the CCFL 4 3 ...

Page 24: ...en cover and then remove the papers from ADF s input paper tray and wait for 3 seconds than close the cover ADF motor moves Yes No ADF paper in sensor error Place paper in the ADF paper tray and wait for 3 seconds Replace ADF paper in sensor or SB12 PCBA Try again ADF motor moves No Yes OK IR sensor error or scanner inside contains paper ADF m moves otor No Yes OK IR sensor error Replace IR sensor...

Page 25: ...n the Ready LED is off and Error LED shows number 6 with the scanner online and there is no paper in the ADF paper tray Group 3 Error Open cover then close the cover Refer to the Result in Table 3 2 Place a piece of paper into ADF Input Paper Tray and waits for 3 secs Check Ready LED on Yes No OK 4 5 ...

Page 26: ...in the following three sections The flowcharts refer you to the appropriate table for detailed troubleshooting 4 2 1 Flowcharts This section provides the following troubleshooting flowcharts Troubleshooting from power on to scanner ready Online troubleshooting ADF operation 4 6 ...

Page 27: ...shooting From Power on Yes Power LED on No See Table 4 3 IR sensor test Cover open test DRAM Test Face down SDRAM test Face up SDRAM test Face down light check Face up light check Yes Warming up Finish No Warming up Check Green LED Blinking Wait for command from host Green LED on 4 7 ...

Page 28: ...equent Paper Jam See Table 4 9 Yes Large skew volume See Table 4 10 Yes Frequent double feed See Table 4 10 No Yes No Large jitter No Reading position deviation See Table 4 6 See Table 4 7 Yes Yes No See Table 4 8 See Table 4 11 No No Yes Yes No Image unclear Strange sound generated End 4 8 ...

Page 29: ...wer switch on AC voltage failure None AC outlet voltage check None Power unit AC input connector disconnected None Visual check Connect the connector Power switch connector disconnected None Visual check Connect the connector Power unit main PCBA connection failure None Visual check Connect the connector Power unit output voltage failure Power unit Output voltage 24V check Replace the power unit P...

Page 30: ...check Close the ADF cover Power supply main control board connection failure None Visual check Connect the connector Power supply fails Power supply Tester check 24V GND Replace the power supply Lamp failure Lamp Visual check Replace the lamp Inverter failure Inverter Visual check Replace the inverter CCD board main control board connection failure None Visual check Connect the connector CCD board...

Page 31: ...ain control board connection failure None Visual check Connect the connector Power supply fails Power supply Tester check 24V GND Replace the power supply Motor main control PCBA connection failure None Visual check Connect the connector Motor failure Motor Visual check Replace the motor Table 4 6 4 11 ...

Page 32: ...supply Motor main control PCBA connection failure None Visual check Connect the connector Motor failure Motor Visual check Replace the motor IR sensor board main control PCBA cable failure None Visual check Connect the connector IR sensor board main control PCBA cable failure Sensor board main control PCBA cable Tester or visual check Replace the IR sensor cable IR sensor board SB21 failure Sensor...

Page 33: ...lcohol None Dirt on the mirrors Mirrors Visual check Clean the mirrors with isopropyl alcohol None Dirt on the lens Lens Visual check Clean the lens with isopropyl alcohol None Table 4 8 4 2 2 7 Frequent paper jam Cause Relevant Unit Check Method Maintenance Method Remark Paper setting failure Operation error Is the paper correctly set in the paper chute Educate users to properly position the pape...

Page 34: ...the specified paper used None Pad assembly failure Pad assembly Check the pad assembly for wear and tear Replace the pad assembly touch spring unit Table 4 10 4 2 2 9 Strange sound generated ADF Cause Relevant Unit Check Method Maintenance Method Paper setting failure Operation error Is the paper correctly set in the paper chute Teach users to properly position the paper paper failure Operation er...

Page 35: ...sary for the maintenance of this equipment No Name Description 1 Minus screwdriver Idler pulley module screw 2 Philips screwdriver magnetic Nominal No 2 M3 M4 3 Oil Shell Terrace Oil 46 4 Grease Shell Alvania Grease No 2 5 Alcohol Isopropyl 91 Cleaning 6 Digital voltmeter With 0 01 V range 7 Oscilloscope 100 MHz or more with external sweep Table 5 1 Maintenance tools 5 1 ...

Page 36: ...wab with some isopropyl alcohol 95 2 Press the ADF Release button on the upper left Open the front door slightly to the left Wipe the upper feeding roller by moving the swab from side to side Rotate the roller forward with your finger and repeat the cleaning steps above until the entire roller is cleaned 3 Wipe the ADF pad in one direction from top to bottom or the other way around Be careful not ...

Page 37: ...r Jam Clearing button Open the front door to the left 2 Wet a cotton swab with some isopropyl alcohol 95 3 Wipe the glass and the white area as illustrated in below by moving the swab from side to side to rid the dust or dirt Calibration Area Glass ADF Front Door 5 3 ...

Page 38: ...e AC plug from the outlet before disassembly and assembly 3 Follow the disassembly and assembly procedures Never loosen the screws of parts that must not be disassembled 4 Store the disassembled parts in a clean place to avoid loss 5 After replacement check the contacts and spare part mounting 6 Assemble the parts in reverse order of disassembly procedure 5 4 ...

Page 39: ...y 2 Hold the Input Paper Tray and lift the Tray to remove it 3 Press the ADF release button to open the cover 4 Remove 2 fixing screws 5 Unscrew the 4 fixing screws on the upper housing 6 Remove the Upper Housing Press inwardly to remove Remove Input Paper Tray the Output Paper Tray Press the ADF release button Remove 2 fixing screws 5 5 ...

Page 40: ...Remove 4 fixing screws Remove the upper housing 5 6 ...

Page 41: ... Paper Jam Release Button to open the cover 2 Loosen 2 fixing screws on the upper case 3 Remove the fixing sponge 4 Loosen 2 fixing screws on the left side 5 Loosen 1 fixing screw on the right side Fixing Screw x 2 Paper Jam Released Button Fixing screws x 2 Sponge 5 7 ...

Page 42: ...6 Disconnect the inverter cable with red and black colors 7 Disconnect the lamp inverter cable in white color to remove the inverter Fixing Screw x 1 Inverter Cable Power cable Inverter 5 8 ...

Page 43: ...l assembly See preceding section 5 3 3 2 Disconnect two cables on the optical chassis Cables Optical Chassis CCD Board Note During assembling or disassembling procedure please pay special attention not to touch the CCD board on the optical chassis Otherwise the scanning quality may be affected 5 9 ...

Page 44: ...y 1 Remove the upper optical chassis See preceding section 5 3 4 2 Loosen two fixing screws on the lamp cover 3 Use a flat screwdriver to loosen the lamp assembly 4 Gently remove the lamp assembly Flat screwdriver Fixing Screw x 2 Lamp assembly 5 10 ...

Page 45: ...Service Manual 5 4 6 Removing the ADF Pad Use your fingers to press two sides of the ADF pad and lift the pad on the upper optical assembly to remove it ADF Pad 5 11 ...

Page 46: ...er 3 Raise the main unit and disconnect the motor cable and flat cable 4 Unscrew all fixing screw 5 Disconnect all cables 6 Remove 4 fixing screws on the main board Remove one fixing screw on the right side Remove two fixing screws on the left side Raise the main unit a bit Disconnect flat cable Disconnect cables Disconnect motor cable 5 12 ...

Page 47: ...Service Manual Power cable 2 Fixing screw 2 fixing screw Remove 4 fixing screw and disconnect the power cable The main board 5 13 ...

Page 48: ...5 4 8 Removing the Motor in Lower Optical Assembly 1 Turn the scanner over 2 Remove 2 fixing screws on the external side of the metal plate 3 Remove the motor Remove 2 fixing screws The motor 5 14 ...

Page 49: ...ower Optical Assembly 1 Cut the cable bondage 2 Remove the inverter from the plastic fixing plate 3 Disconnect the inverter cable Inverter The inverter cable Release the inverter from the plastic plate and disconnect the inverter cable The inverter 5 15 ...

Page 50: ... the left and external side of the metal plate 2 Remove 2 fixing screws on the right and internal side of the metal plate 3 Remove the Optical Chassis Remove 2 fixing screws on the left external side Remove 2 fixing screws on the right internal side Optical Chassis 5 16 ...

Page 51: ...Service Manual 5 4 11 Removing the Lamp in the Lower Optical Assembly 1 Remove 2 fixing screws on the lamp assembly 2 Remove the lamp Remove 2 fixing screws on the lamp assembly The lamp assembly 5 17 ...

Page 52: ...Service Manual 6 PARTS 6 1 Spare Part Diagram Table 6 1 Spare part diagram 6 1 ...

Page 53: ...6 2 ...

Page 54: ...Service Manual 6 3 ...

Page 55: ...PER OUT 65 0255 000 BEARING COVER HINGE 65 0256 000 HOUSING BOTTOM 65 0302 000 PCBA 65 0303 000 POWER S W 5 pin 65 0304 000 ASS Y COVER UNIT 65 0305 000 ASS Y UPPER HOUSING 57 0104 000 ASS Y ADF INPUT TRAY DM252 57 0105 000 ASS Y PAPER OUTPUT TRAY DM252 65 0306 000 OPTICAL UPPER W LAMP 65 0307 000 ASS Y OPTICAL UPPER 65 0308 000 ASS Y LAMP MOUNT FACE UP 65 0258 000 INVERTER CCFL T 65 0310 000 OPTI...

Page 56: ...R 1 TDK RoHS 65 0336 000 S PARTS ASS Y OPTICAL FACE DOWN W LAMP 002 3343 0 W INVERTER 005 0022 09 RoHS 65 0337 000 S PARTS ASS Y OPTICAL FACE DOWN RoHS 65 0398 000 S PARTS ASS Y LAMP FACE DOWN RoHS 65 0339 000 S PARTS INVERTER 24V 6mA 35KHz XAD355 2 TDK WIRE 200mm RoHS 65 0340 000 S PARTS ASS Y PAPER GUIDE LOWER W O LAMP 002 3343 0 RoHS 65 0341 000 S PARTS BELT 58T MXL W 4 8 10PCS RoHS 65 0250 000...

Page 57: ... 0365 000 S PARTS USB CABLE USB A M B M 4P L 1850mm UL2725 28AWG SV 0411016 昇文 COLOR 透明 W CORE RoHS 65 0182 000 S PARTS AC POWER CORD EUR CEE 2P G BASE 16A 250V L 1800mm 3C 0 75mm2 BLACK 良維 PG8B9CIJG0A 05B RoHS 65 0097 000 S PARTS AC POWER CORD US 3P 10A 125V L 1800mm 3C 18AWG BLACK 良維 PH8B2EDJF0A 05B RoHS 65 0183 000 S PARTS AC POWER CORD UK BS PSB 3 P 3A 250V L 1800mm 3C 0 75mm2 BLACK 良維 PG8B9...

Page 58: ...ERTER 65 0337 000 S PARTS ASS Y OPTICAL FACE DOWN RoHS 65 0298 000 S PARTS ASS Y LAMP FACE DOWN RoHS 68 0339 000 S PARTS INVERTER 24V 6mA 35KHz XAD355 2 TDK WIRE 200mm RoHS 65 340 000 S PARTS ASS Y PAPER GUIDE LOWER W O LAMP 002 3343 0 RoHS 65 0341 000 S PARTS BELT 58T MXL W 4 8 10PCS RoHS 65 0250 000 S PARTS ASS Y MOTOR RoHS 65 0343 000 S PARTS ASS Y RELEASE HOOK RoHS 65 0395 000 S PARTS ASS Y AD...

Page 59: ...65 000 S PARTS USB CABLE USB A M B M 4P L 1850mm UL2725 28AWG SV 65 0182 000 S PARTS AC POWER CORD EUR CEE 2P G 65 0097 000 S PARTS AC POWER CORD US 3P 10A 125V L 1800mm 3C 18AWG BLK 65 0183 000 S PARTS AC POWER CORD UK 65 0369 000 FOAM EPS L 310x278x160 發泡倍率 62 5 白色 RoHS 65 0370 000 FOAM EPS R 310x278x160 發泡倍率 62 5 白色 RoHS 65 0371 000 CARTON 470x290x340 A F RoHS ...

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