Korg A4 Guitar, Service Manual

Page 1: ...SERVICE MANUAL CONTENTS 1 SPECIFICATIONS 1 2 STRUCTURAL DIAGRAM 3 3 BLOCK DIAGRAM 5 4 CIRCUIT DIAGRAM 6 5 P C BOARDS 7 6 HOWTO DISASSEMBLY 9 7 DIAGNOSTIC TEST 11 8 REFERENCE DATA 18 9 PARTS LIST 26 ...

Page 2: ...CT KEYSCUP DOWN Display BANK VALUE Display 8 segment LED x 2 Dot type LEDs EFCT PROG LEDs MODE LEDs Peak indicator Rear panel Power Switch DC9V Jack INPUT Terminal OUTPUT Terminals L MONO R PHONE Jack VOLUME PEDAL Jack EXTERNAL CONTROL OUTPUT Terminals 1 2 MIDI Terminals MIDI IN MIDI OUT Sampling Frequency 48 KHz Dynamic Range 90dB or more IHF A when bypassing TUNER Measurement Range A0 C7 Measure...

Page 3: ...UP SWITCH WRITE KEY USER PRESET KEY BYPASS TUNE SWITCH EFCT PROG SWITCHES PROG EDIT SWITCH MODE Effect SELECT KEYS UP DOWN Display BANK VALUE Display 8 segment LED x 2 Dot type LEDs EFCT PROG LEDs MODE LEDs Peak indicator Power Switch DC9V Jack INPUT Terminal OUTPUT Terminals L M0N0 R PHONE Jack VOLUME PEDAL Jack EXTERNAL CONTROL OUTPUT Terminals 1 2 MIDI Terminals MIDI IN MIDI OUT 48 KHz 90dB or ...

Page 4: ...0G PARAMETER SHEET A4 GTR 630018500 4 X 150B PARAMETER SHEET A4 B 630018600 5 ROTARY VR KNOB 620022900 6 X 150 CORD HOOK 646043000 7 POWER SW KNOB 620018200 8 RUBBER SPACER K0C 40577 500019600 9 10 RUBBER FOOT 3x22x3 NAME SEAL 500018300 11 X 507 GND SPRING 644003000 12 P C B ASSEMBLY KLM 1597 MAIN FOR A4G 001159700 12 P C B ASSEMBLY KLM 1597 MAIN FOR A4B 0011597P1 13 P C B ASSEMBLY KLM 1598 PANEL ...

Page 5: ...R CASE ASSEMBLY PART NO PART NAME PART CODE 1 X 150G CASE 646042700 1 X 150B CASE 646043100 X 150 PEDAL 646042800 SW CUSHION KOC F40427 500013100 PEDAL SPRING K0C C40896 644006400 5 X 150 REFLECTOR 646042900 ...

Page 6: ...ONO LEVEL IND CURCUIT LEVEL I ND TUNE TUNER CIRCUIT 1 L J j j MUTE CURCUIT w DRAM OUTPUT LEVEL CPU ROM 256Kbit RAM 6Kbit PHOTO COUPLER n PHONI V MINI MIDI OUT VOL PEDAL EXT CONTROL SWITCH LED H mm t Iv BANK PROG VALUE PARMETER BLOCK DIAGRAM ...

Page 7: ...4 CIRCUIT DIAGRAM KLM 1 597 98 99 INPUT LOR 501 8000 LOR 4 302 8000 6 ...

Page 8: ...5 P C BOARDS ...

Page 9: ......

Page 10: ...MBLY 1 Remove the case assembly 1 Remove 8 pcs of the rotary VR knobs on the upper case 2 Remove 16 pcs of the screws on the chassis PLAX B BZMC 3 x 10 x 16 3 Remove 2 pcs of the harnesses and remove the case assembly ...

Page 11: ...ve it C PLAX B BZMC 3 x 10 x 2 3 Remove the main p c b KLM 1597 99 1 Remove a screw on the regulator CT B BZMC 3 x 8 x 1 2 Remove 4 pcs of the screws on the rear side of the chassis and remove the main p c b for PHONE JACK SUPPORT CT B BZMC 3 x 8 x 2 for MIDI JACK PLAX B BZMC 3 x 10 x 2 10 ...

Page 12: ...The required equipment and settings for the test mode are pictured below SETUP FOR TEST D INPUT OUTPUT L MONO R VOLUME EXT CONTROL OUT 1 2 MIDI IN MIDI OUT 0 ACTIVATING THE TEST MODE 1 Switch the power on while at the same time pressing both the USER PRESET and WRITE buttons on the front panel The test mode will activate and the internal battery voltage and MIDI circuitry will be checked automatic...

Page 13: ...em to be checked 2 MIDI CIRCUITRY CHECK 1 When the above check ends normally the test function automatically checks the MIDI circuitry 2 When an error is found all LEDs on the panel blink except PEAK The display will indicate the error details as below ndand Er will appear alternately 3 When this check ends normally the test function automatically moves on to the next item to be checked 3 CPU CHEC...

Page 14: ...NE PI 8 MODEY MODEY 1 PI 9 MODEY 2 MODEY 2 Pl 10 MODEY 3 MODEY 3 Pl 11 MODEY 4 MODEY 4 PI 12 MODEA MODEA PI 13 MODEA 5 MODEA 5 PI 14 MODEA 6 MODEA 6 PI 15 MODEA 7 MODEA 7 Pl 16 USER PRESET USER USER PRESET USER Pl 17 WRITE 50 WRITE 50 PI 18 WRITE 50 0 WRITE 50 0 PI 19 WRITE 0 Green WRITE 0 Green PI 20 WRITE 0 50 WRITE 0 50 PI 21 WRITE 50 WRITE 50 PI 22 PROG EDIT PROG PROG EDIT PROG PI 23 BANK UP E...

Page 15: ...heck ends press WRITE to proceed to the next check 5 PARAMETER KNOB CHECK 1 Here the parameter knobs A F on the panel and the volume pedal functions are checked 2 First when the knob is turned fully to the right for the volume pedal when the pedal is pressed back as far as possible this check confirms whether the corresponding LED changes from a blinking state to a steady lit state 3 Next when the...

Page 16: ...jack and the synthesizer s damper jack are connected by a patch cord To check EXT CTRL OUT 2 reconnect the patch cord 2 Confirm that the damper effect appears in the connected synthesizer when EXT CTRL OUT is ON Also confirm that the damper effect disappears in the connected synthesizer when the EXT CTRL OUT is OFF NOTE This result will appear in reverse with some synthesizers because of the setti...

Page 17: ...0 test OUT L Check IC10 and 1C11 P4 5 DSP KLM 1597 IC10 test OUT R Check IC10 and IC11 Figure 1 4 When the checks are completed press WRITE to proceed to the next check item 8 TUNER FUNCTION CHECK 1 Here the TUNER function is checked Connect the rear panel INPUT jack to the oscillator 2 Set the INPUT volume and OUTPUT volume on the panel to MAX 3 Input a short wave 27 5Hz 10mVp p to the INPUT jack...

Page 18: ...ctory prior to shipment and therefore are not covered here 10 TEST MODE COMPLETION AND DATA LOADING 1 Note that there are two methods of ending the test mode One method ends the mode without initializing the A4 s data The other method involves loading the preload data into the A4 and then ending the test 2 Press MODEA six times As the check items move forward confirm that all LEDs except PEAK blin...

Page 19: ...P34 P33 P32 P3I PSD P22 P2I P2D PIT PI 5 P15 P14 PIS P12 PH PIO POT POD P05 P04 P03 PQ2 POI POO R5T MB89710 CPU PIN FUNCTION PIN NAME I O FUNCTION P00 P07 I O I O PORT 0 SCAN FOR PANEL SWs P10 P17 I O I O PORT 1 DATA BUS FOR DSP XO I CRYSTAL OSC INPUT XI 0 CRYSTAL OSC OUTPUT MOD I MODE SELECT INPUT RES I RESET SIGNAL INPUT LOW LEVEL ACTIVE START I START SIGNAL INPUT LOW LEVEL ACTIVE NMI I NON MASK...

Page 20: ...8KHz SMODE I INTERFACE CLOCK I O SELECT L SLAVE MODE L R SCLK FSYNC INPUT H MASTER MODE L R SCLK FSYNC OUTPUT L R I O L R CLOCK SLAVE MODE fs CLOCK INPUT MASTER MODE fs CLOCK OUTPUT SCLK I O SERIAL DATA CLOCK SLAVE MODE fs CLOCK INPUT MASTER MODE fs CLOCK OUTPUT SDATA 0 SERIAL DATA OUTPUT FSYNC I O FRAME SYNCHRONIZED CLOCK SLAVE MODE CLOCK INPUT MASTER MODE CLOCK OUTPUT VD POWER SUPPLY FOR DIGITAL...

Page 21: ... Output S ports D 7 0 I O 8b it data input and output of P port STRB I Data Strobe input for P port IR I Write control signal input for P port EMPTY 0 Indicate P port input buffer eapty condition CS I Chip select for P port enable PLOAD I Prograa data load control signal for P port CLOAD I Coefficient data background update request BIO I Branch control signal MUTE I Mute serial port signal OVFM 0 ...

Page 22: ...EL DATA INPUT CK I CLOCK INPUT DR l R CHANNEL DATA INPUT LR I R CHANNEL LATCH ENABLE INPUT DGND GROUND FOR DIGITAL CIRCUIT VBR I BIAS FOR R CHANNEL Vs POWER SUPPLY FOR ANALOG CIRCUIT VOR 0 R CHANNEL SIGNAL OUTPUT NRR I R CHANNEL NOISE REDUCTION AGND GROUND FOR ANALOG CIRCUIT NRL I L CHANNEL NOISE REDUCTION VOL 0 L CHANNEL SIGNAL OUTPUT Vs POWER SUPPLY FOR ANALOG CIRCUIT VBL I BIAS FOR L CHANNEL 21...

Page 23: ...CHECK POINTS AK5349 VP IC2 TMS57002PH IClO ICll 22 ...

Page 24: ...AD1868N J IC4 23 ...

Page 25: ...UPD74HC4040C IC7 24 ...

Page 26: ...1 A 1 i H_NS 2 A PHR HNS 1 ...

Page 27: ... T 77 1597 21 314001700 DIODE SS1 5J4 TPA 1597 2 314025700 DIODE SR1M 2 TP B 1597 1 314026700 ZENER DIODE RD4 3EB2 T1 1597 1 314026800 ZENER DIODE RD6 8EB2 T1 1597 1 315000400 DOUBLE DIODE MC932 T12 1597 1 320001068 IC UPD74HCU04C 1597 HC MOS 1 320001314 IC UPD74HC4040C 1597 HC MOS 1 320001315 IC UPC4572C 1597 OP AMP 1 320003205 IC TC514256AZ 70 1597 D RAM 2 320009028 IC N JM 3404 AD 1597 OP AMP 1...

Page 28: ...97 1 454008300 PHONE JACK YKB21 5130 1597 1 454009100 DIN JACK YKF51 5058 1597 1 470192500 HARNESS HNS 925 1597 1 471070500 CONNECTOR TOP B5B PH 1597 1 471071100 CONNECTOR TOP B11B PH 1597 1 475001837 HARNESS HNS 1 837 BOARD IN 1598 1 475001838 HARNESS HNS 1838 BOARD IN 1598 1 500013100 SW CUSHION K0C F40427 M PART 9 500018300 RUBBER FOOT 3x22x3 M PART 4 500019600 RUBBER SPACER K0C 40577 M PART 1 ...

Page 29: ... M PART 2 644006400 PEDAL SPRING K0C C40896 M PART 9 646042700 X 150G CASE M PART 1 646042800 X 150 PEDAL M PART 9 646042900 X 150 REFLECTOR M PART 9 646043000 X 150 CORD HOOK M PART 1 646043400 X 150G CASE ASSEMBLY M PART 1 715230308 SCREW CT B ZMC 3 x 8 M PART 3 715260308 SCREW CT B BZMC 3x8 M PART 4 745060310 SCREW PLAX B BZMC 3 x 10 M PART 20 28 ...

Page 30: ...1597 21 314001700 DIODE SS1 5J4 TPA 1597 2 314025700 DIODE SR1M 2 TP B 1597 1 314026700 ZENER DIODE RD4 3EB2 T1 1597 1 314026800 ZENER DIODE RD6 8EB2 T1 1597 1 315000400 DOUBLE DIODE MC932 T12 1597 1 320001068 IC UPD74HCU04C 1597 HC MOS 1 320001314 IC UPD74HC4040C 1597 HC MOS 1 320001315 IC UPC4572C 1597 OP AMP 1 320009028 IC NJM 3404AD 1597 OP AMP 1 320009057 IC NJM7805FA 1599 REGULATER 1 3200090...

Page 31: ...1597 1 454008300 PHONE JACK YKB21 5130 1597 1 454009100 DIN JACK YKF51 5058 1597 1 470192500 HARNESS HNS 925 1597 1 471070500 CONNECTOR TOP B5B PH 1597 1 471071100 CONNECTOR TOP B11B PH 1597 1 475001837 HARNESS HNS 1 837 BOARD IN 1598 1 475001838 HARNESS HNS 1838 BOARD IN 1598 1 500013100 SW CUSHION K0C F40427 M PART 9 500018300 RUBBER FOOT 3x22x3 M PART 4 500019600 RUBBER SPACER K0C 40577 M PART ...

Page 32: ...SPRING M PART 2 644006400 PEDAL SPRING K0C C40896 M PART 9 646042800 X 150 PEDAL M PART 9 646042900 X 150 REFLECTOR M PART 9 646043000 X 150 CORD HOOK M PART 1 646043100 X 150B CASE M PART 1 646043500 X 150B CASE ASSEMBLY M PART 1 715230308 SCREW CT B ZMC 3 x 8 M PART 3 715260308 SCREW CT B BZMC 3x8 M PART 4 745060310 SCREW PLAX B BZMC 3 x 10 M PART 20 31 ...

Page 33: ...MEMO ...

Page 34: ...KORG INC 15 12 Shimotakaido 1 chome Suginami ku Tokyo 168 KORG INC 1992 0412 CEH PRINTED IN JAPAN ...