SERVICE MANUAL 1526 • MPS 802 • 4023 PRINTERS APRIL 1985 PN-314003-03 ( ::: C;C .
SERVICE MANUAL 1526 • MPS 802 • 4023 PRINTERS APRIL 1985 PN-314003-03 Commodore Business Machines, Inc. 1200 Wilson Drive, West Chester, Pennsylvania 19380 U.S.A. Commodore makes no expressed or implied warranties with regard to the information contained herein. The information is made available solely on an as is basis, and the entire risk as to quality and accuracy is with the user.
CONTENTS Page Title SPECIFICATIONS SET UP AND TESTING RIBBON CARTRIDGE .................................................................................... 2 PAPER INSTALLATION ................................................................................. 3 SELF TEST ................................................................................................. 4 ACCESSORIES PARTS LIST ............ ............................................. ..................... ...... MAINTENANCE ...........
SPECIFICATIONS • 1526 • MPS 802 • 4023 • PRINT METHOD CHARACTER MATRIX CHARACTERS GRAPHICS CHARACTER CODES PRINT SPEED MAXIMUM COLUMNS • Bi-directional impact dot matrix • 8 X 8 Dot Matrix • Upper & lower case letters with true descenders. Numerals & symbols. All PET graphic characters • 8 Vertical dots - maximum 640 columns • CBM ASCII code • 60 CPS • 80 Columns LINE FEED SPACING • 6 Lines/inch in character mode • 9 Lines/inch in graphics mode LINE FEED SPEED • 5 Lines/sec in character mode • 7.
SET UP AND TESTING VISUAL OBSERVATION is particularly important before attempting to repair a printer. Always check for physical damage to the mechanism. Remove any loose debris that may have accumulated inside the unit. Ribbon Cartridge PRINT HEAD RIBBON CARTRIDGE Before installing the ribbon cartridge, turn the printer off. By carefully pushing the carriage, position the print head in the center of the unit. Turn the dial knob on the cartridge in the direction of the arrow until the ribbon is taut.
SET UP AND TESTING (Continued) Paper Installation PAPER RELEASE LEV To install paper, turn the printer off, remove the paper rack and lift the soundproof cover. Lift the paper hold down shaft and raise the covers of the left and right tractors to allow access to the tractor pins. Align the paper perforations with the tractor pins and close the covers. The left tractor assembly must be firmly pressed against the left stopper. The right tractor assembly slides to allow adjustment for paper width.
SET UP AND TESTING (Continued) Self Test This unit has a pre-programmed self-checking capability. The program may be used to test the print head operation, print quality and printer mechanism (ribbon feed function, linefeed, etc.). The self-test function is initiated by pressing the paper advance switch while turning on the power supply switch. NOTE: Do not operate the self-test function in the no-paper condition. *+ , - • < :z >?~ABCDEFGH I JKLI'r'NOPQRSTUVWXY2 [ 11'+-11.-...1 • . , It-.
ACCESSORIES PARTS LIST C 314597-01 C314598-01 C 314598-02 C 314598-03 C 314599-01 C 1 51 5001 -01 C 903508-04 1526/802/4023 1526 MPS802 4023 1526/802/4023 1526/MPS802 1526/802/4023 PAPER RACK USER'S MANUAL USER'S MANUAL USER'S MANUAL RIBBON 6PIN DIN CABLE POWER CORD MAINTENANCE Cleaning CAUTION Do not use chemicals to clean any of the printer parts. Using a clean, dry brush, remove dust and debris from the ribbon guide, print head, platen area and tractors often.
FUNCTIONAL BLOCK DIAGRAM f--- RS (RAM SelECT) ----I SERIAL 1526 INTERFACE Functional Block Diagram Data Flow Theory I The 1526, MPS 802 and 4023 printers are functionally the same, with the exception of the interface circuits. The 1526 and MPS 802 printers have a serial interface, and the 4023 printer has an IEEE interface. The data flow is the same for all of the printers. 110 DATA ,~I t----I PORT nr.
CIRCUIT THEORY CR26 _::-::-::-:4A:-'I/SO V or 1.S AlSO V on h.~t sink ~-r:----r-:U)"""'::::: +5 V N -. I'" ",I uu o"ai L---~~~-+-~~-~---;uD +5V GND . +. RS 1--+_..::::::.+26 v lO k C7 6800 SOV +26 V GND The Power Supply The Power Supply generates two outputs, + 5VDC and + 26VDC. Both outputs are regulated. The 5VDC output supplies the microprocessor and TTL circuits. The + 26VDC output supplies the print wire coils and the paper feed and carriage motor drive circuits.
CIRCUIT THEORY RESET UIC 1 _2 U20 3 ~4 UIC 6 5 .~ _ UIC POWER ON 7406 74LS14 Jl""o--;:4~_---:..;R:.:E.:.S-t-+-iI-+-i +5V +24 V 021 COLLECTOR ~ o ">::a£ APU N "'>01 U1C5PIN a: >ri R21 ~ U1C6PIN Q21 -------- I, 100 ~r,1-' B I~>.... c:t ." MN U1C4PIN I +5 V -..:- +5 V - GNO APPROX.
1526 AND 4023 CIRCUIT THEORY 1.15 V1 .. MHz 2.2 "H l..r----?": --0-1--'~:-~ , - . C34 .04~ L _ ___ " R56 R55 "o .,C! "I'" 11 8 D--......::..j 74-00 7400 7400 7 U10C 74177 9 117 R57 1 MEG HZ 47 Clock Circuit Crystal Y 1 generates the fundamental 4 MHz clock. The circuit illustrated below the crystal stabilizes and squares the signal. U 1OC divides the input frequency by 4. A 1 MHz clock is output on pin 9 of U 1OC. This is the processor system clock.
1526 AND 4023 CIRCUIT THEORY +26V U5D 6532 Pl Jl PAO 81PF Holdl 1. 14 PA4 PAS 2S 2S 61PMOI 7 (PM1) 0 B W M2 M3 0 ON ON OFF OFF 1 OFF ON ON OFF 2 OFF OFF ON ON 3 ON OFF OFF ON 4 ON ON OFF OFF A R 0 U6D 6522 PA6 M1 R 2626 11 MO F A 81PM21 COIL STEPPING ORDER M 3 27 27 0 282 0 N T I PA7 IllPM31 9 IL _ _ _ _ _ .J NOTE: DURING REVERSE TRANSMISSION. THE CURRENT FLOW IS STEPPED IN REVERSE ORDER - 4. 3. 2. 1. O.
CIRCUIT THEORY , +26 V U5D 6532 J. ~~k ~ R3 3.9 k ? Pl Jl 9 (CA Hold! ~ PA 11--------,-13"...., ?C:>:1:-::"2"""'1'r--+----f..... 018 U7B R5 ? 5 W 470 n ~~----~1313~ CR22 +~ ~r(24 V! lkx:Jcn~, ..... > N~~C.~.N;» ~ {a:: ,a:: a:: PAO 2 (HMO! -- ~t-:!t-!!? ~t-t-i--f~ 3 U6/B'O-:-4 ~ r-----, H-t a:: a:: II-c: "a:: iI' I t.....=0:...+...:::O~O~~t;t.>~_--I21 21 ~-t--:......... al0 3 (HM 11 ""..0:-::;--_!---i_...r-t--.......-+---i~---I22 22~-~--' PA 1 r--'-....:......-----,1...
CIRCUIT THEORY Fl 5OO..s Puis ... ~;"':;";;"""'---3>~TP1_>-----, 680nx8 CR12 CR9 CR6 CR3 (24 VI~~ ~~ ,,;~ ~~ L Jl 10 10 11 11 t------~ PB7 241N071 S U6B PB6 r2.;;,.3.,;. IN.. ,:O.. .:6..:. . 1- d 1 >2=----'-+-+-+-+--+--t---i",-- 07 USB 6 6 PBS 221NOSI 13 U5D 6532 PB4 21 IN041 7 7 r - - 00 0 cf'- - OClQO"\- 12 USB '"::-:::----"-"""-i--+-+-+---i ......---lr---.L-..+-+-+-+---! S S r - - 0000 "\11 ..... ,0 " ' - - OS PB3 '91N031 S USB PB2 181N021 3 4 USB PBl r'.,;..7.;.;.IN,;.;:O;.
CIRCUIT THEORY • +5V PBo~1~0--~-----+-~2 r Triger Rewt U6D 4 >--+_"""1 V~ Reset circuit rewt r--_-+-----.,;6:..j TH 6522 OUT 1-"3_..JV'''---I uaa CR28 R39 7 20 kn"loE----~DIS 022 .----~TPl R23 3.9 k GND C8 .r. 0 10 R37 2.2 k 555 cv 5 TIMING CHART +5V '.'" JLs -tt- ~U~6~D.~P~BO~----·U~----------------- USB·OUT Q22·COllECTOR TP1 I. 500 JLs .1 Print Wire Coil Protection Circuits When a print wire is fired, the output PBO on U6D goes "low". This triggers the 555 USB.
CIRCUIT THEORY +5 V P1 PJ R12 15 K NO-PAPER SENSOR SWITCH PA2~1_0--------------~----~1818~----o U5D (6532) 1616~----------~ +5 V R54 470 P3 J3 n PA3~1_1____________4-____~1 PF KEY 1 U2D PA5 ~1_3____a >---~----~ 3 3 1 2 U5D (6532) ~--;)I------+ PAPER ADVANCE SWITCH AND INDICATOR CIRCUIT Paper Control Logic A normally closed micro switch located behind the platen opens when paper is loaded in the printer.
CIRCUIT THEORY +5V Rll 47 k R9 150 n Rl0 47 k U5D 6532 PA6 U1C 9 8 14 Pl Jl 12 12 ,., 19 19 U1C 20 20 ~~--~--~t5 U6D 6522 "'" CARRIAGE POSITION SENSOR HOME POSITION SENSOR t5~----~----~ iii c: u; '" ....: CAt 40 - iii c: s- I/) CA2 1=-39~-J a: TIMING CHART *TIMING SIGNAL --------lnn _______ __ UUL U1C-9 PIN )I U1C-8 PIN (PA6) " APPROX. 1.5 ms inn nnnrr - - - - -- - -n n uuuuUUL _______ --.
1526 AND MPS 802 CIRCUIT THEORY +SV 1 kn x 4 P5/P6 u; Serial Interface Connector a:: U2C SQR ATTN 2 8 PAO r--t-------....,---=1 3 U2C Clock 4 5 PSIP6 6 U4D 6532 U2D 10 p..:-;'-+.--=...oc Signal Pin No. 1 SERIAL SRQ 2 GND 3 4 SERIAL ATN 5 SERIAL DATA 6 RES t-_ _ _ _....;1~3 PAS U2D 8 r9 _ _ _ _---.:'....:..j4 PA6 U2C Data 5 1--_---01---.:1:..;..1d ~10=-----------':..::.
4023 CIRCUIT THEORY P2 i.1 PATTE~N I JUHf>£1? SHORT ALL The 4023 IEEE Interface Circuit Theory All the signals on the interface are controlled by the I/O device U4D. Eight parallel bi-directional data lines (PBO-PB7) are used as the parallel data bus for the interface. DAV (Data Valid) pin 6 of P2 is a "high" active output from the transmitting device. Valid 8 bit codes are transmitted to the receiving device when DAV is "high".
TROUBLESHOOTING GUIDE SYMPTOM 1: Printer does not initialize when powered up. POSSIBLE CAUSE SOLUTIONS 1. Power cord is damaged. Check that the power cord is connected properly and is in good condition. 2. Power switch is broken. Check and replace it if necessary. 3. Fuse is blown. Replace it. If it blows again, check the power supply unit and PCB. 4. Power supply is defective. Check for proper voltages at the PIS connector J4. 5. Defective logic board.
TROUBLESHOOTING GUIDE (Continued) SYMPTOM 3: Part of a printed character is missing. POSSIBLE CAUSE SOLUTIONS 1. Ribbon is worn out. Replace the ribbon cartridge. 2. Head shift lever is out of position. Re-set the shift lever. 3. Print head on flexible cable is defective. Check flexible cables and wiring harness for continuity. Check the print head by disconnecting the wire harness connector J 1 from P1.
TROUBLESHOOTING GUIDE (Continued) SYMPTOM 5: Improper Ribbon Feed POSSIBLE CAUSE 1. Obstruction of ribbon path. SOLUTIONS Check FPC cables for proper location. Check ribbon guide for foreign matter. 2. Defective ribbon cartridge. Check for proper ribbon insertion. Check the rotation of the cartridge by manually rotating the ribbon in the direction of the arrow. 3. Defective mechanics. SYMPTOM 6: Check the ribbon drive gears for proper lubrication (see page 5) and smooth opertion.
PCB PARTS LIST • 1526 • MPS 802 • 4023 • C - Indicates Commodore Stocked Part Numbers Differences noted in PARENTHESIS! PCB Assy 1526 PCB Assy MPS 802 PCB Assy 4023 INTEGRATED CIRCUITS U1C Ul0 U2C U20 U40 U5B U50 U6B U60 U7B U70 U8B U8C U80~ U9C Ul0C DIODES (Continued) 74LS14 74LSOO 74LS14 (1526, MPS 802) 74LS04 (4023) 7406 C 6532 7406 C 6532 7406 C 6522 VIA 7406 C 6504 CPU 555 74LS42 2364 ROM (1526/MPS 802) C ROM (4023) C 7400 74177 901521-30 901521-01 901521-30 901521-02 901522-06 901458-01 901522-0
PCB PARTS LIST • 1526 • MPS 802 • 4023 • (Continued) C - Indicates Commodore Stocked Part Numbers CAPACITORS (Continued) C32 C33-34 C35 C36-37 Ceramic Ceramic Ceramic Ceramic 200pF, .047p.F, .01p.F, 470pF, MISCELLANEOUS (Continued) 50V 50V 50V 50V P3 P4 P6,P7 MISCELLANEOUS Ferrite Beads 1526/MPS802 L1 L3-6 L15-17 Y1 P1 P2 4023 L 1, 2 L4-14 L 15-17 VR1 28 Pin Connector IEEE-48 Rt.
1526 • MPS 802 SCHEMATIC r----- i ~ ""- 2 2 , +Sy ~! (}7D /( (>'( .---- ~~ - Itt ~~~, ~k" £ : ~:~ .. ",,...-~ ~,-., ]7- ,,~ ~ ! ------------------------, m/-iiiS ~ I 0~~~ ~ c< tk"'''',,,-_:,-I+-~ +-J-V .w "7 L ____________________________ ! i I ~ .. i .. ~ 1526 • MPS 802 ROM UPGRADES .. The PCB for these printers was designed to accommodate a 24 pin ROM or 28 pin EPROM at location USD. A jumper change at J 1-J4 will configure the board for either I.C.
4023 SCHEMATIC "11) r----------------------------------------iI : , I J~:-=~ ~ ii¥S .L'nr 1 1 2 nM~ ~--' ~-dH-~ r-zr,:>$'1~ 4 I ~:k~ r...~ .~~ A.# ,..tJ.ii9-F~ : I ...4-=.j ~., ~·n - ~~.,.., :~I~ -{.
ADJUSTMENTS Head Shift Lever The head shift lever controls the position of the print head in relation to the platen. With the lever in its lowest position, towards the front of the printer, the print head is positioned as far as possible from the platen. With the lever in its highest position, towards the back of the printer, the print head is positioned as close as possible to the platen. HEAD SHIFT LEVER Print Head Set the head shift lever in its lowest position on the right side frame.
ADJUSTMENTS (Continued) Home Sensor To adjust the print start position, loosen the mounting screw for the home sensor. Slide it to the left or right, so that the center of the dot farthest to the left is 32 ± 1 mm away from the inside left frame when printing standard characters. Tighten mounting screw . • 32±1MM 0 0 H 0 0 0 0 SIDE FRAME HOME SENSOR ADJUSTING SCREW FOR THE MOUNTING POSITION OF THE HOME SENSOR. Using the self-test, check for the position of the leftmost dot.
WIRING DIAGRAM FPC CABLE -----'--;~~ HOME I SENSOR ~ I '---RED- - _J '-'-BLACK-. . . . -YELLOW- A EK - ! -C I I I I TO ON CONNECTOR PI MAIN LOGIC BOARD CARRIAGE POSITION SENSOR C-- - -=:LH~~:~:,~¥C~E c~ AI s-- -- ~J BLACK ... -- _..... ... K ...
MECHANICAL DISASSEMBLY The phillips head screws used in the printer mechanism are metric size. Use caution when selecting the proper size screwdriver. 1. To remove the ribbon cartridge: 1 .1 Position the right side tractor assembly to the far right. 1.2 Lift the ribbon cartridge from the printer. 1.1 2. To remove the top case and printer mechanism: 2.1 Remove the manual paper feed knob by firmly pulling it from the shaft. 2.
MECHANICAL DISASSEMBLY (Continued) 2.6 Detach the wiring harness connector from P1 on the PCB. 2.7 Loosen the 3 large phillips head screws at the front of the mechanism. Sliding the mechanism towards the front, lift it from the bottom case. 2.7 3. To remove the print head and ribbon guide: :~, ~~ ('-8-.1 ,I ~ '" - -3:'5 Set the head release lever to its lowest position on the side frame. Remove the 2 head screws. By gently pulling, detach the FPC cable from its connector.
MECHANICAL DISASSEMBLY (Continued) 5. To remove the home position sensor: 5.1 Remove the sensor PCB screw. 5.2 De-solder the wire connections from the wiring harness PCB. (See wiring diagram on page 28). 5.3 Slide the sensor PCB toward the front of the mechanism, pulling it from its bracket. Turn it sideways to fit between the carriage pillars. 6. To remove the paper feed motor assembly: 6.1 Remove the 3 motor bracket screws from the right side -Frame assembly. 6.
MECHANICAL DISASSEMBLY (Continued) 8. To remove printer drive belt: 8.1 Position the carriage at the center of the unit to allow access through the base to the belt holder screw. Remove the screw and bracket. 8.2 Remove the liE" clip to release the belt gear assembly on the right. 8.3 The drive belt will be released from the gear assembly on the left and can be removed. 9. To remove the sprocket frames and tractor assembly: 9.1 The left sprocket frame is detached by removing the 2 frame screws. 9.
MECHANICAL DISASSEMBLY (Continued) . 1--10.1 10. To remove the platen cover: 10.1 Remove the 2 cover screws, as indicated. Lift the cover off of the platen. 11. To remove the platen and reduction gears: 11.1 Remove the "E" clip and pull the reduction gear off of the frame. 11.2 Remove the spring pin from the platen gear by tapping it with a punch. Withdraw the gear from the platen shaft. 11.3 Remove the platen washer and shaft supporter that are now exposed.
----------------------~-- - - MECHANICAL DISASSEMBLY (Continued) 12. To remove the paper roller assembly: q tl 12.1-(1 12.1 Remove the 2 paper holding springs from the right and left frames. 12.2 Remove the left liE" clip and pull the paper roller axle to enable it to slide over the frame pins. G ~ 13. To remove the front carriage guide: 13.1 The front guide pillar is removed by loosening the hex nuts at each end. Next, slide the pillar "from its slots in the right and left frame plates. 14.
MECHANICAL DISASSEMBLY (Continued) ,-15.1 I 15. To remove the FPC cable assembly: 15.1 Remove the cable assembly screws. 15.2 Lift the FPC cable bracket from the carriage. 15.2 16. To remove the carriage and guide pillar: 16.1 Remove the "E" clip from the pillar. 16.2 Gently pry the plastic supporter from the shaft. 16.3 Slide the pillar to the right to release it from the frame. 17. To remove the paper roller assembly: 17.1 Remove the release lever screw and the lever assembly. 1 7.
MECHANICAL DISASSEMBLY (Continued) 18. To remove the platen and paper guide: 18.1 Remove the "E" clip from the platen shaft. 18.2 Pull the platen washer and shaft supporter from the platen shaft. 18.3 Slide the platen to the right to clear the side frame. 18.4 Remove the paper guide screw from the side frame. Slide the paper guide to the right to clear the frame. 19. To remove the gear plate assembly and left side frame: 19.1 Remove the 2 plate screws from the assembly. 19.
CASEWORK Section 1. Casework/Power Supply MECHANICAL ASSEMBLIES REF. NO.
SECTION 2. MECHANICAL ASSEMBLIES SECTION 2. Mechanical Assemblies REF. NO. 2-1 C 31458601.
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