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Mitsubishi Electric M4853 Maintenance Manual

5.25 inch flexible disk drive.
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5.25 INCH FLEXIBLE DISK DRIVE
MODEL M4853
MAINTENANCE MANUAL
STANDARD
MITSUBISH ELECTRIC

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  • Page 1 5.25 INCH FLEXIBLE DISK DRIVE MODEL M4853 MAINTENANCE MANUAL STANDARD MITSUBISH ELECTRIC...
  • Page 2: Table Of Contents

    CONTENT Page 1 . General References (Schematic and Manuals) Names of Unit Parts Operating Information Environment Diskette Handling Regular Maintenance Caution Head Cleaning Check and Adjustment 5.3.1 Diskette rotation cycle adjustment 5.3.2 TK 00 sensor position adjustment 5.3.3 Index sensor position check 5.3.4 Head alignment adjustment 5.3.5...
  • Page 3: General

    1 . General This manual explains the handling, maintenance and adjustment of M4853 Flexible disk unit. References (schematics and manuals) M4852/53 Specifications SJ2-G3375C NAMFB schematic diagram for maintenance TJ2-G30144A Illustrated parts list TJ2-G4865A Packing manual (10 set) TJ2-4869A Names of Unit Parts...
  • Page 4: Operating Information

    Operating Information Environment There is no problem in operating under normal office condi­ tions but when operating out of following conditions, Drive may not work properly or Diskette may get damaged. Temp./Humid. Range During operation During non operation Temperature Range -10°C - 50°C 5°C - 43°C Humidity Range...
  • Page 5 FIGURE 2...
  • Page 6: Regular Maintenance

    R e g u l a r M a i n t e n a n c e "Unit life can be affected by damaged parts as a result of dusty anvironment or excessive operation." So Maintenance by such methods as visual inspection, cleaning/change of damaged parts and regular functional checks will keep the unit in good condition and enable the discovery of any problem at an early stage.
  • Page 7: Head Cleaning

    Head Cleaning on Field Applications Head cleaning is recommended at user's sites, especially when used in severe environments, because the heads may accumulate dust in the air and magnetic coating material of the disk, causing chance of error increase and/or scratch on the disk surface .
  • Page 8: Check And Adjustment

    Check and Adjustments 5.3.1 Diskette rotation cycle adjustments Equipment Disk Tester Scratch Diskette Universal Counter VR Adjustment Driver Adjustment procedure 2)-1 Connect CE Tester to Drive then turn-on power switch. 2)-2 Load diskette then turn-on motor with drive select. 2)-3 Make sure HLMG ON.
  • Page 9 INDEX FIGURE 4 TPD14...
  • Page 10: Tk 00 Sensor Position Adjustment

    5.3.2 TKOO sensor position adjustment Equipment Disk Tester Scratch Diskette No. 1 plus screw driver Oscilloscope Adjustment procedure 2)-1 Connect CE Tester to Drive then turn-on power switch and load diskette. 2)-2 Turn-on motor and select drive. 2)-3 Repeat seek between TKOO and 02 (see Figure 5). 2)-4 Observe waveform (TKOO) at TPB1 using oscilloscope.
  • Page 11 FIGURE 5...
  • Page 12 5.3.3 INDEX sensor position adjustments Equipment Disk Tester CE diskette (DYMEK 502-1D STANDARD DISKETTE) No. 1 plus screw driver Oscilloscope Check procedure 2)-1 Connect Disk Tester to drive (set power off) 2)-2 Load diskette 2)-3 Turn-on power switch 2)-4 Turn-on and select drive 2)-5 Read timing of each waveform at TPB9.
  • Page 13: Head Alignment Adjustment

    5.3.4 Head alignment adjustment Equipment Disk Tester CE Diskette (DYMEK 502-ID STANDARD DISKETTE) No. 1 screw driver Oscilloscope Hex wrench (1.5 mm dia.) (Fine point diagonal cutter) Adjustment procedure 2)-1 Connect Disk Test to drive (set power off) 2)-2 Turn-on power switch and motor on. 2)-3 Select drive and load CE diskette (close clamp door slowly).
  • Page 14 FIGURE 7...
  • Page 15: Head Azimuth Check

    5.3.5 Head Azimuth Equipment Disk Tester CE Diskette (DYMEK 502-ID Standard Diskette) Oscilloscope Check procedure 2)-1 Connect CE Tester to Drive then turn-on power switch. 2)-2 Turn on motor. 2)-3 Select drive and load CE diskette. 2)-4 Seek to TK68. 2)-5 Read azimuth waveform using oscilloscope.
  • Page 16 NOTE The head's azimuth is not adjustable. It is suggested that the drive be sent to an authorized repair center or a new head assembly be installed. In the latter case, all previous adjust­ ments should be made again.
  • Page 17 TJ2-G302 31A 10/31/83 5.25 INCH FLEXIBLE DISK DRIVE M4853 PCB, NAMFF PARTS LIST MITSUBISHI ELECTRIC...
  • Page 18 This parts list is applied to the PCB,NAMFF Part No. DC447987 It means "Custom-made for MELCO Computer Works" It means the parts made by MELCO Semi-Conductor Division Q'ty Reference Part Number Description Designation DC44 79 86-G01 PWB, NAMFF T414562E Terminal Izumi Electric (Japan) TPB,TPC,TPD,TPE...
  • Page 19 Qty . Reference Part Number Description Designation C13,27,63,80,92,101 RPE122-127C103K50 Capacitor, Cer. O.OlyF 50V ±10% MURAT A WORKS 102,103,104,105,106 (Japan 107,108,109 C90, 91 RPE122-127CH102J50 Capacitor, Cer. lOOOpF 50V ±5% MURATA WORKS (Japan) RPE123-127F155Z25 Capacitor, Cer. 1.5yF 25V ±80%±20% C4,9,15,17,18,26,ll C5 ,6 ,28 RPE122-127C223K50 Capacitor, Cer.
  • Page 20 Qty. Reference Part Number Description Designation Texas Inst. IC G6,G2 SN7406N IC, Digital Texas Inst. IC Fl,K2,F6,L2 SN74LS 7 4AN IC, Digital ★ * * IC D5,L2,M2 M74LS14P IC, Digital * * * IC E 6 ,Hl M74LS04P IC, Digital * * * IC E 5 , J2 MR4LS08P...
  • Page 21 Qty. Reference Part Number Description Designation ±1% SEF (Japan) NL%J1200F Resistor 120ft R3 3 NIAJ1002F Resistor lOkft ¼W ±1% SEF (Japan) R42, 51 NL^J1202F Resistor 12kft ±1% R27, 94, 95 NL^J1201F Resistor 1 .2kft^sW ±1% NIAJ3900F Resistor 390ft 3 s W ±1% R3 , 4 NIAJ5601F Resistor...
  • Page 22 Qty. Reference Part Number Description Designation RI 8 NL^J8201F Resistor 8 .2kf^W ±1% SEF (Japan) NL^jJl003F Resistor lOOkfi^W ±1% R4 3, 45, 4 7 NL^s J 4 70 2F Resistor 47kß %W ±1% RI5 , 16 NL%J4 700F Resistor 470fi ±1% RI7 , 81, 91 NL%J1501F...
  • Page 23 Qty. Reference Part Number Description Designation ** * Diode, Zener NZ303 RD6.8FB Diode, Zener 6.8V Dl 0 NEC (Japan) RD5.1FB Diode, Zener 5.1V NEC (Japan) Dl 2 RD3.0EB2 Diode, Zener NEC (Japan) D2,3,4,6,11 IS -954 Diode National Component, Inc . Dl 3 NDP127 Diode...
  • Page 24 PHYSICAL SPECIFICATIONS Installation Direction Install the M4853 disk drive in the directions shown in Pig. 6-1. The slant mount should be within 10 degrees. Fig. 6-1 Disk Drive Installation Directions Dinunensions of M4853 See Fig. 6-2...
  • Page 26 USER OPTIONS Non-standard modes of operation are available to the customer by using option plugs, and some PCB cut and/or jumpers. When using plug, installing the option plug on a pair of square pins is a short" condition, and removing it is an "open". A trace or a soldered wire jumper between two pad3 is a "short", and none is a "open".
  • Page 27 FIGURE 7-1 H and R Jumper Options...
  • Page 28 This plug is installed to cause the spindle motor to turn on and rotate the disk with the input of a logical "0" on the motor on line, Pl-16. This plug is installed to cause the spindle motor to turn on and rotate the disk when the drive is selected by applying a logical "0"...
  • Page 29 7.12 Installing the "R" jumper in position 3 enables a "held status" ready output from the drive. The output will be a logical "0" when a disk is inserted and correctly clamped in the drive. (Index pulses were detected correctly.) This ready condition is held even if the drive is not selected and the motor is not on.
  • Page 30 Nota: See Section 7.17 for description of this unmarked option.
  • Page 31 8.0 RECORDING FORMAT Data to be recorded on the floppy disk is grouped in various blocks. There are bits, bytes, sectors, tracks, and sides. The bits are encoded onto the disk by three possible means: FM, M F M , or MMFM techniques.
  • Page 32 8.1.2 MFM Encoding MFM (Modified Frequency Modulation) encoding records twice the number of bits per inch (linear recording density) as FM encoding, but has the same number of flux changes per inch. It does this by removing the clock pulses, and shrinking the bit cell space by 50%. See Figure 8-2 for specific details.
  • Page 33 8.1.3 MMFM Encoding MMFM (Modified-Modified Frequency Modulation) is also a "double density" encoding method, further reduces the number of clock bits used to fill the empty spaces between data pulses. It is not a standard encoding technique, and should probably be avoided for that reason. See Figure 8-3 for a description of MMFM.
  • Page 34 8 .2 Track Formats M4853 RECOMMENDED FORMATTINGS M4853 5.25 inch (130 mm) Flexible Disk Drives use industry Standard Tunnel Erase type Read/Write Heads, and high accuracy direct-drive brushless motor for spindle rotation, guaranteed ±1.6% index interval and ±2% instaneous speed.
  • Page 40 Error Detection and Correction 8.3.1 Write Errors If an error occurs during a write operation, it can be detected by performing a read operation on the diskette immediately following the write operation. This is generally called a write check, which is an effective means of preventing write errors.
  • Page 41 causing a hard error. It is recommended that the following read operations be performed to correct these soft errors: Step 1: Repeat read operation about times, or until the data is recovered. Step 2: If the data cannot be recovered by Step 1, move the head to another track, the opposite direction of the previous track position before the designated...
  • Page 42 RESHIPMENT PRECAUTIONS When reshipping the drive, make sure the protection sheet for transportation is in place in the drive and the door is secured open.
  • Page 48 TJ2 - 6 3 0 2 3 2 A 5.25 INCH FLEXIBLE DISK DRIVE M4853 ILLUSTRATED PARTS LIST...
  • Page 49 CONTENTS i g - No. P a ge M48S3 FLEXIBLE DISK DRIVE FLEXIBLE DISK DRIVE..MECHANISM ASSY..PC A . NAMFF..Carnage Assy..C a r t r i g e Guide Assy..Frone P a n e i Assy..E j e c t o r Assy..
  • Page 50 M4853 F l e x i b l e Di s k D r i v e...
  • Page 52 F i g u r e 1 . F l e x i b l e D i s k D r i v e...
  • Page 54 F i g u r e 2 . Medianism Assy...
  • Page 63 5.25 INCH FLEXIBLE DISK DRIVE Differences Between M4853 and M4853-1...
  • Page 64 DIFFERENCES BETWEEN M4853 and M4853-1 Item M4853 M4853-1 Remarks •IC socket system 1. Input Terminals •Short-plug system 2.Customer adjusted short-plug •Three kind; HS, HM •HL and HH have been (l)Choosing headload conditions and HC. added. HL performs •Short-plugs can be headload in res­...
  • Page 65 IN USE short plug J3 is signal shorted. 3 . Interchangeability •Parts M4853 and M4853-1 are not interchange­ of parts able. 4 . Others •The electrical interface (power supply interface) with the controller is the same for M4853 and M4853-1.
  • Page 67 •Circuit boards pro­ and printed circuit decreased trude 8mm beyond board are even. back of frame. 1.Interchange- •No interchangeability of parts between the ability M4853 and the M4853-1. 1.Mounting inter­ •The mounting interchangeability is the same changeability the M4853 and the M4853-1.
  • Page 70 TJ2-G30219A 5.25 INCH FLEXIBLE DISK DRIVE MODEL M4853-1 MAINTENANCE MANUAL MITSUBISHI ELECTRIC CORPORATION...
  • Page 71 GENERAL This manual explains the handling, maintenance and adjustments of M4853-1 Flexible disk unit. REFERENCES (SCHEMATICS AND MANUALS) M4853-1 Specifications SJ2-G3446A NAMFG schematic diagram for maintenance TJ2-G30210A Illustrated parts list TJ2-G30199A Packing procedure TJ2-G30150 NAMES OF UNIT PARTS Figure 1...
  • Page 72 OPERATING INFORMATION Environment There is no problem in operating under normal office conditions but when operating out of following conditions, Drive may not work properly or Diskette may get damaged. Temp./Humid. Range During non During operation operation Temperature Range 5°C to 43°C -20°C to 51°C (41°F to 109.4°F) (-4°F to 125°F)
  • Page 73 Do not touch or attempt to clean the disk media surface with alcohol. Do not expose diskette to heat, dust, or sunlight. Do not write anywhere except on the media label and only use a soft felt tip pen. Figure 2...
  • Page 74 REGULAR MAINTENANCE...
  • Page 75 H e a d C l e a n i n g f i e l d a p p l i c a t i o n s...
  • Page 76 Procedures of Cleaning Wet type Dispense the cleaning solution onto the lint- free cleaning disk through the cutout- in the disk jacket. Insert the cleaning disk and activate the drive. Load head and rotate disk for 2 v 3 minutes. Eject cleaning disk and wait for another 2 ^ 3 minutes to dry heads.
  • Page 77 Check and Adjustments 5.3.1 Diskette rotational cycle adjustments Equipment C E . Tester Scratch Diskette Universal Counter VR Adjustment Driver Adjustment procedure 2)-1 Connect CE Tester to Drive then turn-on power switch 2)-2 Load diskette then turn-on motor with drive select 2)-3 Make sure Head Load Magnet activated.
  • Page 78 Figure 4 +INDEX...
  • Page 79 .3.2 T K O O s e n s o r p o s i t i o n a d j u s t m e n t Equipments CE Tester Scratch diskette No. 1 plus screw driver (Phillips #1) Oscilloscope Adjustment procedure 2)-1...
  • Page 80 Figure 5...
  • Page 81 5.3.3 INDEX sensor position adjustments Equipment CE Tester CE diskette (DYMEK 502-ID STANDARD DISKETTE) Hex wrench Oscilloscope Check procedure 2) -1 Connect CE tester to drive (.set power off) 2)-2 Turn-on power switch and motor-on 2)-3 Select drive and load CE diskette (Close clamp door slowly) 2)-4 Read timing of each- waveform at TPA9 .
  • Page 82 5.3.4 Head alignment adjustment Equipment CE Tester CE Diskette (DYMEK 502-ID STANDARD DISKETTE) Oscilloscope Hex wrench (2.0 mm dia.) (Fine point diagonal cutter) Adjustment procedure 2)-1 Connect CE Tester to Drive (set power off). 2)-2 Turn-on power switch and motor on. 2)-3 Select drive and load CE diskette (close clamp door slowly).
  • Page 84 5.3.5 Head Azimuth Equipment CE Tester CE Diskette Oscilloscope Check procedure 2)-1 Connect CE Tester to Drive then turn-on power switch. 2)-2 Turn on motor. 2)-3 Select drive and load CE diskette. 2)-4 Seek to TK68. 2)-5 Read azimuth waveform using oscilloscope. (DC +) (TPB14) EXT - -INDEX...
  • Page 85 NOTE The head's azimuth is not adjustable. It is suggested that the drive be sent to an authorized repair center or a new head assembly be installed. In the latter case, all previous adjustments should be made again.
  • Page 86 - - - M 4853-1 PCB NAMFG SC HEM ATIC----------------------- — M 4853-1 PCB NAMFG PARTS LOCATION DIAGRAM A , B M 48 53 -1 SPINDLE MOTOR ASSY SC HEM ATIC-------- (NAME: E2SLR36 or TS3400N2E13) A MITSUBISHI ELECTRIC CORPORATION TJ2-G30210 3...
  • Page 92 TJ2-G 30 I99C S.2S INCH FLEXIBLE DISK DRIVE M 4 8 5 3 -I ILLUSTRATED PARTS LIST ♦ MITSUBISHI ELECTRIC...
  • Page 93 CONTENTS Fig. No. Page 1. M48S3-1 FLEXIBLE DISK DRIVE...................2 2. FLEXIBLE DISK DRIVE................1 PCA, NAMFG ..................2 3. MECHANISM ASSY (1) ................3-1 Mechanism Assy ( 2 ) ................3-2 Carriage A ssy................... 4 Cartrige Guide Assy...................5 Ejector Assy....................6 Collet Assy....................7 3. FLEXIBLE DISK DRIVE.-WIRING DIAGRAM.........8...
  • Page 94 M4853-1 Flexible Disk Drive...
  • Page 95: Flexible Disk Drive

    Figure 1. Flexible Disk Drive FI47 Q’ty & Index Description A rr* Part Number Number Flexible Disk Drive Fig. 1 0991K008 Mechanism Assy U991K006 PCA, NAMFG U241N014 Screw. Pan H d . , Washered fM3xO.5x8 FE) 0669W201-002...
  • Page 96 Figure 2. PCA, NAMFG Fig. & Index Part Number Description Q’ty Number Fig. 2 U241N014 PCA, NAMFG Connector, PWB (6 5625-214#6) U452W018-002 Index Sensor U Assy U268Q005-001 Write Protector Sensor Assy U268Q006-001 Connector, PWB PS-10PA-D4LT1-PN1) U452W013-010 Connector, PWB (172349-1) U452W012-001 Connector, PWB (IL-S-4P-S2L2-EF) U452W013-009 Holder, Write Protector Sensor...
  • Page 97: Mechanism Assy ( 2 )

    Figure 3-1. Mechanism Assy (1)
  • Page 98: Cartrige Guide Assy

    F i g . Part Number Description & Index Q ’ ty Number Fig. 3-1 Mechanism Assy (1) U991K006 Cartridge Guide Assy U527L006 Front Panel U702L005 Ejector Assy US26Q002-001 Front Chassis Assy U560M002 Screw, Pan Hd., Washered (M3x0.5x8 FE) U669W201-002...
  • Page 99 Figure 3-2. Mechanism Assy (2)
  • Page 100 Fig. Index Part Number Q'ty Description & . Number Fig. U 9 9 1 K 0 0 6 Mechanism Assy (2) Carriage Assy U587L006-G01 TKOO Sensor Assy U268Q007-001 HLMG Assy U296Q002-001 Spindle Assy U288Q00 5-001 Motor Idler Assy U522Q002-001 Holder, Idler B U541M010-00L U581K003 Frame...
  • Page 101 Figure 4. Carriage Assy...
  • Page 102 Fig- Q’ty & Index Part Number Description Number Fig. 4 U587L006-G01 Carriage Assy Carriage U587L004-G01 Arm Assy U587L005-G01 Frame U581L001-001 Stay Spring U541M008-001 Gimbals Head Assy UP U460N004-G01 Gimbals Head Assy DN U460N004-G02 Cover U564M004-001 Shield Plate U565N004-001 Holder, Band C US41N007-G01 Spring CR Assy U572N009-G01...
  • Page 103: Collet Assy

    Figure 5. Cartrige Guide Assy Fig. Q’ty & Index Part Number Description Number Fig. 5 Cartridge Guide Assy U 527L006 Cartridge Guide B Assy U527Q001 Cartridge Guide A U527L005-001 Collet Assy U567M006-G01 Spring, Cartridge Guide ■ 4 US72H008-002 Spacer A, Cartridge Guide U550N006-001 Stopper, Ejector U838M006-001...
  • Page 104 Figure 6. Ejector Assy Fig. Description & Index Part Number Q’ty Number Fig. 6 Ejector Assy U526Q002-001 Holder, Ejector A U526M002-001 Ejector U526M003-001 Shaft, Ejector U531N009-001 Switch (Micro-size) U436Q002-001 Spring, Coil U573N009-001 Screw, Pan. Hd., Washered(M2xlO FE) U669W031-006...
  • Page 105 Assy Figure Collet Fi<* Description Q’ty Index Part Number & . Number U567N006-G01 Collet Assy Fig. 7 Collet A U567M004-001 Collet B U567M005-001 Shaft U531N005-001 Spring, Coil B U573N001-002 Bearing (F604ZZ) U530W001-001 Ring, E (30 SUS) U685W111-001...
  • Page 106 Figure 8. Flexible Disk Drive Wiring Diagram...
  • Page 107 Mitsubishi Electric Corporation 2-3 Marunouchi 2-Chome Chiyoda-Ku, Tokyo 100, Japan Tandon Corporation 20320 Prärie Street...
  • Page 108 Service Manual Tandy® Model 2000...

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