Mitsubishi M4851, Oem Manual

Page 1: ...MITSUBISHI 5 1 4 FLEXIBLE DISK DRIVE MODEL M4851 OEM MANUAL TJ2 G30 11 A 11 83...

Page 2: ...ENERAL OPERATION System Operation Electronics Rotation Mechanism Positioning Mechanism Read Write Heads FUNCTIONAL OPERATION Power On Sequencing Drive Selection Positioning Operation Side Selection Re...

Page 3: ...7 9 H 2 7 10 H 3 7 11 R 2 7 12 R 3 7 13 R 4 7 14 MC 7 15 RD RS 7 16 DI 7 17 Write Protect Inversion 7 18 Terminations 7 19 Options Timing Examples 7 20 Summary Table 8 8 1 8 1 1 8 1 2 8 1 3 8 2 8 3 8...

Page 4: ...performance read write head medium tracking o The steel band flat stepping motor drive system for positioning achieves the best intertrack access time in its class just 6 ms o The maintenance free DC...

Page 5: ...le sided diskettes in double density format o The M485l employs the unique Mitsubishi circular gimbal spring for holding and loading the magnetic heads to assure soft steady contact with the medium Th...

Page 6: ...ccess time Track to track Average Set tling time Head loading time Motor starting time Double Density 500 kilobytes 250 kilobytes 6 25 kilobytes 327 7 kilobytes 163 8 kilobytes 4096 bytes 256 bytes x...

Page 7: ...density Number of cylinders Number of tracks Number of heads Rotation speed Rotation period Index Media Double Density 5922 bits per inch maximum 5922 FeI maximum MFM 48 tracks per inch 40 80 2 300 RP...

Page 8: ...nt panel dimensions Height Width Weight 5 V 5 0 5 A ty ical seeking 12 V 5 0 5 A typical seeking 8 5 watts typical seeking 5 0 watts typical reading in standby mode 4 0 watts typical motor off Except...

Page 9: ...Vibration Altitude Transportation environment conditions max 72 hours Ambient temperature Relative Humidity 5 to 46 Deg C 41 F to 115 F 20 to 80 Maximum wet bulb temperature 29 C 85 F 2 5 G Max 20 mS...

Page 10: ...ars or 20 000 energized hours whichever comes first Media life Insertion Rotational life Tap tap Error rate Soft read error Hard read error Seek error 4 3 x 10 or more 6 3 5 x 10 pass track 5 10 on th...

Page 11: ...RITE CIRCUIT CONTROL LOGIC L___ READ WRITE HEAD 0 READ WRITE HEAD 1 T CKOO DETECTER HEAD LOAD SOLENOID IR I TE PROTECT DETECTOR INDEX LED ACTIVITY LED DISK PRESE T SWITCH INDEX DETECTOR SPINDLE MOTOR...

Page 12: ...over the desired track of the medium Then the head loading solenoid loads the read write head on the medium to read or write data 2 2 Electronic Circuits The electronic circuits driving the individual...

Page 13: ...erature compensated to minimize read write head deviations from the disk tracks caused by ambient temperature change 2 5 Read Write Heads The read write heads use MnZn magnetic ferrite Each read write...

Page 14: ...host system The select lines on the drives must have different numbers if two or more drives are connected If the same number is assigned an operation error occurs due to interference among the ou put...

Page 15: ...mplete description of encoding methods 3 6 Write Operation Write data can be encoded by either FM MFM or MMFM The M485l has good contact stability of the read write heads on the medium and employs hig...

Page 16: ...c to a true state If the disk is not properly seated this will not occur because the index hole in the disk will never allow light to strike the presise location required to activate the photo transis...

Page 17: ...nor I L 104011 Wl OT 250 t I VALm INC2X I FW1J ScU I fr of lus MIN J M lJ J r 1 1 S MIN I I lOOus MIN t L 4 u 1 o J tt I t Oms MIll I 6 3am MIN a o I J l O x p J 1 r Ctl s MI N J r l OOU2 It _ i_6_ _...

Page 18: ...DATA I 1 I 1 I 1 o 1 DATA III I 1I0I l J cis I 1 I o Figure 3 Comparison of FM and MFM encoding...

Page 19: ...tor The DC power interface drives the soindle drive motor of the M485l and supplies power to the electronic circuits and the stepping motor which drives the read write head positioning mechanism via t...

Page 20: ...ITE GATE TRACK 00 WRITE PROTECT READ DATA SIDE ONE SELECT READY Type Input Input Output Input Input Input Input Input Input Input Input Output Output Output Input Output Signal Pin No 2 4 6 8 10 12 14...

Page 21: ...he connected drives are multiplex controlled by drive select lines and anyone of the drives can he accessed The cabling method and input line termination are shown in Fig 4 1 A maximum of seve input s...

Page 22: ...R FDD Sa t DC POWER Figure 4 1 Cabling Method r I 5V l I 50 n 1 4 SN7438N OR EQUIVALENT D Ii d f rl Jy SN74LS14N OR 1 EQUIVALENT I 5 on I V f I S 7 3tS OR EQUIVALEN SN74LS14N OR j C EQUIVALENT T 77 HO...

Page 23: ...rcuit board are used to select the drives to be made active corresoonding to drive select lines DSO is shorted before shipment from the factory so this setting must be changed when establishing other...

Page 24: ...diskette the head moves This interface line is a pulsed signal for moving the read write head in the direction defined by the direction select line The read write head moves by one track each time a s...

Page 25: ...0 S 40ns 8 00i s 40ns _ Figure 4 3 Write Datq Timing FM encodings LJ n I I 200 3 2 ms L J I I I t I I 4 ms 1 0 I 8 0 Figure 4 4 Index Timings 1 Tl Il s 250ns ___ 1 T2 Tl 4 00 us 800 ns Jitter due to r...

Page 26: ...ine starts the spindle motor when it goes to logical 0 See Section 7 0 for related options The motor on line goes logical to stop the motor and keep it off while the drive is out of operation thus red...

Page 27: ...rted into the drive and the door is closed See Section 7 0 for related options Read data This interface line transmits the data that is detected by the read write head on the diskette The read sends a...

Page 28: ...uits and the read write circuit DC Power DC power is supplied via connector J2 P2 on the back of the printed circuit board The specifications of the two DC voltages are shown in Table 4 3 The pin arra...

Page 29: ...card edge type 34 pin for both sides or 17 pins for a single side connector with even numbered pins 2 4 to 34 on the parts side and odd numbered pins 1 3 to 33 on the 50ldered side A key slot is prov...

Page 30: ...274 1 Crimping tool 90268 1 Extraction tool 91073 1 91073 1 Twisted pair cable AWG 26 AWG 26 3 m maximum Table 5 1 Connectors for Twisted Pair Cable PI Parts 3M PiN Connector 1463 0001 Polarity key 34...

Page 31: ...t of the pins as viewed from the side is shown in Fig 5 2 Pin numbers are shown on the parts side The connectors on the drive side and cable side are shown in Table 3 Parts Housing P2 Cab e Side AMP P...

Page 32: ...5 3 Frame Ground Connector J5 p5 FASTON Terminal AMP PIN 60920 1 Cr imp Terminal AMP PIN 60972 1...

Page 33: ...e physical locations of the interface connectors used for the M485l PI CONNECTOR SCOTCH FLEX P N 3365 34 OR AMP P N 583717 5 J5 AMP P N 60920 1 AMP PIN 60972 P5 I P 2 At F P N i 4804 24 0 J 2 At 1P P...

Page 34: ...TALLATION DIRECTION Install the M4851 disk drive in the directions shown in Fig 6 1 Slant mounting perpendicular o should be within 10 degrees peA UPPER Fig 6 1 Disk Drive Installation Directions 6 2...

Page 35: ...E LEO Note All dimensions are in mm 4 MAX SS dimensions in are in inches MOUN l ING HOLES ON BorTOH 6 32 2S0P 2 ON EACH SIDE 6 32 2S0P 203 2 1 2 8 0 05 peA I 9 7 02 J I 2 02 Figure 6 2 Dimensions of M...

Page 36: ...choices to allow the drive to be enabled when the articular select line is taken to a logi al condition Only onedrive per system may be designated for each drive number In other words there n only be...

Page 37: ...after the drive is ready see section 7 8 Do not install HC with this option but HS may also be used at the same time 7 5 HC This plug is installed to cause a constant head load condition which occurs...

Page 38: ...MrrSUmSHIELE R CURRENT READY DRIVE SELECT MOTOR ON 1 HC OHS _ _ _OHM 2 3 HELD READY 4 R H DRIVE SELECT Figure 7 1 Hand R Jumper Options Pl 34 READY HEAD LOAD DRIVER...

Page 39: ...m the drive to the head load circuit ready qualification input This is done when both the Hand R jumpers should be installed on the same option H 2 R 2 or H 3 R 3 which is physically impossible For ex...

Page 40: ...his option is not used at this time 7 16 DI Cut ing this PCB trace disables the in use input to the drive Pl 4 This means that the only time the front panel LED will be lit will be when the drive is s...

Page 41: ...R2 H3 o HS Shorted Head Load with Drive Select o HM Open o R2 Shorted Current Ready Out ut o H3 Shorted Head Load with Held Ready o All other Hand R positions are open Ready delay from Drive Select 6...

Page 42: ...On until drive may be selected 250 mSec min This option setting combination would be used for disk to disk transfers with a minimum of delays Because the head was loaded during motor start uP there is...

Page 43: ...otor On Motor On Input Motor On Drive Select Head Load Drive Ready Head Load Current Status Head Load Held Status Ready Output Current Status Ready Output Held Status Not Used Leave Open Motor Constan...

Page 44: ...ts are collected together in a certain number of bytes per sector to define the actual recording format used All of this is defined by the host system the disk drive just records and detects flux reve...

Page 45: ...inexpensive one shot multivibrators It can do this because each data pulse is between two clock pulses thereby rigidly defining the read window very precisely Figure 8 1 FM Write Timing L s 50ns ___ _...

Page 46: ...nd 8 4 for specific details Clock bits are always written at the leading edge of the cell only if no data bits are written in either the present or preceeding bit cells I L D I I I 8 0 I 1 0 0 1 u U U...

Page 47: ...a clock pulse is encoded only if no clock or data puls s were written in the previous bit cell and no data blt is to be written in the present one o C 0 o DI C Die D I c Die C LL 0 CE L 1 Cl LL 2 CEL...

Page 48: ...in the followinq figures including formatting and data re write modes The drives allow for the following conditions on all 40 tracks 1 The leading edge of a data block should be preceded by the erased...

Page 49: ...IlIdcll Sector J 1 nO EUC 2 Figure 8 7 ISO 7487 2 Style Track 00 Side 0 FM Fi rst Seclor _ l f_I __ ltc Write ilarl I ICJt Seclu l aIII First llata IHod 1 Jp ___ t l i L__ i1P I I I li ddl t SS Dala...

Page 50: ...nato tHock Gap r 67 1l to 90 1E rUl ol_menJcd Figure 8 9 512 Bytes Sector Standard ScctO IJelltificr If IA JJrCSs Mark Identificr 12 OIl Cy I 1 3 A J Side I 1 r1 Sc tor 1 Hrst Sct lor 1 __Cgt _I __ St...

Page 51: ...tes Sector Simplified First Se tor 1tC Wri to nil 1 SC ctor 1 J t I r Still t II atl se l o r IO l Jllud dClltl fie GLl 1 1Il Ii dtl c s I I _ _ _ _ L _M_ _ll _k _ tlCII t_i_fi_e__ _ r i l S t Un t OJ...

Page 52: ...S L 1 U1 Ene 2 Figure 8 13 256 Bytes Sector NEe 765A Fir l Sector I _J OlIllL_I __ Itc Irilc I Slalt 9th Scctor I f _ 00 C Sector First O lt t 1I1oc k I lt l lll0 i r___ 1 G 11 II luck I al t lJ ll l...

Page 53: ...t l C lC Gel 1 1 Block 1 II IAtltlrcss Itnt I ntn me l nl Murk enti fi ur t h rk I ie hi 14 1 1 12 00 yJ 1 22 1H 12 00 1 OH lyles 2 9U I 2 IIU ill ll iido 1 AJ Sector 1 I PO Itltlelt to lUl I rcc o cl...

Page 54: ...diskette is defective re lace it Most data errors that occur are soft errors If a read error occurs repeat the read operation to recover the data The following are possible main causes of soft errors...

Page 55: ...hard error It is recommended that the following read operations be performed to correct these soft errors o Step 1 o Step 2 o Step 3 o Step 4 Repeat the read operation about ten times or until the da...

Page 56: ...he carr ier Contact the carrier for any damage claims 9 2 Reshipping If it proper drive is necessarv to return a drive for any reason steps must be taken to prevent damage to the o Use all the packing...