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Summary of Contents for SA455

Page 1: ...d ferrite ceramic read write head as used in SIIllUml Imge floppy drives Int ernal write protect circuitry activity light and solid die eust chassis Typical applications for the SA455 465 are word processing systems entry level micro processor systems in telligent calculators program storagl hobby computer systems and other applications where low cost rilndoTl ac cess data storage is a requirement...

Page 2: ... 133 4 111m square jacket 1 2 3 Physical Specifications 500 ms 500 ms 500 ms 500 ms 300 rpm 300 rpm 300 rpm 300 rpm 2938 bpi 5876 bpi 2961 bpi 5922 bpi 5876 fcl 5876 fci 5922 fcl 5922 fcl 48 tpi 48 tpi 96 tpl 96 tpl SA154 SA154 SA164 SA164 SA155 SA155 SA165 SA165 SA157 SA157 SA167 SA167 Environmental Limits Ambient Temperature Relative Humiditv Maximum Wet Bulb Shock Vibration Operating 50 to 11so...

Page 3: ...ates the spindle at 300 rpm through a direct drive system An expandable collet spindllB assembly provides precision media positioning to en sure data interchange 1 3 3 Positioning Mechanics The read write head assembly is accul atelypositioned through the use of a band positioner which is attached to the head carriage assembly Precise track location is accomplished as this positioner is rotated in...

Page 4: ...ES CONTROL TRACK 00 LOGIC INOEx SECTOR STepPER MOTOR TRACK 00 SWITCH STEPPER B STEPPER C STEPPER 0 1 t 1 RACK 00 COM TRACK 00 N C _ MOTOR ON SIDE SELECT READY INDEx SECTOR DETECTOR DRIVE SELECT SIDE SELECT DRIVE MOTOR REAO WRITE HEAD ASSEMBL I WRITE WRll E PROTECT N 2 PROTECT 1 SWITCH w RITE PROTECT COM WRITE HEAD 0 WRITE HEAD l It WRITE LOGIC WRITE DATA WRITE GATE WRITE PROTECT J 0 E8 ffi tu o t ...

Page 5: ... the read write heads from one track to another is accomplished by a Activating the DRIVE SELECT line b Selecting desired direction IUslng the DIRECTION SELECT line c WRiTE GATE being inalctive d Pulsing the STEP line Multiple track accessing is accomplished by repeated pulsing of the STEP line with direction valid until the desired track has been reached Each pulse on the STEP line will cause the...

Page 6: ...A X I t j 4 1 P s MIN I I DIRECTION _ c X X STEP 1 FIGURE 1 3 ST EP TO READ DRIVE SELECT VALID WRITE PROTECT VALID READ DATA WRITE GATE WRITE DATA DIRECTION SELECT STEP SIDE SELECT 1I I 50 0 nS MA7 X l 2P s MAX _I I __I Y 200 S M N 1 r l __ _ _ _ __ 500 ns MAX t 1 1 rns MAX I 1 1 5rns MIN ___ __ 1 8 P s MAX J 8 p s MAX 500 ns MAX I r I I ___ _ _ _ j ra 1 LS MAX 18 ms MAX for SA465 SIOE SELECT to V...

Page 7: ...ng the DHIVE SELECT line b Selecting the heCld c WRITE GATE blaing inactive The timing relationships requinad to initiate a read sequence are shown in figure 1 5 These timing specifications are required in order to guarantee that the position of the read write heads has stabilized prior to reading The timing of Read Data FM is shown in figure 1 6 39238 05 A LEADING EDGE OF BIT MAY BE t 80008 FROM ...

Page 8: ...ODE COMPARISONS 1 4 9 Write Operation Writing data to the SA455 465 is accomplished by a Activating the DRIVE SELECT line b Selecting the head c Activating the WHITE GATE line d Pulsing the WRITE DATA line with the data to be written The timing relationships required to Initiate a Write Dalta sequence are shown In figure 1 5 These timinrJ specifica tlonsare required in order to guarantee that the ...

Page 9: ...8 MIN I _I 2100 n8 MAX 8 001 8 t 40 nS I FIG URE 1 8 WRITE DATA TIMING FM I _ 4001 8 20 ns 39238 12 39238 08 C POWER ON MOTOR ON DRIVE SELECT DIRECTION STEP 100m j 1 MIN 1 i I 1 1 MINI y I 11 8 MIN FIGURE 1 9 POWER ON TO STEP ...

Page 10: ...LINE 2 SPARe SIGNAL LINE 1 _ III 4 DRIVE SELECT 4 3 III 6 INDEx SECTOR 5 8 7 DRIVE SELECT 1 1 10 9 1 DRIVE SELECT 2 12 11 DRIVE SELECT 3 14 III 13 _ MOTOR QIN 16 15 DIRECTION S ELECT 1tJ 17 STEP 20 _ 19 WRITE DATA _ 22 WRITE GATE 21 FLAT RIBBON OR TWISTED III 24 23 PAIR TRACK 00 f 26 25 7 r t WRITE PROTECT 28 AC 27 READ DATA GND 14 30 SIDE SELE CT 29 32 READY 31 f4 34 33 TWISTED 5 VDC J2 PAIR 1 4 ...

Page 11: ... are not multiplexed and affect all the drives in 1 daisy chain system The Input signals to be multiplexed are a DIRECTION SELECT b STEP c WRITE DATA d WRITE GATE e SIDE SELECT The Input signals which are Intendep to do the multlple Ing are a DRIVE SELECT 1 b DRIVE SELECT 2 c DRIVE SELECT 3 d DRIVE SELECT 4 MOTOR ON is not multiplexed The Input lines have the following electrical specifications Se...

Page 12: ...allowed before reading or writing This line should be deac tivated for maximum motor life if no commands have be en Issued to the drives within 2 seconds 10 revolutions of the media aher completion of a previous command 2 2 5 Direction Select This Interface line defines the dlrectlion of motion the read write heads will take when the STEP line Is pulsed An open circuit or logical one defines the d...

Page 13: ...s enabled by WRITE GATE being active Write dat must be InaiCtlve during a read operation A write data clamp is provided on the PCB at the Interface which holds tha WRITE DATA line at a logical zero whenever WRITE GATE Is inactlve See figure 2 4 for timings 2 2 9 Side Select I jThls signal defines which side of a two sided diskette is to be written on or read from A logical one selects the side O H...

Page 14: ...ulse on this Interface signal per revolution of the diskette 200 ms This pulse indicates the physical beginning of a track See figure 2 5 for the timing u I 200 4 ma U I 39238 13 A FIGiURE 2 5 INDEX TIMING SA154 164 MEDIA When using SA155 165 or SA157 167 media hard sectored there will be 17 or 11 pulses on this Interface line per revolution 200 ms To Indlcat the beginning of a track once per revo...

Page 15: ...r frequency of occurence When the index pulses are 200 ms apart READY becomes active 2 3 POWER INTERFACE The SA455 465 requires only dc power for operation DC power to the drive is provided via P2 J2 The two dc voltages their specifications and theil P2 J2 pin designatolrs are outlined in table 2 1 The specifications outlined on current requirements are for one drive For multiple drive systems the...

Page 16: ...CAL LOCATIONS 3 1 1 J 1 P1 Connector Connection to J 1 is through a 34 pin PCB e dg connector The dimensions for this connector are shown in figure 3 2 The pins are numbered 1 through 34 with the even numbered pins on the component side of the PCB The oddnumbered pins are on the non component side Pin 2 is located on the end of the PCB connector closest to thesorner and is labeled 2 A key slot Is ...

Page 17: ...CONNECTOR 3 2 FRAME GROUNDING CAUTION The SA455 465 must be frame grounded to the host system to ensure proper opera tlon If the frame of the drive Is not fastened directly to the frame of the host system with a good ac ground a wire from the system ac frame ground must be connected to the SA455 465 For this purpose a faston tab is provided on the drive near the motor control PCB whe re a faston c...

Page 18: ... read write head In general Is a ring with a gap and a coil wound at some point on the ring c During a write operation a bit Is recorded when the flux direction in the ring Is reversed by rilpldly reversing the current In the call d During a read operation a bit is read when the flux direction In the ring is reversed as a result of a flux reversal on the diskette surface The SA455 46 drives use th...

Page 19: ...uses the center tap switch to dose and erase current to flow after the turn on delay of 400 J tsec The output of one of the write drivers allows write cutrent to flow through one half of the read write coil When the write trigger flips the other write driver provides write current to the other half of the read write coil The removal of WRITE GATE causes the turn off delay circuit to time out for 1...

Page 20: ...limit and digitize the read signals sine waves 39211 24 READ DATA LSI l ot f READ READ ENABLE 4 CHIP 5 V REG 1 The drive has no data separato r only a pulse standardizeI for the READ DATA signal ERASE 1 ERASE 0 12V r 1 I I SIDE 0 I I r I I SIDE 1 I I L__ SELECT1 SELECT 0 FIGURE 4 8 READ CIRCUIT 4 6 DRIVE MOTOR CONTROL a Start Stop b Speed Control c Over Current Protection d Speed Adjustm mt The mo...

Page 21: ...pper Motor Four Phase b Stepper Control Logic c Reverse Seek d Forward Seek Seeking the read write head from one track to another is accomplished by selecting the desired direction utilizing the DIRECTION SELECT interface line loading the read write head and pulsing the STEP line Multiple track accessing is atcompllshed by repeah d pulsing of the STEP line with WRITE GATE Inactive until the desire...

Page 22: ...ngle drive system It can be easily modified to operate with other drives in a daisy chained multiplexed drive system This Is done by selecting the specific drive address and jumperlng the appropriate DRIVE SELECT line See figure 4 12 The MX option Is used for sln le drive systems By shorting HMX 1l the I O lines are always enabled The MS option allows the mot r to be enabled from DRIVE SELECT 5V 6...

Page 23: ... 5 V bD wp FIGURE 4 13 WRITE PROTECT 4 12 READY This Interface signal gives the user an Indication that a dlsl 4ette Is Inserted correctly In the drive and the door is clos ed The READY signal Is active a1 a logical 0 level wh m all of the follOWing conditions are met a The door is closed b The door has not been opened since the drive was last deselected and timed out 500 ms c Two INDEX SEeTOn pul...

Page 24: ...0 TRK 00 d Azimuth Anale not field adjustable TRK 33 TRK 64 e 125 k Hz Signal R ecorded to Check TRK 34 TRK 79 Head Position on Inside Track Caution should be used not to de stroy prerecorded alignment tracks The write protect tab must be installed to pre vent accidental writing on the alt nl1nent diskette If the write protect option Is used remove the write protect tab 5 1 2 Exerciser PCB The exe...

Page 25: ...few microseconds c Small defects In written dat and or track not detected during write operation may cause soft er rors during read d Improper groundlng of power supply drive and or host system Refer to SA455 465 OEM manual P N 39238 for PI op42r groundlng requirements e Improper motor speed The folloWlng procedures are recommended to recoverfrom the above mentioned soft errors a Reread track 10 t...

Page 26: ...rm another seel to the original track or do a read ID to find on which track the head is located 5 3 TROUBLE SHOOTING Figures 5 1 through 5 5 provide tr ouble shooting procedures for the SA455 465 AR_T_ INSERT DISKETTE WITH WRITE PROTE CT SLOT UNCOVERED PERFORM WRITE NO PROTECT SENSOR ADJUSTMENT PARA 5 4 7 INSERT DISKETTE WITH WRITE PROTECT SLOT COVERED 1 REPLACE WRITE PROTECT SENSOR YES REPLACE D...

Page 27: ...TAGE AT PCB r CHECK JUMPER OPTIONS AND IF DRIVE IS SELECTED YES NO CHECK DC POWER SOURCE END PERFORM MOTOR SPEED ADJUSTMENT PARA 5 4 1 REPLACE DAIVE MOTOR REPLACE DRIVE PCB 39239 05 FIGURE 5 2 DISKETTE NOT ROTATING 5 4 ...

Page 28: ...9 ECK LOGIC LEVEL AT TP7 ZERO URN CARRIAGE 0 ITS REST P OSITION AT TRACK 00 NO REPLACE TRACK 00 ASSEMBLY PARA 5 5 9 PERFORM TRACK 00 ASSEMBLY ADJUSTMENT PARA 5 4 5 NO REPLACE DRIVE PCB YES STEP TO TRACK 00 CHECK LOGIC LEVEL AT TP7 FIGURES 3 TRACK 00 INDICATOR INOPERATIVE 5 5 39239 06 ...

Page 29: ...URCE INSTALL JUMPER INSTALL JUMPERS NO NO NO NO CHECK NO JUMPER OPTIONS REPLACE DRIVE PCB CHECK 1 0 CABLE OR CONTROLLER CHECK DRIVE SELECT JUMPER YES END NO INSTALL TERMINATOR CHECK TERMINATOR 1500 REPLACE I O CABLE CONTROLLER FIGURES 4 IDRIVE NOT COMING ON LINE 5 6 ...

Page 30: ...E AND NECTORAT J2 CHECK DISKETTE ROTATION YES YES CHECK TP7 FOR PULSE 200 Msec END C __EN_D __ r PERFORM C END DI SKETTE NOT ROTATING FIGURE 5 2 REPLACE INDEX SECTOR PHOTOTRANSISTOR _ N _ O ASSEMBLY PARA 5 5 6 PERFORM INDEX SECTOR ADJUSTMENT PARA 5 4 6 C EN_D 9 19 0fl FIGURE 5 5 INDEX PULSE INOPERATIVE 5 7 ...

Page 31: ...PCB Set inputs to ac ADD and Invert one channel Set vertical deflection to 50 mV dlvlsion e Amplitude of two lobes must be within 70 of each other 80 for 465 If lobes do not fall within specification continue on with procedurc see figure 5 6 100 mV 20 msec j AMPLITUDE DIFFE R ENCE MUST BE WITHIN 70 100 mV 20 msec f EQUAL AMPLITUDE 100 FIGURE 5 6 ALIGNMENT LOBES 39239 25 f g h I j Loosen two mounti...

Page 32: ...oblems MOUNTING SCREWS 39239 09 I IGURE 5 7 STEPPIER MOTOR MOUNTING SCREWS a Install alignment dlsl ette SA455 SA128 SA465 SA126 b Select drive and step to track 33 SA455 or track 64 SA465 c Sync oscilloscope external neUi ltlve on TP7 set lime bast to 0 G m lC pOl division d Connect on probe to TPl and other to TP2 Invert one channel and ground probes to PCB Set inputs to ac ADD and 50 mV per div...

Page 33: ...ivision to 50 mV and time base to 20 msec per division e Select head aand write a 2F pattern on entire track Average minimum amplitude peak to peak should be 100 mV f Select head 1 and write a 2F pattern on entire track Average minimum amplitude peal to peak should be 100 mV g If either head falls to meefmlnlrnum amplitude spe clflcatlons continue with procedure h Install fresh media andrecheck i ...

Page 34: ... detector and verify presence of 125 k Hz signal Repeat stepping untlJ signal Is found h Once 125 k Hz sl nalls present on oscllloscope carriage Is located at track 00 Disconnect pro bes from TP1 TP 2 and TP7 Conned one channel to TP8 and set input to de Set vertical deflection to 2 V per division Trigger oscilloscope on selected input channel I Step to track 01 a nd verify that TP8 goes to zero j...

Page 35: ...ta pulse This should be 200 200 100 J tsec If timing Is not within tc lerance continue on with adjustment See figure 5 10 g Loosen mounting screw In Index detector block until assembly Is just able to be moved See figure 5 11 h Step carriage to track 38 SA455 or track 76 SA465 i Observing timing adjust detector until timing Is 200 200 100 J tsec Ensure that detector assembly is against registrcltl...

Page 36: ...e motor PCB for 5 0 05 Hz Period 200 2 ms 5 4 7 Write Protect Detec tol a Insert diskette in1 0 drive Write proted notch must be open b Set oscilloscope to AUTO SWEEP 2 V div Monitor TP9 c Check to see If IIOgic level changes when diskette Is removed 5 4 8 Test Points On DrI te ItCD Test points for the drive PCB are as follows 1 Read Data 2 Read Data 5 Signal Ground 6 Digital Read Dai a 7 Index 8 ...

Page 37: ...39239 18 FIGURE 5 12 PCB COMPONENT LOCATIONS PIN S 25284 AND 25286 5 14 ...

Page 38: ... hub clamp with spacer and spring in place onto spindle hub Large end of spring Is plac d against hub frame e Press hub frame down towards splndl4 until hub shaft protrudes through mounting hole in hub frame f Reinstall faceplate Re adjustment Is not required 5 5 6 Write Protect Sensor lund Index Detector a Remove connec torfrom PCB b Remove mounting screw from write protect assembly This will fre...

Page 39: ... SA128 SA465 SAI26 f Set track addressc s of 00 and 39 SA455 or 79 SA465 into exerciser g Select drive h Start motor and 14 t drive seek automatilcally for 5 minutes I Check that activity light is on j Using this SA455 465 Service Manual and the Exerciser Instruction Manual as guides perform the follOWing cheeks Index timing Adjustment paragraph 5 4 6 Head Radial Alignment Sides 0 and 1 paragraph ...

Page 40: ...OCO e I I n 4H_ l f Ie h0022 91 15 MD2 SMD2 SMO MX fiJ Iff j nos J V III R 5V g 6MO 22 2r I m 2A 38 5 5K to 1 _ 5 n SUo rtP IeoE t 5 s 5 f f fS 4 D cL JI 4 B j 4 1 9 II V 58 3 IRQ SM04 F2 J 4 n 6A X _ j StA04 bTPI2 Of fift CA SfLT NC __ I _ _ _ _ 1_R_ 2_ I _5K _ ff C tlaf f_ _ __ _ H _t _t t f Z D Q DlR I I 78 V N R q OIMCT 20 10 5V IOOK ooI ff A I It 66 J7 EX r 7 8 7A Q 21 6 t Il T R oTP7 05 RDY ...

Page 41: ...It 2 0 5 n nJR 20 78 78 1r 1 5K 5V 4 t f t t t r 1 1 v q Vl I 10 J t 2 76 _nlJ lCT 1 5V __ I RN2 4 N _ foo 68 t OMAC T v Ulnt lOOK I R4 11 7 5 I X i7K 2 T R 0 TP7 D5 RO l t R R r a J 2 i1 IA 2 R 4 RfADY 6 Y 1 J2 15 z G fOR 38 l 12 51 l oJ IDX TKOO IIA j S 6 T lC DR Jt IA _ j TRACK zeRO fOl I t t t t HLD 5 0 8 J 0 14 53 co yTP1 MM lM CFOb2 0lC If RJ2 0 IA INDEX O T Jf I _ t t 1 MTON m 150 II z a PC...

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