CORVUS 7100-04702 Service Manual Download Page 56 | Manualshive

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Summary of Contents for 7100-04702

Page 1: ...THE CORVUS SERVICE MANUAL Floppy Disk Drive CORVUS SYSTEMS ...

Page 2: ...scribed in this man ual at any time without notice Revised manuals and update sheets will be published as needed and may be purchased by writing to Corvus Systems Inc 2029 O Toole Avenue San Jose CA 95131 Telephone 408 946 7700 TWX 910 338 0226 This manual is copyrighted and contains proprietary information All rights reserved This docu ment may not in whole or in part be copied photocopied reprod...

Page 3: ...ons These are in increasing order of importance NOTE CAUTION and WARNING The NOTE indicates some action to be taken to speed or simplify a procedure The CAUTION indicates that potential damage to the equipment or user data exists and care should be taken to avoid this The WARNING indicates that potential harm or injury to the service technicion or operator exists and extreme care should be taken t...

Page 4: ...CORVUS DEALER SERVICE TABLE OF CONTENTS ...

Page 5: ...e Control 4 2 2 6 Read Amplifier and Digitizer 6 2 3 Concept Interface 7 CHAPTER 3 DISASSEMBLY AND ASSEMBLY PROCEDURES 3 0 Scope of C hapter 9 3 1 Cover Disassembly and Assembly 9 3 2 Power Supply Removal 10 3 3 Power Harness Removal 10 3 4 Rear ConIlectors and Devices 10 CHAPTER 4 CHECKS AND ADJUSTMENTS 4 0 Scope of C hapter 12 4 1 List of Tools 12 4 2 Drive Adjustments 12 4 2 1 Spindle Drive Mot...

Page 6: ... Operation 24 5 1 2 Test Descriptions 24 5 2 System Level Troubleshooting 25 5 2 1 Interface Controller and Cable 26 5 2 2 Floppy Drive 26 5 2 3 Concept Workstation 26 5 3 Floppy Drive Unit 26 5 3 1 Power Supply 26 5 3 2 Diskette Drive Unit 27 5 3 3 Power Harness 27 5 4 Interface Controller Card 27 5 5 Troubleshooting Guide 28 APPENDICES Appendix A Appendix B Appendix C Appendix D Glossary 30 Part...

Page 7: ...CORVUS DEALER SERVICE LIST OF FIGURES ...

Page 8: ...ions 13 4 3 Cats Eye Pattern 14 4 4 Head Module Retaining and Cam Screws 15 4 5 Index to Data Burst 16 4 6 Index Sensor Retaining Screws and Adjustment 17 4 7 Negative Going Pulse Width 18 4 8 Track 00 Sensor Adjustment 18 4 9 Optimum Head Azimuth Alignment 20 4 10 Head Azimuth Acceptable Lower Limit 20 4 11 Head Azimuth Acceptable Upper Limit 21 4 12 Load Arm Adjustment Front View 21 4 13 Interfa...

Page 9: ...CORVUS DEALER SERVICE LIST OF ASSEMBLY DRAWINGS AND SCHEMATICS ...

Page 10: ...ALER SERVICE LIST OF ASSEMBLY DRAWINGS AND SCHEMATICS Drive Schematics 32 Controller Schematic 37 Assembly Drawings Mechanism 38 Power Supply 39 Left Cover 0 40 DC Cable 41 Logic Board 42 Floppy Controller 43 iv ...

Page 11: ...CORVUS DEALER SERVICE SPECIFICATI NS ...

Page 12: ...me including head settling Motor Start Time Disk Rotational Speed Instantaneous Speed Variation Flux Changes per inch inside track Transfer Rate Unformatted Recording Capacity IBM Format Recording Capacity Recording Method v 2 30 inches 8 inches 13 125 inches 6 pounds with power supply 5 volts 5 0 75 amp typical 24 vo ts 10 0 92 amp typical 2 5 amps 400 msec on 24 volts 4 4 C to 46 C 40 C to 71 C ...

Page 13: ...CORVUS DEALER SERVICE CHAPTER 1 OVERVIEW ...

Page 14: ...nted to the floppy chassis assembly 1 1 2 Interface Description The floppy interface is composed of an Interface Controller Card and a fifty pin flat ribbon cable Some drives use a fifty pin twisted pair cable which is acceptable The Controller uses an intelligent Floppy Controller chip and associated circuits Data transfers between the drive and the Controller are in the form of raw serial data c...

Page 15: ... bend or fold the diskettes Be careful when inserting them into the drive 4 Store diskettes at room temperatures in a covered container away from contamination such as smoke or spilled liquids 5 REMOVE DISKETTES BEFORE POWERING ON OR OFF THE DRIVE Random spikes during power on or off can cause noise to be written on the diskette and render it unusable Floppy diskettes have an operating life of abo...

Page 16: ...CORVUS DEALER SERVICE CHAPTER 2 FUNCTIONAL DESCRIPTION ...

Page 17: ...pace between the tracks Data recovery electronics include a low level head amplifier a differentiator a zero crossing detector and digitizing circuits In addition the drive has the following sensors 1 A track 00 sensor that senses when the Head Carriage Assembly is positioned at Track 00 2 The two index sensors each of which consists of an LED light source and a phototransistor 3 The Write Protect...

Page 18: ...e head positioning system uses a bipolar driven motor drive which changes one phase for each track advancement of the read write carriage In addition to the logic necessary for motor control a gate is provided that inhibits positioner motion during a write operation 2 2 5 Write Erase Control Information is recorded on the diskette by using a double frequency code Figure 2 2 illustrates the magneti...

Page 19: ...conds after the drive motor is started 2 Subsequent to any read write operation the positioner must be allowed to settle This requires 18 milliseconds maximum after the last step pulse is initiated i e 3 milliseconds for the step motion and 15 milliseconds for settling 3 The foregoing operations can be overlapped if required Figure 2 3 illustrates the timing diagram for a write operation At t O wh...

Page 20: ... duration of a write operation is from the true going edge of write gate to the false going edge of erase This is indicated by the internal write busy waveform shown figure 2 3 2 2 6 Read Amplifier and Digitizer The Read electronics consist of Read Switch Read Preamplifier Filter Differentiator Time Domain Filter and Digitizer The read switch is used to isolate the read amplifier from the voltage ...

Page 21: ...s The Standard Microsystems FDC1793 chip is the heart of the Controller Board All drive output lines are TTL compatible open collector which are terminated in the Controller Card The Input Lines on the Controller are DISK CHANGE Provides a low true signal if the drive goes Not Ready while deselected Reselecting the drive while Ready will provide a high false signal TWO SIDED Is used to determine t...

Page 22: ...EI Drive select lines SIDE 0 Selects side of diskette for Read Write STEP Move head in direction specified by DIRECTION IN DIRECTION IN Specifies the direction of step High true WRITE GATE Enables write current in the read write head WRITE DATA Enabled by write gate Provides data to be written on the diskette Disabled by WRITE PROTECT 8 ...

Page 23: ...CORVUS DEALER SERVICE CHAPTER 3 DISASSEMBLY AND ASSEMBLY PROCEDURES ...

Page 24: ...ve assembly Lift the rear section of the right cover and remove it 3 With drive mechanism exposed remove the four phillips screws which mount the drive assembly to the left cover You will have to disconnect the green ground wire and the violet and red AC wires leading from the power switch Note the proper position of these wires on the power supply for reassembly 4 Next disconnect the internal fla...

Page 25: ...racket To reassembly the power supplies onto the Diskette Drive unit reverse the removal procedures Assembly information can be found in the assembly drawings in Appendix D 3 3 Power Harness Removal There are two wire harnesses connected to the power supplies 1 A two wire harness provides AC power to the supplies and is easily removed by pulling the fast on from the rear of the power switch The ot...

Page 26: ... held in place by spring loaded retainers on the inside of the cover These must be depressed on the top and bottom of the switch to allow the unit to be pulled through and out of the cover 3 To remove the Fuse Holder pull the fast ons from the Power Filter and the power switch Remove the plastic retainer nut on the inside of the cover The Fuse Holder can be pulled through and out of the hole 4 The...

Page 27: ...CORVUS DEALER SERVICE CHAPTER 4 CHECKS AND ADJUSTMENTS ...

Page 28: ...of Allen wrenches 6 A blank diskette 7 Alignment diskette Dysan PIN 240 2A or equivalent 8 I C dip clip for 14 pin 9 Digital Voltmeter 4 2 Drive Adjustments The checks and adjustments in this section should be done with a known good Concept Interface Controller and Cable 4 2 1 Spindle Drive Motor The motor speed specification is 360 RPM 4 5 RPM 1 Verify the power supply voltages of 24 VDC 2 4V 5 V...

Page 29: ...ard Assembly Test Points 4 2 2 Cats Eye Alignment The Cats Eye CE alignment procedure positions the Read Write Head at the proper radial distance from the hub center line ensuring the accuracy of the track alignment see figure 4 2 This procedure is necessary only after other servicing or if diskette interchange problems are suspected f I L J41 HUB CE NTER LINE TRACK 76 Figure 4 2 Hub Center Line a...

Page 30: ...bserve the pattern see figure 4 3 M J i I I a Vt t fo lJ V EQUAL AMPLITUDE LOBES SHOWN AT 100 PERCENT ON TRACT 38 TIME SCALE 20MS Figure 4 3 Cats Eye Pattern 6 Verify that the smaller of the two Cats Eye patterns is not less than 75 percent of amplitude of the other one 7 Using FDIAG step to track 00 then step it back to 38 8 Reverify the Cats Eye pattern 9 Using FDIAG step to track 76 then step i...

Page 31: ...rify the alignment section 4 2 2 4 2 4 Index Sensor Checks and Adjustments The index adjustment changes the time period from the index pulse to the start of the data The adjustment should be checked after the drive has been aligned section 4 2 2 or when diskette interchange errors are suspected 4 2 4 1 Index to Data Burst Check Before this adjustment is performed the spindle speed must be within t...

Page 32: ...ut of specification then perform the adjustment in the next section 4 2 4 2 6 When the index measurements meet the specification then check the index to data burst on track 76 7 If any index measurement does not meet the specification then the index sensor must be adjusted 4 2 4 2 Index Sensor Adjustment 1 Loosen the index sensor s retaining screw located on the underside of the chassis see figure...

Page 33: ... retaining screw 4 Reverify the index to data burst section 4 2 4 1 4 2 4 3 Index Pulse Width Check The index pulse width is non adjustable If the index pulse width is not within specifications replace the drive mechanism 1 Set the oscilloscope Channel A R33 Ground Test Point 1 Time Base 0 5 milliseconds Vertical 2 volts per div Trigger Negative leading edge at R33 2 Power on the drive load blank ...

Page 34: ...FDIAG step the carriage to track 38 4 Confirm the position by observing the Cats Eye see section 4 2 2 5 Attach channel A to test point 10 6 Using FDIAG TrackO restore to track 00 Ensure that track 00 is detected 7 Seek to track I and ensure that the signal at test point 10 is high 8 Seek to track 2 and ensure that this line is low 9 Seek to track 3 and ensure that this line is low 10 If the signa...

Page 35: ...skette 6 If the amplitude is less than the specification inspect the heads to ensure they are not contaminated Use a cleaning diskette if necessary 7 If the amplitude is not within specifications the drive mechanism must be replaced 4 2 7 Azimuth Check Azimuth is the angle of the heads with respect to the track at the point of the read write gap Azimuth is measured in minutes one minute 1 60 degre...

Page 36: ... the lower limit of allowable error Bursts 1 and 2 are of equal amplitude If this signal is observed the Cats Eye alignment should be checked 3 2 4 figure 4 10 Head Azimuth Acceptable Lower Limit 6 Figure 4 11 depicts an alignment of exactly plus 9 12 or 18 minutes depending upon the manufacturer of the diskette Burts 3 and 4 are of equal amplitude This is the upper limit of allowable error If thi...

Page 37: ...iskette lever to load the disk and seek to track 00 There should be a space of 1 16 inch between the head load arm and the load plate 3 Seek to track 76 and ensure that a space of 1 16 inch remains between the head load arm and the plate 4 Adjust the Allen screw located behind the head load cam until there is a space of 1 16 inch see figure 4 12 ADJUSTMENT SCREW PLATEN l r Figure 4 12 Load Arm Adj...

Page 38: ...gure 4 13 4 3 2 Range Adjustment The range adjustment is accomplished by connecting the input lead of a frequency counter or oscilloscope to test point 2 and negative lead or ground lead to ground Ul 7 Apply power to the card and adjust R4 labeled RA until a frequency of 4 00 MHZ is obtained see figure 4 13 for locations 4 3 3 Precomp Adjustment The precompensation circuitry is used for double den...

Page 39: ... Power Supply Adjustments The two power supplies mounted on the drive chasis provide S volts DC and 24 volts DC Each voltage must be adjusted to within 0 1 volts with a digital voltmeter see figure 4 14 ADJUST Figure 4 14 Power Supply Adjustments 23 ...

Page 40: ...CORVUS DEALER SERVICE CHAPTER 5 TROUBLESHOOTING ...

Page 41: ... have it copied to a volume to which he does have access 5 1 1 Operation To run the diagnostic program FDIAG it must be loaded from the hard disk This can be done by setting the volume to CCUTIL From the dispatch level type in CCUTIL and press the softkey F4 SetVol Now that the volume is set you may run the diagnostic program by typing FDIAG and pressing RETURN The screen will display the followin...

Page 42: ...nd performs a check of these peripherals during power up A Systems Test 6 failure indicates one or more devices connected to the I O slots is not ready for communication with the Concept If the Floppy drive is suspected to be at fault a modular replacement of subsections will be necessary in order to pinpoint the defective device CAUTION Always power off the Concept and Floppy Drive before removin...

Page 43: ...with a known good one and check the operation by running DiskChk in the FDIAG program If all checks out well the Floppy Drive is defective Go to Floppy Drive Troubleshooting in section 5 3 5 2 3 Concept Workstation If the problem still persists the Concept Workstation should be examined Refer to the Concept Service Manual for troubleshooting procedures 5 3 Floppy Drive Troubleshooting After isolat...

Page 44: ...should be taken 1 Perform the checks and adjustments chapter 4 Spindle Drive Motor Speed Adjustment Cats Eye Alignment Head Carriage Adjustment Index Adjustments Track Zero Sensor Alignment Amplitude Check Azimith Check Load Arm Adjustment 2 If the adjustments are made and the problem still exists check the Interface Controller see section 5 4 3 If the steps above did not remedy the problem the dr...

Page 45: ...sconnected Spindle Motor speed bad Index out of adjustment Adjust 4 2 5 Incorrect installation Diskette Write protected Interface Card not functioning properly Bad diskette Bad Interface cable Defective Drive Defective Power Supply Track 00 Sensor out of adjustment Load Arm defective 28 REMEDY Insert diskette Check loading procedure 1 2 Verify unit select and jumper configurations Verify signal MO...

Page 46: ... Index incorrect Spindle Motor speed out of tolerance Track 00 misadjusted Power Supply voltage Head Azimuth misaligned Load Arm defective 29 REMEDY Replace with known good diskette Adjust 4 3 Replace with known good card Align Heads 4 2 2 Replace diskette Replace mechanism Replace cable Adjust 4 2 4 Adjust 4 2 1 Adjust 4 2 5 Adjust 4 4 Check 4 2 7 Replace mechanism Adjust 4 2 8 Replace mechanism ...

Page 47: ...CORVUS DEALER SERVICE APPENDIX A GLOSSARY OF TERMS AND ABBREVIATIONS ...

Page 48: ...e data SECTOR A segment of a track which contains 128 256 or 512 bytes of data The number of sectors per track and the size is determined by the number of index holes Hard sectoring or by the computer s Operating System SOFT SECTOR A sector which has it s size determined by the host computer s Operating System TRACK The concentric ring of serial bits written on the diskette Typically there are 77 ...

Page 49: ...CORVUS DEALER SERVICE APPENDIXB FLOPPY DISK DRIVE PART NUMBERS ...

Page 50: ...mbers Description Drive Mechanism Power Supply DC Harness Internal Flat Cable External Flat Cable Controller PCA AC Power Cord Right Cover Left Cover Assembly 31 Part Number 2200 02948 8010 08735 8010 08391 8010 08392 8010 08389 8010 08357 6010 01447 2400 02425 8010 08731 ...

Page 51: ...CORVUS DEALER SERVICE APPENDIXC SCHEMATIC DIAGRAMS ...

Page 52: ...K Rll VpO 7 0 5 5V 150 R l 7 sv 150 R4 VOP 4 y l 2 21 RPS I SIDE OS __ l DIR 4 S2 51 r i V INDE I I Rf 9 LED T I 7 L t7 7 I I I I 1 i P II lDE f 2 R 5V LED T 10 t 9 1 I I 1 I I a l 5V I I I INDEX I I 5 i R 1 l Vpo 10 9 2 2 1 I RP Z I cf 5V II RP5 L_ l Q t L DII I f L 02 DIi SE L r l DOR 150 J __ J r 4 U I I I __ __ 1 I A03 2 U5 1 1 I l t 4 I p J z D lV 5V 14 12 I 100 TlVITY I 14 u I 04 I I LE O F ...

Page 53: ... WRITE ELE CTRO i C5 6 ERASE ELECTRONICS 5V Jrae 1 2K I RIDE RS 5 Tf 2 21 J P R C R 40 9K R 1 54 K I Yo R5 7 1 12V 12V oCa CRIc R47 91G IZV R II I I 5 L 5V D a WR ITE 7 lI 24G O 4T 1CR 7 5 5 7 IS Z 1 0 5V t IURT DATA 1U77jl 2 _ J WR CU REN T 2 __ Ifl SUJIICH 8 I I I I I I I I I I I I I I I I I I L _ T I I I B c D I Rts TOR TE D l R SrOR P C K RP A NOTES UNLESS OTHERWISE SPECIFIED 8 7 6 5 4 I I NEX...

Page 54: ...II 2 2 QF 2 1C CLR II IZV 470 R C Z20 J 470 R 29 RI loa 4 12 V I 0 00 1 1 C O I I I I I n I CT I I I I I I TPI READ LEC TROA IC s lK l IZ V R2 0 1 C2 7 Z v lEAD SELECTION R Z C 15K 1 lZV CRI4 CRI tl2V R57 R 59 3 63 l fl Z K J YD R Ol 390 12V 12Y R5el 3 831 1 R DI RDZ I WR TE I I 1 I I I INI WRT I BUSY I I I I IOE I I L _ B c APPUCATlON 3 AI I NOTES UNLESS OTHERWISE SPECIFIED 8 7 6 5 4 NEXT ASSY FI...

Page 55: ...I 44 109 I NO cz 4 r IM4735 f CRI 7 4 7 uf 4 0 5 0 P R A Io oV TYP I PL CCoS 7CD I0 wI TYPZPL WRITE DRS L 5 DIR 6 r I I I I I I I I I I I I I I I I I I I L I I I 4 UJRITE I PROTE CT I DIe POWERJ _ _ w S O iT_ ICONNECTOR P7 r i r l I I 1 1 1 _5__ I I I I I I I Z I D I TR CK 25 I I I I LOR TE PROTECT D I I r SE oOR I I I I E LSC TRON C5 I L 1 C I I I R J L J F PC POWER ONLY CQ VNEcrOR PADS TP7 7 t5V...

Page 56: ...0 2 12 V2 RIl7 4 7K R12 El 20K 33 Jf C DO B 1 4 2 r __ RIZ5 47K SPINDLE ADJU TL t3 co ULlI MS1970t C5 SPEED COIVTROL 0 022 f SIP PACI I V 7 5 c R Co C S2 0 1p IK 0 022 1 20K I Z r 12VZ T O 1 MT CCoI 7 U 5 POR 5V IR O iK S55 3 7 2 U2fl RCoe SCOOK G 5V 5V R72 10K C45 12 VI SU 4 MSEL f O I u C5G 2 15K 0 0 ____ _ _1 O _ SV 1 73 II OPEN V 2 o lif OO l CIIZ o I J RIDO II 5V M 740 0 M I DR E L 12 114 f 5...

Page 57: ...CORVUS DEALER SERVICE APPENDIXD ASSEMBLY DRAWINGS ...

Page 58: ... J U6 Y2 t W O T F l L r t l W I IE LS 3 p 7 R O F G ___ I__ ___ AB2 J 1 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 13 I 11 IIIr r _ _ _ _ _ _ _ _ lV Rib 17 Di 8 7_ 3 LZ tA rM FM 4 L H I K IO i 3 I IT 25 P GG 1 t t D b 6_ 11 t v H 41 3 P DRQ IQ _DB 5 1 r M _O _ TO P O N t J CS l l84 13 3UI 3 12 DE I D7 11 I H f I _ _ _ j 7 DE 0 UC 15 Dfll 7 I D 1 DFr D 1 04 ri 1 5 I ...

Page 59: ... an 2 MECHANICAL ASSY I a I t t 3 15 e 7 0 0 D 0 0 d O 0 u 0 f0 ZI JlSlcl 11 11 _ _ Mill or sa J ITtlll flllT sIt 0 0 0 0 0 c 0 000 et l tf 0 D D 0 000 Z ZI B 0 0 A ...

Page 60: ...I 7 2PL 6 I 4PL 2 FARSlOE ...

Page 61: ...STEMS aJ29 0 CA r Il J SCAU NOfJE T his cont In end ciet LCJOfttN c ord1l1on that n II be u 10 IN at CORVUS SYSTEMS UNl SS OTMERWlSE SPECIFIED DIMENSIONS ARE IN INCHES TOt ERAHCES ON APPUCAnON 8010 06 33 AHGlBl DECIMALS L n r XX ct H BUI 0 25 82 LEFT COVER ASSY 8 LOPPY J J xxx _ f Q1EO Bl8T A LFPOHMAN NOTE5 uNLE SS OT rRY i5 5I EC It IED ...

Page 62: ...EMS c Af JO 9 LM I I BC jD I ANGLES DECIMALS UNLESS OTHERWISE SPECIFIED DIMENSIONS ARE IN INCHES TOLERANCES ON CORVUS SYSTEMS 2029 O oo6e San Jose CA 95131 tJOTES UtJLESS OTHERVlISE SPECIFIED xx This oocument contaons proprietary onformatlon and III delivered upon the expressed conollion that It WI not be used directly or indirectly on any way detremenlal to tile Interest of CORVLJS SYSTEMS DRAVvN...

Page 63: ......

Page 64: ...n that II will not be used directly or Inc lreclly in any way detrernental to the Interest of CORVUS SYSTEMS DRAWN BY UNLESS OTHERWISE SPECIFIED DIMENSIONS ARE IN INCHES TOLERANCES ON t XX to ANGLES DECIMALS DATE OF DRAWING t H B UI 3 5 8 2 1 8 1 FLOPPY CONTROLLER ASSY 1 M AT E RIA L XX x III CH E Y _ L_EFR_GI_NO_EH_M_A_N t 8Do5 tJa7 rf f3t c5 8731 APPROVE r N EXT AS Sy r US E D O N 1 FIN ISS HH J...

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