HP 7942 Service Manual Download

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Summary of Contents for 7942

Page 1: ...HEWLETT PACKARD HP 7942 AND HP 7946 DISC TAPE DRIVES SERVICE MANUAL ...

Page 2: ...pecifications Actual inspection and test data per taining to this order is on file and available for examination Hewlett Packard s calibration measurements are traceable to the National Bureau of Standards to the extent allowed by the Bureau s calibration facilities The Hewlett Packard Quality Program satisfies the require ments of FAR 52 246 15 ...

Page 3: ...d to comply with the limits for a Class B computing disc tape drive in accordance with the specifications in Subpart J of Part 15 of FCC Rules which are designed to provide reasonable protection against such interference ill a residential installation However there is no guarantee that interference will not occur in a par ticular install ltion If this equipment does cause interference to radio or ...

Page 4: ...bject to change without notice HEWLETT PACKARD MAKES NO WARRANTY OF ANY KIND WITH REGARD TO THIS MATERIAL INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE Hewlett Packard shall not be liable for errors contained herein or for incidental or consequential damages in connection with the furnish ing performance or use of this material This doc...

Page 5: ...ruction Set commands applicable to the disc tape drive Section III Describes the operating principles of the disc tape drive Section IV Contains servicing information for the disc tape drive Section V Supplies step by step removal and replacement procedures for field replaceable assemblies and parts in the disc tape drive Section VI Lists and illustrates the field replaceable assemblies and parts ...

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Page 7: ...alll l Poll Universal Device Clear Message Structure Section III THEORY OF OPERATION Introduction Disc Drive Introduction Disc Format HOC peA AS HOC Internal Bus Architecture HP IB Data Bus RAM Data Bus Microprocessor Address Bus Microprocessor Data Bus DMA Gate Array Data Bus Read Write Data Bus Data Control Interface Bus Control Status Data Bus Control Status Read Strobe Control Status Write Str...

Page 8: ...OC Disc Drive A1 Communication Controller IC and Register Decode Logic HDA Desc r ipt ion PROM Self Test Register GPC Register DOC Err0 r s Regi s t e r PUPO Register Disc Controller IC Phase Loc ked Loop IC Latch DMA Handshake Cont rol Clock Generator Write Precompensation Disc Drive A1 Disc Drive A1 DDC Control Communication Input Buffers Output Drivers Disc Drive A1 DDC Data Communication Micro...

Page 9: ...eek Operation Restore to Track 0 Operation Read Wri t e Data Channel Head SelE ct and Control Logic Read Chain Ampli f ier Signal Condi tioner Differential Line Driver Wri te Chain Line Receiver Transition Generator Write Current Source Write Fault Detector Sel f test Power Supph A4 AC Input Circuits Swi tch Mc de Supply Power On Reset Section IV SERVICE INI4 ORMATION Introduction Service Tools FR...

Page 10: ... Clear CICLEAR Clear Logs CLEAR LOGS Describe Selected Unit DESCRIBE Perform Internal Diagnostics DIAG Output Error Rate Test Log ERT LOG Exit Program EXIT Output Fault Log FAULT LOG Output Help Information HELP Initialize Media INIT MEDIA Update Device Logs PRESET Request Status REQSTAT Perform Read Only Error Rate Test RO ERT Output Run Log RUN LOG Spare Sector SPARE Output Spare Table SPARE TAB...

Page 11: ...LED Cable Removal Section VI REPLACEABLE PARTS Page Introduction 6 1 Ordering Information 6 1 Appendix A REMOVAL AND REPLACEMENT Introduction Preparation For Service Removal And Replacement Top Shroud EPROM Ki ts FRA5 HDC PCA A5 Front Panel U1 FRAl Tape Drive Assembly A1 Fan UO FRA4 Power Supply Assembly A4 UO FRAl Disc Drive Assembly A1 UO FRA2 Disc Drive DOC PCA A2 U1 FRA2 Tape Dr i ve DOC PCA A...

Page 12: ...tion Cable Assembly Wl 1 of 3 2 of 3 3 of 3 UO FRA4 Power Supply Assembly A4 Layout and Cable Connections UO FRA4 Power Supply Assembly A4 Test Points and Voltages FRA5 HOC PCA A5 Layout and Cable Connections FRAl Disc Drive Al Layout and Cable Connections FRA2 DOC PCA A2 Layout and Cable Connections Disc Tape Cabling Diagram Disc Signal Distribution Order of Disassembly HP 7942 HP 7946 Cable Inte...

Page 13: ...Self Test Subtest List Disc Drive Unit 0 Self Test Subtest List Disc Drive Error Condition List Fault Code List Diagnostic Summary Disc Tape Drive Replaceable Parts Abb rev iat ion s Code list o f Manufacturers Disc Tape Drive Replaceable Parts Abbreviations Code list o f Manufacturers TABLES Page 1 3 1 4 2 2 2 9 2 12 2 12 2 14 3 23 4 14 4 15 4 20 4 24 4 27 6 2 6 4 6 5 6 6 A6 2 A6 4 A6 5 A6 6 xi ...

Page 14: ... set Whenever it is likely that the protection has been impaired the product must be made inoperative and be secured against any unintended operation xii BEFORE APPLYING POWER Verify that the product is configured to match the available main power source according to the input power con figuration instructions provided in this manual If this product is to be operated with an autotrans former make ...

Page 15: ...paring The tape drive is compatible with existing 1 4 inch cartridge tape drives contained in other HP disc tape drives Also included in the drive are a Hewlett Packard Interface Bus HP IB controller and a power supply The drive contains internal self test diagnostics and a fault finding system which exercise key functions of the drive Self test is performed au tomatically at power on and can also...

Page 16: ...l servicing information refer to the CS 80 External Exerciser Reference Manual part no 5955 3462 The HP 7942 and HP 7946 Disc Tape Drive CE Handbook is part no 07942 90905 1 2 1 4 OPTIONS The following options are available for the drive Option 015 For non U S shipments Voltage selector switch set at factory for 230 Vac operation Option 550 Deletion of the HP 1083 3A HP IB Interface Cable Assembly...

Page 17: ... VOLTAGE SELECTOR switch Voltage true RMS 115V range 100V 115V 120V single phase inclusive tolerance range is 90V to 132V Frequency 230V range 220V 240v single phase inclusive tolerance range is 1Bov to 264V 47 5 to 66 Hz Typical Current true RMS 115V range 1 50A 230V range O BOA Typical Power SIZE WEIGHT Height Width Depth Net Weight Shipping Weight 115V range 120W 230V range 120W 20B nun B 19 in...

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Page 19: ... 1 illustrates the transaction structure and shows the relationship between the disc drive operating states and the channel activity relative to each phase A unit is a separately addressable entity within a device disc drive A volume is a separately ad dressable portion of the storage media within a given unit 2 4 REAL TIME COMMANDS Real time commands are optimized for execution time These command...

Page 20: ...dress No variables or parameters LOCATE AND VERIFY GENERAL PURPOSE FUNCTION OPCODE FORMAT Instructs the device to perform an internal verification of a section of data to ensure that it can be read No variables or parameters SPARE BLOCK GENERAL PURPOSE FUNCTION OPCODE FORMAT 2 2 Gives the device permission to become temporarily busy while sparing the block indicated by the target address 00000110 ...

Page 21: ...mitive state No variables or parameters REQUEST STATUS DIAGNOSTIC FUNCTION OPCOIDE FORMj T Instructs the device to return in an execution message the status report No variables or parameters RELEASE GENERAL PURPOSE FUNCTION Releases the device OPCOIDE FORMAT No variables or parameters RELEASE DENIED GENERAL PURPOSE FUNCTION Prohibits the device from releasing itself OPCODE FORM AT No variables or ...

Page 22: ...r Single vector format 6 byte binary number 3 vector format P1 P3 cylinder address P4 head address P5 P6 sector address SET BLOCK DISPLACEMENT COMPLEMENTARY FUNCTION OPCODE FORMAT Adjusts the target address by the number of blocks indicated by the parameter field 00010010 P1 P6 Parameter format 6 byte signed two s complement binary number SET LENGTH COMPLEMENTARY FUNCTION Defines the number of byt...

Page 23: ... 16 5010 001100102 0628 3216 001000XX Pl n parameter xx execution message qualifier 00 no execution message bytes 01 device will receive execution message 10 device will send execution message Pl utility number device specific There can be up to 8 bytes in the parameter field The number and content of these bytes is determined by Pl INITIAl E DIAGNOSTIC DIAGNOSTIC FUNCTION OPCODE FORM AT Directs t...

Page 24: ...OOOCWZ Pl P2 P1 initialize options byte Options for disc media CWZ 000 Retain both factory primary and field secondary spares CWZ 001 Retain factory spares only CWZ 010 Retain no spares f 0 r CE use only P2 Block interleave byte SET RPS COMPLEMENTARY FUNCTION OPCODE FORMAT 2 6 Sets time to target and window size time intervals for RPS data transfers The command is accepted but the RPS function is ...

Page 25: ...ef ines how a dev ice wi 11 respond to an in te rnal release request 00111011 T2000000 T Suppress release timeout 2 Release automatically during idle time SET BlJRST COMPLEMENTARY FUNCTION OPCODE FORMAT Activates and deactivates burst mode 6010 001111002 0748 3C16 61 10 00111101 2 0758 3D16 0011110T P1 T 0 Only the last burst is tagged with the message terminator EOI on HP IB T All bursts are tagg...

Page 26: ...ons in the status message Refer to paragraph 2 45 in the CS 80 Programming Manual 1 masked error SET VOLUME COMPLEMENTARY FUNCTION Selects a specific volume on the currently selected unit OPCODE 6410 010000002 FORMAT 01000YYY YYY volume number SET RETURN ADDRESSING MODE COMPLEMENTARY FUNCTION OPCODE FORMAT 2 8 Specifies the address format single or 3 vector returned in the parameter field of the s...

Page 27: ... and initial ize media 2 7 DIAGNOSTIC COMMANDS Diagnostic commands are intended to assist the host in isolating problems in the device to the replaceable assembly level Some commands allow protected access to variables or data maintained by the device such as error information while others cause tests to be performed within the device or on a specific area of the storage media Diagnostic commands ...

Page 28: ...rifies command If command is valid Logical Machine moves to execution state If not Logical Machine moves to reporting state 4 Unit begins execution of command 5 6 If command involves data transfer Logical Machine requests an execution message If not unit completes execution 6 7 Execution message is established if command involves a data transfer 8 Unit completes execution of command If command inv...

Page 29: ...her five lines are for bus management Information is transmitted on the data lines under sequential control of the three handshake lines DAV L NRFD L and NDAC L No step in the sequence can be initiated until the previous step has been completed Information transfer can proceed as fast as devices can respond but no faster than allowed by the slowest device presently ad dressed This permits several ...

Page 30: ...the HP IB commands messages and transac tions that occur between the Controller In Charge CIC and the disc drive The following list explains the terms used in this section talk and the address of a particular device The primary II command terminates the message with an unlisten or untalk command COMMAND A parcel of information transmit ted over the channel HP IB relating to a specific operation Ch...

Page 31: ...evice requiring service If more than one device requires service the CIC addresses the device with the highest priority lowest address first Parallel Poll Enable PPE and Parallel Poll Channel Interface 7942 and 7946 Disable PPD are internal states of the disc drive controller PPE occurs when the disc drive requires service from the CIC PPD is the opposite state and occurs whenever the disc drive i...

Page 32: ...ce CIC to device Begins message Addresses device to LISTEN or TALK Universal 2 14 Set up device for further action TEXT TRAILER DEVICE COMMAND OR DATA PRIMARY II ATN Bidirectional ONE BYTE Qualifying instructions Unidirectional to device CIC to device Write data to device Terminates Read data to CIC message Status data to CIC Unaddresses device Unlisten Untalk ...

Page 33: ... drive mechanisms are mounted above The HOC PCA is located above the two drive mechanisms The PCA s power supply and drive mechanisms are in terconnected by a number of cable assemblies Circuits in the HOC PCA include an HP IB inter face integrated circuit IC a microprocessor firmware in ROM RAM a custom designed DMA gate array IC and self test controls and display The DOC PCA s contain drive rela...

Page 34: ...ith the DDC is a disc drive assembly which contains a sealed head disc module and electronic control and read write circuits These circuits operate in conjunction with the circuitry in the DDC to interpret and generate control sig nals position and maintain the read write heads over the desired track maintain precise disc rota tional speed and perform read and write opera tions The HDC is capable ...

Page 35: ...M and sent to the host computer When the data transfer is complete the nnc gives ending unit status to Theory of Operation 7942 and 7946 the exec code The ending status is sent to the host computer A locate and write operation is similar to the lo cate and read operation previously described except for the direction in which the user data flows The set up and head positioning operations are the sa...

Page 36: ...e 3 1 The self test maintenance tracks are located 3 4 at the inner diameter ID and outer diameter OD of the disc to permit read write testing at these locations Also duplicating the service information at two locations reduces the possibility of loss of data due to recording medium failure The 968 data tracks are used for reading and writing data This provides the user with 968 addressable cylind...

Page 37: ...ENANCE TRACK CONTENTS SECTOR OUTER INNE ADDRESS DIANETER 00 OI AMETER 10 0 PRODUCT NO SERIAL NO 1 5 RUN TIME LOG RUN TINE LOG 6 10 ERRO RffE ERRO TE TEST ERT LOG TEST ERT LOG 11 15 FAULT LOG F ULT LOG 16 18 SPARE TABLE SPARE T 6BLE 19 20 SELF TEST SELF TEST LOC TION LOCATlON 21 22 SELF TEST SELF TEST LOC TION LOCATlON 23 31 NOT USED NOT USED FILE FSJEFl2A Figure 3 1 Disc Recording Format 3 5 ...

Page 38: ...erface IC a mic roprocessor firmware in EPROM RAM a custom designed DMA gate array IC and self test switches and display 3 6 The firmware in the HDC consists of three seg ments One segment is the executive operating sys tem EXEC EPROM which controls resource al location including the DMA gate array IC and RAM and the passing of messages and informa tion between the DDC firmware and the host in ter...

Page 39: ... 7946 3 9 MICROPROCESSOR DATA BUS The Mic roprocessor Data Bus interconnects the micro processor the EXEC EPROM the DOC 0 EPROM and the DOC 1 EPROM The microprocessor RAM exists on a separate bus so that the RAM can be shared by the microprocessor and the DMA gate array IC The bidirectional data on the Micro processor Data Bus includes preprogrammed con trol sequences algorithms in EPROM and con t...

Page 40: ...rated DMA strobe lines which accompany the transferring of data be tween the HOC and the DOC 3 8 3 21 HP IB INTERFACE IC The HP IB interface integrated circuit is a talker listener device This IC provides the inter face between the host data channel HP IB and the mass storage device The IC is accessed by the microprocessor and by the DMA gate array IC in put and output processes The microprocessor...

Page 41: ... RAM is a temporary storage location for all data transfers The use of RAM is time multiplexed so that for one half of a microprocessor clock cycle the microprocessor has access to RAM and for the other half the DMA gate array IC has access to RAM 3 29 EXEC EPROM Theory of Operation 7942 and 7946 The executive EXEC EPROM contains the firmware which controls operation of the HDC microprocessor and ...

Page 42: ...he host computer s request for disc information 3 37 DOC PCA A2 Device dependent controller DOC PCA A2 per forms the following functions in the peripheral mass storage control structure used in the disc drive Accepts high level disc drive control com mands issued by the host dependent controller 3 10 HOC over the OC IB bus and provides high level status commands to the HOC Executes these high leve...

Page 43: ...L lines are used to handshake data into the HDC from the DDC In both the write and read operations described above the Data Request lines signal the readiness of the DDC to transfer a byte Data Strobe lines are activated by the HDC to clock data in or out Theory of Operation 7942 and 7946 3 41 RECEIVER DRIVER Two different types of receivers and drivers are employed in the DDC The receiver and dri...

Page 44: ... the control signals to manage the ST 506 Interface To perform disc storage func tions command information is written into regist ers in the disc controller via the Control Status Interface Bus DC IB At the end of the com mand the disc controller carries out the command by manipulating the ST 506 Interface and the DMA control lines as needed Operation of the disc drive begins when the HDC initiate...

Page 45: ... contained in the raw MFM encoded read data sig nal This signal received from the read chain in disc drive assembly A I is labeled RMFM RMFM The PLL IC passes synchronized data and a read clock to the disc controller IC where the actual data separation and byte packing takes place Theory of Operation 7942 and 7946 3 52 LATCH The latch is an octal D type flip flop that latches in head and disc driv...

Page 46: ...e errors are reported by read preamplifier write driver IC s in the read write 3 14 data channel Contamination protection for the heads actuator and recording medium is achieved by enclosing these components in a sealed head disc module having a built in air filter The following paragraphs provide a more detailed description of the disc drive assembly A 1 com ponents and electronic circuits as sho...

Page 47: ...Ready Fault Track 0 Off Track On Peak Direction In Write Gate and 9 216 MHz clock Internal inputs to the PLA include Power On Reset Fault Write Gate Drive Select Stop Seek Complete and At Speed 3 63 CLOCK GENERATOR The clock generator consists of a crystal oscillator and a number of count down registers The clock generator has five outputs 9 216 MHz for the microprocessor 1152 kHz and 576 kHz for ...

Page 48: ...used by a write current polarity change generates a readback volt age pulse There are read preamplifier write driver IC s mounted on the rotary arm of the actuator ad 3 16 jacent to the heads Each IC provides write current head selection and read signal amplification for four read write heads The IC s are connected to the read write data channel electronics external to the sealed head disc module ...

Page 49: ...e speed control circuit such that the speed of the motor is maintained at 3 600 rpm 3 6 rpm Theory of Operation 7942 and 7946 At power on after the Power On Reset signal is turned off the microprocessor sets the Stop Motor signal false causing the spindle motor dynamic brake to activate At the same time the micro processor disables the spindle speed control circuit by deactivating the Normal Regul...

Page 50: ...low pass filters in the mixer channels The two outputs from the mixer channels are rectified averaged and fed to the in 3 18 put of a difference amplifier The output of this amplifier is Position Error Signal PES When the servo head is positioned exactly between two servo tracks read write head on track PES is zero Dis placement from this position read write head off track causes PES to go either ...

Page 51: ...nal and provides an Off Track output to the micro processor whenever the PES voltage exceeds plus or minus 1 5 volts 3 90 SEEK OPERATION The disc drive must have Ready RDY L and Seek Complete SKCMP L true before a seek operation can begin With the disc drive in this state the microprocessor is in its basic loop monitoring Motor Speed Off Track and looking for either a Step STEP L pulse or Write Ga...

Page 52: ...ic level pulses one for every signal peak These MFM encoded pulses are sent to the DDC for decoding The read chain circuitry includes an 3 20 amplifier signal conditioner stage and a differen tial line driver 3 95 Amplifier Signal Conditioner In the amplifier section of the block the differential DX DY input is amplified filtered and subjected to au tomatic gain control AGC A diode matrix at the i...

Page 53: ...he following paragraphs Theory of Operation 7942 and 7946 Power supply assembly A4 develops dc operating voltages from the ac line voltage and distributes these voltages throughout the drive The power supply assembly also generates a power on reset signal Power supply assembly A4 is a self contained switch mode power supply mounted on a printed circuit assembly Located in the assembly are all of t...

Page 54: ...o thermistors that limit the initial power on surge current to approximately 25 amperes peak at 115 Vac and 230 Vac 3 22 3 106 POWER ON RESET The power on reset circuit is activated by the switch mode supply and produces Power Valid sig nal PVAL H At power on PVAL H remains low for at least 100 milliseconds after the 5V output reaches 4 7 5V or higher Signal PVAL H then goes to a high level Signal...

Page 55: ... the read preamplifier write driver IC in the head disc module of disc drive assembly AI DC IB signals used to access the registers in a selected DOC which comprise the Control Status Data Bus CSBO H through CSB7 H Output to DOC PCA A2111 via cable W2 DC IB bidirectional 8 bit bus used to pass control and status data between the HOC and a selected DOC Out put to DOC PCA A2 III via cable W2 DC IB s...

Page 56: ...ectional data input out put I O bus used for the transfer of data commands and other messages between the host computer and the HDC Transfer is bit parallel byte serial ST S06 Interface control signal DIR L defines the direction of mo tion of the read write heads when Step signal STEP L is pulsed An in active high DIR L defines an out direction and when STEP L is pulsed the read write heads move a...

Page 57: ...gh DATA7 H Differential signal lines to from read preamplifier write driver IC s HP IB control signal used to indicate the end of multiple byte transfers or used with signal ATN L to perform a parallel polling sequence Drive for green LED in front panel FAULT ON LINE indicator Output to the front panel via cable W4 ST 506 Interface control signals These lines provide a means of select ing each ind...

Page 58: ... amount and direction of head off track displacement Indicates that power supply A4 out puts are up to their proper values Output to DOC PCA A2 III via cable Wl ST 506 Interface control signal ROY L becomes active low follow ing power on if a dc voltages are within specification b discs are at speed and c head position is recalibrated Output to DOC PCA A2 IIIvia cable W2 If there is a fault in the...

Page 59: ...nts a flux reversal on the track Output to DDC peA A2 III via cable W4 DC IB signal used to select which DDC will respond to a given con trol status bus operation When low SEL L selects DDC 0 disc drive ST 506 Interface control signal SKCMP L indicates that the read write heads have settled on the final track at the end of a seek opera tion Reading or writing should not be attempted when SKCMP L i...

Page 60: ... the read preamplifier write driver IC s ST 506 Interface control signal WFLT L warns that a condition ex ists in disc drive assembly A 1 which makes writing unsafe Output to DDC PCA A2 III via cable W3 Signal becomes active for the following reasons WRITING Open head Shorted head Improper write current An off track condition occurs Invalid or multiple heads are selected Spindle speed loss when wr...

Page 61: ... inactive high it en abIes data to be read from the disc Output to disc drive assembly Al III via cable W3 ST 506 Interface data signal A dif ferential MFM signal which defines the transitions to be written on a track The transition of the WMFM line going more positive than the WMFM line will cause a flux rever salon a track provided that Write Gate WGATE L is active Output to disc drive assembly ...

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Page 63: ...__ C ON TA O l ST A TU S DA T A aU s _ r_r I I CONTROL sa TUS ADDRESS aus L_______________J w tSV t2y I SUPPLY tt2y ASS EMBLY POWER ON RESET tI2YP FILE PULL05A IOEV ICEDmN DEN T l I CONTROLLER I UNIT 1 PCA A2j I MICRO COMPUTER ioEvICE 1 I DEPENDENT I CONTROLLER I UNIT 0 PCA A2j I I I N I I DIS C CONTROLLER 14 1 I C CONTROL I ___J FAULT ON LINE INDICATOR ...

Page 64: ...ITE I W RITE I PCA A3 I I HEADS I I I I Theory of Operation 7942 and 7946 roEV ICE I S A M I I DEPENDENT I I UNIT 0 Ail I CONTROLLER I I UNIT 0 PCA A2 I I I I INE R5rO 6cE I i E O O M L 1 1 H I I I MFM R I REA D H PLL 14 _ _ _ HI __ M FM R I W_DA_TA______ R II I DATA PRE AMP 1 IC I m I II CHD NT EL i DR I fIvREIRTErc S I _______________J t5V 12V I CON lEA I J EDR H m I I IC I I MrCRO Ii I PROCESSO...

Page 65: ...A 6 CE II I HU DATA CONTROL r I PCA A5 INTERFACE r PLL BUS I IC I M FM F I D C I BI __ D A H l HP I B READ WRITE DAH BUS B CDNTRDL STATUS DATA BUS I P NNcNi 40 gRWE RAM MICRO bO O EPI11J 11 I I DISPLAY IC PROCESSOR SELF TEST SELF TEST SELF TEST CONTROL I I 1 r CO ROl IS TAT ADO RE BUS I H I I i____ L _______________J L_ J I FAULT ON LINE INDICATOR I ...

Page 66: ...ICATOR Theory of Operation 7942 and 7946 SC D R I V E A 1 I I I ST 506 I INTERFACE I SEALED HEAD DISC ASSEMBLY I I I I I I I I I I I I NFM R M DATA MICRO PROCESSOR PLA RfW oAT A CHANNEL NFl R M READ I DAlA PREAMP I WRITE I DRIVER IC S ACTU TOR R M I DRIVE HEADS DISCS DATA ACTUATOR SERVO CONTROL SPINDLE SPEED CONTROL I ACTUATOR I I DA TA I SERVO SERVO SERVO HEAD _ DA TA I I I I I I I SERV0 PREAMP I...

Page 67: ...IM l OS IN l DAOUT L oSOU T l CONTROl STATUS DATA BUS 45 IiII _C_SB_O_ H_ _C_SB_l_ _H 7 H n CSR S l 13 CSWS l PYAL H CONTROL STATUS rP 3 5 7 O 12 I 19 24 i 29 34 ADDRESS BUS 18 17 _ _Si __ 5 H 11 2 SEL L 2 2 t5Y J r I ______________________________________________________________ J r 1 I I I I I I J WI PI 112YP 4 8 8 SWITCH t5Y 5 7 9 3A ODE t 12Y 13 250 Y NONTUE SUPPLY 12Y DEll Y 15 10 12 POWER SU...

Page 68: ... I I 1 I IS I I Theory of Operation 7942 and 7946 13 3 0111 IS 4 CONTROL I 15 19 2 4 I DOC I PUPO ERRORS 1 REGISTER REGISTER I H50 L I I I I 1 1 I 1 1 1 1 I I 1 I I I 1 1 I 1 1 1 1 IIP3 I 19 34 S9 H 0 50 01110 H lOOP liCK SElEC T J R ER I 35 38 DllIl H lL j 40 43 45 9 r I ___ DRIVER 1 I 1 DI5C 1 1 1 1 DAIN l REIO IRIlf DIH 8U5 I 1 OHA r l HAN 0 1 DSIN l 1 SHAKE L _ I CON TR0L 1 OROUT l 1 1 1 DSDUl...

Page 69: ...PlETE WAITE GATE 9 ES ON I PEAK oET I I PES Off TRACK DE T I I ON PEAK Off TRACK SEEK CDMPL EIE HILL SENSORS 1311 3 PHISE OAIVE 14 ___ 5_PE_E_O_ _ 1 _ _0R_M_I_L_R_E_GU_L_A_TI_O_N I SPIN DLE I 5Y POWER 12Y ON lOY _ RESET STOP MOTOA SPEED 350 HZ CLOCK _ CONTROL 121 _ L ____ J SPINDLE SPEED CONTROL 5 TOP MOT 0 R I I SPINDLE MOTOR BRA KE RELAY RELA Y DRIVER HAlL SENSOR INDEI POMER ON AESET SPINDLE 92 ...

Page 70: ...rd Interface Bus HP IB Do not cycle the LINE switch on and off unnecessarily Do not connect or disconnect the HP IB cable s from the drive when the system is transferring data on the HP lB This section contains information useful for troubleshooting the drive Information provided includes field replaceable assembly FRA locations parts location details and cabling connections This information repla...

Page 71: ... wiring and dc power distribu tion are shown in figure 3 4 and in figure 4 11 4 7 SIGNAL NOTATION In the disc drive logic circuits a digital signal is applied to its destination in one of two states ac tive or inactive The signal is active when its volt age level high or low makes the action occur for which the signal was designed This action is usual ly identified by a signal mnemonic Refer to ta...

Page 72: ...by controls on the rear panel of the drive or by the host computer using the In itiate Diagnostic command Details of the diagnos tic tests are provided in the individual service manuals for the disc drive and the tape drive Service Information 7942 and 7946 4 12 SELF TEST CONTROLS The disc tape drive self test controls consist of the following Tape drive FAULT indicator Tape drive BUSY indicator D...

Page 73: ...mal display which reports the results of the internal self test and diagnostic routines Whenever self test is initiated either by operation of the SELF TEST switch or when line voltage is applied the display will first show an 4 4 8 8 readout to indicate that all segments of the display are functioning The display will then go blank until self test is completed In the case of a self test command i...

Page 74: ...drive unit 0 and tape drive unit 1 subtest numbers together with a brief de Service Information 7942 and 7946 scription of the subtests are listed in the respective service manuals Note The sequence mode described above is distinct from the pass fail mode When sequencing test results all of the results must be displayed with the DISPLAY RESULTS switch before the device will go back on line return ...

Page 75: ...rms further checks of the disc drive assembly A 1 servo mechanism and the read function as far as position sensing A scan ID command verifies that the sector headers can be 4 6 read A more exhaustive sequence of seeks is then executed both verifying the subsequent location as well as monitoring the speed performance The fifth group of subtests 26H through SEH table 4 2 checks seek read and write b...

Page 76: ...ble Ass y See HP IB HP IB O F number 1 6 figure 4 1 address 0 7 address 0 7 Failing self test subtest number low digit Refer to tables 4 1 4 2 Service Information 7942 and 7946 Refer to tables 4 1 4 2 The following are examples of typical display readout sequences SELF TEST PASS DISPLAY MESSAGE P 3 Indicates that unit 0 disc drive and unit 2 host dependent controller have passed self test The HP I...

Page 77: ...metimes referred to as the Error Fault Field of the 20 bytes returned from the Request Status command When bit 24 is set PI P2 P3 P7 and P8 contain specific self test results as detailed below PI Identifies the most suspect FRA 4 8 1 FRA 1 disc drive assembly A 1 2 FRA2 DDC PCA A2 4 FRA4 power supply assembly A4 S FRAS HDC PCA AS 6 Connectors P2 Identifies the next most suspect FRA Same code as PI...

Page 78: ...e 4 4 should be consulted Table 4 4 lists AEH as Verify position operation reveals drive is on the wrong head as the fault 4 27 RUN TIME ERROR AND FAULT REPORTING The return of a QSTAT of 1 following the issuance of a nonself test command to the disc drive implies that a full status should be requested A Request Status command should thus be issued to get back the reason for the QSTAT of 1 Assumin...

Page 79: ...ng three HOC tests as well as the unit oself test HOC RAM Test Performs the two pass RAM test on an empty lk data buffer RAM allocated to the units and or the operating system is not tested 4 10 2 DMA Test Performs the DMA test run at power on 3 Timer Test Performs the timer test run at power on If the command is directed to unit 0 the valid value range is also 0 through 3 These values correspond ...

Page 80: ...SPARE utility physically relocates a track to an address which is reserved for sparing 4 46 OUTPUT SPARE TABLE SPARE TABLE The SPARE TABLE command accesses the information in the spare table 4 47 OUTPUT DEVICE TABLE TABLES The TABLES command accesses the tables stored internally within the device in order to determine the operational status of the device 4 48 PERFORM SERVO TEST SERVO The SERVO tes...

Page 81: ...ervals The head must be cleaned each week and after using a new tape cartridge for the first time Also head cleaning is recommended after every three to five back up operations requiring the use of the 600 foot tape cartridge Above all it is important that the tape head be cleaned any time data errors are encountered Tape head cleaning instructions are given in the Tape Drive Service Manual Sectio...

Page 82: ... AND 4 3 FOR CONDITIONS S794 2A01 GO NO GO TEST RESULT HP IB ADDRESS UNIT FAILED A O NOT DISCERNABLE AN ASSEMBLY FAILED AND IT TESTED AS GOOD A 1 DRIVE UECHANIS INCLUDES CAPSTAN MOTOR AND HEAD STEPPER MOTOR A 2 DEVICE DEPENDENT CONTROLLER A 3 READ WRITE ASSEMBLY A 4 DIRTY HEAD A 5 HOST DEPENDENT CONTROLLER A 7 SERVO ASSEMBLY A S HEAD STEPPER MOTOR A 9 CAPSTAN MOTOR INCLUDES TACHOMETER 0 0 TAPE DRI...

Page 83: ... 02 03 04 05 06 07 4 14 SUBTEST GROUP 1 Microprocessor failed Test of the first 1 kilobyte of RAM failed Checksum of EXEC EPROM failed Test of last 15 kilobyte of RAM failed DMA machine test failed HDC timer circuitry not within specification HP IB interface test failed Configuration failure cannot find a valid unit O ...

Page 84: ...f test register not set Value read from a disc controller IC register not value written GROUP 3 Timeout occurred after drive selected while waiting for drive ready status Restore Command issued and failed Seek completed seek complete bit is not set in the disc controller IC status but is set in bit 3 of DDC self test register Seek command completed Seek complete not set in either disc controller I...

Page 85: ...empting to read one sector at the outer diameter either the seek or the read failed While attempting a write then read of one sector at the 00 either the seek or the write failed While attempting a write then read of one sector at the 00 either the read failed or the data read did not match that written While attempting a write then read of one sector on surface 0 either the seek of the write fail...

Page 86: ... read of one sector on every surface with a unique pattern for each surface test produced a seek failure a read failure or data different from that written While attempting a write then read of one sector on surface 4 either the seek or the write failed While attempting a write and then read of one sector on surface 4 either the read failed or the data read did not match that written After a succe...

Page 87: ...attempting a write then read of one sector at the ID either the seek or the write failed While attempting a write then read of one sector at the ID either the read failed or the data read did not match that written While attempting to read two sectors at the ID either the seek or the read failed While attempting a write then read of two sectors at the ID either the seek or the write failed While a...

Page 88: ...btest List Continued SUBTEST Service Information 7942 and 7946 ECC uncorrectable test read operation failed or value read indicated that correction was attempted Product number cannot be read Product number value read was unitialized Product number wrong number 4 19 ...

Page 89: ...t head Data errors occurred on every location Seek timeout disc controller IC has not completed command Seek timeout Command completed seek complete bit not set Seek write fault Seek drive not ready Seek fault R W data byte count invalid Command aborted Disc controller IC timeout reset Disc controller IC timeout cannot reset Unit fault Fault occurred but unable to identify condition Verify positio...

Page 90: ...Z Z Z Z Z Z E Z Z S S S S E E DATA ERROR BYTE E DISC CONTROLl R IC ERROR REGISTER FC FAULT CODE UST S E Z Z Z S Z Z E S F e F C N E S Fe DE DE N S S N S S S S S S S S E E E F e Fe S S S S S S Fe Fe Fe Fe Fe Fe FC N NUMBER OF SEEKS S DISC CONTROLLER IC STATUS REGISTER Z ALL ZERO S Z DE DE S S S S E Fe Fe S S S S S S Fe EC Fe Fe Fe tOF3 ALE F 5 JEF18A Figure 4 3 P8 Signal Source Sheet 1 of 3 4 21 ...

Page 91: ...Fe Fe Fe DE DATA ERROR BYTE E DISC CONTROLLER IC ERROR REGISTER Fe FAULT CODE usr Z DE DE S S S S S S S S E E Fe Fe S S S S S S Fe Fe Fe Fe Fe Fe Z Z DE DE S S S S E Fe Fe S S S S S S Fe Fe Fe Fe Fe Z Z Z Z Z Z Z Z DE DE DE DE DE DE DE DE DE DE DE DE DE S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S E E E E E E E E E Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe S S S S S S S S S S S...

Page 92: ... S FC FC FC FC FC FC FC FC Fe Fe FC Fe FC FC FC FC FC FC FC FC Fe Fe FC Fe FC FC FC FC FC Fe FC Fe IDE DATA ERROR BYTE IE DISC CONTROLLER IC ERROR REGISTER Fe FAULT CODE LIST DE S S S S E Fe S S S Fe FC Fe Z DE DE S S S S E Fe Fe s S S S S S Fe Fe FC Fe Fe Z Z Z Z Z Z Z Fe Fe Z DE DE DE DE DE E DE DE DE DE S S S S E Fe s S S Fe Fe Fe S S S S S S S S S S S S S S S S E E E E Fe Fe Fe Fe Fe Fe Fe Fe ...

Page 93: ...on was used to recover the data 23 Uncorrectable data error 24 Recoverable data error ID field 25 Marginal ID field 27 Unrecoverable ID field 28 Recoverable data address mark not found 29 Marginal data address mark not found 2B Unrecoverable data address mark not found 2F Unrecoverable data error on write operation ID field not readable General faults that don t map to a specific status error bit ...

Page 94: ...operation Unit fault during correction operation Retries exhausted on full sector operation Track 000 error on restore Unit fault on restore Format unit fault Unit fault during seek operation Unit faults with Disc Controller IC Status Register Refer to s Disc Controller IC Status Register paragraph 4 25 on how to interpret the P8 status byte Write fault on retry of Seek Drive not ready on retry of...

Page 95: ...st spare tables Zeroing of spare tracks operation failed in Deallocate Spares Seek to deallocated spare failed in Deallocate Spares Copy of track to be spared has failed Write of spare track failed spare allocated but not assigned Track Sparing cannot obtain resources Track Sparing failed while writing spare tables to disc Verify failed on second spare track Seek failure during verify of spare tra...

Page 96: ...ge format Bit 24 set P1 Most likely failed FRA P2 Second most likely failed FRA P3 Failed subtest P7 Failed error condition P8 Supplementary error codes data error byte disc controller Ie error register fault code list number of seeks and disc controller Ie status register UNIT O RUN TIME ERROR AND FAULT REPORTING RUN TIME ERROR AND FAULT REPORTING 1 QSTAT l 2 REQUEST STATUS message format Bit 24 ...

Page 97: ...PPLY 5 HOST DEPENDENT CONTROLLER 6 CONNECTORS NOT SHOWN 1 DRIVE MECHANISM INCLUDES CAPSTAN MOTOR AND HEAD STEPPER MOTOR 2 DRIVE DEPENDENT CONTROLLER 3 READ WRITE ASSEMBLY 4 DIRTY HEAD NOT SHOWNI 5 HOST DEPENDENT CONTROLLER 7 SERVO ASSEMBLY 8 HEAD STEPPER MOTOR 9 CAPSTAN MOTOR INCLUDES TACHOMETER 5 HOST DEPENDENT CONTROLLER Figure 4 4 Field Replaceable Assembly FRA Locations 4 28 COMPONENT SIDE ...

Page 98: ...V GND 6V GNO 5V POWER SUPPLY UO A4 J2 W1P6 I FILE PAILL09A A B C 0 0 0 1 1 1 2 2 2 3 J 3 4 4 5 S 5 6 6 6 7 7 7 8 8 8 9 9 9 FAN B1 Figure 4 S Power Distribution Cable Assembly WI Service Information 7942 and 7946 W1P2 I J4 I I HOC I A5 I I I I L ______ J W1P3 I J1 DISC DRIVE DOC UO A2 TAPE DRIVE DOC U1 A2 L _____ _ W1P i J4 I DISC DRIVE ASSY UO A1 W1P8 I JJ I TAPE I DRIVE I ASSY I U1 A1 I I I _____...

Page 99: ...ormation 7942 and 7946 S7V420407 FANB1 W1 J4 J 1 J4 J3 J3 H DC PCA AS tUO FRA5 DOC PCA A2 UO A2 DOC PCA A2 U1 A2 J4 A1 UO A 1 A1 U1 A1 Figure 4 6 UO FRA4 Power Supply Assembly A4 Layout and Cable Connections 4 30 ...

Page 100: ...0V 4 85 TO 5 15V 11 0 TO lJ OV NOTE USE GND TEST POINT VOLT METER RETURN WHEN MAKING VOLTAGE MEASUREMENTS 2 THE OUTPUT VOLTAGES ARE NOT ADJUSTABLE 3 MAXIMUM RIPPLE 5V SUPPLY 5OmV P P 12V SUPPLIES Ioamv P P Service Information 7942 and 7946 Figure 4 7 UO FRA4 Power Supply Assembly A4 Test Points and Voltages 4 31 ...

Page 101: ...Service Information 7942 and 7946 J2 DOC PCA A2 FRA2 FILE PAILL03A HP IB CONNECTOR REAR PANEU EXEC EPROM P2 Wl J2 A4 FRA4 Figure 4 8 FRA 5 HDC PCA A 5 Layout and Cable Connections 4 32 ...

Page 102: ...HERE IS A KEYSEAT BETWEEN PINS 4 AND 6 2 J2 PINS ARE NU BERED 1 THRU 34 EVEN NUMBERED PINS ARE ON SOLDER SIDE OF PCA THERE IS A KEYSEAT BETWEEN PINS 4 AND 6 J JJ IS NU BERED AS SHOWN Figure 4 9 FRA 1 Disc Drive A 1 Layout and Cable Connections Service Information 7942 and 7946 4 33 ...

Page 103: ...Service Information 7942 and 7946 J2 A4 FRA4 FILE FSJEF09A A1 FRA1 j J2 i W3 W4 FAULTION LINE INDICATOR J2 HOC peA AS FRA5 i W2 P2 Figure 4 10 FRA2 DOC PCA A2 Layout and Cable Connections 4 34 ...

Page 104: ...nformation 7942 and 7946 r ITAPE DRIVE I ASSEMBLY U1 A1 I DEVICE DEPENDENT I CONTROLLER U1 A2 V5 UNIT 1 FRA2 I UNIT 1 FRAil DC POWER Vi I ___ ___ J IDISC DRIVE I IDEVICE DEPENDENT I ICONTROLLER UO A2 UNIT 0 FRA2 I J2 I I 1 r il I I I I I I I J REF SERVO ASSEMBLY Ui A7 UPi UP2 I ST 501 INTERfACE I I I I J3 ___ L ___ __ J WIPI DC POWEA IDISC DRIVE I ASSEMBLY UO A1 I UNIT D FRAil Ji J2 DC POIER W2 I ...

Page 105: ...SBO H CSBI H CSB2 H CSB3 H CSB4 H CSBS H CSB6 H CSB7 H DATAO H OATAI H DATA2 H DATA3 H OATA4 H OATA5 H OATA6 H DATA7 H ORIN L OROUT L OSIN L OSOUT L GND t 5V GND f 2V PVAl H W2P2 DEVICE I DEPENDENT I J2 CON TR0LL ER J3 1 PCA A2 FRA2 I 6 I 113 I I 114 I 16 I 17 I 18 I 120 I I 121 I 22 I 23 I 12 S I I 126 I 27 I 2 B I 130 I I 131 I AlL ODD PINS 6 I I B I I I 0 I I I 12 I I 4 I 18 I 20 I I 22 I I I 2...

Page 106: ...lacement procedures for FRAs and parts in the drive The locations of the FRAs are shown in figure 4 3 Note Removal and replacement procedures for the following FRA s contained within tape drive assemb ly U 1 FRA 1 are not provided in this section For this information refer to the Tape Drive Service Manual Section IV Replaceable Parts U I FRA3 read write assembly U I FRA7 servo assembly U I FRA7 he...

Page 107: ...sconnected from the AC LINE connector on the rear panel of the drive c Remove the five T 10 screws 2 which secure the top shroud to the mainframe SO d Carefully slide the top shroud 1 toward the rear of the drive When the shroud is clear of the mainframe SO remove it from the drive e Ground the mainframe to the antistatic pad before removing any FRAs from the drive Reinstallation is a reversal of ...

Page 108: ... 7 for the locations of W1 W2 and W3 Install the EPROM kits 3 4 and 5 as described in paragraph 5 5 Ensure also that the cable assembly connectors disconnected in Removal and Replacement 7942 and 7946 steps e and f are firmly seated in their mating con nectors 5 7 FRONT PANEL Note When replacing the front panel on disc tape drives with serial number prefix 2519 and below it is man datory that the ...

Page 109: ... cable assembly connectors disconnected in steps d e h and j are firmly seated in their mating connectors 5 4 5 9 FAN To remove the fan 23 proceed as follows a Perform the preparation for service procedure outlined in paragraph 5 2 b Ensure that the power cord is disconnected from the AC LINE connector on the rear panel of the drive c Remove the top shroud refer to paragraph 5 4 front panel refer ...

Page 110: ...y UO FRA4 41 to the mainframe assembly 50 h Remove the TI0 screw 39 and spacer 40 which secure power supply assembly UO FRA4 41 to the mainframe assembly 50 Removal and Replacement 7942 and 7946 i Carefully slide power supply assembly UO FRA4 41 forward and out of the drive CAUTION Ensure that the two TIS screws 38 T 10 screw 39 and spacer 40 removed in steps g and hare reinstalled These attaching...

Page 111: ...the top shroud refer to paragraph 5 4 and the front panel refer to paragraph 5 7 d Disconnect connector P3 on power cable assemb ly WI 37 from connector J 1 on disc drive DDC UO FRA2 48 5 6 e Disconnect connectors PI and P2 on ribbon cable assembly W3 36 from connectors J3 and J4 respectively on disc drive DDC UO FRA2 49 f Disconnect connector Pion LED cable assembly W4 12 from connector J5 on dis...

Page 112: ... properly seated in their mating connectors Removal and Replacement 7942 and 7946 5 14 LED CABLE REMOVAL a Perform the preparation for service procedure outlined in paragraph 5 2 b Ensure that the power cord is disconnected from the AC LINE connector on the rear panel of the disc drive c Remove the top shroud refer to paragraph 5 4 and the front panel refer to paragraph 5 7 d Remove the LED Cable ...

Page 113: ...RA4 PARA 5 10 FRONT PANEL PARA 5 n l DISC DRIVE DISC DRIVE ASSY DOC UO FRA1 U1 FRA2 PARA 5 11 PARA 5 12 NOTE REFER TO THE TAPE DRIVE SERVICE MANUAL FOR TH E ORDER OF DISASSEMBLY OF THE FOLLOWING COMPONENTS WITHIN TAPE DRIVE ASSEMBLY U1 FRA1 READ WRITE ASSEMBLY U1 FRA3 SERVO ASSEMBLY U1 FRA7 HEAD STEPPER MOTOR U1 FRA8 TAPE DRIVE DOC U1 FRA2 PARA 5 13 CAPSTAN MOTOR AND TACHOMETER U1 FRA9 Figure 5 1 ...

Page 114: ...S794GAOI P6 WI P2 WI 81P1 P8 W1 CONNECTED TO BACK OF TAPE DRIVE ASSE LY P7 WI Removal and Replacement 7942 and 7946 P1 W5 P1 W3 Figure 5 2 HP 7942 HP 7946 Cable Interconnections 5 9 5 10 ...

Page 115: ......

Page 116: ... DRIVE ASSY 09144 63101 DISC DRIVE ASSY V UO FRA1 07941 60121 07945 60121 HOC FRA5 07940 60195 CABLE ASSY W6 07942 60030 DDC U1 FRA2 TAPE 09144 66512 HP IB CABLE ASSY 8120 3445 CABLE ASSY W5 09144 61608 CABLE ASSY W1 07942 60011 FRONT PANEL ASSY 07942 60116 07946 60116 CABLE ASSY W3 07942 60013 d Replacement Removal an d 7946 7942 an Assemblies 7942 HP 7946 Major Figure 5 3 HP 5 11 5 12 ...

Page 117: ...strated b HP PART NO The Hewlett Packard number for the replaceable part c DESCRIPTION The description of the replace able part Refer to table 6 2 for an explanation of the ab breviations used in the DESCRIPTION column d MFR CODE The 5 digit code that denotes a typical manufacturer of a part Refer to table 6 3 for a listing of manufacturers that correspond to the codes e MFR PART NO The manufactur...

Page 118: ...66506 FRONT PANEL PCA ASSEMBLY 17 09144 61608 CABLE ASSEMBLY W5 18 07942 40003 PUSHBUTTON ASSEMBLY 19 07942 40006 CAP eject 20 07942 40007 WINDOW LED 21 8160 0280 CONTACT finger 22 07942 60116 FRONT PANEL ASSEMBLY 7942 for Disc Tape Drives serial number prefixed 2606 and above 07946 60116 FRONT PANEL ASSEMBLY 7946 for Disc Tape Drives serial number prefixed 2606 and above 23 07942 60016 FAN ASSEMB...

Page 119: ...0380 1655 HOLDER shaft 46 07942 40002 SHAFT swit c h 47 07942 20004 SHIELD power supply 48 07941 60102 DISC DRIVE DDC PCA UO A2 49 09144 66512 TAPE DRIVE DDC PCA UI A2 50 07942 60041 MAINFRAME ASSEMBLY 51 09121 48303 FOOT front 52 0403 0427 FOOT rear 53 8160 0280 CONTACT finger 54 1400 0510 CLAMP cable 55 56 1400 0972 8120 0698 8120 1378 8120 1351 8120 1369 8120 1689 8120 1860 CLAMP cable POWER CO...

Page 120: ...044 1 o by 0 5 00000 aBO 4 28480 09144 63101 1 rial ref e r mbers 28480 07942 60030 1 28480 07942 00028 1 o by 0 5 00000 aBO 1 28480 07942 60015 1 28480 07942 60013 1 28480 07942 60011 1 56 0 by 0 70 00000 aBO 2 0 by 0 5 00000 aBO 1 28480 0380 1746 1 28480 07942 60024 1 28480 2110 0565 1 Iy 75915 2A250V5 0A 1 9 28480 5014 1203 1 57 28480 0380 1655 1 28480 07942 40002 1 28480 07942 20004 1 28480 07...

Page 121: ...23 56 I I I 51 I 50 I I 57 S7942802 2 47 35 W2 J4 48 J4 10 J4 36 W3 Replaceable Parts 7942 and 7946 P1 Figure 6 1 D lSC Tape Drive Exploded View 6 3 ...

Page 122: ...itting diode left hand me ga 10 6 megohm mi 11 i 10 3 machine medium blow metal oxide manufacturer miscellaneous millimetre mounting Mylar 9 nano 10 normally closed number not separately replaceable no time delay order by description outside diameter oval head oxide 12 pico 10 I printed circuit assembly phillips head pan head part of potentiometer Pozidriv qty rd h rec t re f rf rfi rh rpm rwv sb ...

Page 123: ...MANUFACTURER o2 r68 Illinois Tool Works Inc 281 80 Hewlett Packard Co 75915 Tracor Littlefuse Inc 94959 3M Co Adhesives Coatings and Sealers Div ADDRESS Des Plaines Replaceable Parts 7942 and 7946 IL Palo Alto CA Des Plaines IL St Paul MN 6 5 6 6 ...

Page 124: ......

Page 125: ...nual for theory of operation and service information for HP 7942 and HP 7946 Disc Drives with serial numbers prefixed 2 605 and prior If it is desired to upgrade the old LED cable 07942 60033 to the new LED cable 07941 60003 the front panel assembly 07942 60106 07946 60016 must be replaced with the new front panel assembly 07942 60116 7946 60116 2 SectioIl i V and VI in this backdating supplement ...

Page 126: ......

Page 127: ...cement procedures for FRAs and parts in the drive The locations of the FRAs are shown in figure 4 3 Note Removal and replacement procedures for the following FRA s contained within tape drive assemb ly U1 FRA I are not provided in this section For this information refer to the Tape Drive Service Manual Section IV Replaceable Parts UI FRA3 read write assembly UI FRA7 servo assembly U I FRA8 head st...

Page 128: ... the AC LINE connector on the rear panel of the drive c Remove the five T 10 screws 2 which secure the top shroud to the mainframe 51 d Carefully slide the top shroud 1 toward the rear of the drive When the shroud is clear of the mainframe 51 remove it from the drive e Ground the mainframe to the antistatic pad before removing any FRAs from the drive Reinstallation is a reversal of the removal pro...

Page 129: ...d S as de scribed ili paragraph AS S Ensure also that the cable a mblY connectors disconnec ted in steps e and f are firmly seated in their mating connectors Backdating Information 7942 and 7946 AS 7 FRONT PANEL Note When replacing the front panel on disc tape drives with serial number prefix 2S19 and below it is man datory that the top shroud also be replaced To remove the front panel 22 proceed ...

Page 130: ...rform the preparation for service procedure outlined in paragraph AS 2 AS 4 b Ensure that the power cord is disconnected from the AC LINE connector on the rear panel of the drive c Remove the top shroud refer to paragraph A5 4 front panel refer to paragraph AS 6 and tape drive assembly refer to paragraph AS 8 d Remove the two 6 32 hex standoffs 8 and lock washers 9 which secure the HP IB connector...

Page 131: ...rts are re tluired to properly ground the Backdating Information 7942 and 7946 power supply to the mainframe as sembly Reinstallation is a reversal of the removal prace dure Check that the cable assembly connectors disconnected in steps d e and f are properly seated in their mating connectors AS It UO FRAt DISC DRIVE ASSEMBLY AI To remove disc drive assembly UO FRAI 35 proceed as follows Note The ...

Page 132: ...disc drive DOC UO FRA2 49 g Remove the T 10 screw 29 which secures cover plate 28 to the rear panel of the mainframe as sembly 51 and remove the cover plate AS 6 h Disconnect connector P2 on cable assembly W2 30 from connector J2 on disc drive DOC UO FRA2 49 i Carefully slide disc drive DOC UO FRA2 49 forward and out of the drive Reinstallation is a reversal of the removal prace dure Before instal...

Page 133: ...bly i Carefully slide tape drive DOC UI FRA2 SO forward and out of the drive Backdating Information 7942 and 7946 Reinstallation is a reversal of the removal proce dure Ensure that the cable assembly connectors disconnected in steps d e g and h are properly seated in their mating connectors AS 7 ...

Page 134: ...RA4 PARA 5 10 FRONT PANEL PARA 5 7 r r DISC DRIVE DISC DRIVE ASSY DOC UO FRA1 PARA 5 11 U1 FRA2 PARA 5 12 NOTE REFER TO THE TAPE DRIVE SERVICE MANUAL FOR THE ORDER OF DISASSEMBlY OF THE FOLLOWING COMPONENTS WITHIN TAPE DRIVE ASSEMBLY U1 FRAt REAOIWRITE ASSEMBLY U1 FRA3 SERVO ASSEMBLY U1 FRA7 HEAD STEPPER MOTOR U1 FRA8 TAPE DRIVE DOC U1 FRA2 PARA 5 13 CAPSTAN MOTOR ANO TACHOMETER U1 FRA9 Figure AS ...

Page 135: ...ed b HP PART NO The Hewlett Packard number for the replaceable part c DESCRIPTION The description of the replace able part Refer to table A6 2 for an explanation of the ab breviations used in the DESCRIPTION column d MFR CODE The S digit code that denotes a typical manufacturer of a part Refer to table A6 3 for a listing of manufacturers that cor respond to the codes e MFR PART NO The manufacturer...

Page 136: ...142 10106 FIIONT PANEL ASSEMBLY 7942 07141 10018 FRONT PANEL ASSEMBLY 7148 2 3 07142 10016 FAN ASSEMBLY Attaching Parts 24 2310 0417 SCREW machine pnh T15 6 32 0 750 in long 25 07142 00008 GRILLE fan X 21 07141 10121 DISC DRIVE ASSEMBLY 7941 UO Al 07145 10121 DlSC DRIVE ASSEMBLY 7945 UO Al Attaching Parts 27 0515 0372 SCREW machine pnh TI0 M3 0 by 0 5 8mm long w scw X 28 0515 0372 SCREW machine pn...

Page 137: ...42 40002 1 47 07842 20004 SHIELD power supply 28480 07942 20004 1 48 07941 60102 DISC DRIVE DOC PCA UO A2 28480 07841 80102 1 58 49 09144 88512 TAPE DRIVE DOC PCA UI A2 28480 09144 88512 1 07842 80041 MAINFRAME ASSEMBLY 28480 07942 80041 1 50 08121 48303 FOOT front 28480 09121 48303 2 51 0403 0427 FOOT rear 94959 SJ 5008 2 52 0403 0288 GUIDE PCA 5 in long 28480 0403 0288 2 53 0403 0102 GUIDE PCA 8...

Page 138: ...23 56 I I I I 5 1 I I I 42 43 57 S7142A02 5 3 47 15 J4 J4 36 W3 Replaceable Parts 7942 and 7946 Figure A6 1 O IIC Tape Drive Exploded View A6 3 ...

Page 139: ...xide mfr manufacturer misc miscellaneous mm millimetre mtg mounting My Mylar n n c no NSR ntd OBO 00 ovh axd P PCA pM pnh P O pot pozi 9 nano 10 normally closed number not separately replaceable no time delay order by dele ript ion outside diameter oval head oxlde 12 pico 10 printed circuit assembly m 111 11 s h ead pan head part of potentiometer Pozidriv qty rdh rect ref rf rfi rh rpm rwv sb SCR ...

Page 140: ...rmation 7942 and 7946 Table A6 3 Code List of Manufacturers MANUtACTURER ADDRESS Illinois Tool Works Inc Des Plaines IL Hewlett Packard Co Palo Alto CA Tracor Littletuse Inc Des Plaines IL 3M Co Adhesives Coatings and St Paul MN Sealers Div A6 S A6 6 ...

Page 141: ......

Page 142: ...7942 and HP 7946 Disc Tape Drives 7942A 7946A Ol End of File Error during Copy Data B 3 B 4 7942A 7946A 02 OEM Bracket Removal B 4 B 5 7942A 7946A 3 S PRODUCT SAFETY SERVICE NOTE Power Supply 07942 60024 B 7 7942A 7946A 04 Shunt Block Modification B ll 7942A 7946A 05 Potential Loss of Data Firmware Bug B 12 B l B 2 ...

Page 143: ......

Page 144: ...ll volume copy data from the tape to the disc is initiated by the From Tape push button then the operation will complete without error If the restore tape was cre ted without an End of File mark then a syste initiated copy data routine to restore the entire volume from tape to disc will complete without error This bug appears with the following 9000 system utilities Series 200 Basic 3 0 TAPEBACKUP...

Page 145: ......

Page 146: ...from completely sliding into the cabinet SOLU1 ION Remove and discard the OEM Bracket It is held to the Disc Mechanism by four TI0 Torx screws It is located at the opposite end of the Disc Mechanism from the power and edge connectors and covers the back edges of the Data and Servo PCA s This bracket is not required in any product HW rl 9320 4766 MADE IN U S A Remove 4 Torx Head Screws T Remove and...

Page 147: ......

Page 148: ...e VOLTAGE SELECTOR switch SOLUTION It is mandatory that all the drives in the serial number prefix range listed above be up dated as soon as possible to eliminate the possibility of an electrical accident due to this problem MT sg 8320 5180 C 1 83 The following procedure and figure I should be used when performing the update Note The two parts needed to update the the drive plastic insulator part ...

Page 149: ...e the paper backing from the adhesive surface of the plastic insulator 5 With the power supply in a vertical position hold the plastic insulator on the edge of the power supply at the location shown in figure 1 6 Press the power supply shield onto the adhesive surface of the insulator 7 Reattach the power supply shield to the power supply with the plastic spacer ICAUTION I Metal spacer part no 079...

Page 150: ...s mandatory that Hewlett Packard track the updating of every disc tape drive identified above To accomplish this we have implemented a special Service Code which is to be entered onto the Customer Service Order in the Service Code Block after the update has been completed The number to be entered is 20027 This number will be used to verify updates and each office will be audited to en sure that th...

Page 151: ......

Page 152: ...41 6X021 or 07945 6X021 per procedure 5 11 in 7941 45A Service Manual 2 Remove the mounting tray attached to the bottom of the Disc Mechanism and lay the Disc Mechanism on its top to expose the component side of the Data PCA 3 Locate the Shunt Block J6 It is a socketted jumper block located between edge connectors J1 and J2 on the Disc Mechanism 4 Cut the following three shunts on the Shunt Block ...

Page 153: ...6 7941 i c BEFORE 7945 BEFORE 1 Jl AFTER AFTER cut cut cut cut cut cut 5 Bill DMD 1 2 hour labor extended warranty using Ser1vce Code 20024 in the Service Code Block on a CSO fOTE Please upgrade all Disc Mechanism s in FSI 8 12 ...

Page 154: ...0 systems but may occur on others Solution If the Disc Tape Drive is used on an HP 260 System then upgrade the firmware immediately If the Disc Tape Drive is used on any other system then upgrade the firmware on next site visit Only bill warranty for travel when the Disc Tape Drive is used on HP 260 systems HW sg If the Drive Serial Prefix is 2515A or less DMD 4800 warranty will pay to upgrade the...

Page 155: ...ve the mounting tray This will expose the spindle ground button assembly which is attached to the Data PCA 4 Pull on the spindle ground assembly so that it no longer makes contact with the spindle motor S Reassemble the drive If you have a new mounting tray part no 07941 67902 then carefully follow the reassembly procedure outlined in Service Note 07945 08 Anew mounting tray has a reinforced base ...

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