Cromemco 299B Technical Manual Download Page 34

Summary of Contents for 299B

Page 1: ...H N IC A L M A N U A L C R O M E M C O I n c 2 8 O B e rn a rd o A v e nu e M o unta i n V i e w C A 9 4 0 4 3 P a rt N 0 0 2 3 6 0 0 0 A p ri l 1 9 8 1 C opyri ght C 19 8 0 B y C R O M E M C O l n c...

Page 2: ...r a st im u lu s s re ce ived the p ro ce sso r sto ps w ha tev e r it w a s do ing a t the t me id en t if ie s the so u rce o f the in te rru p t and t re a ts it a pp ro p r ia te ly T he ve l o c...

Page 3: ...c ted d iske tte Two s zded index is sam p led w hen E ITH ER IND EX 1 1 is h lgh and sto red fo r ou tpu t to the ho st E ra se De la y T im ing T he u se o f tunne l e rase head s mandates a de lay...

Page 4: ...tte Load ing and onload p ng 1 8 ChaSSI S Ground 1 10 Drive Select Options 1 10 1 7 k k r1 vt pt n 1 0ne Drive Rotary Option 1 11 F ur r1 vi pt 1 n 1 11 E1 ght D4 7 v pt1on 1 11 L 7 n l r y w r r1 nat...

Page 5: ...ucer and Logic Checks 2 7 lr l dex Transducer A ll gnment 2 8 Index Transducer Replacement 2 9 Spind le Cone Check 2 10 Spindle Cone Replacement 2 12 Positl oning Sy stem 2 12 Positioner Servo Check 2...

Page 6: ...untlnj Screw s Slde 1 2 14 2 7C Cat Eyes and Head Azimuth Display 2 15 2 7D Head Azl muth A lignment 2 15 2 8 Dr ive Electronl cs PC8 2 16 2 9 Load Cam Shutter A lignment 2 20 2 10A Eject Motor Cam Al...

Page 7: ...a Remove a1l packing material b Check pac king list c Check for shlppins dam age d Remove carriage restra int inserted in S ide 1 Hechan ical Chec ks a Check that carr age dssembly moves free ly o ve...

Page 8: ...evltent a Contact the carrier b Contact the manufacturer Unpac king After perform ing a prel m inary inspection unpack the d skette drive as follow s a Remcve a11 material from shipping container Rem...

Page 9: ...The load mechanism w ill automatically close when the d iskette is fully inserted a Insert a d iskette and ver ify that the load mechan ism closes b press the button and Merify that the load mecNan is...

Page 10: ...s between the drive and ty pical pcwer Gources Fabricate and check pcwer cable as listed f0r 3 P3 DC Pow e r connectp r 10 Pin Molex 0 156 center Pin Func tion Pin Functlon Mating c c nce cto r 1 Chas...

Page 11: ...nated diskette drive is used for the diskette drlve to controller connection The I 0 cable is sim ply connec ted to the co nnecto r c S igna l Cable Fa bricat io n 1 Fabricate the interface signal cab...

Page 12: ...4 REMOTE EJECT CUST OPTION 15 16 HEAD LOA D 17 18 DISKETTE SELECT 3 DS3 19 20 INDEX SECTOR 21 22 READ 23 24 DOUBLE DENS ITY S NC 25 26 DISKETTE SELECT 1 DS1 27 28 DISKETTE SELECT 2 DS2 29 30 DISKETTE...

Page 13: ...ed the w ide portion of the slide should be mounted to the upper inside surface of the sy stem enclosure The narrcwer port ion o f the slide is fastened to the upper edge of the d iskette d rive frame...

Page 14: ...Drive assembly heat d issipation under max imum seek activity is 291 BTU hr 85 watts To limit the maximum allowable operating tempera ture of the media to 125 F 46 1 C an unrestrlcted flow of 30 cubi...

Page 15: ...Flgure 1 4 Vertlcal Retma Rack Mountlng e 1 1 Figure 1 5 Hor izontal Retma Rack Hounting l 9...

Page 16: ...c signal grqund near the power ccnnector on the drlve electronlcs PCB This connectpon s easily broken by cutting trace cut A Trace cut A s located near the chassis ground inj lead If this trace cut is...

Page 17: ...ry code to select each of the 8 d iskettes and slde se lect to obta in two sided recording ln this mode c f operation DS1 is used as un enable line 1ow to enable and DS2 DS3 and DS4 are decoded ln a b...

Page 18: ...2 8 TA BLE 1 4 B INA RY SELECT ION 0F EIGHT DR IVES S vstem orive Diskette Selected Diskette DS1 S2 DS3 DS4 pr ive Diskette Selected L0H H IGH H IGH H IGH 1 1 1 L0H L0H H IGH H IGH 1 2 2 L0H H IGH L0...

Page 19: ...dependent Index sector Lines Optjon 10 allows independent monitoring Qf index sectors from each diskette of a drive Pin 20 will have index sector pulses from Diskette 1 and Pin 8 wil have index sector...

Page 20: ...ect output P in 44 s 1ow when the w rite pro tected diskette is selected Customer lnstallable Opt ion 14 W ill prevent writlng off speed data during nsertion or ejection of a diskette l krite protect...

Page 21: ...ne and cloc k pulses alway s on the c loc k l ine Separated data is in 48 and separated clock P in 50 of the signal interface connector 0ne Shot Emu lat ion To funct ion pro perly in controlle rs desi...

Page 22: ...d usinq the fo llow ing procedure 1 Observe the sawtooth VC0 at T 1 Approx mately 4 4V p p Observe the kC0 control koltage range 0 4V to 0 4V at T 2 The oscilloscope srounds m ay ba connected to TP5 o...

Page 23: ...w ithin 20 n second s Double Dens ty Data Compensa tjon The 2998 comes supplied from the factor y to read I FN or M Fn coted diskettes that are w rjtten w thout w rite precompensation The read electro...

Page 24: ...C12 NORMAL DRIVE 1 0 F 2 0 J 0 J J J J 2 DRIVE 2 OF 2 J J 0 d J J 0 3 1 DRIVE NO SS J J 0 J J J J 4 4 DRIVES 8 X DISKETTES 4 1 DRIVE 1 OF 4 J 0 J O J 0 O 4 2 DR IVE 2 0F 4 0 0 J 0 J O J 4 3 DRIVE 3 O...

Page 25: ...T0 T0 T9 T0 T0 T0 C2 C4 C5 C6 C8 C10 C12 5 3 DRIVE 3 0 F 8 0 0 J 0 J 0 J 5 4 DRIVE 4 OF 8 0 0 0 0 J J 0 J 5 5 DRIVE 5 OF 8 J 0 J 0 0 0 0 5 6 DRIVE 6 O F 8 0 0 J 0 0 0 J 5 7 DRIVE 7 OF 8 J 0 0 0 0 0 J...

Page 26: ...ION CONNECT ION D ISKETTE EJECT D1 D3 D5 D7 U2 U23 U28 5454 yy45y 75453 T0 T0 T0 T0 D2 94 D6 D8 NORHAL BEZEL SH ITCH J J J J OH IT OH IT USE OR REMOT E EJECT 7 8EZEL SM ITCH ONLY OMIT OHIT 0H1T X N0 R...

Page 27: ...HHON I O J 0 J 0 J J 0 0 J 0 0 J G J G OMIT OHIT 10 INDEPENDENT I O 0 J 0 J 0 0 J J 0 0 0 J G J G 0H1T OHIT 11 32 SECT0R5 J 0 J 0 J J 0 0 0 J J J 32 J 32 OMI T 0M1 T SEPARATED 12 I6 SECTORS J 0 J 0 J...

Page 28: ...H2 H3 T0 H4 COHPENSAT ION NORHAL USE RITH HRITE J 0 PRECOHPENSAT ION 16 USE H ITH RITE 0 J PRECOHPENSAT ION DOU8LE DENS IT B3 T0 B2 B3 T0 B4 DATA SEPARATOR NORHAL EXTERNAL SYNC J 0 SYNC SOFT SECTORED...

Page 29: ...s are particularly detrimental to po sit ioner performance c Clean posit ioner guide ra il w ith dry lint free c 10th d Clean read write head using alcohol Drive System Test a Run available d iagnosti...

Page 30: ...nd scope at TP8 or TP14 c Output must be at least 200 mv p p d lf the proper reading cannot be p bta ined the possible problem a r e a s a r e 1 Defective w rite drivers 2 Defective med ia Repeat test...

Page 31: ...JACKS AND PLUGS ASSEHBL CONNECTOR Drive Electronics P1 Customer Signal Interface PCB 02 Voice Coil Motor Assembly 03 DC power lnput 04 Eject and Harness PCB 15 Servo Lamp Assembly 06 Hask Assembly J7...

Page 32: ...ndle motor PCB Replacement a Disconnect a71 the connectors along the upper board edge b Remove the screw hold ng the lower board etge to the d iskette frame and re lease the catch c Remove three screw...

Page 33: ...ARATOR PCB READ HRITE HODULE PCB J 2 J 4 2 5 J l A l A z 3 J3 J I J 2 J4 EJECT AND HARNESS S IDE 1 PC2 EJECT AND HARNESS SIDE 2 PCB M J 7 6J J g J 3 A I l l P1 l l DRIVE ELECTRONICS PCB Figure 2 1 P1Q...

Page 34: ...f bind ing is ev ident replace motor d Verify be lt tension e Verify drive belt tracks in center of both drive and driven pulley s retrack be lt if necessary Drive Belt Tension Adjustment To adjust dr...

Page 35: ...s do n0t occer w hen the selected diskette is removed both sides lf optional interfaces are used refer to the options section to determine index sector output character istics I f the drive is be ng u...

Page 36: ...age read lnq should be taken Excessive varlations w ith d iskette insert ion i e greater than 1 50 psec indicate a media concentric ity or registration problem lf this occurs perform the spindle cone...

Page 37: ...eck plate and reposltion sach that the photosecse and lam p re cpposite each other 5 Insert d lskette and proceed w ith alignment frcm Step Index Transducer Rep lacement The ndex transducer consbsts o...

Page 38: ...NG j CONE 1 I Figure 2 4 Index Transducer and Ccne Assembly Spindle Cone Check a Connect the Channel 1 scope prcbe to T l3 on the diskette electron ics PCB and ground at TP14 and the trigger probe to...

Page 39: ...s patte rn c Carefully notice the amplitude cf the s ignal and the modulation char acteristics You w ill be looking fnr changes in amplitude and modula tion characteristics so study them before procee...

Page 40: ...Figure 2 6 Positioner Servo Check Using the osc illosco pe observe the posit on transducer output at TFC A signal sw ing of 3 25 25V p p is expected Ground the osc illoscope at T P2 Synchronize the o...

Page 41: ...ts a 1 mi1 position error Figure 2 6 1 mi1 s the maximum tolerable error Machine azimuth is important to and need nnly be chec ked for hard sector drives De lete tests f g h and f0r soft sector drives...

Page 42: ...C C O Z HEX S0C HD CAP SCRE S 4 40 X 5 8 LG Figure 2 7A Head Assem bly Mount ng Screw s Side 2 HEX S0C HD CAP SCREHS HEX S0C BUTTON HD SCRE S 4 40 i 1 2 LG 4 40 X 1 4 LG RECESSED 1 O O o o HE S0C HD C...

Page 43: ...20 mS Dlk DELAtED SHEEP I I l 1 mS DIV Figure 2 7C Cat Ey es and Head Azimuth Display 12 M INTUES 0F ANGLE 2 M INUTES 0F ANGLE 0 M INUTES OF A8GLE Figure 2 7D Head Azimuth A lijnment 2 15...

Page 44: ...rvo Adjustment lf the positioner servo did nct pass the check of the preceed inj section alignment m ght be requ red prelimlpary Adjustments The positioner servo adjustments are located on the drive e...

Page 45: ...Should be more negative toward Track 76 Fine R 67 R 68 Tp4 Adjust fcr 3 25V p p 1 25V position balanced about ground as posi tioner moved back and forth by hand R 67 is balance and R 68 is ga in Trac...

Page 46: ...screw holding Side 2 head assembly to carriage c ccess Track 76 d Insert alignment d iskette S ide 2 e Hon tor read data at TP13 using a Te ktronix 465 or equivalent scope Wh ich has a m ixed sweep f...

Page 47: ...d assembly must be properly aligned before Side 1 can be al igned The procedure for ali gnment is the same as Si de 1 except thit radial a7ign ment of Head 1 fixed button head s accomplished by movlng...

Page 48: ...aring follower and carrier See F ig ure 2 l0A T h i s c h e c k d o e s n o t a p p l y to d r lv e s w i th S N a b o v e 5 3 5 0 0 C r a n k C a m A l ig n m n t C h e c k T h e c r a n k c a m a n...

Page 49: ...il desired alignment is achieved g T ighten 2 motor bracket screw s afte r align ins suppo rt arm h After align ing the crank cam check the space betweec the phctcseqse assembly on the carrier and the...

Page 50: ...S S E M B LY Figare 2 11 Crank Cam Alignment Check D ISKETTE DR IkE E ERCISSR Malntenance checks and adjustment prccedqres cen be accomplished on llne using the controller of off line usln the M del 4...

Page 51: ...4 Q GRP YD Cd TA co N T u k u v u x z sj prw j x y o yqx va v ww H 4 l Rie t 12 CR WEM G ER E rx l c a a h e x a txtttl re r toc t u xf x o O o O o O o O o C o Cp d O o w a co 0 a z 1 so r f v w o a I...

Page 52: ...to lower numbered tracks unt il T rack 1 is reached and then the process repeats CRESCENDO program s seeks to alternate between Trac k 00 and successively higher num bered tracks untll seeklng T rack...

Page 53: ...groups of 3 l s HFH COFTINUOUS HRITE SHITCH Pujhbutton Holds Rr te Gate 0N continuousl y w hlle pressed data as se lected by Fattern p Se lect Sw itch is transferred Destroy s format I on di sk ett e...

Page 54: ...5V TEST PQI NT 5 olts is available at this test point fcr mon ltoring SEEK COHFLETE TEST PO INT Monitors Seek Com plete s gnal returned from dr ive HR ITE DATA TEST PO INT Honitors Hrite Data sent to...

Page 55: ...a ra t o r P c B s c h em a t ic 2 0 0 5 9 2D 3 D r iv e E l e c t r o n i c s P cB A s s e m b ly 2 0 07 4 0 D riv e ele c tron ic s Pc B sch em a tic 200741M 1 4 4 Eject and Harness B oa rd Side 1 P...

Page 56: ...o r p 4 r e s Q O r ps T P l l r o U S t e k t v UB Q 9 UI 0 D O 3 O O Q RE MOVE KE YI NGPI NSPRI ORI D I NS T AL L ATI ON PcB 2 S C H EM AT I C R EF 2 0 0 5 3 1 D MARK REVI SI ON ANDGERI AL NUMBERS I...

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Page 58: ...ONON PCB 3 S C H EM A TIC REF 20 0 5 9 2 Q THEJ UMPER BETWEEN A CI S AN ETCHEDC Y DUCT OR W H EN AN Y O T H E R JU M P ER LO C A T I O N l S R EQ U I R ED SEE TABULATEDW CUT AWAY ETCH TRACE AND A D D...

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Page 60: ...V 1 I TQ 3 ta a t l l z z l c r a z1 s o t g y p y j r o u t l j c t 5 Y C 6 e 1 4z A a 4 1 r o i c x 5 v x a a 5 x 5 u t I q a u A if T j c t js Q z w fB s s p l f 3 j l Q oe os q4 1 t l 1 1 u o u X...

Page 61: ...us I sss 1 1 g s w yR4 E JE I T 1 0 1 4 d 73 c s ss czl l Q4C1 O e v sk t 1 I a I1 s e a a t yi y R C K 5 K u c u o o k n 4 o I n sv 1 1 I a a tz c x 7 rw a M 0 1 15 4 I u2 1 1 1I us 5 4 I u j c r js...

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Page 64: ...l 4 pp sc H2v 9 2o K TP6 2 I o D Q R1 R 2 440 u z 1 z U2b 1 R m F I x 1 3 0 J 1 0 e1 k x 9 74 6 t cm a j o I 2 1 2 SP 4 2 I a v Si 4 T o1 o Mt S7 pr QYx 19 M c cwo L M X R C e l l 2 90A A 1 3 02 T 05...

Page 65: ...ss sa cl nEn p P 0 W R S A 4 1 6 A cp i ecK 7 p goc t s pe r stI jn o u pEqscI nX A t 1 3 F r oRc ossE c r oRKEYI NG RE MOVEpl Nsj a a 3a J 4 a pql oR T o al r z t Ls zR I N S TA L L AT I O N o N p c...

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Page 67: ...X 8 X 1 3 R E q MOV EC O Q N E C T ORPI NS A SS P E C I F 1 E D 1N CO N N EC TO K E IN G C H AR I PR I Im TO CO N N ECTO R I N STA LLA T I O N CO N N 6C TO R K EY I C CG RT 2 SC BEM AT I C R EF 2 O 0...

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