Cromemco 299B Technical Manual
r @ e # @ ''
2 9 9 8 D IS K D R IV E
T E C H N I C A L M A N U A L
C R O M E M C O . Inc .
2 8 O B e rn a rd o A v e nu e
M o un ta in V ie w , C A 9 4 0 4 3
P art N 0 .0 2 3 - 6 0 0 0 A p ril 1 9 8 1
C opyright (C) 19 8 0
B y C R O M E M C O , lnc .
A L L R IG H T S R E S E R V E D
FUNCT ION OF H ICROPROCESSOR IN 299 6
Tbe m icroprocessor implementation on 299 B performs three malor functlons .
T he se a re se rvo con t ro l, read y s ta tus , and e ra se de lay t im ing . The pro ce sso r
co nt inuo us ly execu tes a sequence o f ro ut ine s wh lch t rack the statu s o f ready
and se rve fun c t ion s , an d tes t the co nd lt ion o f th e se lec t l ine s to d e te rm ine
w he the r to o utp ut suc h sta tus . Beca use se e k ing a nd w r lt ing a re mu tua lly ex -
c lu s îve fu nc t io n s . T he p roc es so r a lso ha s t im e to ca lcu la te e ra se t lm ing .
Se rvo Co n t ro l
R he n the po s it po ne r 7s bo ld ing o n t rac k , the p ro ce sso r is ou t o f the se rvo
loo p , a llow ing 1' F INE PO S IT IO N SENS E '' to ke e p t he po s ît io ne r Cn p lace . khe n
seek ing to a track , the p roce sso r outputs a ve loc ity va lue wh ic h d ire ct ly co n-
tro ls the po s it io ne r w h ile co un t lng ste p an d de ten t p ulse s . Th e p roce sso r also
de te rm lne s w he n to sw itch itse lf into and o ut o f the feed bac k loo p . To e nsu re
m in im um re spo nse time to ch a nge s in se rvo sta tu s , b0 th ET EP p u lse s and DET ENT
pu lse s a re t ied to the INTE RRUP T inpu t o f the proce sso r . Th us , wh ene ve r a
st im u lus îs re ce ive d , the p roc e sso r sto ps w ha te ve r it w a s do ing a t the t /me ,
ide nt if ies the sou rce o f the in te r rup t , and tre a ts it app ro p ria te ly . T he ve l-
oc ity fo r the se rvo is de pend en t upon th e d istan ce re m a in in: to t rave l , a nd a
va lue for each ha lf-track of rem a ln ing d istance up to 63 tracks is sto red
in a look-up tab le ln memory . For greater than 6) tracks the max imum ve loc ity
b ou tp ut . T he D IRE CT IO N l ine ls sam p led a t the sta rt of a se ek and sto red fo r
the d u ra t io n o f tha t see û . lt is o u tp u t to th e D to A c on ve rte r a s the m o s t s ig -
nificant bit or slgn bit. By inlecting a current equal to one half the full
scale output through R1O3 and R10ù înto the D-A co nve rte r outpu t , a un i-po la r
dev lce ca n be use d to pro v ide s ig n ed d ua l po lar ity o u tpu t .
Upo n reach lng a d lf fe ren ce o f ze ro be twee n ste ps and d e ts n ts , the se rvo îs
sw itched to the HO LD mode fo r f lna l se tt ling to t rack . The proce sso r clea ns up
reglsters and track counters, and samples TKCENT (track center) and TKJ; (track
zero), storing them for future outgut conditîonal on selected status.
T he p roce s so r a lso co n t ro ls the RE ST OR E fu nc t îon . REST OR E ma y be în it ia te d
by the ho s t v la the RE STO RE inp u t , o r w il l o cc u r if a n il leg a l se e k is com -
manded ltoo many step pulses) or Cf a detent is received while hold in: on track.
The bu ilt- in exe rciser on the 29j 8 automatica lly w r ite-protects tbe drive
by ho ld ing SEEK COMPL ETE fa lse in the e xe rc zse r mo de .
Re ad y Sta tus
The proce sso r wa tc he s the fou r index lln e s fo r change s . A com ple te low -h igh -
1ow se que nce be lng de te cted o n e ithe r d lske tte sta rt s a t im e r fo r tha t d iske tte .
The coun t ls te sted f requen tly , a nd shou ld 2Q0m S e la pse be fo re anothe r index
pulse is sensed , the d iskette îs logged no t ready . In 299 B it is stored
Inte rna l ly and o u tput on ly fo r the se lecte d d iske tte . Tw o -s zded inde x is sam p led
whe n '' EITHER INDEX 11 is h lg h and sto red fo r ou tpu t to the ho st .
E ra se De la y T im ing
Th e use o f tunne l-e ra se head s ma nda tes a de lay c ha nge s in % R IT E G AT E and
ERASE GATE. The processor allows a refinement of this delay by adlustlng it
acco rd ing to the t rac k loca t ion . T he INT ERRU PT c lrcu it is co nf lgu red such tha t
either edge of WRITE GATE (turn-on or turn-off) causes an lnterrupt. When thls
inte rrupt is lden t if îed , R R IT E GAT E ST AT U S is te ste d a nd the a pp ro pr îa te d e lay
Is ge ne ra ted ; longe r de lay s fo r tu rn -o ff and va ry lng length s depe nde nt upon the
track loca tlon . De nse r fo rmats tha n w e re ava ilab le w ith fixes de lay s can be
o bta lne d .
TABLE O F CONTENTS
PAGE
SECT IOK 1 - INSTALLAT ION ...............................
. . . . . . . . . . 1-1
INSTALLAT ION CHECK LIST .................,......
. . . . . . . . . . . . . . . . . .
1-1
14 i s u a 1 I n s ;) (, c 1; 1- () n . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . .
1 - 1
hltl C h a n 1* (: a 1 C h (, c k S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . .
1 - 3
1::1 (512 1::1 1::j lkhdr 152! 14*% 1::2 iilk I1:i *1 -1' 4'11 !g4l . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . .
-1 --- 111:
P3 - DC power Connecto r ...............................
. . . . . .
1-4
/1 C P 0 k:e r C a b ) 1 n g . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.
) - 4
? 4 - /$ C C 0 n n e C t 0 r . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . .
. . . . . . . . .
1 - 4
S 1- g n a 1 C a b l 1- n g . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . - . . . . . . . .
. . . . . .
1 - S
h1 ; t 1- n g C 0 n n e C t O r S . . . . . . . . . . * . . . . . . . . . . . . . . , . . . . . . . .
. . . . . . . . .
1 - 7
INSTALL D ISKETTE DR IVE .................................
. . . . . . . . . .
)-7
Vert ical lg-inc h Retma Rac k Installat ion ..............
. . . . . .
1-7
Ho rizontal 19- 1'nch Retma Rack lnstallat l'on ............
. . . . . .
1-8
E) (! S k 17 () p h1 () u n t i n g . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . .
1 - E$
Diskette Load ing and onload p'ng ........................
. . . . , .
1-8
ChaSSI'S Ground ...................................,.........
. 1-10
Drive Select Options .......................................
.
1-10
17 kk () () r 1- v t! () p t )- () n - . . - . . - . . . . . . . . . . . . . . . . . . - . . . . . . . . . . . . . . . . . . ) 1 )
0ne Drive (Rotary) Option ................................... 1-11
F () u r () r 1- v i? () p t 1- () n . - . . . . . . . . . . . . . . . . . . - . . - . . . . . . . . . -
. . . . . . . . .
1 - 1 1
E 1- g h t D 4% 7- v (, () p t 1 o n . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . 1 - 1 1
L 7- n (, lr (, ywrr 1- n a t 1- () n . . . . . . - - . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . .
) - 1 1
lndex/sector ................................................ 1-13
Independent Index/sector Lines .............................. 1-13
Sepa ra ted Inde x and Sec to rs . ,. .... .,., ... ...
. . . . . . . . . . . . . . . .
1-13
(2h 1* 1; $( (, 1: 17 (? !! J- (! (2 1: . . . . . . . . . . . , . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . 1 -- 1 :$
l!1 k, 1* 1) (! F' ke (:p 1: (, (: 1: . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . .
1 -- 1 dl
l'la n u al E je c t I n hi bi t . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 -1 5
Di s k e t t e Eje c t Re q u e s t . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . . . . . 1 -1 5
Da t; Se P; r; t1'0 9 ... .. .... .... .. .. .... .. .... .. .... ..
. . . . . . . . . . 1 -1 6
FM Da ta Se pa ra t0 r ....... ...... ........ ... .. ........ ...... ..
.
1 - 1 S
0n e
.
ShO t Em ul a t ion ..... ...... .... ....... ... .... ...... .... ... 1 -1 5
P ha Se L0C ked C1 Oc k ........ ... ....... ...... -.......
. . . . . . . . . .
1 -1 5@
FH Data Se paration ..........................
. . . . . . . . , .
1-15MFH/H
FR Data Separator Adjustment ..........................,..... 1-162
FM Data Separator Adjustment ....................,..... 1-16HFM/M
Do ub le De nsity Data Com pensat l'o n .....,.........,...,........ 1-17
Configu rat ion o f Opt ion s ... ................................. 1-17
1
TABLE 0F CONTENTS (Continued)
PAGE
SECT ION 2 - HAINTENANCE
PREVENT IVE HA INTENANCE SCHEDULE
kuarterly Cleanl'ng ..,....................................... 2-1
DriMe Sy stem Test ......................,.................... 2-1
FREkENT IVE HA INTENANCE PROCEDURES .......,........................ 2-1
Splndle Dr ive Sy stem ........ ............,.............. ..... 2-1
Drive Belt Tens l'on .......................................... 2 -2
Read/krl'te Data Amplitude ....,.............................. 2-2
MA INTENANCE PROCEDURES ........................................... 2-2
Tools and Test Eqe l'pment ..............,..................... 2-2
JACQS and P1u9S ............................................. 2-3
Drive Elect'ronl'cs PCB ....................................... 2-4
PCB Replacement .......................................,..... 2-4
Voltage Adjustment .......................................... 2-4
Drive H otor and Belt Checks .................,............... 2-6
Drive Belt Tenslon Adjustment ............,.................. .2-6
Drive Belt Replacement ...................................... 2-7
lndex Transducer and Logic Checks ........................... 2-7
lrldex T ransducer A ll'gnment .................................. 2-8
Index Transducer Replacement ................................ 2-9
Spind le Cone Check .......................................... 2-10
Sp indle Cone Replacement .................................... 2-12
Positl'on ing Sy stem .......................................... 2-12
Positioner Servo Check .,.................................... 2 -12
Head Assembly Track A ll'gnment and Haciine Azimuth ........... 2-13
Positioner Servo Adjustment ........,...,..........,......... 2-16
prell'minary Adjustments ............................,..,..... 2-16
Final Adjustments ...............................,........... 2-17
Head Assem bly T rac k and Head Azimuth A ll'gnment Side 2 ....... 2-18
Head A ssembly Track and Head Azimuth Allgnment S ide 1 ....... 2-19
Load Cam Shutter Al ignment .................................. 2-19
Eject Motor Cam Allgnment Check ............................, 2-20
Crank Cam Alignment Check ................................... 2 -20
Crank Cam Alignment procedure ............................... 2-21
DISKETT E DRIVE EïERC ISER ..............
.
. . . . . . . . . . . . . . . . . . . . . , . . . . .
2-22
Contrcls , Indicators. and Test Po 'lnts ..............,....,... 2-22
D r aw 1- n g s a n d Ha t e r 1 a 1 L 1 s t s
1 1
LISI 0 F ILLUST RAT IONS
FIGURE T ITLE PAG E
1- 1 Diskette Drive Shipplnq Con flguration .................... 1-2
l-2 Prope r Load ing of Dlskette ............................... 1-3
)-3 Slide Hountinq Dlmenspons ..... ,......................... 1-7
1-4 Ve rt ical Retma Rac k Hount lng .. .............. ............ 1-9
1-5 Hor izon ta l Retma Rack Mountinq ........................... 1-9
1 -6 Outl ine o l'men sïo ns - .. .. .... - .. ... .... ....... ... ... ... . . 1 -1 0
1 -7 H r l'te ? rotec t Notc h Loca t ion .- ..... . ... .. .... .... ., .... . 1 -1 4
2-1 P1 ug s and Jac ks Id en t î fl ca tion .....,... .. ..... ... .
. . . . . . . 2- 5
2-@ Dr1've S# StQm .................. ......... ............ .
. . . .
2-6
2-3 Index Pu lse and lata Bu rst .... ...... ... ... .. ... ... ... .. 2-8
2-4 Index Transduc er and Coce A ssem bly ................
. . . . . , .
2-10
2-5 Exam ple of Good Cone ......... ....... ........,........... 2-11
2-6 T rac k A lïjnm en t ..... .................................
. . . .
2- 13
2-7A Head Assem bly Hount qnç Sc rew s S lde 2 .... ............
. . . . .
2-14
2-78 Head Assem bly Mount lnj Screw s S lde 1 .............
. . . . . . . .
2-14
2-7C Cat Ey es and Head Azimuth D isplay ................
. . . . . . . .
2-15
2-7D Head Az l'm uth Alignment ..................................
.
2-1 5
2-8 Dr ive Elect ronl'cs PC8 ... ................................
. 2- 16
2-9 Load Cam Shutter A lignm ent ......... ..................
. . . . 2-20
2-10A Eject Motor Cam Alignment Check-carrier Open ............. 2-21
2-10B Eject Hotor Cam Alignment Check-carrier Clnsed ........... 2-21
2-11 Cran k Cam Alignment Check .........................
. . . . . . .
2-22
2-12 Control panel , D iskette Exerc iser , Model 499 ............
. 2 -23
LIST OF TA8LES
NUH8Eq T ITLE FAGE
7-1 Installat ion Check Llst ........ ..........
. . . . . . . . . . . . . .
1- 1
l-2 Inte rface P 1n Connect l'ons ......,.... .......
. . . . . . . . . . . . . .
1-6
1-3 Binary Se lectlon of Four Dr q'ves . ......... ..
. . . . . . . . . . . . . .
1-12
1-4 B inary Selection of Elçht Drives ........
. . . . . . . . . . . . . . . . .
1-12
l-5 Opt ion Com ponents , Jum pers , and I race Cuts
. . . . . . . . . . . . . . .
1-18
2 - 1 J a c k S a n d P 1 u g S . . . . . . . . . . . . - . . . . .
. . . . . . . - - . . . . . . . . . . . . . .
2 - 3
2-2 Po sit ione r Servo Prelim lnary Adlustments .
. . . , . . . . . . . . . . . .
2-17
2-3 Exe rc iser Sw itch , lnd icator and Test Po int Functions
. . . . .
2-24
7 1 1
SECT ION )
IhSTALLAT ION
This sec tion contains procedu res to verîfy the operat ional integrity nf
the d iskette dr ive pr ior to on-line oper at ion .
INSTALLAT IOh CHECK LIST
The insta llation chec k llst , Table 1-1 , is desijned for trained personne l
to use as a guide in performing installation checks necessart for proper
operat ion . If more de ta qled insta llation info rmat ion is de slred . refer
to the appropr iate paragraph in this sect ion .
TABLE 7-1 . INSTA LLAT ION CHE CK LIST
Visual In spectlon
a . Remo ve a1l pac king m aterial .
b . Chec k packing l ist .
c . Check for shlppins dam age .
d . Remove carriage restra int inserted in S ide 1 .
Hec han ical Chec ks
a . Chec k that carrïage dssem bly moves free ly over entlre stroke .
Cable s
a . Fabricate DC and sig nal cables .
b. Check pin to pin resistance (a11 cables).
c. Check pin to conductor continuity (a11 cables).
d. Check for prcper pin alignments (a11 cables).
Houn ting
a . Insta ll d iskette dr ive ,
b . Connect ca bles to d iskette dr ive .
Chec kout
a. Operational checkout with exerciser (optional).
b . Ope ra tiona l c hec kout w ith sy stem .
kisua l In spec tio n
The d iskette drive is packaged to ensure adequate pro tect îon for shipp ing
and handling (See Figure 1-1).
1-1
ûUTSIOE CARDBOARD B0 X - -
%
%
x e N x
8 CORNER BLOCKS .-
l
%. I
l
*
-
*
I
I I l
1 --
INNER
CARDBOARD
-
B0XN
x N -DRIVE
CARRIAGE
RESTRA INT - e
Figure 1-1 . Diskette Drive Shipping Configuration
Inspect the shiqping container for evidence of any in-transit damage.
If damage is evlten t :
a . Contact the carrier .
b . Contact the manu facturer .
Unpac king
After performing a prel îm inary inspect ion , unpack the dîskette drive a s
fo llow s :
a . Remcve a11 material from shipping container . Remove inner pac king
materlal .
b . Check m ateria l rece ived against packîng list . If pack ing shortage ,
con tac t ma nufactu rer .
c. kîsually insqect a11 items received for physical damage. lf
dam age qs ev lden t :
Contact the carrier .
Co ntact the manufacturer .
1-2
- , '
A
x
LA BEL
d
!
N
<
HEAD SLOT
FORHARD
INDEï HO LE
Fijure 1-2 . pro per Load ing of Diskette
Mechcnlcal Checks
To chec k the proper loading and unload ing of a diskette , the d iske tte pow er
cable must be connected . A button is located at the front of the beze l
adjacent to the diskette aperture. Hhen the button is pressed, the load
mechanism moves to the open position and the diskette is ejected. The
load mechanism w ill automatically close when the d iskette is fully inserted .
a . Inse rt a d iskette and ver ify that the load mechan ism clo se s.
b . press the button and Mer ify that the load mecNan ism releases and
that the diskette is ejected approximately 1/2'%
CABLES
Three cables are necessary to connect power to the d iskette d rive and signals
tn t he host sy stem .
DC Power Cable
AC Power Cable
Slgnal Cable
DC power Cabling
A11 DC pow er llne s shall have lengths and w ire d iameters consistent w ith
meeting the power regulation reguirements of the d iskette dr ive as fcllows :
1-3
15V DE l 5% 2 .0 Am ps Max ., 50 mv p-p ripple
-
5k DC à 5% 0 .25 Amps M4x ., 50 mv p-p ripple
+24/ DC 1 5% 1 .0 Am ps Yax . seekinj w ith 2 .0 Amps
Max . peak
Seven lines are used to transmit DC power throu:h the power connector from
the power supply into a diskette drive. Qne lqne palr (high and ground)
is used for +5V DC , nne for +24V DC . and one for -5V DC . Iq addltïon , one
extra ground and one chassls :round are provsded .
Five-foot lengths of 418 AHG w ire are normally acceptable for use as DC
power lines 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 Chassis Gnd 6 Ground Connector Molex 09-50-3101
2 +5V DC 7 Grcqnd Termlnal Molex 08 -50 -0106
3 Spare 8 Ground Polarizinq Key Holex
15-04-0219
4 Key 9 Ground
5 +24: DC 10 -5V DC
AC Power Cabling
AC power cabling should be fabricatrd from U.L. accepted ccrd capable Qf
carry ing 1 amp at the Moltage at w hlch the drive is to be operated .
P4 - AC Connector
3 P1 n Amp
Pin Funct fon Ha ti nq Connector
1 Motor Power ''A'' Houssng Amp 35076 6-1
2 Frame Groepd Termlnal Amp 350550 -3
3 Ho tor Power ''B ''
1-4
AOTE
For re liab le ope rat po n of the 2998 d is kette d rive , o r mo st
com puter pe rlpheral equ ipme nt . an AC l ine filter o n a11 AC
inc lud ing that to the OC power supply is requ ired .
S lgna l Cabl ing
Sy stem con nec tlo n be twee n the con tro lle r and d iske tte dr ive is opt iona lly
co nnected in e ither a rad lal or da isy cha in arrangement . T0 accommodate
eithe r app licatlon , plug-in te rm inato rs are prov ided .
a . Hu lt iple Dis kette Dr ive A pplicat ion s
Term ina to rs must be remo ved from a 11 but the dr ive electr ically furthest
from the controller ; the last d rive te rm înate s the l ine .
b . S inq le Diskette Drlve Appl ica tion
For single drive apqlication, the terminated diskette drive is used
for the diskette drlve-to-controller connection. The I/0 cable is
sim ply c onnected to t he co nne cto r .
c . S igna l C able Fabr icat io n
1. Fabr icate the interface s ignal cable accord ing to Table 1-2 by
using tbe appropriate connectors . T he interface s ignal cable
shou ld be a twisted pa ir w ith return grounds on odd num ber p ins .
I/0 wire is No . 24 or No. 26 AHG conductor. approximately 30
tw ists per foot . w ith max imum length of 20 fee t. Alternately
an eq uivalent flat cable may be used .
2 . T he g round side of each tw isted pa ïr term inate s w it hin a few
inc he s o f the line rece iver or tra nsm itter ground on the d isk-
ette dr îve .
3 . Usinj a V0H . check each cable for pin-to-pin shorts .
4 . Check for continu ity between each p in and its conductor , at the
oppos ite end o f the cab le .
5 . A fter che cking a11 cables co nnect them into the sy stem .
1-5
TABLE 1 .2 INTERFACE P IN CONNECT IONS
(50 P1N EDGE CONNECTOR - 0.1.' CENTERS)
GND P IN S IGNAL P IN SIGNAL NAH E
1 2 -SIDE SELECT (CUST. OPTION)
3 4 -DISKETTE SELECT 4 (9S4)
5 6 -THO-S IDED
7 8 -INDEX
9 10 -SEEK COHFLETE
11 12 -RESTORE
13 14 -REMOTE EJECT (CUST. OPTION)
15 16 -H EAD 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 EJECT RECUEST
(CUST. OPTION)
31 32 -PHASE LOC KED CLOCK
33 34 -DIRECT ION SELECT
35 36 -STE?
37 38 -HR ITE DATA
39 40 -HRITE GATE
41 42 -TRAC K 00
43 44 -HRITE PROT ECT
45 46 -READ DATA
47 48 -SEP. DATA (0pTI0N)
49 50 -SEP. CLOCK (0PTl0N)
1-6
Ha ting Connecto rs
Vend or
kendor Part N
-
um ber com ment
Scotch Flex 3415-0000 Flat Cable
T & B Ansley 609-5005 Flat Cable
Viking 3VH25/1JN-5 Solder
Texas Instruments H312125 Solder
INSTALL D ISKETTE DRIVE
There are two methods of installing the diskette dr ive in a lg- inch Retma
rac k ;
Vert ical - 4 maximum
Horizon tal - 2 max imum
a . kertica l 19-înch Retma Rack Installation
For vertical rack mounting the use of a slide (Figure 1-3) mounted to
the top o f the d is kette drive is o pt iona l . If a sl ide is used t he w ide
portion of the slide should be m ounted to the uppe r inside surface of
the system enclosure . The narrcwe r port ion o f the slide is fastened
to the uppe r edge of the d iskette d rive frame v ia Three 8-32 Screw s 0
.
25
long . Tapped ho les on the lower ed ge of the diske tte d rive m ay be used
to secure the d iskette dr ive tn a hold ing m ember w ith in the system
enc lo sure .
V .0â. û3 Y - TRAVEL à œ X - LENGTH 1 .X
'
1 1 .t 02 ' ç . VK* ** R-Q Q < l '
-
# - - - -. + . -+ - - - + - +- - + --- - Y - # j
= - - . .
.
r .c - - . . l
i A j . 75M D q752 X.t Q2 B c
- F G
H
c L E N G T H JT q A V E L v lEwA U A C H T O D 8 IV
x Y A B C () E F G 8
STA N D A R (7 M O U N T IN G
14 1 s 4 a ) 8 00 1 2 (% 1 (m a 6,3 8 50 1 1 50 1 2 508 O LE S 4Z E ! 77 (3 IA
Fi gure 1 -3 . S 1 1 de Hount i ng Di men s 1 o ns
1 - 7
Alternatively îf a slide is not used , ''skid rails'' w ithin the system
enclosure may be used . Up to four dr ives m ay be moqnted vertically
in a lg-inch Retma rack. (Flgure 1-û.) The vertical orientation of
the diskette drive must be as shnwn . Vertical mounting of the diskette
drive is preferred over horizontal mounting .
b . Hor izontal lg-inch zetm
-
a R
-
ac k Insta
.
llat îon
If two drïves are mounted horizontally, ''sk#d Rails'' must be used as
there is insufficïent space to use slldes . lf a sfngle d iskette drive
is mounted hor izonta lly s tw0 slides , cne on each side o f the d fske tte
frame , shou ld be used . The w ide porticn o f the sllde should be fastened
t: the system enclcsure and the narrow portion to the d iskette frame .
The hor izontal orientaticn of the drive is shown in Figure 1-5 .
Powe r and signal cables may be c onnected to the drive prior to slld ing
into the system enc losure provid ing there ls enough service loop . or
if there is r ear access to the system enclo sure , the power and slgna!
cables can be installed after the d bskette drlve is mounted .
Dr ive assembly hea t dissipation under maximum 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 cubic
feet per minute (CFH) cooling eir is reqoired.
Desk Top M ount ing
The dbskette d rlve may be desk top mounted , i .e ., Positioner Vertical .
Proper compensation is automatically made for the ma ss of the carriage
assem blies .
Diskette Load inq and Unlo.ad ïng
Prope r load ing of the diskette is vital to the operat ion of the d iskette
dr ive . Figure 1-2 show s the proper loca tion of the diske tte open inj for
lo ad ing .
Procedure for loading/unlcading the diskette is ûs fcllows :
a . lnsert the d iskette into t he desired side Df the diskette drive such
tha t the lab el is a t the oppos ite end of the slot from the pushbu tton
eject switch. A sensing devïce in the drbve will automatically close
the carrier when the d ïskette ïs inserted . D iskette 1 is on the left
side of an observer fac ing the dr ïve w hich is mounted such tha t the
slot ïs vert ïcal . Dïskette 2 ïs then on the r îght side .
b . To remo ke the d iske tte , press the pushbutton located nea r the slo t con -
taining the dïskette. The diskette w111 be ejected to where dt can
easily be remc ved from the d rive .
1-8
@ *
* *
@ *
ê *
* #
. *
. @
@ @
Flgure 1-4 . Vertlcal Retma Rack Mountlng
e @
@ .
: @
11
@ @
Fi gure 1 -5 . Hor i zontal Retma Rac k Hount i ng
l - 9
SLIDE MTG .
8 .00 .80 opy loNAk
2 MTG . HOLES Typ
98-32. .38 DEEP 2.19 j--
'
! !I
1
'
#
'
1
1
1
l
l
O 8 54
1 I I $
l : DIs- rIs-
4 HOLES *8-32 , .38 DEEP KETTE xgyyE
4 .00 ) ?0N 4
. 00 CE8TERS TYP
15 .00 u .2s = 4 .38
Figure 1-6 . Outline D imensions
OPTIONS
ln ork er to meet varying requïrements of different customers , persc i provides
the follow ing Customer-lnstallable Optîons:
Chassis Ground
Chassi! grcund is bcnnected tc signal grqund near the power ccnnector on
the drlve electronlcs PCB . This connectpon îs easily broken by cutting
trace cut A . Trace cut A îs located near the chassis ground inj lead . If
this trace cut is made , P 1n 1 of the power connec tor become s a chassis ground
line only .
Drive S elec
-
t Options
Fcur d iskette select inputs and a side select input are provided . T he
normal configurat icn uses Diskette Se lect 1 and 2 to select the d iskette .
and side se lect to select the side o f the diskette . Side se lect high w ill
select the normal side of the d iskette . and 10W the reverse side .
1-10
Two Drive Option
Th is nc rma l conf igura tïon is de fïned as Dr ive 1 o f 2 dr ïves
.
To ope ra te
two dr ives in parallel , one drive must be this No rma l 1 o f 2
, a nd the
other m ust be c on figured a s Drive 2 of 2 d rives . Dr ive 2 uses oiskette
Selec t 3 and D iskette Sele ct 4 to se lect the d ïske tte a nd s ide se lec t f0r
the side Gf that diskette . Drive 2 of 2 d rives is option 2
. Re fer to
Tab le 1-5 for the connections regu ired for these configura tions
.
One Drive (Rotary) Option
The one drive (rotary) option uses the 4 diskette select lines to select
the d iskette and s ide of the d iskette . The side se lect line m ust be le ft
hig h o r open for th is co nfigura tion .
Diskette select 1 (DS1) selects Diskette 1 Side 0 (normal), DS2 selects
Diskette 1 Side 1 (reverse), DS3 selects Diskette 2 Side 0 (normal)! and
DSô selects Diskette 2 Side 1 (reverse). This configuration is Optlûn
3 , and may be im pleme nted by ma klng the connect bons found Jn Table 1
-
5 .
Four Drive Option
Four drives may be operated in parallel using the diskette select linesi
n a binary code to se lect each of the 8 d iskettes and slde se lect to
obta in two-sided record ing . ln this mode cf operation , DS1 is u sed as
un enable line . 1ow to enable ; and DS2 , DS3 . and DS4 are decoded ln a
binary fashion . Diskettes are selected according tn Table 1-3
.
Bina ry
Selection nf 4 Drives. This confisuratinn is option 4 . and can be im ple-
mented by referring to Table 1-5 to determine the connections required by
each o f the 4 d rives .
Eight Drtve Opt
-i-
o n
Eight d rives m ay be operated in para llel usic: the four d iskette select
lines in a b inary code . See Table 1-4 . If a 11 e fght dr fves are used
.
n o
state will be available f0r a11 d rives to be de-selected
.
i.e ., there w i11
alway s be one drive selected . This conflguratbon ls optson 5 and can be
implemented by making the requ ired connectfons as defined by Table 1-5
.
Line Term ination
A 220/330 chm resistor pack is iqstalled in U8. This kûck is used to match
the impedance of the input sijnal line pairs. Mhen drlves are used ln
parallel , this resistor pack must be removed from a11 drives but the 0ne
electrically farthest from the controller. The 220/330 ohm resistor pack
must be left in the drive electrically farthest from the controller to
maintain proper line term inat ion .
1-11
TABLE 1-3 . BINARY SSLECT ION 0 F FOUR DRIVES
System
Drjve/Diskette Sllected Dqskette
DS l DS2 DS3 DS4 Dr lve Dlskette Se lected
HIGH ANY ANY ANY NONE hONE NONE
L0H H IGH H IGH H IGH 1 1 1
L0H L0% H IGH H IGH 1 2 2
L0k HIGH L0% H IGH 2 1 3
L0H L0k L0% HIGH 2 2 4
L0% HIGH H IGH L0% 3 1 5
L0H L0H H IGH L0% 3 2 6
L0k H IGH L0k L0% 4 1 7
L0M L0H L0H L0H 4 2 8
TA BLE 1-4 . BINARY SELECT ION 0F EIGHT DR IVES
Svstem
orive/Diskette Selected Diskette
DS 1 :S2 DS3 DS4 pr ive Diskette Selected
L0H H IGH H IGH H IGH 1 1 1
L0H L0H HIGH H IGH 1 2 2
L0H H IGH L0H H IGH 2 1 3
L0H t0% L0% H IGH 2 2 4
L0N H IGH H IGH L0H 3 1 5
L0H L0H H IGH L0H 3 2 6
LO% H IGH L0% L0l4 4 1 7
L0H L0M L0H L0H 4 2 8
H IGH H IGH H IGH H IGH 5 1 9
H IGB L0H H IGH HIGH 5 2 10
H IGH H IGH L0% H IGH 6 1 11
HIGH L0: L0: HIGB 6 2 12
H IGH H IGH H IGH L0% 7 1 13
H IGH L0% B IGH L0% 7 2 14
HIGH H IGH L0M L0H 8 1 15
HIGH L0M L0% L0H 0 2 16
1-12
He ad Load
The noçm al co nf7gurat qon ls suc h that if a diskette is selected . the heads
are loaded . Head load input , P in 16 . serve s as an OR funct ion w ith select ;
th ls lnput may be used to lo ad the heads of the non -selec ted dr ives in
antlclpatlon of read/wrïte activïty . The normal connection utilizes a
75451 ln the U26 qosition. Head unload ls delayed approximately 5 seconds
for accessin: varlous diskettes without W ait ing fcr head 7oad when the
Se lec t comes bac k to the orïg ina l head .
Optbona lly , the 754 51 can be removed from U26 and a 75453 installed . This
makes head load an AND function With diskette select, allowing ready, index
two -sided and write protect funct ion s of a selec ted drive to be m on ltored
w ithout load ing the heads . This is Opt ion 6 .
lndex/sector
The drive norma lly com es from the facto ry w ired to prcduce a 1 ms pulse
from h lgh to 1ow logic leve l at Pins 8 and 20 each t ime an index or sector
hole is sensed on the selected dJskette . Refer to Table 1-5 for the connec-
tions o f th is implemen tat ion .
Independent 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 pulses from Diskette 2 . When either diskette is
selected . This option may be configured by m akin: the connect ion s found
ïn Table 1-5 .
Sepa ra ted Index and Sectors
Opticns 11 . 12 . and 13 prov ide for separatinq the index pulse from the
sector pulses on a hard sector d iskette . 32 . 16 . or 8 sectors can be pro-
vided . The lndex pulse appears on p in 8 wh ile the sector pulse s appear
on Pin 20 of the I/0 connector . -
lm plementat ion is accomplîshed by making the connection s listed in T able
1-5 .
Although only the selected diskette 's index and sectors are availab le .
sepa ratlon and countdown are ma întained for both d iskettes to prevent
loss o f synchro nizat ion for an unse lec ted d iskette .
Diskette Eject
The Model 2998 comes from the factory confijured such that diskettes may
be ejected (whenever write gate is false) elther by a nushbutton switch
at the bezel or. (for the selected diskette only) by a 100 ns minimum
pulse o r level to log ic 1ow on the ssgnal interface P in 14 . Refer to
Table 1-5 for connec tion de ta ils of th is configuratlon .
1-13
I II()E' ï HOt E
v = 6 . 175 z . 005 ( 1 56 . 8 :!: . l nml ( S INGLF S I DE.D )
x = . 1 50 :t . 005 ( 3 .81 0 :t . 1 mm)
Y = . 200 :!: . 01 0 ( 5. 080 :!: . ?50 mm) INDEï HOLE
( DUAL S I DED )
Z = .075 :f .005 ( : .905 :f . 1 mm) O
Z
HEAD ACCESS
OPEN ING
Y
.
= k > - 't y
Figure 1-7. Vrite Protect Notch Lccation
kr ite Pro tect
The 299 drive as supplied from the facto ry implements ANS I proposed Optlon
1 , utilizing a nctched d iskette . An optical sensor is installed to sense
the notch in the diske tte . Tc un-prc tect a d iskette s cover the no tc b w ith
an opaque tape (Avery DGF-KI-D-IZ or equivalent). See Fiqure 1-7.
Hritinq is inhibited on a w rite protected diskette and the w rite protect
output . Pin 44 , îs 1ow when the w rite pro tected diskette is selected .
Cu stomer- lnstallable Opt ion 14 Will prevent writlng o ff-speed data dur ing
însertion or ejection of a diskette. lkrite protect logic is actîvated
durinq insertion or ejection, by remote eject, or bezel switch. of eîther
d iskette . Hrite is inhib ited and Wr ite protec t output ls true turinj these
operat ion s. lf the insert ion takes place w hile W rite qate is true , the
carrier closure Js depayed until write gate is false. lf an eject command,
either from the bezel sw itch or controller is gqven wh ile w rite gate is
true, then the eject coFmand is ignored.
This option may be implemented by installing jumpers in G1 to G2 and G3
to G4 .
Optionally, write protect can be defeated by removing U35 (AH5072). This
is Optlon 15 .
1-14
Hanual Eject lnhibit
Optîon 9 is the manual eject inhiblt option. Rith this configuration a
logic 1ow on Pin 30 of the signal înterface will prevent ejecticn by the
bezel pushbutton ; allow ing the controlle r to loc k in a d iskette until
reat/write operatjons in prcgress (i.e., closing files) are complete.
Refer to Tab le 1-5 for con nection deta ils .
Diskette Eject Request
Hhen Opt ion 8 is configured : the function of the bezel pu shbutton is
changed from ejecting the dlskette to prcducin: a logic 1ow at Pin 30.
The controller can then recognize this signal and issue an eject command
when a11 processinj is finished . Re fer to Table 1-5 for connection deta ils .
Data Sepa rat ion
The 2998 c an be ordered W ith no data se parator . or w ith FM data sepa rator ;
or with HFM/MZ FM data separator installed
.
Fh1 Data Se pa rato r
The FH data Separator use s a p hase loc ked loop techn ique to pro pe rly sep-
arate clock and data pulses from the FH (double frequency) code. Proper
se parat ion is ma inta ined over th e three dropped c locks o f an IBH type
address m ark . Separated data and separated clock pulses are sycchron ized
to the phase loc ked loop. Froper separation is : data pulses alway s on the
data l ine and clock pu lses a lway s on the c loc k line . Sep arated data is
?in 48 and se parated cloc k P in 50 of the signal interface connec tor .
0ne Shot Emu lat ion
To funct ion pro per ly in con trolle rs de signed to opera te w ith one shot data
separators the phase locked data separator can be jumpered such that the
cloc k pu lses w ill appear on the d ata line , and data pul ses on the cloc k
line ! after the first m issing cloc k o f an IBH type addre ss mark . Th is
condltion continues until the first misslng data qulse of the address mark;
at w hich time cloc k and data pulse s appear on the lr proper l ine s . Phase
locked tracking and synchron izat ion of data is ma ïnta ined While emulating
one sho t ty pe t iming . Cut Trace A to C and install Jum per B to C on the
data separator to implement this o pt ion .
phase Locked Clocq
The single den sîty data separator provides a 250 KHz square w ave phase
loc ked to the incom ing d ata . T his signa l is pos itive go in; at the lead ing
edge of separated data and negat ive go ïng at the le ad ing edge of separated
cloc k pulses . Except w hen the loop is acquiring lock there are no m issing
pulse s on this signal , T his signal m ay be used for very simple address
mar k de tect ion and da ta serial to para llel conversïo n . To obtaïn this
output J um per B3 to B1 on the dr ive e lectron ics PCB . The phase locked
cloc k output is Fin 32 of the sîgna l interface connector .
1-15
MFM/H2FH Data separation
A data sepa rator is ava ilab le wh ich may be used for both of these codes .
A pulse appears cn the separated data l ine . Pin 48 of the signal interface ,
for each data pu lse in the cnde . These pulse s are synchron #zed to the phase
locked loop such that timing jbtter due to density effects is fîltered.
A reccnstructed c loc k derived from the phase locked loop appears on the
separated c lock line , Pin 50 o f the sîgnal in terface connec tor .
The HFH/M2FM data separatcr reguires a synchronizing pulse at the beginning
of eac h field independently w ritten on the d isk . In a hard sectored system
where sec tors are separated and co unted in the 2998 : Jum perïng B3 to B4
w ill prc vide this . o the rw ise , Jumpering B3 to B2 w 171 connect the sync
line to Pin 24 of the s igna l inter face connector .
FH Data Separator Adjustment
The FH data separator was adjusted at the factory. and normally needs no
maintenance. The only adjustment is the VC0 center frequency. This may
be adjusted wîth potentiometer R-12. Adjust while installed usinq the
fo llow in g proced ure :
1. Observe the sawtooth VC0 at T?1 (Approxïmately 4.4V p-p). Observe the
kC0 control koltage (range +0.4V to -0.4V) at T?2. The oscilloscope
sround s m ay ba connecte d to TP5 or T P6 .
2. Hrîte a dîsk using either a 4998 exerciser (STD. pattern) or the host
system for the drlve. (An a11 0's FH pattern gives least phase Jltter.)
Read this d isk fo r data input to the data separato r.
3. Adjust R12 until the system locks the saWt0oth to read data with the
sawtooth at Approximately 500 KHz. (Actual frequency is determined
by data frequency , : 2% average.)
4. Sontînue to adjust R12 such that the average value at TP2 is 0k t 50 mv
while locked at 500 KHz . rlote that ISV W ill cause this voltage to
oscillate about qround as the loo p tracks drive spee d .
MFM/MZFH Data Separator Adjustment
The MFM/HZFM data separator was adjusted at the factory o it normally requires
no malntenance. There are three adjustments; sync pulse. frequency, and
phase .
Sync pulse 7s adjusted With 229, frequency with Rl6, and phase With R4.
Adgust w ith the fo llow ing procedure W ith da ta separato r insta lled .
1. Prepare a disk of al1 0's using either a 4998 exercîser OIFM pattern)
or the ho st sy stem . Read this disk fo r da ta to the da ta separa tor .
1-16
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