Mitsubishi Electric M4853 User manual

5.25 INCH FLEXIBLE DISK DRIVE
MODEL M4853
MAINTENANCE MANUAL
STANDARD
MITSUBISH ELECTRIC

CONTENT
Pag
1. G n ral 1
2. R f r nc s (Sch matic and Manuals) 1
3. Nam s of Unit Parts 1
4. Op rating Information 2
4.1 Environm nt 2
4.2 Disk tt Handling 3
5. R gular Maint nanc 4
5.1 Caution 4
5.2 H ad Cl aning 5
5.3 Ch ck and Adjustm nt 6
5.3.1 Disk tt rotation cycl adjustm nt 6
5.3.2 TK 00 s nsor position adjustm nt 8
5.3.3 Ind x s nsor position ch ck 10
5.3.4 H ad alignm nt adjustm nt 11
5.3.5 H ad Azimuth ch ck 13

1. G n ral
This manual xplains th handling, maint nanc and
adjustm nt of M4853 Fl xibl disk unit.
2. R f r nc s (sch matics and manuals)
M4852/53 Sp cifications SJ2-G3375C
PCA NAMFB sch matic diagram for maint nanc TJ2-G30144A
Illustrat d parts list TJ2-G4865A
Packing manual (10 s t) TJ2-4869A
3. Nam s of Unit Parts
FIGURE 1

4. Op rating Information
4.1 Environm nt
Th r is no probl m in op rating und r normal offic condi
tions but wh n op rating out of following conditions, Driv
may not work prop rly or Disk tt may g t damag d.
1 T mp./Humid. Rang
During op ration During non op ration
T mp ratur Rang 5°C - 43°C -10°C - 50°C
Humidity Rang 20% - 80% RH 20% - 80% RH
(DEW LESS) (DEW LESS)
(Maximum w t bulb t mp 29.4°C)
Impact shock Vibration
During op ration : L ss than 0.25G (5 - 100 HZ)
During non op ration : Continuous vibration
Dust
l ss than 3.0G (5 - 100 HZ)
B xtra car ful of dust ant ring unit b caus it may caus
damag to h ad or disk tt m dia.
4.2 Disk tt Handling
(B xtra car ful of th following)
1 K p disk tt m dia away from any applianc which may
g n rat magn tic fi ld.
( x, Radio, TV, Motor/Dynamo and oth r l ctrical applianc s)
2 Do not bring any f rro magn tic mat rials n ar th disk tt .
3 Do not b nd m dia und r any condition.
4 R turn th disk tt to storag nv lop wh n transporting
and storing it.
5 Do not touch or att mpt to cl an th disk m dia surfac
with alcohol.
6 Do not xpos disk tt to h ad, dust, or sunlight.
7 Do not writ anywh r xc pt on th m dia lab l and only
us a soft f lt tip p n.

FIGURE 2

5. Regular Maintenance
"Unit lif can b aff ct d by damag d parts as a r sult of dusty
anvironm nt or xc ssiv op ration." So Maint nanc by such
m thods as visual insp ction, cl aning/chang of damag d parts
and r gular functional ch cks will k p th unit in good condition
and nabl th discov ry of any probl m at an arly stag .
Tim span b tw n maint nanc is calculat d at an actual op ration
rat of 8 hours a day so in cas of gr at r rat , diff r nc s
modification is n d d. Wh n op rating at a normal nvironm nt
condition, p rform maint nanc onc a y ar.
5.1 Caution
1 During maint nanc , b car ful of dust nt ring unit, and
damaging h ad.
2 Mak sur pow r switch is off first, wh n starting maint nanc .
3 Wh n put off/on Print d circuit Board (P.C.B.)
Assy, mak sur pow r switch is "off" to prot ct
s miconductors and ICs.
4 Do not touch Disk m dia surfac or h ad dir ctly and do not
bring any f rro magn tic mat rials n ar it.
5 Wh n using this unit for R ad data only (wh n using CE Disk),
b car ful of writ mod mishandling to prot ct data.
6 Do not touch st l b lt and do not adjust r lat d m chanism.
7 Avoid static shock or xc ssiv forc to h ad carriag
ass mbly b caus it has b n car fully adjust d. To not
r adjust any scr ws xc pt wh r sp cifi d in this manual.

5.2 H ad Cl aning on Fi ld Applications
H ad cl aning is r comm nd d at us r's sit s, sp cially wh n
us d in s v r nvironm nts, b caus th h ads may accumulat
dust in th air and magn tic coating mat rial of th disk,
causing chanc of rror incr as and/or scratch on th disk
surfac .
R comm nd d sch dul s and proc dur s ar as follows:
1) Cl aning Sch dul s
(1) P riodical cl aning using w t typ cl aning disk.
i. Onc a month for normal usag in normal
nvironm nts.
ii. Should b incr as d to about onc a w k wh n
us d in s v r nvironm nts such as dusty ar a,
high humidity, high and low xtr m t mparatur s.
Low t mp ratur such as 5 to 10°C (41 to 50°F)
und r high humidity is most s v r for disk tt s.
iii. High r fr qu ncy for brand n w driv s would b
r comm nd d, for about onc a w k. B tt r
matchning b tw n h ad and m dium would b
produc d by a long tim us , as xp ri nc d.
(2) Wh n fr qu nt rrors ar d t ct d. (W t or dry typ
may b us d.)
(3) Wh n scratch ( s) ar found on th m dium surfac .
(W t or dry typ may b us d.)
2) R comm nd d H ad Cl aning Mat rial
(1) W t typ
Innovativ Comput r Products*, H ad Cl aning Kit
(or quival nt).
*9174 D ring Av ., Chatsworth, CA 91311
(213) 998-24 00/TWX 910-493-2188
(2) Dry typ
To b suppli d by Mitsubishi r pr s ntativ s. No
substitutions would b allowabl unl ss acc pt d
by factory t st.

5.3 Ch ck and Adjustm nts
5.3.1 Disk tt rotation cycl adjustm nts
1) Equipm nt
Disk T st r
Scratch Disk tt
Univ rsal Count r
VR Adjustm nt Driv r
2) Adjustm nt proc dur
2)-1 Conn ct CE T st r to Driv th n turn-on pow r switch.
2)-2 Load disk tt th n turn-on motor with driv s l ct.
2)-3 Mak sur HLMG ON.
2)-4 S k to TKOO.
2)-5 Conn ct univ rsal count r to INDEX (int rfac signal
TPD14) and m asur rotational cycl rat .
2)-6 Adjust count r r ading until it com s within
sp cifications using SPM VR (s Figur 4).
2) -7 Aft r this adjustm nt, Lock VR with whit paint.
3) T st sp cification
3) -1 Ch ck: ±1.6% (196.8 - 203.2 ms)
3)-2 Adjust: ±1.0% (198.0 - 202.0 ms)

INDEX
TPD14 FIGURE 4

5.3.2 TKOO s nsor position adjustm nt
1) Equipm nt
Disk T st r
Scratch Disk tt
No. 1 plus scr w driv r
Oscilloscop
2) Adjustm nt proc dur
2)-1 Conn ct CE T st r to Driv th n turn-on pow r switch
and load disk tt .
2)-2 Turn-on motor and s l ct driv .
2)-3 R p at s k b tw n TKOO and 02 (s Figur 5).
2)-4 Obs rv wav form (TKOO) at TPB1 using oscilloscop .
trigg r CHI— st p (DC, -) TPD15
signal CH2— TKOO (DC ) TPE1
2)-5 Loos n scr w and adjust Tim T until it com s to
within 3-4ms by moving TKOO in th dir ction of
th arrow (s Figur ).
3) Not :
3)-1 S t st p rat at 3ms using Disk T st r
3)-2 Mak sur th r ar 2 puls s on st p signals.