3
SAFETY PRECAUTIONS
1. The d esign of th is pr od uct con ta in s sp eci al har d wa re , ma ny
circuits and components specially for safety purposes. For
con tinu ed prot ecti on , n o chan g es sh ou ld b e ma de to the o rig i nal
d esign un less a uth or ized i n writin g by th e ma nu fact ur er .
Rep lacem en t p ar ts m ust b e i d ent ic al to thos e u sed i n th e or igi n al
circu it s. S er vi ce sho ul d b e p er for m ed by qu al if i ed p ers on nel
on ly.
2. Al te r ation s of t he desig n or ci rcuitry of t he prod ucts sh ould not be
made. Any design alterations or additions will void the
m anu fact ur er's warra nt y and wi ll f ur th er r eli eve t he ma nu factu r er
of r esp onsi b ility for per so na l inj ury or p r op er ty d am ag e r esult in g
th er efr om .
3. M an y e lectr ical an d m ech anica l p arts i n th e pr od ucts ha ve
special saf ety-related characteristics. T hese characteristics are
oft en no t e vi den t f r om vi sua l insp ection n or ca n t he pr o tect io n
aff or de d by th em nece ssar il y b e ob tai n ed b y u sin g r ep lacem en t
com po ne nts ra ted f or hi g he r vo l tag e, watt ag e, etc. Rep l acem en t
p arts wh ic h ha ve th ese sp ecial s afet y ch ar act er ist ics ar e
identified in the parts list of S ervic e manual. El ec tric al
components having su ch features are identified by shading
on t he sche matics and by (!
!!
!) on the parts list in Service
manual. The us e of a sub sti tu te r ep la cem en t w hich do es n ot
h ave th e sam e saf ety ch ar act er ist ics as t he r eco mmen de d
r eplac em ent part sh own in th e p ar ts li st of S er vi ce m an ual m ay
cause shock, fire, or other hazards .
4. Do n't shor t between the LIVE side ground and ISOL ATE D
(NEUTRAL) side ground or EARTH side ground when
repairing.
Some model's power circuit is partly different in the GND. The
diff er enc e of th e G ND i s sho wn b y th e LIV E : (") side GND, the
ISO LATE D( NEUTR AL) : (#) side G ND and EARTH : ($) side
GN D. D o n't sh or t b et we en th e LIV E sid e GN D an d
ISO LATE D(NEUTRAL) side GND or EARTH sid e GND and
n ever mea sur e wit h a m ea sur ing a ppa r atus ( osci llo scop e etc.)
th e LI VE si d e GND an d IS OLA TED(NE UTRAL ) sid e G ND or
EARTH sid e GND at th e s ame time.
If above note will not be kept, a fuse or any parts will be broken.
5. If any repair has been made to the chassis, it is recommended
th at t he B1 set ting shou ld b e ch ecke d or adju ste d ( Se e
ADJUSTMENT OF B 1 POW E R SUPPL Y) .
6. The hi gh vol ta ge app lie d t o th e pictu re tu be mu st con for m w it h
th at sp eci fi ed in S er vice m an ual. E xcessi ve h igh vo lt ag e ca n
cau se an i ncr e ase i n X- Ray em issi on , ar ci ng an d possib le
component damage, therefore operation under excessive high
voltage conditions should be kept to a minimum, or should be
preve nt ed. If s evere arc ing occurs, remove t he AC power
immed i ate l y an d de ter mi ne th e ca use b y vi sua l insp ect io n
( in cor r ect in stal lat ion, cr acke d or m elte d high vo lt age har n ess,
p oor so ld er ing, et c.). To m aint ai n the p rope r min im u m le vel of
sof t X- Ray em issi on, c omp on en ts i n th e hi gh vol tag e ci rcui tr y
includ ing t he pi ct ur e tu be must b e t he e xact r ep lacem e nts or
alte rn at i ves ap pr ove d b y th e ma nuf act ur er of th e c om plet e
pr od uct.
7. Do n ot c hec k high volt ag e b y drawing an arc. Use a high volt ag e
m eter or a hig h v oltag e pr ob e wi t h a V TVM . D ischa rg e th e
picture tube before attempting meter connection, by connecting
a clip le ad to th e gr ou nd f ra me a nd c onn ectin g th e oth er end of
the lead through a 10kΩ2W resi sto r to the an od e b utt on .
8. W hen se r vi ce i s r equ ir e d, ob ser ve th e origina l lea d dress. E xtr a
pr ec aut i on sh ou ld b e g i ve n t o assur e cor rect lea d dr ess i n th e
hig h vol tag e ci rcuit a rea. W her e a s hor t ci rcui t h as occu rre d,
th ose co mp on ent s tha t indica te evide nce of ove r hea ti ng sho uld
b e r e place d. A l wa ys u se th e ma nuf act ur er 's r ep lacem en t
components.
9. Isolation Check
(Safety for Electrical Shock Hazard)
Af ter re- ass emb lin g th e p rodu ct, alw ays per f orm an isol at io n
ch eck on the expo sed me tal p ar ts of t he cabi n et ( a nte nn a
ter m ina ls, vid eo /au di o inpu t and ou tpu t t er mi n als, Con tr ol kn obs,
m etal cabin et, scr ewhe ad s, ea r ph one jack, con trol shaf ts, etc.)
to be su re th e p rodu ct is s af e t o o pe r ate wi th ou t d an ger of
elect rical shoc k.
(1) Dielectric Strength Test
The iso l ati on be tw een the A C pr im a ry circu i t an d al l me tal p ar ts
exp ose d t o th e us er , p ar ti cul arl y an y e xp os ed met al p art h avi ng a
r etu rn p ath to t he chass is sho uld withs tan d a volt age of 3 000 V
AC (r.m.s.) for a period of one second.
( . . . . W it hstan d a vo lt ag e of 1 10 0V A C ( r.m. s.) t o an ap plianc e
r ate d up to 12 0V , an d 3 00 0V AC ( r .m. s.) to an ap pl ian ce rat ed
200V or more, for a periodof one second.)
This method of test requires a t est equipment n ot g enerally found
in t he servic e tr ad e.
(2) Leakage Current Check
Pl ug th e A C lin e c ord d ir ect l y in to th e A C ou tl et ( d o n ot use a li n e
isolatio n tr ansf or mer du r in g this ch eck.). U si n g a " Lea kag e
Cur rent Teste r", me asur e th e lea kag e cu rre nt f rom each exp osed
m etal p art of the ca bi ne t, p art icu l arl y any e xpos ed me tal p ar t
h aving a re turn pa th to t he ch assis , t o a kn own go od ea rt h
gr ou nd (wa ter pi p e, e tc.). An y l eaka ge curr en t must n ot e xceed
0.5mA AC (r.m.s.).
Howeve r, i n trop ic al ar ea , th is mu st no t exce ed 0.2 mA AC
(r.m.s.).
"
""
"Alte rnat e Che ck M et hod
Pl ug th e A C lin e c ord d ir ect l y in to th e A C ou tl et ( d o n ot use a li n e
isolatio n tr an sfor mer dur ing t hi s che ck.). Use an AC vo lt me ter
h aving 1 00 0 oh ms pe r vol t or m ore sens it ivi ty i n th e fo llow ing
m ann er. C on nec t a 1 50 0Ω10W res ist or par a ll e le d b y a 0 .1 5µF
AC -type c apa cit or bet we en an expo sed met al pa rt a nd a kno wn
g ood e ar th gr o un d ( wa ter pi pe , etc.). Meas ur e th e A C vo lt ag e
acr oss th e r es ist or w ith th e AC vo l tm eter . M ove th e r esistor
con nec tion to e ach exp ose d me tal par t, p art i cul arly a ny exp osed
m etal p ar t havin g a r etu rn pat h to t he ch assis, an d measu r e th e
AC voltag e ac ro ss the r es ist or . N o w, re verse th e pl u g i n th e AC
ou tl et and r e pe at eac h mea sur emen t. An y volt ag e me asu re d
must not exc eed 0.7 5V AC (r.m. s.). This c orre sponds to 0.5mA
AC (r.m.s.).
Howeve r, in tropica l area, this must not exceed 0.3V AC ( r.m. s.).
This corresponds to 0.2mA AC (r.m.s.).
0.15μF AC-T YPE
1500 Ω10W
GOODEARTH GROUND
PLACE THIS PROBE
ON E A CH EX PO SE D
ME T AL PA RT
ACVOLTMETER
(HAVING 1000 Ω/V,
OR MOR E SENSIT IVITY)
