3
SAFETY PRECAUTIONS
1. The d esign of th is pr od uct con ta in s sp ecial har d wa re , ma ny
circuit s and components specially for saf ety purposes. For
con ti nu ed pr ot ecti on , n o chan g es sh ou ld b e ma de to the o rig i nal
d esi gn un less a uth or ized i n wri tin g by th e ma nu fact urer .
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 igin al
ci rcu it s. S er vi ce sho ul d b e p er for med by qu alif i ed p ers on nel
on ly.
2. Al te r ation s of t he desi g n or ci rcuitr y of t he pr od ucts sh ould not be
made. Any design alterations or additions will void the
m anu fact urer 's warra nt y and will f urth er r eli eve t he ma nu factu r er
of r esp onsi b ility for per so na l injur y or p r op erty d am ag e r esult in g
th er efr om .
3. M an y e l ectr ical an d m ech anica l p ar ts in th e pr od ucts ha ve
special safety-related characteristics. T hese characteristics are
oft en no t e vi den t f rom vi sua l i nsp ection n or ca n t he pr o tect io n
aff orde d by th em nece ssar ily b e ob tain ed b y u sin g r ep lacem en t
com po ne nts ra ted f or hi g he r vo ltag e, watt ag e, etc. R ep lacemen t
p arts wh ic h ha ve th ese sp ecial s afet y ch ar act erist ics ar e
identified in the parts list of Servic e manual. El ec tric al
components having su ch features are identified by shading
on the schemat ic s and by (!
!!
!) on the parts list in Service
manual. The us e of a sub sti tu te r ep la cemen t which do es n ot
h ave th e same saf ety ch ar act er ist ics as t he r eco mmen de d
r eplac em ent par t sh ow n i n th e p ar ts l ist of S er vi ce m an ual may
cause shock, fire, or other hazards .
4. Do n't short between the LIVE side ground and ISOL ATED
(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(N EUTRAL) : ( #) side G ND and EARTH : ($) side
GN D. D o n't sh or t b et we en th e LIV E si d e GN D an d
ISO LATE D(NEUTRAL) side GND or EARTH side GND and
n ever m ea sur e w it 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 T ED(N E UTR AL ) sid e G ND or
EARTH sid e GND at the 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 l d b e ch ecke d or adju ste d ( Se e
ADJUSTM ENT OF B 1 POW E R SU PPLY).
6. The hi gh vol ta ge app lie d t o th e pi ctu r e tu be mu st con for m wit h
th at sp eci fi ed i n S er vi ce m an ual. E xcessive h i gh vo lt ag e ca n
cau se an i ncr e ase i n X- Ray em ission , ar ci ng an d possi b le
component damage, therefore operation under excessive high
voltage conditions should be kept to a minimum, or should be
preve nt ed. If s ever e arc ing occurs, remove t he AC power
imm ed iate l y an d de ter mi ne th e ca use b y visua l i nsp ect io n
( in cor rect in stal lat i on, cr acke d or melte d high vo lt age har n ess,
p oor so ld ering, et c.) . To m aint ai n the p r ope r mi n imu m le vel of
sof t X- Ray em ission, c omp on en ts in th e high vol tag e circui tr y
incl ud ing t he pict ur e tu be must b e t he e xact rep 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 ecti n g th e oth er end of
the lead through a 10kΩ2W resisto r to the an od e b utt on .
8. W hen se r vice i s r equ ir e d, ob ser ve th e or igina l lea d dr ess. E xtr a
pr ec aut i on sh ou ld b e g ive n t o assur e corr ect l ea d dr ess in th e
hig h voltag e cir cui t a r ea. W her e a s hor t circui t h as occu rre d,
th ose co mp on ent s tha t indica te evi de nce of ove r hea ti ng sho ul d
b e r e place d. A lwa ys u se th e ma nuf act ur er's r ep lacemen t
components.
9. Isolation Check
(Safety for Electrical Shock Hazard)
Af ter r e-ass emb lin g th e p r odu ct, alw ays perf orm an i sol 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 min al s, Con tr ol kn obs,
m etal cabi n et, scr ewhe ad s, ea r ph one j ack, con tr ol shaf ts, etc.)
to be su re th e p rodu ct i s 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 i so lati on be tween 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 cular ly 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 ul d 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 r at ed
200V or more, for a periodof one second.)
This method of test requires a t est equipment not generally found
in t he ser vic e trad e.
(2) Leakage Current Check
Pl ug th e A C lin e c ord d irect l y in to th e A C ou tl et ( d o n ot use a li n e
isol atio n tr ansf or mer du r in g thi s ch eck.) . U si n g a " Lea kag e
Curr ent T este r", me asur e th e lea kag e cu rr e nt f rom each exp osed
m etal p ar t of the ca bi ne t, p art icu lar ly any e xpos ed me tal p ar t
h aving a r e turn pa th to t he ch assis , t o a kn own good ea rt h
gr ou nd (wa ter pi p e, e tc.) . An y leaka ge cur ren t m ust n ot e xceed
0.5mA AC (r.m.s.).
Howeve r, i n tr op 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 ethod
Pl ug th e A C lin e c ord d irect l y in to th e A C ou tl et ( d o n ot use a li n e
isol atio n tr an sfor m er dur ing t hi s che ck.) . U se an AC vo lt me ter
h avi ng 1 00 0 oh ms pe r vol t or m or e sens it ivi ty in th e fo llow ing
m ann er. C on nec t a 1 50 0Ω10W res ist or para lle 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 arth gr o un d ( wa ter pipe , etc.) . Meas ur e th e A C vo lt ag e
acr oss th e r es ist or with th e AC vo ltm eter . M ove th e r esi stor
con nec ti on to e ach exp ose d me tal par t, p art i cular ly a ny exp osed
m etal p ar t havin g a r etu rn pat h to t he ch assi s, an d m easu r e th e
AC vol tag e ac ro ss the r es ist or . No w, re ver se th e plu g i n th e AC
ou tl et and r e pe at eac h m ea sur emen t. An y vol t ag e me asu re d
must not exc eed 0.75V AC (r.m.s.). This c orresponds to 0.5mA
AC (r.m.s.).
However, in tropical area, this must not exceed 0.3V AC ( r.m. s.).
This corresponds to 0.2mA AC (r.m.s.).
0.15μF A C-T YPE
1500 Ω10W
GOODEARTH GROUND
PLACE THIS PROBE
ON E A CH EX PO SE D
ME T AL PA R T
ACVOLTMETER
(HAVING 1000 Ω/V,
OR MOR E SENSITIVITY)
