No.52056
V-25BT6ENS
V-25BT6ENB
4
SAFETY PRECAUTIONS
1. T he d esi gn of th is pr od uct con ta in s sp eci al hard wa re , ma ny
circuits and components specially for saf ety purposes. For
con ti nu ed prot ection , n o chan g es sh ou ld b e ma de to the o rig inal
d esi gn un l ess a uth or ized in writi n g by th e ma nu fact urer .
Rep lacem en t p ar ts m ust b e id ent ic al to thos e u sed in th e or igin al
ci rcu it s. Se r vic e sh ou ld be pe rf or me d b y q ua lifi e d per so nn el
on ly.
2. Alte r ation s of t he desig n or cir cuitr y of t he pr od ucts sh oul d not be
made. Any design alterations or additions will void the
m anu fact ur er's w arra nt y and will f ur th er relieve t he ma nu factu r er
of r esp onsi b il ity for per so na l injury or p r op erty d am ag e resul t in g
th er efr om .
3. M an y e lectr ical an d m ech ani ca 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 r om vi sua l insp ecti on n or ca n t he pro tect io n
aff or de 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 hig he r vo ltag e, watt ag e, etc. Rep lacem en t
p arts wh ic h ha ve th ese sp eci al s afet y ch ar act er ist ics are
identified in the parts list of Servic e manual. El ec tric al
components having su ch features ar e identified by shading
on the sche matic s and by (!
!!
!) on the parts list in Service
manual. The us e of a sub sti tu te rep la cem en t which do es n ot
h ave th e sam e saf ety ch ar act er ist ics as t he r eco mm en de d
r eplac em ent part sh ow n in th e p ar ts l ist of S er vi ce m an ual m ay
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 the GND i s sh own b y th e LI VE side G ND, th e
ISO LATE D( NEUTRAL) side GND a nd EA RTH side GN D. Don' t
sh ort b etwee n the L IVE si de GND a nd IS OLATE D(NEU TR AL)
side GND or EA RTH side GND and ne ver meas ure with a
m easu r in g app ar atu s ( osc illosc ope et c.) th e LIV E sid e GN D an d
ISOLATED(NEUTRAL) side GND or EARTH side GND at the
same 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
ADJU STM ENT OF B 1 POW E R SU PPLY).
6. T he 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 ecifi ed in S ervice man ual. E xcessi ve h igh vo lt ag e ca n
cau se an incr e ase i n X- Ray em ission , 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
prevent ed. If s evere arc in g occurs, rem ove t he AC power
immed iate l y an d de ter mine th e ca use b y vi sua l i nsp ect io n
( in corr ect in stal lat i on, cr acke d or m elte d high vo lt age harn ess,
p oor so ld er ing, et c.) . To m aint ai n the p r ope r min imu m l e vel of
sof t X- Ray em ission, c omp on en ts i n th e high vol tag e ci rcui tr y
incl ud ing t he pict 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 omplet e
pr od uct.
7. Do n ot c hec k high volt ag e b y drawing an ar c. Use a high volt ag e
m eter or a hi g h v ol tag e prob e wit h a V T VM. 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 ire 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 i ve n t o assur e cor rect l ea d dr ess i n th e
hig h voltag e cir cui t a r ea. W her e a s hor t circui t h as occu rr e d,
th ose co mp on ent s tha t i ndica te evide nce of ove rhea ting sho uld
b e r e place d. A lwa ys u se th e ma nuf act ur er's rep lacem en t
components.
9. Isolation Check
(Safety for Electrical Shock Hazard)
Af ter re- ass emb lin g th e p r odu ct, always per f orm an isol at io n
ch eck on the expo sed me tal p ar ts of t he cabin et ( a nte nn a
ter m ina ls, vid eo /au di o inpu t and ou tpu t t ermin als, Con tr ol kn obs,
metal cabinet, screwheads, earphone jack , control shafts, et c.)
to be su re th e p r odu ct is s af e t o o pe r ate with ou t d an ger of
elect rical shoc k.
(1) Dielectric Strength Test
The iso l ati on be tween the A C pr im a ry circu it an d al l me tal p ar ts
exp ose d t o th e us er , p ar ti cul arly 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 pli an ce r at ed
200V or more, for a period of one second.)
This method of test requires a test equipment not generally found
in t he ser vic e tr ad 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 tlet ( d o n ot use a lin e
isol atio n tr ansf or mer du r in g thi s ch eck.) . Usi 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 ar t of the ca bine t, p art icu l arly 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 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 tlet ( d o n ot use a lin e
isol atio n tr an sfor mer during t hi s che ck.) . Use an AC vo lt me ter
h avi ng 1 00 0 oh ms pe r volt or m ore sens it ivi ty in th e fo llowing
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 arth gr o un d ( wa ter pipe , etc.) . M eas ur e th e A C vo lt ag e
acr oss th e res ist or w ith th e AC vo l tm eter . M ove th e r esistor
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 voltag e ac ro ss the r es ist or . No w, re ver se th e pl u g in th e AC
ou tl et and r e pe at eac h mea sur em en t. An y volt ag e me asu re d
mu st not exc eed 0.7 5V AC (r.m.s.). This c orresponds to 0.5mA
AC (r.m.s.).
However, in tropical area, this mu st n ot 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)
