V-36320
3
SAFETY PRECAUTIONS
1. The d esi gn of t hi s p ro du ct c ont ai ns spec ial h ar dwar e, m an y
ci rcu it s a nd co mp on ent s s pecial ly for saf ety pur p oses. For
continued protection, no changes should be made to the
or igi na l des ig n u nless a uth or ized in writi ng by t he m an uf actu re r.
Rep lacem en t par ts m ust be i d ent ic al t o t hos e u sed in th e
or igi na l circui t s. S er vic e sho ul d be per f or me d b y qu al ified
p ers onn el o nl y.
2. Al te r ation s of th e desi g n o r ci rcu itr y of th e p r odu cts s hou ld n ot
b e mad e. A ny de si gn alte ra tions o r ad ditio ns wi ll vo id th e
manufacturer's warranty and will further relieve the
m anu fact ur er of r esp ons ib i li t y f or pe rs ona l in ju ry or p rope rt y
d am age r esu lt in g t her ef r om .
3. M an y e l ectr ical an d mech an ic al pa rt s in th e p r odu cts h ave
sp ecial saf ety- relat ed c haract er is tics. Th ese charac teristics ar e
oft en n ot e vi d en t from visu al in spe cti on no r can t he pr ote cti on
aff or de d by th em n ecess ar il y be o bta in ed b y using
r eplac em ent co mp on ent s ra ted for h ig her vo ltag e, w a ttag e, etc.
Rep lacem en t pa rt s wh ic h h ave t hes e sp ecial s afet y
ch ar acter isti cs a re id enti fie d in th e par ts l ist of S ervice m an ua l.
Electrical components having such features are identified
by shading on the schematics and by (!
!!
!) on the parts list
in S ervice manual . Th e u se of a su bst itu te re plac emen t w hich
does not have the same saf et y charact eristics as the
r eco mm en de d re plac em en t pa rt sho wn in the pa rts l ist of
Se rvice ma nu al may c aus e sh ock, f ire, or o th er haz ar ds.
4. Use iso la t ion tr an sfo rme r when hot c hass is .
The chassis and any sub-chassis contained in s ome products
ar e c on nect ed to on e side of th e AC p ow er li ne . An isol a ti on
tr ansf or m er of ad equ ate cap acity sh ou l d be inser t ed bet we en
th e p r odu ct and t he AC p ow er su pp l y p oi nt while p er for mi ng
an y ser vice on so me pro ducts wh en th e H OT ch assis is
exp ose d.
5. Do n't short between the LIVE side ground and ISOLATED
(NEUTRAL) side ground or EARTH side ground when
repairing.
So m e m od el's p ow er c ircui t i s par t ly dif fer en t in t he GND . Th e
diff er enc e of t he GND is sh own by the LI VE : (") side GND,
th e ISO LATED( NEUTRA L) : (#) sid e GND an d EARTH : ( $)
si de GN D. Don 't sho rt be twee n t he LIVE si d e GND a nd
ISO LATE D(NEUTRAL) side GND or EARTH side GND a nd
never measure with a measuring apparatus (oscilloscope etc.)
th e LI VE side GND a nd ISO LATED( NEUTRA L) 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.
6. If an y re pa ir h as b ee n mad e to th e ch assi s, i t is re comm end ed
th at t he B1 se ttin g sh ou ld b e chec ked or ad juste d (S ee
ADJUSTM ENT OF B 1 POW E R SUPPL Y).
7. The hi g h vol t ag e a pp lied t o th e pi ctu re tu be mu st co nfo rm with
that specified in Service manual. Excessive high voltage can
cau se an i ncr ea se i n X- Ray e mi ssion , arc in g an d possib l e
com po ne nt d am ag e, th eref or e op er atio n un der excess i ve high
vol ta ge c ond it ions sh ou ld be ke pt to a m in i mu m, or sh ou l d be
pr eve nt ed. I f seve re arc in g occu rs, r emove th e AC p ower
immediately and determine the cause by visual inspection
( in cor r ect i nsta lla tion , cr ac ked o r m elte d hi gh voltag e h ar ness,
p oor s ol de ri n g, etc. ). T o ma in ta in the pr op er m ini mum le vel of
sof t X- Ray e missi on , com p one nts i n th e hig h vo l tag e cir cuitr y
incl ud ing the pi ctu r e tu be mu st be the exa ct rep l acem en ts or
alte rn at i ves a ppr o ved b y th e ma nuf actu r er of th e co mp lete
pr od uct.
8. Do n ot c hec k hi gh vol ta ge by d r awin g a n ar c. U s e a hi gh
vol ta ge m ete r or a h igh volt age p ro be with a VTVM. Disch ar ge
th e p ictu re tu be bef or e a tte mp ti ng me ter co nne ction , b y
con nec ting a clip lead t o th e grou nd frame a nd con n ecting t he
oth er e nd of t he l ead th r oug h a 10 kΩ2W resist or to t he ano de
bu tto n.
9. W hen se rvi ce i s r equ ir ed, ob ser ve th e o rig in al l ea d dr ess.
Extr a p r ecau ti on sh ou ld be given t o assu r e cor re ct lea d dr es s
in the h i gh vol ta ge c ircu it ar ea . W her e a sh ort ci rcuit ha s
occu rre d, th ose c omp on en ts th at i nd ic ate eviden ce of
overheating should be replaced. Always use the
m anu fact ur er 's r eplace m ent com p on ents.
10 . Isolation Check
(Safety for Electrical Shock Hazard)
Af ter re- a ssem bling th e pr od uct , al ways pe rf or m an i so l ati on
ch eck on th e expo sed m eta l p ar ts of th e c abi n et ( ant en na
ter m ina ls, vi de o/a ud i o in pu t and out put t er min al s, C on tr ol
knobs, metal cabinet, screwheads, earphone jack, control
sh afts, etc.) to be sur e th e pr o duct is saf e t o op er at e with out
d ang er of elect rica l shoc k.
(1) Dielectric Strength Test
The is ol at io n b etw e en the AC pr ima r y circu it and al l m eta l parts
exp ose d t o th e us er , par t icu lar ly an y expo sed m etal p ar t h aving
a return pat h to the ch assis sh ou ld withst and a volta ge of
11 00V AC ( r .m .s.) f or a p er iod of on e sec ond .
(. . . . Withs tand a voltage of 1100V AC (r.m. s.) to an appliance
r ate d up to 1 20V , a nd 3 00 0V AC ( r .m. s.) t o an ap pl ianc e r a ted
200V or more, for a periodof one second.)
Thi s m eth od of test r e qu ir es a t est eq uip me nt n ot g en er all y
fou nd i n t he ser vi ce t ra de.
(2) Leakage Current Check
Plug t he A C line c or d dir ect ly int o th e AC ou tlet (do not u se a
lin e is ol ati on tr a nsf ormer dur ing t hi s che ck.) . U sing a "L eaka ge
Cur rent Test er ", m ea sure t he lea kag e curr en t fr om each
exp ose d m eta l par t of th e ca bine t, p ar tic ul arl y an y expo sed
metal part having a return path to the chassis , to a known good
ea rt h gr o und ( wa ter p i pe, etc.) . A ny lea kag e cur ren t m ust not
exce ed 0. 5m A AC ( r.m. s.).
Howeve r, i n t ro pical a r ea, this m ust no t e xc eed 0 .2m A AC
(r .m.s. ).
"
""
"Alte rnat e Che ck M et hod
Plug t he A C line c or d dir ect ly int o th e AC ou tlet (do not u se a
line isolation transformer during this check.). Use an AC
vol tm et er h avi ng 100 0 o hm s per volt or m or e sen siti vit y in the
fol lo win g ma nne r. C on nec t a 1 50 0Ω1 0W r esistor pa ra lle led
by a 0.15μF AC -typ e cap aci tor b etwe en an exp ose d meta l
p art an d a kno wn g o od ear th gr ou nd (wate r pip e, et c.).
M easu r e th e A C vo l tag e across th e r esi st or w it h t he AC
voltmeter. Move the res istor connection to each exposed metal
part, particularly any exposed metalpart having a return path to
th e ch assis , an d m ea sur e t he A C vol ta ge acr oss th e r esi sto r.
Now, r eve rs e th e pl u g in t he A C out l et a nd r ep e at e ach
m easu r em en t. An y vol ta ge me asu re d m ust not exce ed 0.7 5V
AC (r.m. s.). This corresp on ds t o 0 .5mA AC ( r.m. s.).
Howeve r, i n tr op ic al ar ea, this m ust n ot excee d 0 .3V AC
(r .m.s. ). This corr esp on ds t o 0 .2mA A C ( r.m.s.).
0.15μF AC-T YP E
1500Ω10W
GOOD
EARTH
GR OUND
PLACE THIS PROBE
ON E A C H EX PO SE D
ME T AL PA RT
ACVOLTMETER
(HAVING 1000 Ω/V,
OR MOR E SENSIT IVITY)
11 . High voltage hold down circuit check.
Af ter rep ai r of th e high vol t ag e h old d own cir cuit, th is circu i t
sh al l b e c hec ked to op er ate cor rectl y.
See ite m "Ho w to check the high voltage hold down
cir cuit".
A V
This mark shows a fast
operating fuse, the
letters indicated below
show the rating.
