No. 51961
TM-H1950CG
3
SAFETY PRECAUTIONS
1. The d esign of t hi s p ro du ct c ont ai ns spec ial h ar dwar e, m an y
circu it s a nd co mp on ent s sp eci ally f or s afet y p urpos es. For
continued protection, no changes should be made to the
or igina l des ig n u nless a uth or ized in wri ti ng by t he m an uf actu re r.
Rep lacem en t par ts m ust be id ent ic al t o t hos e u sed in th e
or igina l circui t s. Se r vic e sho ul d be per fo rmed b y qu alified
p ers onn el o nl y.
2. Al te r ation s of th e desi g n o r circu itr y of th e p r odu cts s hou ld n ot
b e m ad e. A ny de sign al te ra tions o r ad ditio ns will 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 r y or p rope rt y
d am age r esu lt in g t heref r om .
3. M an y e lectrical an d m ech an ic al pa rt s in th e p r odu cts h ave
sp ecial saf ety-r elat ed c haract er is tics. Th ese charac teristics are
oft en n ot e vi d en t fr om visu al in spe cti on no r can t he pr ote ction
aff or de d by th em n ecess ar ily be o bta in ed b y usi ng
r eplac em ent co mp on ent s ra ted for h ig her vo l tag e, w a ttag e, etc.
Rep lacem en t p art s which h ave t he se sp eci al s afet y
ch ar acter istics a re i d entifie 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 em en t which
does not have the same safety characteristics as the
r eco mm en de d re plac em en t pa rt sho wn i n the pa rts li st of
Se rvice ma nu al may c aus e sh ock, f ire, or o th er haz ar ds.
4. Use isola tio n tr an sforme 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 si de of th e AC p ower li ne . An isol a tion
tr ansf or m er of ad equ ate cap acity sh ou ld be i nsert ed bet we en
th e p r odu ct and t he AC p ower su pp ly p oint whi le p er for ming
an y ser vice on so me pr o ducts wh en th e HOT 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 ir cuit i s par t ly di f feren t in t he GN D. 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 EAR TH : ( $)
side GND . D on '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 meas uring apparatus (oscilloscope etc.)
th e LI VE side GND and ISO LATED(NEUTRA L) sid e G ND or
EARTH side GND at th e s ame time.
If above note will not be kept, a fuse or any parts will be brok en.
6. If an y re pa ir h as b ee n m ad e to th e ch assi s, i t is re comm end ed
th at t he B1 se tti n g sh ou ld b e chec ked or ad juste d (S ee
ADJUSTMENT 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 wi t h
that specified in Service manual. Excessive high voltage can
cau se an i ncr ea se in X-Ra y em ission , a rcin g and p ossi ble
com po ne nt d am ag e, th er ef or e op er ati o n un der excess ive hi gh
volta ge c ond it i ons sh ou ld be ke pt to a m in imu 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 insta lla ti on , cr ac ked o r m elte d high vol tag e h ar ness,
p oor s ol de rin g, etc. ). T o ma in ta in the pr op er m inim um le vel of
soft X-Ray emission, components in the high voltage circuitry
includ ing the pi ctu r e tu be mu st be the exa ct r ep lacem 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 high vol ta ge by d r awin g a n ar c. Us e a hi gh
volta ge m ete r or a h igh vol t age p ro be w ith a VT VM. Di sch arge
th e p ictu r e 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 is r equ ir ed, ob ser ve th e o rig in al lea d dr ess.
Extr a p r ecau ti on sh ou l d be gi ven t o assu r e cor re ct lea d dr es s
in the h i gh volta ge c ir cu it ar ea . W her e a sh ort cir cuit ha s
occu rre d, th ose c omp on en ts th at ind ic ate evi den 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 r e-a ssem bli ng th e pr od uct , al ways pe rf or m an iso l ation
ch eck on th e expo sed m eta l p ar ts of th e c abin et (ant en na
ter m ina ls, vide o/a ud io in pu t and out put t er min als, 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 el ect rica l shoc k.
(1) Dielectric Strength Test
The is olat io n b etwe en the AC pr ima ry cir cu it and al l m eta l par ts
exp ose d t o th e us er , par t icu l arl y an y expo sed m etal p ar t h avi ng
a return pat h to the ch assis sh ould withst and a voltage 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 plianc e r a ted
200V or more, for a period of one second.)
Thi s m eth od of test r e qu ir es a t est eq uipm en t no t g ene r all y
fou nd in t he ser vice 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 his che ck.). Usi ng a " L eaka ge
Cur rent T est er ", m ea sur e t he lea kag e cur r en t from each
exp ose d meta l par t of th e ca bi ne t, p ar tic ul arly an y expo sed
metal part having a return p ath to t he chassis , to a known good
ea rt h gr o und ( wa ter p ipe, etc.) . A ny l ea kag e cur r en t m ust not
exce ed 0. 5m A AC (r.m. s.).
Howeve r, i n t ro pical a r ea, this must no t e xc eed 0 .2m A AC
(r.m.s. ).
"
""
"Alte rnat e Che ck M ethod
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
voltmet er h avi ng 100 0 o hm s per volt or m ore sen si tivit y i n the
fol lo win g ma nne r. Con nec t a 1 50 0Ω1 0W r esi stor pa ra ll e led
by a 0.15
μF AC -typ e cap acitor b etwe en an exp ose d m eta l
p art an d a kno wn g o od ear th grou nd ( wate r pi p e, et c.).
M easu r e th e A C vo l tag e acr oss th e resi st or w it h t he AC
voltmet er. Move the res istor connection to each exposed metal
part, particularly any exposed metalpart having a returnpath to
th e ch assis , an d m ea sur e t he A C vol ta ge acr oss th e r esisto r.
Now, r eve rs e th e pl u g i n t he A C out let 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 A C (r .m. s.) .
Howeve r, i n trop ic al ar ea, this m ust n ot excee d 0 .3V AC
(r.m.s. ). This corresp 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 . Hi gh voltage hold down circuit check.
Af ter r ep air of th e hi gh volt ag e h old d ow n ci rcui t, th is circu it
sh all b e c hec ked to op er ate cor rectly.
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.
POWER CORD
REPLACEMENT WARNING.
Co nne cting t he w hi te l ine side of pow er
cord to “WHT” chara cter side.
For District of power requiremen t is 120V AC
(Mainly North America)
