CONTENTS
SAFETYPRECAUTIONS..........................................................................................................................................................2
SERVICE HINTS.......................................................................................................................................................................3
ADJUSTMENTPROCEDURE ANDFACTORYSETTINGS.....................................................................................................4
WAVEFORMPATTERN TABLE...............................................................................................................................................5
ALIGNMENTSETTINGS...........................................................................................................................................................6
BLOCK DIAGRAMS..................................................................................................................................................................7
PARTS LOCATION.................................................................................................................................................................10
REPLACEMENTPARTSLIST................................................................................................................................................11
SCHEMATICDIAGRAMS.......................................................................................................................................................17
CONDUCTORVIEWS.............................................................................................................................................................20
SAFETYPRECAUTIONS
GENERALGUIDELINES
1.It isadvisabletoinsertan isolation transformerinthe
a.c.supplybeforeservicingahot chassis.
2.When servicing,observe the original leaddressinthe
highvoltagecircuits. If ashort circuitisfound, replace
all partsthat havebeenoverheatedordamagedby
theshort circuit.
3.After servicing,seethatalltheprotective devices
such as insulationbarriers,insulationpapers,shields
andisolationR-Ccombinationsarecorrectly
installed.
4.When thereceiverisnotbeingused foralongperiod
of time,unplugthepowercordfromthea.c.outlet.
5.Potentialsas high as 29kV{29kV}arepresentwhen
thisreceiverisinoperation. Operationofthereceiver
without therearcover involvesthe dangerofashock
hazardfromthereceiver power supply. Servicing
shouldnot beattemptedbyanyonewhoisnot
familiarwiththeprecautionsnecessary whenworking
onhighvoltageequipment. Alwaysdischargethe
anodeofthetube.
6.After servicingmake the followingleakage current
checkstopreventthecustomerfrombeing exposed
toshockhazard.
LEAKAGECURRENTCOLDCHECK
1.Unplugthea.c.cordandconnectajumper between
thetwoprongsoftheplug.
2.Turnonthereceiver spowerswitch.
3.Measuretheresistance valuewithan ohmmeter,
betweenthejumpered a.c. plug andeachexposed
metalliccabinet part on the receiver, suchas screw
heads, aerials,connectors, control shaftsetc.When
theexposedmetallicpart hasareturnpathtothe
chassis, the readingshouldbe between4Mohmand
20Mohm.Whenthe exposedmetaldoesnothavea
returnpathtothe chassis,thereadingmustbe
infinite.
LEAKAGECURRENTHOTCHECK
1.Plugthea.c.corddirectlyintothea.c. outlet. Donot
useanisolationtransformer forthischeck.
2.Connect a2k 10Wresistorinseries withan
exposedmetallicpart onthereceiverandanearth,
such asawaterpipe.
3.Usean a.c.voltmeterwithhighimpedanceto
measurethepotential acrosstheresistor.
4.Check eachexposed metallicpartand check the
voltageateachpoint.
5.Reversethea.c. plug atthe outletandrepeat eachof
theabove measurements.
6.Thepotentialat anypointshouldnotexceed
1,4Vrms.Incaseameasurementisoutside the limits
specified, thereisapossibilityofashockhazard, and
thereceivershouldbe repairedandrecheckedbefore
it isreturnedtothe customer.
X-RADIATIONWARNING
1.ThepotentialsourcesofX-Radiation inTVsetsare
thehighvoltagesection andthepicturetube.
2.When usingapicturetube testjigforservice,ensure
thatthe jigiscapableof handling 29kV{29kV}
without causingX-Radiation.
NOTE: It isimportant touseanaccurateperiodically
calibrated high voltage meter.
1.Set thebrightnesstominimum.
2.Measurethehighvoltage. Themetershouldindicate.
TX-28CK1, TX-25CK128kV±1kV.
If themeterindicationisoutof tolerance,immediate
serviceand correctionisrequiredtoprevent the possibility
of prematurecomponentfailure.
3.Toprevent any X-Radiationpossibility,it isessential
tousethe specified tube.
HOTCHECKCIRCUIT
a.c.VOLTMETER
WATERPIPE
(EARTH)
TOINSTRUMENT'SEXPOSED
METALLICPARTS Fig. 1.
2k 10Watts
