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CTV991206 TELEVISION TECHNICAL BULLETIN
Month of Issue: December 1999 Classification: White Page 1 of 1
MODELS
DV5105H
DV5107H
DV5132H
SYMPTOM Intermittent failure of the power supply. CAUSE ACTION Various components. If Q702 immediately goes short circuit when the set is turned on, check that D716 has not gone short circuit or that T700 (chopper transformer) is not short circuit across pins 7 and 2. Note that D716 is connected across Q702 emitter earth return resistor, as this is only 0.22, D716 needs to be removed before testing. If the power supply works, but fails after being run on soak test, replace D708 and D709, also check that the main smoothing block (C705) has not got loose rivets. In some cases it is possible for the HT to rise significantly during standby, the normal value of the HT in standby is anywhere between 120VDC and 130VDC ( this rise is due to the line output load being removed). If this increases above 130VDC, there is a problem. Check the feedback circuit around the opto coupler and D751. Note that it is important that Q702 is replaced with the correct type or long term reliability problems will ensue (MJF18006). The HT voltage should be set to 113VDC on a blue screen (pull out the aerial and wait a few minutes - the screen will turn blue due to lack of line sync).
REF NO C705 D708 D709 D716 D751 Q702 T700
DESCRIPTION Capacitor, 100uF 400V Diode, 1N4934 Diode, 1N4934 Diode, 1N4148 Diode Transistor, MJF18006 Chopper transformer
PART NUMBER RC-EZ0104BMZZ RH-DX0519BMZZ RH-DX0519BMZZ RH-DX0045BMZZ RH-DX0226CEZZ RH-TX0119BMZZ RTRNZ0514BMZZ
PRICE CODE AP AB AB AA AC AL AU
Sharp Electronics (UK) Limited
Reference AVW031299-1 Revision 1 White Carry out as required, Yellow Carry out as required and whenever the unit comes in for service, Red Carry out on all units