Sharp DV-5105H (serv.man9) Service Manual / Technical Bulletin ▷ View online
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
CTV991206
Month of Issue: December 1999
Classification: White
TELEVISION TECHNICAL BULLETIN
Page 1 of 1
MODELS
DV5105H
DV5107H
DV5132H
SYMPTOM Intermittent failure of the power supply.
CAUSE Various components.
ACTION 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
pins 7 and 2. Note that D716 is connected across Q702 emitter earth return resistor,
as this is only 0.22
Ω
, 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).
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
DESCRIPTION
PART NUMBER
PRICE CODE
C705
Capacitor, 100uF 400V
RC-EZ0104BMZZ
AP
D708
Diode, 1N4934
RH-DX0519BMZZ
AB
D709
Diode, 1N4934
RH-DX0519BMZZ
AB
D716
Diode, 1N4148
RH-DX0045BMZZ
AA
D751
Diode
RH-DX0226CEZZ
AC
Q702
Transistor, MJF18006
RH-TX0119BMZZ
AL
T700
Chopper transformer
RTRNZ0514BMZZ
AU
Display