View Sharp DV-5132H (serv.man7) Technical Bulletin online
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
pins 7 and 2. Note that D716 is connected across Q702 emitter earth return resistor,
as this is only 0.22
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).