Hitachi 42HDS52A/DW1-UB, Service Manual

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31
DW1U
BACK TO ADJUSTMENTS
R1540 Vs potenciometer
/*KTWMCYC
4. Vs, Va voltage adjustment
Item Power Unit Vs, Va Adjustment Adj. point Refer to following
Adjustment Preparations Adjustment Procedures Remarks
(1) Turn on the set and perform
pre-heat run more than 1 min
on burn-in screen.
(1) Turn Vs ADJ to adjust Vs voltage
to be within
r
0.1V of the value
specified in the label on the panel.
Permissive level of voltage in
sufficient time of heat-run
performed is:
Vs: within
r
0.45V
Va: within r 0.55V
(2) Receive full black pattern signal
(or video silence signal; but the
power will be automatically turned
off after a few seconds by power
save function.)
(2) Turn Va ADJ to adjust Va voltage
to be within
r
0.2V of the value
specified in the label on the panel.
Reconfirm that Vs voltage remains
within
r 0.1V of the specified value.
Readjust if it’s outside of the margin .
(3) Connect voltmeter (which has an
error within 0.02V or less) leads
to Vs (or Va) and GND test points
of the power unit.
(3)
Label example Label position (Reference)
: Upper left
If it’s hard to read the voltage
value because of the wiring
positions, write it down by a
marker at visible place in
advance.
<LOT>N6
Vs= 80.0V Va=60.0V
V
䌷
=140.0V Vx=60.0V
CN64 㧦 Vs/Va
Test pins
Ԙ pin: Va
ԡ pin: Vs
Ԝ pin: GND
̪
Never touch this VR ! (PFC)
(This is already adjusted.)
R1573
㧦
Va ADJ. VR
Adjustment driver insert into this
hole to adjust Vs VR R1540.
R1540
㧦
Vs ADJ. VR
(UNDER the FIN)
̪ Never touch this VR ! (OLP)
(This is already adjusted.)
6 GI