44
CIRCUIT DESCRIPTION
Use the ZP94/95 Series Power On and Off Diagram along with this explanation:
The power supply in the ZP94/95 chassis works very similar to the previous models, with only a few
exceptions. This power supply runs all the time when the AC is applied. The use of the power supply to
create Stand by Voltage supplies eliminates the need for a Stand-By transformer. The following explanation
will describe the Turning ON and OFF of the projection television. The Microprocessor I001 generates the
ON-OFF control signal from pin (53). The logic states of this pin are High = On and Low = Off. When the
set is turned On, the high from pin (53) is routed to the Relay Driver Q002 base. This turns on Q002 and
its collector goes low.
This On/Off from the Relay Driver Q002 will perform the following:
· Turns on the SW5+V I907 and SW+12V I908 regulators. Which do not operated in Standby.
· Turns on the Shut down Power Shorted detection circuit, Q908 and Q909.
· Turns on the Horizontal Vcc supply to the Horizontal and Vertical drive IC, I701.
· Turns on the Relay providing AC to the Deflection Power Supply on the Power/Deflection PWB.
HORIZONTAL B+ ON AND OFF CIRCUIT: (See Figure 1)
When the power supply goes into Stand-By mode (TV Off), the Horizontal Drive signal for deflection is
shut off. Q002 and QP04 accomplish this. The Low out produced from the Power On/Off pin 53 of the
Microprocessor routed through Q002 located on the Signal PWB. This low is sent through the PQS1
connector, pin (8) to the Sub Power Supply PWB and then through PQD2 connector, pin (1) and sent to
the Deflection PWB. This Low is detected by the base of QP04 turning it ON and the SBY +11V con-
nected to its emitter is made available at its collector. The collector is connected to the Deflection B+ pin
(22) of the Horizontal and Vertical Drive IC, I701 via pin (8). This action stops I701 from producing a
horizontal deflection drive signal.
Power On/Off
ZP94/95 SERIES "POWER ON & OFF" DIAGRAM
RP36
CP44
HVcc
C964
Deflection PWB
I701
H Drive IC
15
8
Def.
B+
Hoz.
Out
Signal PWB
C544
SBY11V
PQD2
1
DP21
RP38
RP37
QP04
DP35
DP36
3
L701
I001
Microprocessor
53
PQS1
8
Power
On/Off
ON = Hi
OFF = Lo
Q002
ON = Hi
OFF = Lo
Sub Power
Supply PWB