Hitachi 57S715 User manual

CONTENTS... 2004 DP-4X Chassis Projection Television Information
Materials Prepared by… Alvie Rodgers C.E.T. (Chamblee, GA.)
September 2006 (ver v)
2004 MODEL RELEASE
DIGITAL HD READY PTV
Model Chassis Remote P/N
57S715 DP-47 CLU-3842WL HL02062
51S715 DP-47 CLU-3842WL HL02062
65F710 DP-45 CLU-4341UG2 HL02071
57F710 DP-45 CLU-4341UG2 HL02071
51F710 DP-45 CLU-4341UG2 HL02071
51F510 *DP-43 CLU-4341UG2 HL02071
57F510 *DP-43 CLU-4341UG2 HL02071
Service Web Site
http://www.hitachiserviceusa.com
HITACHI
PROJECTION
TELEVISION
* Does Not Have a
Digital Module. No
ATSC Tuner.

DP-4X BLANK PAGE (NOTES)
BLANK PAGE

DP-4X TABLE OF CONTENTS
Table of Contents Page 1 of 2
September 2006(ver v) Materials prepared by
Alvie Rodgers C.E.T.
TOPICS PAGE
Continued on Next Page
SECTION (1) POWER SUPPLY DIAGRAMS:
•Generic Power Supply Circuits Explained ---------------------------------------------------------- 01-01
•Deflection Side Shutdown Circuit Diagram Explained ------------------------------------------- 01-04
•Deflection Side Shutdown Circuit Diagram Explained ------------------------------------------- 01-05
•PROT_OVP and PROT_OCP Shut Down Circuit Diagram Explanation -------------------- 01-06
•PROT_OVP and PROT_OCP Shut Down Circuit Diagram ----------------------------------- 01-07
•Deflection Power Supply Shutdown Output Circuit Diagram Explained -------------------- 01-08
•Deflection Power Supply Shutdown Output Circuit Diagram --------------------------------- 01-09
•Signal Power Supply Shutdown Circuit Diagram Explained ----------------------------------- 01-10
•Signal Power Supply Shutdown Circuit Diagram ------------------------------------------------ 01-12
•Stand By +5V Power Supply Generation Circuit Diagram and Explanation ----------------- 01-13
•Power Supply Relay Control Circuit Diagram Explained --------------------------------------- 01-14
•Power Supply Relay Control Circuit Diagram ---------------------------------------------------- 01-15
•SW +115V Hi Voltage Regulation Circuit Diagram Explained --------------------------------- 01-17
•SW +115V Hi Voltage Regulation Circuit Diagram ---------------------------------------------- 01-18
•IP01 Voltages and Waveforms ---------------------------------------------------------------------- 01-18A
•5.7V Volt Regulation Circuit Diagram Explained ------------------------------------------------- 01-19
•5.7V Volt Regulation Circuit Diagram -------------------------------------------------------------- 01-20
•LEDs (Visual Trouble Shooting) Deflection Power Supply Circuit Diagram Explained ----- 01-21
•LEDs (Visual Trouble Shooting) Deflection Power Supply Circuit Diagram ------------------ 01-22
SECTION (2) MICROPROCESSOR INFORMATION:
•Microprocessor DATA COMMUNICATION Explanation ------------------------------------- 02-01
•Microprocessor DATA COMMUNICATION Circuit Diagram ------------------------------------ 02-05
•Audio Video Mute Circuit Diagram Explanation -------------------------------------------------- 02-06
•Audio Video Mute Circuit Diagram------------------------------------------------------------------ 02-09
•Microprocessor NTSC Sync Input Circuit Diagram Explained --------------------------------- 02-10
•Microprocessor NTSC Sync Input Circuit Diagram Circuit Diagram ------------------------------ 02-11
SECTION (3) VIDEO CIRCUIT INFORMATION:
•Video Signal Selection Circuit Diagram Explained ----------------------------------------------- 03-01
•Video Signal Selection Circuit Diagram ------------------------------------------------------------ 03-03
•Composite Video Signal Path 1H NTSC Circuit Diagram Explanation ----------------------- 03-04
•Composite Video Signal Path 1H NTSC Circuit Diagram -------------------------------------- 03-06
•RGB Processor (Rainforest) Circuit Explanation ------------------------------------------------- 03-07
•RGB Processor (Rainforest) Circuit Explanation ------------------------------------------------- 03-09
•ABL Circuit Diagram Explanation-------------------------------------------------------------------- 03-10
•ABL Circuit Diagram ----------------------------------------------------------------------------------- 03-11
•H and V Sync to the Rainforest IC Circuit Diagram Explanation ----------------------------- 03-12
•H and V Sync to the Rainforest IC Circuit Diagram --------------------------------------------- 03-14

DP-4X TABLE OF CONTENTS
Table of Contents Page 2 of 2
September 2006(ver v) Materials prepared by
Alvie Rodgers C.E.T.
TOPICS PAGE
SECTION (4) AUDIO CIRCUIT INFORMATION:
•Audio Signal Selection Circuit Diagram Explanation --------------------------------------------- 04-01
•Audio Signal Selection Circuit Diagram Explanation --------------------------------------------- 04-03
SECTION (5) DEFLECTION CIRCUIT:
•Horizontal Drive Circuit Diagram Explanation ---------------------------------------------------- 05-01
•Horizontal Drive Circuit Diagram ------------------------------------------------------------------- 05-03
•IH01 Horizontal Drive IC Voltages and Waveforms (Also, Not Running Info.) ------------- 05-04
•Sweep Loss Detection Circuit Diagram Explanation ----------------------------------------------- 05-05
•Sweep Loss Detection Circuit Diagram--------------------------------------------------------------- 05-06
•Vertical Output Circuit Diagram Explanation ----------------------------------------------------- 05-07
•Vertical Output Circuit Diagram --------------------------------------------------------------------- 05-08
•Side Pincushion Circuit Diagram --------------------------------------------------------------------- 05-09
•Side Pincushion Circuit Diagram --------------------------------------------------------------------- 05-10
SECTION (6) DIGITAL CONVERGENCE CIRCUIT INFORMATION:
•Digital Convergence Interconnect Circuit Diagram Explanation ------------------------------- 06-01
•Digital Convergence Interconnect Circuit Diagram ---------------------------------------------- 06-06
•CLU-3842WL Remote Control ----------------------------------------------------------------------- 06-07
•CLU-4341UG2 Remote Control ---------------------------------------------------------------------- 06-08
•Adjustment Marker On/Off Explanation ----------------------------------------------------------- 06-09
•Adjustment Marker Movement by CH UP and CH DOWN Explanation --------------------- 06-10
•Convergence Adjustment Using and Outside Signal Explanation ------------------------------ 06-12
•Sensor Error Codes Explanation and Chart -------------------------------------------------------- 06-13
SECTION (7) CHASSIS PICTURES:
•Main Chassis Picture ---------------------------------------------------------------------------------- 07-01
•Signal PWB Picture ------------------------------------------------------------------------------------ 07-01
•Deflection PWB Picture ------------------------------------------------------------------------------- 07-02
•Convergence Output PWB Picture ----------------------------------------------------------------- 07-02
•Digital Convergence Unit (DCU) Picture --------------------------------------------------------- 07-03
•Sub (Signal) Power Supply PWB Picture --------------------------------------------------------- 07-03
•Tuner PWB Picture ------------------------------------------------------------------------------------ 07-04
•HDMI to DVI Adaptor Cable Comparison Picture --------------------------------------------- 07-04
•DP-43 Rear Panel (Rear Inputs) Picture ---------------------------------------------------------- 07-05
•DP-45 Rear Panel (Rear Inputs) Picture ---------------------------------------------------------- 07-06
•DP-47 Rear Panel (Rear Inputs) Picture ---------------------------------------------------------- 07-07
SECTION (8) SERVICE ADJUSTMENTS:
•See the index for this section after the Section 8 Divider. -------------------------------------- 08-00
SECTION (9) THINGS YOU SHOULD KNOW: Must be downloaded separately.
•See the index for this section after the Section 9 Divider. -------------------------------------- 09-00
SECTION (10) SERVICE POLICY:
Service Policy and PWB Part Numbers. --------------------------------------------------------------------- 10-01

DP-4X
CHASSIS INFORMATION
POWER SUPPLY
INFORMATION
SECTION 1

DP-4X BLANK PAGE “NOTES”
BLANK PAGE

DP-4X GENERIC POWER SUPPLY SHUTDOWN EXPLANATION
PAGE 01-01
GENERIC SHUTDOWN CIRCUITS EXPLAINED:
The following circuits are commonly used in Hitachi product and relate to the drawings for Shutdown:
SW +115V EXCESSIVE CURRENT DETECTION
(See Figure 1)
One very common circuit used in many Hitachi tele-
vision products is the B+ Excessive Current Sens-
ing circuit. In this circuit is a low ohm resistor RP34
in series with the SW +115V. The value of this resis-
tor is 0.39 ohm. When the current demand in-
creases, the voltage drop across the resistor in-
creases. If the voltage drop is sufficient to reduce the
voltage on the base of QP05, the transistor will con-
duct, producing a Shutdown signal that is directed to
the appropriate circuits indicated on the drawing for
Deflection Power Supply Shutdown Output Circuit,
OCP & OVP.
NEGATIVE VOLTAGE LOSS DETECTION
(See Figure 2)
The purpose of the Negative Voltage Loss detection circuit is to
compare the negative voltage with its counter part positive volt-
age. If at any time, the negative voltage drops or disappears, the
circuit will produce a Shutdown signal.
In Figure 2, there are two resistors. One to the positive voltage
+5V and one to the negative voltage –5V. At their tie point,
(neutral point), the voltage is effectually zero (0) volts, actually
about 1 Volt negative. If however, the negative voltage is lost,
the neutral point will go positive. This in turn will create a Shut-
down Signal through DK18 and on to the appropriate circuit in-
dicated on the drawing for Deflection Power Supply Shutdown
Output Circuit, OCP & OVP.
VOLTAGE TOO HIGH DETECTION
(See Figure 3)
Another circuit used is the Voltage Too High Detec-
tion circuit. In the example shown in Figure 3, the
zener diode DP39 is connected to a voltage divider
RP38 and RP39. If the voltage source rises too high,
the voltage at the divider center point will rise as well
and trigger or fire the zener diode which produces a
Shutdown signal through DP38 and on to the appro-
priate circuit indicated on the drawing for Deflection
Power Supply Shutdown Output Circuit, OCP & OVP.
Figure 1
SW +5V
Shutdown Signal
DK18
SW -5V
RK23
2.7K
RK22
1.8K
Negative
Voltage Loss
Detector
Figure 2
SW +115V
Voltage Too
High Detector
Shutdown
Signal
DP39
DP38
RP38
RP39
Figure 3
(Continued on page 6)
Current Sensor
Base
Bias
Shutdown Signal
RP34
0.39
QP05
SW+115V
CP46
RP36
RP35

DP-4X GENERIC POWER SUPPLY SHUTDOWN EXPLANATION
PAGE 01-02
GENERAL INFORMATION:
This explains the Overall Power Supply Shutdown Circuits:
Which turns off the Relay Driver for the Deflection Power Supply and the Relay for the Signal Power Supply.
DEFLECTION (High Voltage) POWER SUPPLY:
The Deflection Power supply is centered around the Switching Transformer TP01 and the driver IC, IP01.
This power supply creates voltages that are Switched on when the Set is turned on.
1. SW +115V 2. +220V
3. +28V 4. SW-28V
5. +7V 6. SW +6.3V
Other supplies are generated from these 6 main voltages.
SIGNAL (Low Voltage) POWER SUPPLY:
The Signal Power supply is centered around the Switching Transformer T201 and the driver IC, I201.
This power supply creates voltages that are Switched on when the Set is turned on.
1. 38.5V or 29V 2. +10.5V
3. +21V 4. SW-5.6V
5. +16V 6. SW +5.7V
Other supplies are generated from these 6 main voltages.
Q204 and Q203 Relay Inhibit Activation. (SHUTDOWN) called COMMON ACTION CIRCUIT.
All Shutdown events will cause the main power relays to turn off. This action will stop all secondary power supplies.
The Low Voltage power supply (Stand-By) will Shutdown along with the Deflection Power Supply.
See the DP-4X Signal Power Supply Shutdown Circuit for details.
If any of the shutdown circuits activate, the base of Q203 will go High. This turns on Q203 and removes the Power On Highs
from PPS1 connector pins 9(Power_Sig) and 11 (Power_Def) called Power_1 and Power_3. With this, the main power sup-
plies will STOP. Q204 operates as a “latch”. This prevents Q203 from turning off if the shutdown signal disappears after
shutdown.
SOME SHUTDOWN CIRCUITS ARE DEFEATED IN STANDBY MODE. (Set Off).
When the set is turned off (called Stand By), some of the shutdown inputs are not active because the voltages being monitored
are not on.
•Shorted FAN +10V (from from pin 3of IC303). This voltage is monitored by D313.
•Stopped Fans PPF2 and PPF3 pin 2. This is monitored by D313.
•Shorted Drv 16.5V (from pin 2of IC301) This voltage is monitored by D312.
•Prot_Drv (from pin 48 of PPS1) This voltage is monitored by D312.
•Prot_OCP (6 shutdown inputs) This voltage is monitored by D944.
1. SW +2.2V (IV01) * 2. SW +3.3V (IY01) * 3. SW +9V (IY07) *
4. VM +220V (QEA8) * 5. SW +6.3V (QP04) ** 6. SW +28V (DP30) **
* See the PROT_OVP and PROT_OCP Shutdown Diagram.
** See the Deflection Power Supply Shutdown Output Circuit Diagram. (Continued on page 3)
Any Positive
B+ Supply
B+
Q1
Shutdown Signal
Voltage
Loss
Detector
Figure 4
VOLTAGE LOSS or SHORT DETECTION
(See Figure 4)
One circuit used is the Voltage Loss Detection cir-
cuit. This is a very simple circuit that detects a loss of
a particular power supply and supplies a Pull-Down
path for the base of a PNP transistor.
This circuit consist of a diode connected by its cath-
ode to a positive B+ power supply. Under normal
conditions, the diode is reversed biases, which keeps
the base of Q1 pulled up, forcing it OFF. However, if
there is a short or excessive load on the B+ line that’s
being monitored, the diode in effect will have a LOW
on its cathode, turning it ON. This will allow a cur-
rent path for the base bias of Q1, which will turn it
ON and generates a Shutdown Signal.

DP-4X GENERIC POWER SUPPLY SHUTDOWN EXPLANATION
PAGE 01-03
(Continued from page 2)
See the DP-4X Signal Power Supply Shutdown Circuit for details.
These shutdown circuits are defeated because the SW (Switched) power supplies are turned off in standby. So to prevent
faults triggering of the shutdown circuit, the sensing circuits are turned off also..
Q206 generates the shutdown high signal if any of the shutdown circuits attached to its base become low. Q206 requires emit-
ter voltage to operated. RY05 supplies the 5.7V to the Emitter of Q206. This voltage must be active for Q206 to function.
When the set is turned off, RY05 opens and the 5.7V disappears so Q206 can no longer operate.
SHUTDOWN INPUTS EXPLAINED:
GENERAL INFORMATION CONTINUED: (See previous two pages for generic shutdown circuit details):
All of the Power Supply Shutdown circuitry can be broken down into the following categories;
•Voltage Missing Detection or Short Detection or Negative Voltage Loss Detection
•Voltage Too High Detection
•Excessive Current Detection
COLD GROUND SIDE SHUTDOWN SENSING CIRCUITS. (AC must be removed to recover).
All shutdown events arrive at the base of Q203. The shutdown events are categorized in the following pages.
The shutdown circuit are broken down into four pages. The shutdown outputs from each page are interconnected and indi-
cated by symbols shown below;
A
Please refer to the following Diagrams as you continue to read the following explanations.
1. The DP-4X Deflection Side Shutdown Diagram for (A), (B), (C), (D).
2. The DP-4X PROT_OVP and PROT_OCP Shutdown Diagram for (A), (B), (E), (F).
3. The DP-4X Deflection Power Supply Shutdown Output Circuit Diagram for (C), (D).
4. The DP-4X Signal Power Supply Shutdown Circuit for (E), (F).
B C D E F

DP-4X DEFLECTION SIDE SHUTDOWN DIAGRAM EXPLANATION
PAGE 01-04
See The DP-4X Deflection Side Shutdown Diagram for (A), (B), (C), (D).
HIGH VOLTAGE TOO HIGH DETECTION: One of the Shutdown circuits for output (A).
•DH15 High Voltage Too High Sensing Circuit.
This circuit monitors the High Voltage line generated by rectifying the pulse from the flyback TH01 pin
7. If the voltage created by rectifier DH13 and capacitor CH17 at the cathode of DH15 goes too high, this
zener will fire. This high will be routed to pin 8of PDS3 PROT_OVP (A) to the PROT_OVP and
PROT_OCP Shutdown Diagram.
•At the same time, the zener diode DH14 will fire and this high will be routed to pin 7of IH01. This is the
Horizontal Drive for High Voltage and this IC will shut off, turning off High Voltage drive pulses.
•The ABL is tied to the cathode of DH15 via RH32. This resistor offers slight “Trigger Point” deviations
as the screen brightness fluctuates and caused the High Voltage to bounce. By tying ABL to the Excessive
High Voltage detection voltage, the firing point is slightly altered.
VERTICAL OUTPUT CIRCUIT EXCESSIVE CURRENT DETECTION: One of the Shutdown circuits for
output (A).
•Q604 Vertical Circuit Excessive Current Sensing Circuit.
This circuit monitors the SW+28V line going to I601 Vertical Output IC. If the IC draws too much cur-
rent, R629 will develop a larger voltage drop. This will cause the base voltage of Q604 to fall turning on
this transistor. When this happens, its collector will go high. This high will be routed through D608 and to
pin 8of PDS3 PROT_OVP (A) to the PROT_OVP and PROT_OCP Shutdown Diagram.
-5V NEGATIVE VOLTAGE LOSS DETECTION: One of the Shutdown circuits for output (A).
•DK18 –5V Loss Detection Circuit.
The purpose of the Negative Voltage Loss detection circuit is to compare the negative voltage with its
counter part positive voltage. If at any time, the negative voltage drops or disappears, the circuit will pro-
duce a Shutdown signal.
There are two resistors. One to the positive voltage +5V RK23 and one to the negative voltage –5V
RK22. At their tie point, (neutral point), the voltage is approximately (-1V). If however, the negative
voltage is lost, the neutral point will go positive. This in turn will create a Shutdown Signal through
DK18. This high will be routed to pin 8of PDS3 PROT_OVP (A) to the PROT_OVP and PROT_OCP
Shutdown Diagram.
PROT_OVP INPUT INDICATED BY (C) One of several Shutdown outputs for item (A).
•The PROT_OVP signal (Active High) is shown in the center left hand side of the diagram. This is an in-
put from the Deflection Power Supply Shutdown Circuit Diagram. There are 3 circuits from the Deflec-
tion Power Supply Shutdown Circuit Diagram that provide inputs to this diagram.
•This is explained on Page 01-06.
SW +10.5V SHORT DETECT INDICATED BY (D) Shutdown output for item (B).
•D723 is attached to the B+ SW +10.5V line which is generated on the Signal PWB by QY62. If this volt-
age disappears or is shorted, D723 cathode will be pulled low generating a Low on Pin 9of PDS3 and
output as a shutdown signal on the PROTECT_OCP indicated as item (B).

PROTECT _OVP
DP-4X DEFLECTION SIDE SHUTDOWN DIAGRAM
PAGE 01-05
Flyback
5OP
29.01V
TH01
TH02
RH32
7
LH06
Excessive Hi
Voltage Det.
RH23
CH17
Normal
Active
8
ABL
I601
7
Vertical Output Circuit
R630 R631
C610
DH15
R629
0.68 Ohm
Q604
SW 28V
D608
Excessive Vertical Current Det.
R632
From Deflection Power Supply Shut
Down Output Circuits Diagram.
RH32 allows ABL fluctuations to
manipulate the Trigger Point of Shut
Down as screen brightness varies.
ABL is inverse proportionate to
brightness.
This prevents false Shut Down triggering.
Any fluctuations in High Voltage will also be
reflected by the 50P output P/P.
By monitoring the 50P (50 Pulse) rises in High Voltage
will be sensed. If High Voltage climbs too high, DH15
will fire and trigger a shut down event.
DH14 will fire and stop High Voltage Horz. Drive
If the Vertical Output IC has a problem, R629
will sense the current rise. The voltage drop will
be reflected at the base of Q604 turning it on
and producing a Shut Down high.
DK18 Monitors the -5V and +5V lines going to the DCU.
If the -5V line is loss, the +5V line provides the Shut Down Hi.
On the Convergence Circuit Diagram Power Def. page 2 of 3.
High Voltage
Sensing Circuit
DH13
4
RK22
1.8K
RH24
C604
RH25
RK23
2.7K
-5V
+5V
IH01
OVP
Hi Volt
H. Drive
7
Stops H. Drive
DH14
RH26
CH10 RH09
H. Drive
1
-5V Loss Det.
110
L603
PROTECT _OVP
To Signal PWB
8
PDS3
See Protect_OVP and Protect_OCP
Shut Down Diagram for Details.
PROTECT _OCP
To Signal PWB
9
SW +10.5V From QY62 SW +10.5V Regulator on Signal 5 of 5 Schematic.
A
6
B
C
3
1
DK18
D723
10 SW
+10.5V
SW +10.5V
D

DP-4X PROT_OVP and PROT_OCP SHUTDOWN DIAGRAM EXPLANATION
PAGE 01-06
PROT_OVP and PROT_OCP SHUTDOWN CIRCUITS EXPLAINED: (A) (B) (E) (F)
(See the PROT_OVP and PROT_OCP Shutdown Diagram for Details).
CPT PROTECT (+200V Excessive Current Detection): One of several Shutdown outputs for (E).
•On the RED CRT PWB +220V (VM 200V) Excessive Current Detection
Monitored by RE35. If the 220V draws too much current, the base voltage of QE08 will fall turning it on.
The collector will go high. This high will go to the connector ERG1 pin 7 labeled as VM PROT. This
high continues to the Green CRT PWB connector PSC pin 3 labeled VM PROT on the Green CRT PWB
and CPT PROTECT on the Signal PWB.
•This line is connected to the PDS3 connector which ties the inputs from the Deflection Side Shutdown
Circuit, identified as (A) 6 inputs active High.
•Any High from this line is then routed to the PPS1 connector pin 47 identified as (E). From here this high
is routed to the Signal Power Supply Shutdown Circuit Diagram identified as (E).
VM GAIN CONTROL (VM 200V Excessive Current Detection): One of several Shutdown outputs for (F).
•On the BLUE CRT PWB VM+220V Excessive Current Detection
Monitored by REF1. If the VM220V draws too much current, the base voltage of QEA8 will fall turning
it on.
The collector will go high. This high will go to the connector EGB1 pin 8 labeled GAIN CONT. This
high continues to the Green CRT PWB connector PSC pin 2 labeled VM GAIN.
•This line is connected to the VM Signal generation circuit and turns it off.
•This line is also connected to the base of QY60. This transistor acts as an inverter to change the output
High to a Low on its collector.
•The collector of QY60 is tied to several circuits. The Voltage Loss Detection Circuits explained below
and the PROT_OCP from the Deflection Side Shutdown Circuit from PDS3 connector pin 9. Labeled as
PROT_OCP (B) which represents 1 shut down input from the Deflection Side Shutdown circuits.
VOLTAGE LOSS DETECTION CIRCUITS: One of several Shutdown outputs for (F).
•IV01 generates the SW +2.5V. If this line is shorted or missing, this line will drop Low.
•IY01 generates the SW +3.3V. DY03 is connected to the SW +3.3V line. If this line is shorted or
missing, the cathode of DY03 goes low which pulls the PROT_OCP line low.
•IY07 generates the SW +9V. DY04 is connected to the SW +9V line. If this line is shorted or miss-
ing, the cathode of DY04 goes low which pulls the PROT_OCP line low.
•PROT_OCP: LABELED AS OUTPUT (F).
Any low from this line is then routed to the PPS1 connector pin 45 identified as PROT_OCP
(F). From here this low is routed to the Signal Power Supply Shutdown Circuit Diagram and
again identified as (F).

RE31
PROT_OCP
VM GAIN
CONT
REF5
RZ60
DP-4X PROT_OVP and PROT_OCP SHUTDOWN DIAGRAM
RE35
2.2 Ohm
1
PDC1
+220V
RE29
QE08
CE10
RE34
7
ERG1
3
PSC
GREEN
CRT
PWB
PDS3PDS3
SIGNAL PWB
VM PROT VM PROT CPT
PROTECT
REF1
10 Ohm
2
EGB2
VM
220V
REE9
QEA8
REF5
VM Circuit
8
EGB1
2
PSC
GREEN
CRT
PWB
SIGNAL PWB
GAIN
CONT
RED CRT PWB
BLUE CRT PWB
REF2
CEC1
VM 200V
R.G.B. Drives
VM GAIN
CONT
CZ04
DY04
QY60
RL50
RZHD
SW +3.3V
IY01
SW +3.3V Reg
3
SW +5.7V
1
SW +2.5V
IV01 7
SW +2.2V Reg
1
DM +10.5V
DY03
SIGNAL PWB 2 of 3
PAGE 01-07
PROT_OCP SHUT DOWN DIAGRAM
PROT_OVP SHUT DOWN DIAGRAM
Active Hi
DEB6
REF4
Also Shuts Off
VM Signal
Generation Circuit
RZ62
PPS1
45
SIG
POWER
PWB
3 8
IY07 35
SW +9V
SW +9V Reg
DEF. PWB /
DEF. POWER
RE27
8
See Signal
Power Supply
Shut Down
Circuit
Text Indicates the Labels on the Schematic
9
PDS3
DEF. PWB /
DEF. POWER
From Deflection
Side Shut Down
Circuit
PROT_OCP
47
Active Lo
PROT_OVP
Active Hi
From Deflection
Side Shut Down
Circuit
PROT_OVP
A
6
B
1
E
F
7
5
4
3
1

DP-4X DEFLECTION POWER SUPPLY SHUTDOWN OUTPUT DIAGRAM EXPLANATION
PAGE 01-08
DEFLECTION POWER SUPPLY SHUTDOWN OUTPUT CIRCUIT DIAGRAM EXPLAINED: (C)
(See the Deflection Power Supply Shutdown Output Circuit Diagram for Details).
PROT_OVP: Identified as (C).
EXCESSIVE DEFLECTION 115V B+ CURRENT DETECTION: Part of several Shutdown outputs to (C).
•QP05 monitors RP34 current draw. RP34 is a 0.39 low ohm resistor. Normally the current draw isn’t
enough to turn on QP05. However, if there is a problem, the current draw through RP34 increases caus-
ing an increase in the voltage drop across this resistor. If there is enough current the base voltage of QP05
will drop enough to turn on this transistor. When QP05 turns on, its collector goes high. This high will
fire zener diode DP36 and generate a high on the anode of DP37.
•CP49 and RP37 prevent faults triggering of the shut down line due to High Voltage bounce by smoothing
out and fluctuations on the anode of DP36.
•DP37 cathode is connected the anode of DP38. This line is connected to the line labeled PROT_OVP
and identified as (C).
•PROT_OVP is routed to the Deflection Side Power Supply Shutdown Diagram also identified as (C).
EXCESSIVE DEFLECTION 115V B+ VOLTAGE DETECTION: Part of several Shutdown outputs to (C).
•DP39 monitors the Deflection 115V B+ line via the Voltage divider consisting of RP38 and RP39. If the
Deflection 115V B+ line goes too high, DP39 will fire and generate a high on the anode of DP37.
•DP37 cathode is connected the anode of DP38. This line is connected to the line labeled PROT_OVP
and identified as (C).
•PROT_OVP Identified as (C) is routed to the Deflection Side Power Supply Shutdown Diagram also
identified as (C).
SW -28 VOLT SHORTED or MISSING DETECTION: Part of several Shutdown outputs to (C).
•SW -28V Shorted or Missing Detection
Monitored by DP46. If the SW-28V is shorted or missing, the cathode will be pulled high causing the
zener to fire. This high will be routed through DP47. This line is connected to the line labeled
PROT_OVP and identified as (C).
•PROT_OVP Identified as (C) is routed to the Deflection Side Power Supply Shutdown Diagram also
identified as (C).

0.69A
3
2
DP31
DP-4X CHASSIS
Deflection Power Supply Shutdown Output Circuit Diagram
OCP and OVP
CP30
15
16
GREEN L.E.D.
CP45
0.85A SW + 115V
11
10
1.26A
CP32
+115V
DP34 RP34
0.39 Ohm
DP40
LP37
RP38
RP39
+115V Over Current
Detection
QP05
GREEN
L.E.D.
SW+ 28V
DP50
RP46
DP46 DP47
CP46
TP01
RP47
PAGE 01-09
LP30
CP35
CP31
CP33
-28V LP31
14
RP35
+28V DP30
CP34
LP33
SW -28V
0.65A
LP34
+
+
+
+
11
14
EP02
2 Amp
PROT_OVP
To Deflection Side
Power Supply Shut
Down Diagram
DP36
RP36
DP37
CP49
RP37
DP39
DP38
SW + 7V
3
2
CP36
18
DP32
17
14
+7V
SW + 6.3V
DP48DP49
CP39
0.19A
Active High
+115V Over Voltage
Detection
C
3
-28V Short or Loss Detection
QP04

DP-4X SIGNAL POWER SUPPLY SHUTDOWN CIRCUIT EXPLANATION
PAGE 01-10
See the DP-4X Signal Power Supply Shutdown Circuit for details. This includes inputs (E) and (F).
There are a total of 20 individual Shutdown inputs to the Relay Inhibit transistor Q203 shown on the Signal
Power Supply Shutdown Circuit.
•There are 8individual Shutdown detection circuits on the Signal Power Supply Circuit Diagram.
•There are a total of 5individual Shutdown inputs from the Deflection PWB via PROT_OCP (active
Low). Input from the PPS1 connector pin 45
•There are a total of 7shutdown inputs from PROT_OVP (active High) input from the PPS1 connector
pin 47.
SHUTDOWN INPUTS EXPLAINED:
Q204 and Q203 Relay Inhibit Activation. (SHUTDOWN) called COMMON ACTION CIRCUIT.
All Shutdown events will cause the main power relays to turn off. This action will stop all secondary power
supplies. The Low Voltage Signal Power Supply will Shutdown along with the Deflection Power Supply.
•Q203 CIRCUIT EXPLAINED:
•If any of the shutdown circuits activate, the base of Q203 will go High. This turns on Q203 and removes
the Power On Highs from PPS1 connector pins 9(Power_Sig) and 11 (Power_Def) called Power_1 and
Power_3. With this, the main power supplies will STOP. Q204 operates as a “latch”. This prevents
Q203 from turning off if the shutdown signal disappears after shutdown.
POWER ON/OFF RELAYS RY101 and RY102:
RY101 Explained:
•The Relay RY101 supplies AC to the Signal Power Supply bridge rectifier DS201. When this relay en-
gages, the Signal Power Supply starts up and supplies the voltages mentioned below.
SIGNAL (Low Voltage) POWER SUPPLY:
•The Signal Power supply is centered around the Switching Transformer T201 and the driver IC, IP01.
•This power supply creates voltages that are Switched on when the Set is turned on.
1. 38.5V or 29V 2. +10.5V 3. +21V
4. SW-5.6V 5. +16V 6. SW +5.7V
•Other supplies are generated from these 6 main voltages.
RY102 Explained:
•The Relay RY102 supplies AC to the Deflection Power Supply bridge rectifier DP01. When this relay
engages, the Deflection Power Supply starts up and supplies the voltages mentioned below.
DEFLECTION (High Voltage) POWER SUPPLY:
•The Deflection Power supply is centered around the Switching Transformer TP01 and the driver IC, IC201.
•This power supply creates voltages that are Switched on when the Set is turned on.
1. SW +115V 2. +220V 3. +28V
4. SW-28V 5. +7V 6. SW +6.3V
•Other supplies are generated from these 6 main voltages.
CIRCUITS ATTACHED TO THE BASE OF Q203:
This year, Hitachi is utilizing a three legged diode OR gate style of input device for feeding shutdown inputs
to the base of Q203. These diode OR gates and circuits attached are explained next.
(Continued on page 11)

DP-4X SIGNAL POWER SUPPLY SHUTDOWN CIRCUIT EXPLANATION
PAGE 01-11
(Continued from page 10)
D214 Left Hand Input Circuits:
The left hand input to D214 is connected to the collector of Q205. This transistor works as an inverter. Its
base inputs are monitoring DC voltages for shorts.
Q205 base input circuits.
•D115:
1. The left hand input monitors the 5.7V line for shorts.
2. The right hand input monitors the 35V line for shorts.
•D116:
1. The left hand input monitors the 10.5V line for shorts.
2. The right hand input monitors the 3.3V line for shorts.
The Emitter of Q205 pull up voltage is supplied through D213. The left hand input to D213 is 5.7V and the
right hand input is 10.5V. This assures the emitter voltage is always present and allows Q205 to monitor
these voltages without fail. If either the 10.5V or the 3.3V line is shorted, this transistor will still function.
D214 Right Hand Input Circuit:
The right hand input to D214 is connected to the anode of ZD204. This monitors the DC voltage 3.3V for an
over voltage condition. If this voltage rises too much, the zener will fire generating a high on its anode and
through D214 to the Common Action Circuit.
D217 input circuits.
•D217 Left Hand Input:
1. ZD202. This monitors the DC voltage 5.7V for an over voltage condition. If this voltage rises too
much, the zener will fire generating a high on its anode and through D217 to the Common Action
Circuit.
•D217 Right Hand Input:
1. ZD203. This monitors the DC voltage 10.5V for an over voltage condition. If this voltage rises too
much, the zener will fire generating a high on its anode and through D217 to the Common Action
Circuit.
D218 input circuits.
•D218 Left Hand Input:
1. ZD205. This monitors the DC voltage -5.6V for a loss or short. If this voltage disappears, the posi-
tive voltage fed through R241 will pull the cathode of zener diode ZD205 high. The zener will fire
generating a high on its anode and through D218 to the Common Action Circuit.
•D218 Right Hand Input:
1. This monitors the PROT_OVP inputs also labeled as (E) to the connector PPS1 pin 47. There are a
total of 7 inputs fed to this pin described in the previous 9 pages. If this voltage goes high, the high
will be directed through D218 to the Common Action Circuit.
•See references to (E) on the PROT_OVP and PROT_OCP SHUTDOWN DIAGRAM.
D220 input circuits.
The anode of diode D220 is connected to the collector of Q206. This transistor works as an inverter. Its base
input is monitoring the PROT_OCP inputs also identified as (F) from the connector PPS1 pin 45. These
inputs will be Low in nature. There are a total of 5inputs fed to this pin described in the previous 9 pages.
•See references to (F) on the PROT_OVP and PROT_OCP SHUTDOWN DIAGRAM.

RY102
RY101
R126
C235
R125R120
R122
RY105
R241
C237
D111
AC
SBY +5V
R118
D109
R231
R230
Q203
Q204
C238
onoff
Relay
Driver
Relay
Driver
D104
For
Signal
Power
Supply
DS201
Q101
AC
SBY +5V
R121
D110
D105
For
Deflection
Power
Supply
DP01
Q102
R110
9
Power 1
11
Power 3
R232
D213 D115 D116
D214 D217 D218
ZD202 ZD203 ZD205
35V 3.3V
R224
Q205
R233
ZD206
R235
ZD204
10.5V
R236
R240
D220
R239
R237
D219
SBY +5V
5.7V
12
Power 2
Q104
PPS1
DP-4X SIGNAL POWER SUPPLY SHUTDOWN CIRCUIT
EF
7
5
PROT_OVPPROT_OCP
45 47
Active Low Active High
C232
R238
Q206
-5.6V
5825
20
PAGE 01-12

DP-4X STAND BY +5V POWER SUPPLY GENERATION EXPLANATION
PAGE 01-13
STAND-BY +5V POWER SUPPLY GENERATION EXPLANATION:
The Stand By power supply operates anytime the set is plugged into an AC outlet. Shown
below in Figure 1 is the Stand By power supply. IC101 is the Driver IC for this supply. It’s
a self contained Oscillator, Driver IC. It switches the primary of T101.
The secondary of T101 produces the SBY +5V via the rectifier D103 and filter C106. Then
the voltage is clamped by ZD101.
A feedback to IC101 is supplied by the photo coupler PC102 for regulation purposes.
•IC102 works as a variable resistor attached to the cathode of the internal LED inside
IC102. As the SBY +5V changes so will the resistance of IC102. Voltage Up, Resis-
tance goes Down. As the Resistance goes down the Light emitted from the LED will in-
crease. As the Light increases from the LED, the receiver will conduct more heavily.
This decreases the voltage fed back to IC101 causing the internal circuits within IC101
to reduce the primary switching of T101 and reduce the SBY 5.7V line back to normal.
Figure 1
DS101
C105
L102
F103
-+
D102
PC102
T101
D103
C106 ZD101
IC102
SBY +5V
IC101
C106R110
R113
R114
R115
R111
C109
R112
C110C107

DP-4X POWER SUPPLY RELAY CONTROL EXPLANATION
PAGE 01-14
See The DP-4X Stand By +5.7V Generation Circuit Explanation for details. (Previous Page)
See The DP-4X Power On and Off Circuit Diagram for details. (Page01-16)
Power Supply On and Off Circuit Explanation:
The DP-4X Chassis utilizes 5 relays.
1. RY101 AC Supply to the Signal Power Supply Relay
2. RY102 AC Supply to the Deflection Power Supply Relay
3. RY103 DC Supply to the Audio Output Relay
4. RY104 AC Supply to all AC Relays Relay
5. RY105 DC (SW +5.7V) Supply to the Low Voltage Regulators Relay
(4) RY104 AC Supply to all AC Relays Relay
Starting with RY104 because this Relay supplies AC to RY101 and RY102 which in turn
supplies AC to the Bridge Rectifiers for the Signal and Deflection Power Supplies.
When The Stand By Power Supply develops the SBY +5V, (see previous page) this DC
voltage is delivered to the primary windings of RY104 and to the relay driver Q105 for
RY104. This turns on the relay and supplies AC to the above mentioned circuits.
(1) RY101 AC Supply to the Signal Power Supply Relay
When the set is turned on, the POWER SIG command is supplied from pin 59 of the Mi-
croprocessor I004. (This high also turns on the Power LED on the front of the set). This
high is sent to Q018 and Q021 then to the PPS1 connector pin 9 labeled POWER 1.
From here this high goes to the Deflection PWB through R120, R110, D109 to the Base
of Q101 goes high and the transistor turns on. This action supplies a ground return for the
coil inside RY101 and the relay turns on supplying AC to the Signal Power Supply recti-
fier DS201 and the Signal Power Supply begins to operate.
(2) RY102 AC Supply to the Deflection Power Supply Relay
When the set is turned on, the POWER DEF command is supplied from pin 58 of the Mi-
croprocessor I004. (This high also turns on the Power LED on the front of the set). This
high is sent to Q023 and Q024 then to the PPS1 connector pin 11 labeled POWER 3.
From here this high goes to the Deflection PWB through R125, R122, D110 to the Base
of Q102. The base goes high and the transistor turns on. This action supplies a ground re-
turn for the coil inside RY102 and the relay turns on supplying AC to the connector PC2.
Then to the Deflection Power Supply rectifier DP01 and the Deflection Power Supply be-
gins to operate.
(3) RY103 DC Supply to the Audio Output Relay
When the set is turned on, the POWER DM command is supplied from pin 91 of the Mi-
croprocessor I004. This high is sent to Q028 and Q029 then to the PPS1 connector pin 12
labeled POWER 2. From here this high goes to the Deflection PWB through R124 to the
Base of Q103. The Base goes high and the transistor turns on. This action supplies a
ground return for the coil inside RY103 and the relay turns on supplying Audio B+ to the
connector PPS1 pins 1,2 and 3.Then to the Signal PWB and
on to the Audio Output IC IA02. Continued on Next Page