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Training Manual |
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Projection
Television
Circuit Description and Troubleshooting
Course: TVP-08
Course Description
and Troubleshooting:
RA-4 Chassis
Prepared by: National Training Department
Sony Service Company
A Division of Sony Electronics Inc.
Course presented by______________________________________
Date___________________________________________________
Student Name ___________________________________________
Sony Service Company
A Division of Sony Electronics Inc ©1998
All Rights Reserved
Printed in U.S.A.
Sony and Trinitron are registered trademarks of Sony.
Table of Contents
Features |
1 |
Overview |
1 |
Picture |
1 |
Audio |
1 |
Self-Diagnostics |
3 |
Board Descriptions |
5 |
Power Supply Block |
7 |
AC Input |
7 |
Power ON |
7 |
Converter |
7 |
Regulation |
7 |
Protection |
7 |
AC Input and Switching B+ |
9 |
Overview |
9 |
AC Input |
9 |
B+ Rectifier |
9 |
Standby Power Supply |
11 |
Overview |
11 |
Standby Switching supply |
11 |
Vcc Switch (Power On) |
13 |
Overview |
13 |
Power ON |
13 |
DC Protect |
13 |
AC Protect |
13 |
Soft Start |
15 |
Overview |
15 |
Soft Start - Power ON |
15 |
Converter |
17 |
Overview |
17 |
Operation |
17 |
T602 Secondary (Audio B+) |
19 |
Overview |
19 |
Operation |
19 |
T601 Secondary-1 |
21 |
Overview |
21 |
+/- 15 Volts |
21 |
+ 11 Volts |
21 |
+/- 22 Volts |
21 |
Distribution |
21 |
T601 Secondary-2 |
23 |
+7 Volts |
23 |
+135 Volts |
23 |
-135 Volts |
23 |
+33 Volts |
23 |
Distribution |
23 |
Regulation |
25 |
Overview |
25 |
Operation |
25 |
DC Protection |
27 |
Overview |
27 |
Shut Down |
27 |
+135 Volt Over Voltage |
27 |
+135 Volt Over Current Protection |
27 |
+19, +22, +7 Volt LVP |
27 |
PS Troubleshooting |
29 |
Overview |
29 |
Troubleshooting |
29 |
Protection Block |
31 |
Overview |
31 |
Diagnostic Indication |
31 |
Circuit Description |
33 |
Reset |
35 |
Overview |
35 |
Initial Reset |
35 |
Power ON Reset |
35 |
System Block Diagram |
37 |
Overview |
37 |
B (Standby) Bus |
37 |
M (Main) Bus |
37 |
P (Auto Registration) Bus |
37 |
MID Bus |
37 |
Video Path Block |
39 |
Inputs |
39 |
Main Video |
39 |
Sub-Video |
39 |
IC511 Video Processor |
39 |
Input Switching |
41 |
Overview |
41 |
Inputs |
41 |
Outputs |
41 |
Main Y and C Buffers |
43 |
Overview |
43 |
Y Buffer |
43 |
Sync Separator |
43 |
C Buffer |
43 |
3D Comb Filter |
45 |
Overview |
45 |
What is a 3D Comb Filter? |
45 |
Circuit Description |
45 |
Main Chroma Decoder |
49 |
Overview |
49 |
C Processing |
49 |
Y Processing |
49 |
H and V Sync |
49 |
3.58 MHz |
49 |
Main YUV Switch |
51 |
Overview |
51 |
Inputs |
51 |
Output Selection |
51 |
DRC - Digital Reality Creation |
53 |
DRC Block |
57 |
Overview |
57 |
Inputs |
57 |
DRC Processing |
57 |
Outputs |
57 |
Troubleshooting |
57 |
MID - Multi Image Driver |
59 |
MID Block |
63 |
Overview |
63 |
MID Inputs |
63 |
MID Processing |
63 |
MID Outputs |
63 |
MID Troubleshooting |
63 |
Video Processor |
65 |
Overview |
65 |
Video Processing |
65 |
Sync Processing |
65 |
IK/AKB |
69 |
Overview |
69 |
Video Drive |
69 |
IK |
69 |
Troubleshooting |
69 |
Sync Paths |
71 |
Overview |
71 |
Sync Paths |
71 |
Deflection Block |
73 |
Overview |
73 |
Vertical |
73 |
Horizontal |
73 |
High Voltage |
73 |
Convergence |
73 |
Horizontal Deflection Block |
75 |
Horizontal Jungle |
77 |
Overview |
77 |
H Drive |
77 |
H Out |
79 |
Overview |
79 |
H Drive |
79 |
H Out |
79 |
Horizontal Centering |
79 |
Pin Amp |
81 |
Overview |
81 |
Pin Amp |
81 |
H Protect/HP |
83 |
Overview |
83 |
HP |
83 |
H Protect |
83 |
Vertical Deflection Block |
85 |
H BLK Delay and 1/2 H + Odd/Even |
87 |
Overview |
87 |
H BLK Delay |
87 |
1/2 H and Odd/Even |
87 |
VDSP |
89 |
Overview |
89 |
VCO |
89 |
CDP |
89 |
DSP |
89 |
DAC |
89 |
V Out |
91 |
Overview |
91 |
V Out |
91 |
V Protect |
91 |
High Voltage Block |
93 |
HV Drive |
95 |
Overview |
95 |
HV Drive |
95 |
Peak Drive |
95 |
HV Regulation Control |
99 |
Overview |
99 |
Regulation Control |
99 |
+12 High Voltage LVP |
99 |
HV Regulation PWM |
101 |
Overview |
101 |
Sawtooth Generator |
101 |
PWM |
101 |
HV Stop 2 |
103 |
Overview |
103 |
ABL |
103 |
Hold Down |
103 |
HV Stop 1 |
105 |
Overview |
105 |
ABL |
105 |
High Voltage Block Tap |
105 |
+125 Volt OVP |
105 |
Convergence Block |
107 |
Overview |
107 |
Convergence |
107 |
Auto Focus (Auto Registration) |
107 |
Sensor Amp |
109 |
Overview |
109 |
Auto Focus |
109 |
Circuit Description |
113 |
BD Input |
115 |
Overview |
115 |
Digital Convergence |
115 |
BD Output |
117 |
Overview |
117 |
IC1707 Regi Correction |
117 |
Convergence Out |
119 |
Overview |
119 |
Regi Mute |
119 |
Convergence Amp |
119 |
Service Mode |
121 |
Overview |
121 |
Normal Service Mode |
121 |
PJED Mode |
121 |
Protection Block |
127 |
Overview |
127 |
Diagnostic Indication |
127 |
Circuit Description |
129 |
Overview
The models covered by this manual are the new KP53XBR200 and the KP61XBR200. These two models are electrically identical. The differences have to do with screen size. Therefore they use different cabinets, screens, mirrors and tubes. These sets also have a Self Diagnostic system.
Picture
The two models share the following picture features:
·Advanced Pro-Optic System – Sony technology that allows full corner to corner focusing.
·New Extended Definition CRT – Allows corner to corner focusing to be increased by 25% over last year’s model.
·MICROFOCUS Lens System
·Digital Reality Creation (DRC) – DRC uses line doubling and pattern recognition algorithms to take the NTSC signal to a near HDTV equivalent. This will be discussed in more detail later.
·Double Scan Technology
·Auto Focus Full Digital Convergence – Allows the setting of V and H center and skew by the customer. This convergence system can produce a sharper picture and is less susceptible to drift due to aging or shipment.
·High Performance Video Processor
·3D Digital Comb Filter
·Brightview Dual Component Screen – The screen contains a Thin Film Fresnel that brightens and sharpens the picture, and a Fine Pitch Lenticular screen that achieves higher resolution by using black stripes to increase contrast.
·Built-in High Contrast Screen
1
·First Surface Mirror – Unlike most mirrors, the reflective surface is on the front of the mirror glass. This improves brightness and contrast, and eliminates ghosting caused by the reflected light passing through the glass.
·Advanced Velocity Modulation
·Advanced High Voltage Regulation – Eliminates distortion and focus fluctuations that occur when changes in brightness levels cause changes in the high voltage.
·Noise Reduction
·Shading Compensation – Eliminates color shift and hot spots that can occur due to the angle of the picture tubes to the mirror.
·Wideband Video Amplifier
·Multi Image Driver – Digital-editing technology that provides versatility in controlling on-screen images. Used in Picture and Picture and Channel Index modes.
·Twin View Picture-in-Picture – Allows for viewing two pictures simultaneously and the ability to expand either image up to double its normal size.
·Free Layout Picture-in-Picture – Allows the PIP window to be placed anywhere on the screen.
·XDS (Extended Data Service) – Receives data information services that some stations may broadcast. This data includes time, station call letters, etc.
Audio
The two models share the following audio features:
·MTS Stereo with dbx NR
·Dolby Pro Logic Surround Sound
·Front Left/Right Audio Power - 20Wx2
·Center Audio Power – 20W
·Surround Audio Power – 15Wx2
·Center speaker input for use with a separate Dolby Pro Logic A/ V Reciever
NOTES
2
3
The number of times the LED blinks may correspond to that shown in the following table:
Overview
The RA-4 chassis employs a Self-Diagnostic system that uses the Timer LED and an on screen menu to help indicate where the problem with the set has occurred. You will generally have to use the flashing LEDs since the set will be shut down. AC power must be disconnected in order to turn the set off once shutdown has occurred.
When a failure occurs, all of the circuits covered by the Self-Diagnostics, except AKB, send a signal to the OSD CPU. The OSD CPU sends data to the Main CPU that indicates how many times the Timer LED will flash. The AKB circuit located in the Video Processor IC sends data over the I2C bus directly to the Main CPU. In addition, each circuit, except AKB and High Voltage, send a signal to the latch circuit to shut the set down when failure occurs.
< FRONT PANEL > |
•EXAMPLE |
|
<Diagnosis Items> |
|
• +B overcurrent |
|
• +B overvoltage |
TIMER/STANDBY indicator |
• Vertical deflection stop |
<Number of Blinks>
2 times
3 times
4 times
Lamp ON : 0.3 seconds
Diagnosis item |
Standby/ |
|
Self-diagnosis |
|
|
sleep lamp, |
|
screen display, |
|
|
Number of blinks |
|
Diagnosis item:Results |
|
|
|
|
|
|
• Power not ON |
Not lit |
|
|
|
+B OCP detection |
LED blinks 2 times |
2 |
: +B OCP |
XX |
+B OVP detection |
LED blinks 3 times |
3 |
: +B OVP |
XX |
V detection |
LED blinks 4 times |
4 : V STOP |
XX |
|
AKB detection |
LED blinks 5 times |
5 |
: AKB |
XX |
H detection |
LED blinks 6 times |
6 : H STOP |
XX |
|
HV abnormality detection |
LED blinks 7 times |
7 |
: HV |
XX |
Audio abnormality detection |
LED blinks 8 times |
8 |
: AUDIO |
XX |
|
|
|
|
|
*: XX the range of values for number of operations is 00-99. For 99 or higher there is no count up and the number remains at 99.
If the problem is intermittent and you can get the set to operate, you can display a menu showing the number of times failures have occurred. This is done by pressing the following sequence of buttons on the remote.
Display Channel 5 Vol - Enter
The display will look as follows.
SELF CHECK
2 |
: +B OCP |
XX |
3 |
: +B OVP |
XX |
4 |
: V STOP |
XX |
5 |
: AKB |
XX |
6 |
: H STOP |
XX |
7 |
: HV |
XX |
8 |
: AUDIO |
XX |
9 |
: WDT |
XX |
2 : +B OCP XX
Diagnosis
Results
XX the range of values for number of operations is 00-99.
For 99 or higher there is no count up and the numberremainsat 99.
Lamp OFF : 0.3 seconds |
|
|
|
Lamp OFF : |
|
|
|
3.0 seconds |
|
|
|
|
|
4 |
5
Overview
The models covered by this manual are the new KP53XBR200 and the KP61XBR200. These two models are electrically identical. The differences have to do with screen size. The table below shows which circuits are present on each of the boards. This will help if you are doing board level (SAYS) or component level repair.
Name |
Circuits contained |
|
|
A |
Tuners, A/V switching, RGB processing, H Jungle, VDSP, Syscon |
|
|
BD |
Auto registration (Digital Convergence) |
|
|
BM |
MID (Multi Image Driver) |
|
|
BR |
DRC (Digital Reality Creation) |
|
|
CR,CB,CG |
CRT drive and IK feedback. |
|
|
D |
H and V deflection, Sub-deflection, HV, HV Regulation |
|
|
G |
Power supply |
|
|
HA |
Front panel controls, Power and Timer LEDs |
|
|
HB |
Front video inputs, Auto Focus and Setup buttons |
|
|
HC |
Remote sensor |
|
|
K |
Audio Processing and Audio Outputs |
|
|
U |
S Link Input/Output |
|
|
ZR,ZG,ZB |
Hor. and Vert. deflection and sub-deflection coils, VM |
|
|
ZG
HC
ZR
HA
CR
HB
CG
ZB
CB
K
U
|
|
A |
G |
|
BM |
D |
BD BR |
|
|
|
6
AC Input
When the unit is first plugged in, AC power passes through two line filters and is applied to the Standby Power Supply. This is a switching power supply that produces the Vcc source voltage and the standby +5V (RM+5V) for System Control. When the set is turned ON, the AC input is applied through RY6001 Power Relay to the switching B+ rectifier, which supplies power to the Converter circuit. The switching B+ rectifier is monitored at each of its outputs. The negative side of the switching B+ rectifier is monitored to ensure that RY6002 is activated. RY6002 is closed to bypass the In-Rush Current Limiter Resistor when the set is turned ON. When RY6002 is closed, it shunts In-Rush Current Limiter Resistor so that the negative side of the bridge is connected to ground. If the relay is not closed, a voltage will be developed to shut down the set. The positive side of the switching B+ rectifier is monitored to hold the secondary voltages down if the AC voltage should be too low. This is performed by monitoring the switching B+ voltage and applying that voltage to the soft start circuit. This is done because of the excessive current draw when the switching B+ is low.
Power ON
When Power ON is selected using the remote or the front panel switch, a signal is sent from IC1008 Main-CPU to the Vcc switch section on the G board. The Vcc circuit sends voltage from the Standby supply to the Oscillator and Soft Start circuits. When this voltage reaches IC6003 Oscillator, it begins oscillating. The Soft Start circuit is activated at the same time. This circuit keeps the oscillator at a certain frequency (175KHz) for a specified period of time. This keeps the initial start up voltage low and prevents excessive back EMF from destroying the converter transistors. When regulation begins, the normal operating frequency is around 73KHz.
7
Converter
When the Oscillator circuit begins oscillating, it outputs two signals that are 180 degrees out of phase. These signals are applied to the converter circuit. The converter circuit contains two Driver ICs that drive two push pull transistor circuits. These circuits drive two transformers that create the AC voltages, which are rectified by the two secondary supply circuits to power the rest of the set.
Regulation
Once the secondary supplies begin to generate DC voltages we can begin to regulate their output. This is done using the +11 volt and +135 volt lines. The +11 volt line is used to power the regulation circuit while the +135 volt line is monitored to regulate the supplies. The +135 volt line is sent to the regulation circuit to produce an error voltage that is fed back to the oscillator circuit. This voltage controls the pulse width and frequency of the oscillator. Changes in the frequency cause changes in efficiency of the transformers, which in turn cause the voltage to become lower or higher.
Protection
In addition to the three protection circuits on the AC side of the supply, there are additional circuits on the DC side. The +135V line is checked for OVP and OCP. If one of these conditions occurs, a voltage is sent to the protect latch to turn it ON. The latch shuts down the set by turning OFF the Vcc switch. A voltage is also sent to the System Control circuit for the self-diagnostic system. In addition, the 11V line is compared to the +19, +22 and +7 volt lines. If these voltages fall below a specified level, the protect latch will be activated and the set will shut down. There is no indication in the self-diagnostic menu that this circuit has been activated.
8 |
Overview
The AC Input and Switching B+ circuit is used to filter the AC line voltage and generate the DC voltage necessaary to run the switching supply.
AC Input
AC enters the G board at CN6004 when the unit is plugged in. It then passes through F6001 and L6001 and L6002 Line Filters. L6002/3 is the High side of the AC line and splits off to two places. It is used to power the Standby +5V supply and is connected to one of the contacts of RY6001 Power Relay.
There are a few protection components in place in addition to F6001 Fuse. There are two spark gaps across the AC line at CN6004 AC Input. There is also one across the AC line after F6001 Fuse. Two capacitors, C6001 and C6002, are present on either side of L6001 Line Filter. VD6001 is a VDR across the L6002/1 and 3 for spike protection.
Troubleshooting
Problems in this area are usually the result of line spikes or lightning. If you have a dead set and suspect lightning damage, you should remove the G board by removing one screw and pulling it out. A quick visual check can be performed by looking on both sides of the board for burnt traces or components. If F6001 is open, be sure to check for any burnt components. If everything looks OK, then check the voltage across VD6001. If the line voltage is not present there, continue to work your way back checking across the AC line until you find an open component.
9
B+ Rectifier
When power is turned ON, the AC line voltage is applied across D602 Bridge Rectifier because RY6001 Power Relay is closed. D602/3 + outputs 130 volts which is filtered by C6008, C6010 and L6003. This voltage is used as the B+ for the switching power supply converter circuit and is fused by F6002. D602/4 is connected to ground through R6010 In-Rush Current Limiter at initial power ON. When the secondary supplies begin to run, RY6002 will be closed which connects D602/4 - to Hot ground.
Switching B+ Low Voltage Protect
Both outputs of the D602 Bridge Rectifier are monitored to cause shutdown of the set. D602/3 + has a sample voltage sent to the Soft Start circuit to monitor for under voltage. If the voltage at this point is too low, the Soft Start circuit will raise the frequency of the switching supply, thereby lowering the secondary output voltages and disabling regulation. The lowering of the secondary voltages will also cause RY6002 to open or may shut the set down. Due to the fact that the power supply voltages will be lowered, the set will indicate an AKB shutdown by flashing the Timer LED five times, pausing, and then repeating. This action will be discussed in greater detail in the Soft Start section.
In-Rush Current Limiter Protect
D602/4 is monitored to ensure that the R6010 In-Rush Current Limiter has been switched out of the circuit by RY6002. If it has not, a voltage will be developed across it that is rectified and sent to the base of Q6004 AC Protect. If Q6004 AC Protect is turned on, IC6003 Oscillator will be shut down. This will cause no output from the switching supply. Keep in mind that there will be 150 volts present at F6002 since the power relay is still turned ON. In addition, the Timer LED will flash twice, pause and repeat. You will not be able to shut the set OFF using the remote or the front panel switch. The set will have to be unplugged to attempt to restart the set.
10
11
Overview
The Standby Power Supply is used to develop the voltages that are required by the set in order for it to turn ON. One of these voltages is used to supply power to the System Control ICs. This voltage is a regulated 5 volts and is called RM+5. The other voltage is used as the source voltage for Vcc, which is the low voltage supply for the switching power supply. The AC input to the standby supply is monitored for overvoltage. It will shut the Vcc switch OFF if there is a problem.
Standby Switching Supply
The line AC from L6002/3 is rectified by D6001 and D6003 and filtered by C6009. This voltage is monitored for overvoltage via D6035 and is used to power the standby supply. This voltage then passes through fusible resistor R6012, then to T603 SRT. IC6001 is connected to T6003/ 1 and begins switching when the voltage arrives. IC6001 PWMSW is a self-starting N-channel MOSFET switching device with a self contained oscillator and error loop amplifier used for regulation.
RM+5
As IC6001 PWMSW voltages are induced in the secondary windings of T6003 SRT, one of these voltages is used to develop the RM+5 line. The signal from T6003/7 is rectified by D6120 and filtered by C6137, C6138 and L6113. This voltage is input to IC6104/1. IC6104 5-Volt Regulator outputs 5 volts from pin 2. This is the RM+5 line on the G board. It is called ST-5V on the A board.
Regulation
The secondary winding at pins 3 and 4 of T6003 SRT develops a voltage that is rectified by D6015. This voltage is used for two purposes. It is the source voltage for the Vcc switch and the feedback voltage for regulation. This voltage passes through D6012, D6011 and R6021, and is input to IC6001/4. Pin 4 is the regulation input for IC6001 PWMSW.
12
Overview
When Power On is selected, IC1008 Main CPU sends a signal to the G board to turn ON the Vcc switch. The Vcc voltage powers the Soft Start, Oscillator and Driver circuits. There is a connection from the latch circuit to shut OFF the set if there is a problem on the DC side of the power supply. In addition, there is a connection from the Standby Source Voltage that will shut down the supply if the AC line voltage becomes to high.
Power ON
When Power ON is selected using either the remote or the front panel switch, 5 volts is output from IC1008/56 O Relay. This voltage travels from CN505/3 on the A board to CN6101/3 on the G board. It then goes through R6112, R6121 and D6112, placing .6V at Q6104/B. This turns Q6104 ON and causes Q6104/C to pull IC6104/2 to ground. This turns the phototransistor inside IC6104 Vcc Switch ON. When this occurs, current flows through the B-E junction of Q6001. When Q6001 turns ON, it causes Q6011 VccSW to turn ON. This switches the Standby voltage through Q6011 VccSW where it is called Vcc. Vcc turns RY6001 Power Relay ON, as well as powering the Soft Start, Oscillator and Driver circuits.
13
DC Protect
The DC protection latch circuit is connected through D6111 to the power ON line at the junction of R6112 and R6121. When the protection latch is activated, it pulls the O Relay line LOW and turns power OFF by turning and holding Q6014 OFF.
AC Protect
The Standby Source voltage is monitored in case there is an overvoltage problem on that line. If the voltage from the Standby Source voltage goes too high, it will cause the voltage at the cathode of D6035 to rise above 12.6 volts. The voltage at Q6013/B will be enough to turn it ON. When this occurs, Q6013 conducts, causing Q6012 to conduct. This action causes the Q6001 to turn OFF, thereby shutting down the set.
14 |
15
Overview
A Soft Start circuit is necessary to keep the oscillator that drives the switching circuit above the normal operating frequency of the tuned circuit that is in the switching supply circuit. If this frequency is not above the normal operating frequency at start up, the voltage at the secondary could become too high and cause damage to the set. The soft start circuit causes the oscillator to start at a frequency high above the normal operating frequency by holding the regulating voltage down at initial turn ON of the set. This circuit is also activated if the Switching B+ voltage falls below a certain level.
Soft Start – Power ON
When Power ON is selected, the Vcc switch supplies voltage to IC6003 Oscillator. This oscillator is connected to the regulation line that begins to develop voltage. This voltage is held LOW at Q6006/E while C6016 is charging. Once C6016 is charged, the regulation line is controlled by IC6005/4.
Q6005 provides a discharge path for C6016 when the set is turned OFF. This is important because if C6016 is not completely discharged, the oscillator may output the normal operating frequency during Power ON. The discharge path would be through Q6005/C-E junction. Q6005 is OFF during the set’s operation because of the voltage applied to it from IC6011/ 3. Be careful when measuring voltages at Q6005/B as this circuit is easily loaded by a meter or a scope. It is best measured using a scope and a 10X probe.
Soft Start - LVP
The soft start circuit can also be activated if the voltage from D602/3 Switching B+ goes too low. When the voltage across R6007 drops below 12.6 volts, it will cause Q6002 to turn OFF. This causes Q6003 to turn ON. When Q6003 is ON, the cathode of D6014 will be held at ground potential. This is the same condition that occurs at turn ON, therefore the oscillator will oscillate at a high frequency and this will reduce the output voltages from the secondary supplies. If this occurs while the set is operating, it will shutdown. The set will act as if there was an AKB failure, the Timer LED will flash five times, pause and then repeat.
16
17
Overview
Simply put, the converter circuit switches the DC Switching Supply B+ ON and OFF to create an AC signal. The converter in this set consists of two Driver ICs that drive two sets of N-channel MOSFET transistors. The drivers use the output signal from the oscillator to switch the transistors. These transistors are switched 180 degrees out of phase and are parallel with the two Power Input Transformers.
Operation
Two signals 180 degrees out of phase are applied to the Hi and Lo side inputs. The Hi side input of IC6002/10 is the same phase as the Lo side input at IC6004/12. The Low side input at IC6002/12 is the same phase as the Hi side input at IC6004/10. These signals are amplified and output in phase with their inputs.
The Hi side of each of these drivers has a floating power supply that boosts the output level of the signal. The input to this supply is at IC6002/ 6 and IC6004/6. The return is at pin 5 of IC6002 and IC6004. This floating supply allows a 130 Vpp signal to be output for each Hi side driver.
If IC6002/7 is outputting a High signal, then Q6008 turns ON. When Q6008 is ON, it allows the 130-volt Switching B+ to be present at Q6008/ S. This voltage is applied to IC6002/6, the floating supply input, and also to C6022 and C6023. The signal seeks ground through Q6009, which is always ON when Q6008 is ON. Current flows through the transformers T602 and T601 while C6022 and C6023 are charging. At the same time, the signal outside of IC6002/1 Lo side output is Low. When the signal at Q6008/G goes Low, the signal at Q6007/G goes High. This causes C6022 and C6023 to be connected to ground. At the same time, Q6010 is turned ON and Q6009 is turned OFF. This causes current to flow through the transformers T601 and T602 and capacitors C6022 and C6023. This cycle continues while the set is running and causes sine waves to be seen at T601/1 and T602/4. This signal is induced into the secondary of the transformers to produce the power supply output.
18
19
Overview
The secondary winding of T602 PIT is used to develop two voltages - +/- 19 volts. These voltages are used to power the K board, which contains all of the audio circuits.
Operation
The voltage induced into the secondary winding of T602 is used to develop +/- 19 volts. This voltage is used to supply the Audio section (K board) and is fused with PS6103 and PS6104.
This voltage is rectified by D6116 and filtered by C6121 and C6129 to create the +19 volt supply. It is also rectified by D6114 and filtered by C6120 and C6128 to create the –19 volts. The +19 volt supply is output at CN6102/7 and 8. It also goes to D6122/A, which is part of the protection circuitry. The –19 volt supply is output at CN6102/2 and 3.
Troubleshooting
If the rest of the power supply is working, but there is a problem with these supplies, you should suspect a problem on the K board. The set can be run with CN6102 unplugged. If the correct voltages are measured at CN6102, then the problem is on the K board. If PS6104 and PS6103 are open, it would be a good idea to power the unit without CN6102 disconnected. If everything appears to be OK, check the K board for shorts on the +/- 19 volt lines. If none are found, then plug CN6102 in and power up the unit.
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Overview
There are four secondary windings on T601 PIT. The voltages induced in these windings are used to power everything in the set, except for the audio section. The voltages developed here are +/- 15 volts, +/- 22 volts, +11 volts, +7 volts, +/- 135 volts and +33 volts.
+/- 15 Volts
The voltage from the winding of T601/11 and 12 is applied across D6105 Bridge Rectifier. C6119, C6132 and L6108 filter the positive output of D6105/3. This output is used for three things. First, it is applied to Q6106/ E, which turns Q6106 ON and allows current to flow through its E-C junction. It passes through R6141 to RY6002 In Rush Current Limiter Relay. It turns the relay ON when the voltage is sufficient. If the voltage does not rise to a sufficient level or there is a problem with Q6106, the set will shut down. Next it is sent to D6126/A, which is part of the protection circuitry. Lastly it is sent to CN6105/3, CN6106/5 and CN6104/2 where it is sent to the D and A boards.
The negative output from D6105/3 goes through R6122, R6123 and R6124, which are parallel. C6118, C6131 and L6109 then filter this voltage. It is then output from CN6105/4 and CN6106/6, both of which go to the D board.
These lines are used to produce other voltages on the D board. These voltages are +/- 12 volts and +/- 5 volts.
+ 11 Volts
The voltage from the winding of T601/11 and 12 is applied across D6102 through L6103 and L6104. C6122, C6133 and L6110 filter the rectified voltage. This voltage is used on the G board by the regulation and protection circuits and it exits the G board at CN6104/11 to the A board.
The +11 volt supply is used on the A board to produce the +9 volt supply.
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+/- 22 Volts
The voltage from the winding of T601/14 and 15 is applied across D6108 through PS6105 and PS6106. C6125, C6135 and L6112 filter the rectified voltage. The voltage is used on the G board by the protection circuit and it exits the G board at CN6105/1.
The winding of T601/14 and 15 is applied across D6117 through PS6105 and PS6106. C6124, C6134 and L6111 filter the rectified voltage which leaves the G board at CN6105/6.
The +/- 22volt lines are used to power only the Convergence amplifiers on the D board.
Distribution
The table below shows the circuits powered by the voltages previously discussed:
Supply |
Circuits |
+15 |
Vertical Out IC5004, 12 Volt regulator IC5002 (D board), IC502 12 |
|
Volt regulator (A board) |
-15 |
Vertical Out IC5004, -12 Volt regulator IC5001 |
+12(D) |
V, H, B+, HV, and IK protection circuits, Shading, HV control, PWM, |
|
H Saw, Auto Registration sense and switching, 5 Volt regulator |
|
IC8004 |
+12V(A) |
H Jungle IC507, VM and IK buffers |
-12 |
Shading, HV control, H Saw, H pulse shaper,-5 Volt regulator IC8003 |
+5 |
BD board (Auto Registration) |
-5 |
BD board (Auto Registration) |
+11 |
Off Mute Q547, 9 Volt regulator IC505 |
+9 |
TU501, TU502 Video Processing, AVU switch |
+22 |
Convergence Amplifiers IC5005 and IC5006 |
-22 |
Convergence Amplifiers IC5005 and IC5006 |
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