Philips PTV500 series User manual

Philips Consumer
Electronics Company
A Division of North American Philips Corporation In-Home
Service
Guide
Projection Television
PTV500 Series

1993 PTV500 CHASSIS IN-HOME TROUBLESHOOTING GUIDE
CONTENTS
Subjects ............................................................................ Page
SECTION 1
General:
Servicing and Safety Precautions ................................... 3
Introduction ..................................................................... 4
Signal Flow ..................................................................... 5
PTV Power Supply Module ............................................. 6
Shutdown Circuitry .......................................................... 7
SECTION 2
Troubleshooting the PTV System:
Access ............................................................................ 9
Diagnostic LEDs of the Power Supply ............................ 9
Deflection Failures, Video Blanking,
and High Voltage Shutdown .......................................... 10
Video Troubles ................................................................ 11
SECTION 3
In-Home Adjustments:
Ground Connections For Test Equipment ....................... 12
Unless Otherwise Specified: ........................................... 12
On-Screen Menu Positioning .......................................... 12
RF AGC Delay ................................................................ 12
VCO & AFT Adjustment .................................................. 13
Sound Alignment ............................................................ 14
Sub-Contrast Alignment .................................................. 14
Comb Filter Alignment .................................................... 14
Sub-Brightness Adjustment ............................................ 14
Dynamic Gamma ............................................................ 15
High Voltage Frequency Adjustment .............................. 15
Video Level Alignment .................................................... 15
Vertical Height Adjustment .............................................. 16
Vertical Blanker Adjustment ............................................ 16
130Vdc Adjust ................................................................. 16
Stereo Decoder Alignments ............................................ 17
Composite Input Level Adjustment ................................. 17
Stereo DBX Filter ............................................................ 17
Pilot VCO Adjustment ................................. :.; ................. 17
300Hz Separation ........................................................... 18
3kHz Separation ............................................................. 18
Focus Adjustments (Electrical and Optical) ........ i........... 18

Screen (G2) Adjustment Procedure ................................ 19
Gray Scale Tracking,
Sub-Brightness Adjustment Procedure ........................... 20
Screen Geometric And Centering Adjustments .............. 21
Green Screen Geometry Adjustments ............................ 22
Blue Screen Convergence Procedure ............................ 22
Red Screen Convergence Procedure ............................. 23
Programming Factory Default Values ............................. 25
Test Mode Entry and Exit ................................................ 25
Adjustment of Registers in Test Mode ............................ 25
Description of Test Mode "C". ......................................... 26
System Information/Diagnostics ..................................... 27
SECTION 4
Figure 2 -
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
.Figure 8
Figure 9
Simplified Drawings:
Figure 1 - PTV510 Frontview .......................................... 29
PTV510 Rearview .......................................... 30
PTV520 Frontview .......................................... 31
PTV520 Rearview .......................................... 32
PTV535 Frontview .......................................... 33
PTV535 Rearview .......................................... 34
PTV500 72 Degree Light Path ....................... 35
PTV500 Block Diagram .................................. 36
PTV500 Power Supply Module
Block Diagram ................................................................ 37
Figure 10 - PTVS00 Power Supply Connections ............ 38
Figure 11 - PTV500 Shutdown Circuitry .......................... 39
Figure 12 - PTV500 Signal/Deflection Module Layout....40
Figure 13 - PTV500 Cable Connections ......................... 41
Figure 14 - PTV500 Customer Keyboard & IR Receiver
Connections .................................................................... 42
Figure 15 - PTV500 Jack Panel Connections ................. 43
Figure 16 - PTVS00 Automatic Volume Level Control ....44
Figure 17 - PTV500 CRT Connections ........................... 45
Figure 18 - PTV510 Simplified Diagram ......................... 46
2

SECTION 1
Servicing And Safety Precautions
Always use safe servicing procedures:
1. Use an Isolation Transformer when servicing the Projection
Television to protect both the set and test equipment.
2. Be careful of shock hazard when operating the set with the
back removed.
3. When servicing the CRTs, always wear safety glasses. Be
careful when handling liquid cooled CRTs to protect the over-
flow bellows.
4. Do not remove solid state devices while the set is turned On.
5. Be careful that the correct Ground Reference is used when
making measurements.
6. Be certain that all grounds, ground straps, and wires are
properly connected to protect the set and user from shock.
7. Always check for shock hazards after completion of chassis
repairs. Refer to Service Manual 7524 for proper "Safety
Check" procedures.
8. The 160Vdc Source is present and the Standby Power
Supply is running on the Power Supply Module anytime the
set is connected to an AC Power Source.
In-Home Recommended Test Equipment:
1. Isolation Transformer (Not required when using a hand held
DVM)
2. DVM (High Impedance)
3. Pattern Generator (RF and Video)
4. Two pairs of jumpers
3

Introduction
The 1993 Projection Television (PTV) comes in three basic con-
figurations, the PTV510, PTV520, and PTV535 Series (see
Figures 1 through Figure 6 in Simplified Drawings section).
Figure 7 shows the new 72 degree light path. The CRT's are
90 degree Hitachi tubes which are matched to Delta 25 Lens.
These sets feature a stand-alone, high-end single board chassis
design for signal and high voltage circuits. The new board is
called the Signal/Deflection/High Voltage Module. A separate
basic Power Supply Module is located to the right of the main
Printed Circuit Board (PCB). Other feature differences in these
sets include Color MDPIP (Picture-in-Picture), AVIO (Audio-
Video-Input-Output) Jack Panel, CCD Comb Filter, Closed-
Caption Module, Automatic Volume Level Module (not in all
Models), and many Audio System options.
The new PTV features the TS-3D Tuning System (Figure 8).
The TS-3D Tuning System is an On-Screen, Total Remote,
Menu Driven Tuning System. The Tuning System is mounted
on the Signal/Deflection/High Voltage Module. The
Microcomputer for the Tuning System communicates via an 12C
Bus with the DAC IC, RF Switcher (optional), U/V Tuner, AVIO
Jack Panel, MDPIP Module, Closed-Caption Decoder Module,
and Convergence Panel.
Dedicated Serial Data and Serial Clock lines (SDA1 AND SCL1)
communicate with the Clock/Calendar and EEPROM IC's. The
Clock/Calendar and EEPROM IC's are used by the Tuning
System to store information needed later. The DAC (Digital-to-
Analog Convertor) IC receives serial digital data from the
Microcomputer and converts it into analog information for the
Brightness, Picture, Color, Tint, and Sharpness controls. A
Character Generator IC develops the RGB and Fast Blanking
signals for the On-Screen Graphics.
The PTV Signal/Deflection/High Voltage Module also features
an IF Signal Processor integrated circuit (IC200) and a NTSC
Signal Processor IC (IC600). The RGB signals from IC600 are
sent to the CRTs. A full-featured, one-chip, SteTeo Decoder IC
(IC120) is also included on the Signal/Deflection/Hiah VoltaGe
Module.
4

Signal Flow
The Signal/Deflection/High Voltage Module features split Audio
and Video IF processing. The TV signal is.applied to the U/V
Tuner, or through an optional RF Switch then to the UN Tuner.
The IF signal is developed in the UN Tuner and sent through a
dual output SAW Filter to the Audio and Video IF inputs of
IC200. The detected Baseband Audio signal exits IC200 and is
sent to the Stereo Decoder IC, IC120. Left and Right channel
audio signals exit the Stereo Decoder and are sent to the Jack
Panel for distribution. Some Models feature an Automatic
Volume Level control Module that is located on the frame of the
AVIO Jack Panel. This module acts like an AGC circuit for both
channels of audio.
The Video signal is developed by IC200 and is applied directly
to the Color MDPIP Module and also to the AVIO Jack Panel for
switching. The MDPIP Module is mounted on the Main Chassis
PCB next to the U/V Tuner. If an optional, chassis mounted,
Color MDPIP Module is used in the set, the composite video is
routed from the Jack Panel to the Color MDPIP Module to be
used as the PIP Picture. ReModulated Video (RMV) is sent
from the Color MDPIP Module to the S-VHS Switch IC, IC670.
External Video input from an External Video source can be
applied through the Jack Panel to the Color MDPIP Module.
Control of the Color MDPIP Module is via the 12C Bus.
The S-VHS Switch IC selects either the tuner signal or the
Super VHS signals from the Jack Panel. This composite video
is applied to the CCD Comb Filter, Closed-Caption Decoder
Module, and the NTSC Signal Processor. The combed
Chrominance signal is sent from the CCD Comb Filter Module
through the S-VHS Switch IC before being applied to IC600.
The combed Luminance is applied directly to IC600. The RGB
and Fast Blanking signals from the Character Generator, IC308,
are applied to the Closed-Caption Decoder before being applied
to IC600. These signals are matrixed when Closed-Caption or
On-Screen Graphics are needed and the product is output via
RGB lines to the Green CRT Board. Without RGB input from
IC308 or data from the Closed Caption Module, normal program
material is presented to the Green CRT Board. Both the Red
and Blue video information go through the Green CRT Board
before going to their respective boards.
5

The composite video signal from the Switch IC is also applied to
the NTSC Signal Processor to develop sync for the Vertical and
Horizontal Oscillators. The horizontal drive signal is applied to
the Horizontal Circuitry where the scan-derived voltages are
developed. The Horizontal Pulse (H Pulse) is sent to the High
Voltage Sync Processor, IC900, which drives the High Voltage
Output Circuit. This circuit develops the High Voltage, Screen
(G2) Voltage, and Focus Voltage. The vertical signal exits
IC600 and is applied to the Vertical Deflection IC, IC550. The
amplified vertical signal drives the vertical windings of the Yoke.
The Horizontal and Vertical signals are monitored by the
Shutdown Circuitry which will stop High Voltage development if
either signal is missing.
PTV Power Supply Module
The PTV Power Supply Block Diagram is shown in Figure 9.
The 120Vac Source is applied to a Bridge Rectifier circuit, which
produces approximately 155Vdc for the Switching Mode Power
Supply. There are two separate Switching Mode Power Supply
circuits used in the PTV. The 155V is supplied to both of these
circuits. Each circuit has its own transformer and Power MOS-
FET regulator. Both regulator circuits are controlled by one
Controller IC, IC401. One of the circuits is used for Standby
operation, with both circuits being used for Full Power operation.
As soon as the TV Set is plugged into an AC Receptacle, the
Standby Power Supply starts running from the voltage applied
through R415 to IC401-16. As the Standby Power Supply
comes up to full operation, approximately 12Vdc is provided via
Diode D405 to the Controller IC for the continuing Source
Voltage. A 15V-Standby Source is used as the source for the
5V Regulator, IC408.
The Standby Power Supply runs all the time the chassis is con-
nected to the AC Power Source. A square-wave signal exits
IC401-7 to drive the Standby Regulator, Q402. Q402 is a
Power MOSFET device that drives the Standby Transformer,
T402. The SMPS is switched to full-power by logic level control
from the Microcomputer. This logic level is input to the Control
IC, IC402-16. The Control IC operates the On/Off Opto-lsolator,
IC406. During Full Power On, the transister side of the Opto-
Isolator effectively opens and IC405 is allowed to control the
regulation of the Full Power Supply via IC401. A rectangular
wave signal is then allowed to exit IC401-10 to the Full Power
6

Regulator, Q401. Regulation is accomplished by monitoring the
130V Source via a voltage divider network. This feedback refer-
ence voltage is sent through the Control IC and the Output
Voltage Regulator Opto-lsolator to the Dual Controller IC. The
130V Source can be adjusted by changing the reference volt-
age via the 130V Adjust potentiometer.
Cable connections and voltage check points for the Power
Supply are shown in Figure 10. To assist in making connec-
tions, plugs and jacks have been color coded in the 1993
Projection Television. Note, Jack 402 has a yellow plug and
Jack 404 has a red plug. Another feature is that all boards have
been coded with a letter. The Signal/Deflection/High Voltage
board is the "A" Board and the Power Supply board is the "P"
Board (see Figure 18). The 404 cable end that connects to the
"A" Board is labeled "A404" and the other end of the cable that
connects to the "P" Board is labeled "P404". This labeling
method will help prevent incorrect connections.
All voltages from the Power Supply can be checked at the jacks
of either the "P" Board or the "A" Board. Also shown in Figure
10 are the Scan Derived voltages.
Shutdown Circuitry
The High Voltage circuitry, even though it is located on the main
chassis PCB, is separate from the Horizontal circuitry (Figure
11). The High Voltage is phase locked to the Horizontal signal
via the "Horiz Pulse" as input through Q900. This pulse is
applied to IC900-3, the High Voltage Sync Processor. Its output
drives the High Voltage stages to the HV Output Transformer,
T900. Here, the High Voltage and Focus/Screen Voltage is
developed. A Shutdown/Phase Sense winding from T900
develops the signal used for phase correction (input to IC900-8)
and Overvoltage Shutdown (input to IC902-1). Beam Current is
monitored from the bottom of the Diode Stack, Pin 10
(Aquadag).
The PTV will go into Shutdown when the High Voltage or Beam
Current increases beyond the designed safety limits. There are
four basic shutdown areas; too much High Voltage, too much
Beam Current, no Horizontal Scan, and no .Vertical Scan. In the
case of no Horizontal or Vertical scan, beam current must be
stopped quickly to prevent damage to the CRT's phosphor.
7

A sample of the High Voltage is taken from Pin 15 of T900 and
applied to the Programmable Shunt Regulator, IC901-1. This
sample can be adjusted by R943 to attain the desired High
Voltage. IC901 sends the product of this sample voltage
through Q903 to IC900-8 to regulate the output voltage. The
output of IC900 can be completely stopped if Q904 turns On
and inhibits the feedback path between IC901 and Q903. This
input via Q904 is the shutdown input for a scan type of failure.
There is also a sense input for the 15V Source called Low
Voltage Detection. Either one of these failures will blank the
Picture Tubes and turn On Q904, placing the set in shutdown.
The Shutdown Control IC, tC902, watches for too much High
Voltage and/or too much Beam Current. If IC902 is turned On
from either of these conditions, it must be reset by turning the
set Off and On again. Beam Current is monitored from the bot-
tom of the diode stack and applied to Q907/Q908. The output
from Q907/Q908 is applied to the Picture Control circuitry to
modify the contrast level and to IC900-8 to help control the reg-
ulation of High Voltage. When IC902 is turned On, Q901 is also
turned On, placing the set in shutdown.
The High Voltage shutdown comes from the Shutdown/Phase
Sense winding on the HV Output Transformer. If the level of
this pulse becomes too high, IC902 will turn On and shut the set
down.
8

SECTION 2
Troubleshooting the PTV System:
Access
To gain access to the various Modules and Panels in the PTV,
such as the Convergence Panel, CRT Boards, and Yokes - pro-
ceed as follows:
Gently pull off the two plastic railings on either side of the
Customer Keyboard. Next, remove the speaker grille. Now,
remove the screws holding the Convergence Panel and
place it into the service position.
Other Modules - remove the back cover.
The Signal/Deflection/High Voltage Module can be placed into a
troubleshooting position by removing one screw on each side of
the frame and two long screws from the top of the frame. Next,
release two tabs at the top and the module will hinge out. This
facilitates getting to the main board copper side without remov-
ing it from the set.
Diagnostic LEDs of the Power Supply
The Power Supply Module is equipped with two LEDs that are
visible when the cabinet back is removed. These LEDs are a
quick check for several possible problems or conditions. Under
normal operating (On) conditions both LEDs should be lit. If not,
these are the other possible conditions and what they indicate:
D429 (located on the front edge of the module):
On: Normal (lights up whenever AC is applied).
Blinking: Problem with 15Vdc Standby Supply.
D430 (located at the top of the module):
On: Normal (lights up at "Power-On" command).
Off: No 130Vdc Supply is present.
If there is a failure of the Power Supply Module, the voltages
shown in Figure 10 should be checked with a DVM. There are
three fuses located on the Power Supply Module that should be
checked. With the set connected to an AC Source, the 5V
Standby (P403-1) Source and 15V Standby (P403-2) Source
9