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

should be present. If not, the Standby Power Supply circuitry
should be repaired or the Module should be replaced.
If the Standby Supplies are okay and the Full Power Supplies
do not come up to normal voltage, repair the Full Power Supply
or replace the Module. The 130V-A Source is available from
P402-1, while the 130V-B Source should be present at two loca-
tions, P404-5 and P404-6. The 130V-C Source can be checked
at P404-7. The 9V and 15V Sources can be checked at P402-5
and P402-2 respectively. If only one voltage is missing, that cir-
cuit can be repaired to restore the complete Power Supply.
There is also a Fuse, F404, which is soldered into the PCB for
the 26Vdc Source. This voltage source is used by the Audio
Amplifier. Some boards may be labeled as L412 for this fuse
location. Later boards will show the fuse as F404.
Deflection Failures, Video Blanking, and High Voltage
Shutdown
The CRTs in a Projection Television can be damaged if deflec-
tion stops and the beam current is not stopped immediately.
The CRTs can be damaged if the beam is allowed to be On for
as little as a thousandth of a second with no deflection. It is
important NOT to defeat the deflection failsafe and CRT phos-
phor protection circuits as shown in Figure 11. If horizontal or
vertical deflection circuits are not operating properly, blanking of
the video will occur from the collector of Q500. Keep in mind, a
failure of the protection circuits can also cause blanking of the
video or shutdown of high voltage. With a set operating normal-
ly, Q501, Q502, and Q904 are turned Off. Q500 is turned On
which allows a High level to be placed on the Blanking line.
This High level allows the picture tubes to operate, while a Low
level will cause the CRTs to shut Off.
Vertical and horizontal deflection waveforms are peak detected
by Diodes D502 and D504. These voltages are stored in capac-
itors C501 and C503. The capacitor is discharged by a resistor
so that if deflection stops, the capacitor will be discharged and
blanking will be activated. An oscilloscope can be used to verify
the proper operation of horizontal deflection by looking at the
cathode of D503. For Vertical deflection, IObk at the cathode of
D501. If the lowest voltage at either check point drops below
approximately 15 Volts, blanking will occur. If the 15 Volt supply
is not high enough, Z500 will not be conducting (voltage less
10

than 10 volts) and Q5OO will not be turned On. The collector of
Q5OO will be Low and the high voltage will be shutdown and
video blanking will occur. The high voltage is shut down
because the base of Q502 is Low and the emitter of Q502 pulls
down the high voltage Slow-Start capacitor, C911.
Video Troubles
The video processing circuitry can be divided into two sections
(Figure 8). One is the tuner video from the U/V Tuner to the
NTSC Signal Processor IC. The other is the video from the
Character Generator IC to the NTSC Signal Processor. If the
system Menu or On-Screen Graphics can be viewed and there
is no video, check for composite video at TP1 (Figure 12). TP1
is located next to the U/V Tuner. This same test can be made at
J620-4 on the main chassis. This is the point where the video
leaves the main chassis and goes to the AVIO Jack Panel. The
video returns from the AVIO Jack Panel on J620-1. This Pin
should also be checked because the video could be going to the
AVIO Jack Panel, but not returning to the main chassis (Notice
J620 in the Cable Connections drawing of Figure 13).
If the set does not have a Color MDPIP Module, the next place
to check is J600, Pins 5, 3, and 1. This is the Red, Green, and
Blue output signals to the CRTs. If these signals are missing,
the Signal/Deflection/High Voltage Module should be replaced
or repaired.
If the set is equipped with a Color MDPIP Module, the video
path can be checked at J621, Pins 3 and 1. J621 is where the
MDPIP Module is soldered to the Main PCB. Pin 3 is the tuner
video to the MDPIP Module and Pin 1 is the video coming back
to the main chassis. If either the MDPIP Module or the AVIO
Jack Panel shows a failure in video processing, replacement or
repair will be necessary.
If the set will not show the Menu information, the problem is
usually located in the output circuitry or there is a 3roblem caus-
ing blanking.
For troubleshooting, cable connections are shown in Figures 14
through 17. These drawings cover the,Customer Keyboard
and IR Receiver Connections, AVIO Jack Panel, Automatic
Volume Level Control, and CRT Connections.
11

SECTION 3
In-Home Adjustments:
Caution: The PTV510/520/535 incorporate a "HOT" ground
system on the Power Supply Module. Always use an
Isolation Transformer when applying power to the exposed
chassis.
Ground Connections For Test Equipment
1. The TUNING SHIELD can be used as the COLD GROUND
connection for ALL COLD GROUND related measurements
(All COLD GROUND points are interconnected between
modules).
2. The Power Supply Module contains both HOT and COLD
GROUND connections. The Cathode of D404 can be used
for HOT GROUND related measurements ONLY on the
Power Supply Module.
Unless Otherwise Specified:
1. All service adjustments are "HOT" with respect to voltage.
For maximum safety, use only properly insulated tools.
2. Refer to the Signal/Deflection Module Layout Diagram
(Figure 12) for the location of test points or service
adjustable controls.
On-Screen Menu Positioning
Some Signal/Deflection Modules may have C341 screened on
the board. In the past, this trimmer capacitor was used for posi-
tioning of the On-Screen Customer Menu. However, on this
chassis On-Screen positioning is now under software control
(see Modifying Factory Default Values later in this section).
Refer to DAC registers 10 & 11 for vertical & horizontal position-
ing of the On-Screen Display.
RF AGO Delay
1. Tune to a weak station, or loosely couple the antenna to
observe a snowy picture.
2. Set the R.F. AGC Delay (R202) to it's full counter-clockwise
(CCW) position.
12

3. Slowly advance R202 clockwise (CW) to a point slightly
beyond the point of minimum snow.
Note: Do not advance the control any further as it may result in
an overload caused by a strong signal, The range of the AGC
voltage supplied to Pin 5 of the U/V Tuner will vary from 8Vdc
(Without Signal) to just less than a lVdc.
VCO & AFT Adjustment
1. Cut the shield break-points around IC200 and the IF
Circuitry. Peel back the top cover of the shield to gain
access to the internal circuitry.
2. Short Test Points 16A & 16B together at the bottom of the
U/V Tuner.
3. Short Test Point 23 (Pin 13 of IC200) to ground (Shield
around IC200 is good).
4. Connect a DC Voltmeter to Test Point 7 (Pin 18 of IC200).
5. Turn the set On and record the voltage reading from Test
Point 7 (typically 4.5 to 5.0Vdc).
6. urn Off the set and remove both shorts from Test Points
TP16A/B and TP23.
7 .Adjust the VCO Coil (L204) to obtain the same dc voltage
reading at Test Point 7 that was recorded in step 5.
8. Connect the Coincidence line at the collector of Q203
(jumper B37, near the J-TEST Connector) to 5Vdc (Pin 3 of
IC401 or the Anode of D401).
9. Apply a local broadcast signal (air signal) to the antenna ter-
minals and turn the set On.
10 Select the Cable Tuning from the menu system. Select any
high band inactive cable channel (Channel 36).
11. While still in the cable mode, now select a local VHF broad-
cast channel. The Tuning System will attempt to tune three
times and then lock onto the FCC assigned frequency for
that channel.
12. Adjust the AFT Coil (L202) to obtain a reading of 7.1Vdc (+/-
25mVdc) at TP2.
13. Remove the jumper from the Coincidence line.
14 Verify this adjustment by changing between the high band
(inactive cable channel) and your local VHF broadcast chan-
nel (ensure that the local broadcast channels lock in quickly).
13

Sound Alignment
1. Select an active channel and loosely couple the antenna
until noise/distortion is apparent in the output.
2. While keeping input signal weak enough to produce noise,
adjust the Sound Discriminator (L201) for maximum output
and minimum distortion.
Sub-Contrast Alignment (this adjustment requires the use of
equipment not normally carried into the home)
1. Apply an NTSC Color Bar Pattern Signal to the antenna ter-
minals.
2. Tune the receiver to the applied signal in step 1.
3. Connect an oscilloscope to Pin 53 of IC600. Adjust the Sub-
Contrast Control (R639) until the video signal observed on
the oscilloscope is 1Vp-p +/-10mV.
Comb Filter Alignment (this adjustment requires the use of
equipment not normally carried into the home)
Note:The following procedure covers the only Field Adjustable
Controls contained within the CCD Comb Filter Module. These
are also the only controls accessible through holes provided in
the top shield of the Module.
1. Apply a Color Bar signal from a Color Bar Generator to the
Tuner Input.
2. Connect an Oscilloscope to TP34.
3. Adjust R20 for minimum color sub-carrier as seen on the
oscilloscope.
4. Adjust R56 for minimum color sub-carrier as seen on the
oscilloscope. Repeat steps 3 and 4 for best results.
Sub-Brightness Adjustment
Note:Refer to the Gray Scale Tracking and Sub-Brightness pro-
cedure contained later in this section for the precise setting of all
interrelated controls.
14

Dynamic Gamma (this adjustment requires the use of equip-
ment not normally carried into the home)
1 .Apply a Crosshatch pattern utilizing 1001RE (100% white) to
the antenna terminals (Very important step, anything less
than 1001RE will not work correctly).
2. Tune set to this signal and adjust the Customer Brightness
and Picture Controls to maximum.
3. Set the Gamma Adjust Control (R603) to its full counter-
clockwise (CCW) position.
4. Display the main customer menu on the screen. Note the
blue bleeding at the blanked boarder area on the left-hand
edge of the menu.
5. Rotate the Gamma Control (R603) slowly clockwise (CW) to
just eliminate the blue bleeding in to the menu area.
High Voltage Frequency Adjustment (this adjustment requires
the use of equipment not normally carried into the home)
1. Turn the set Off and disconnect power supplied to the chas-
sis.
2. Undo cable restraints and fold the chassis down (in order to
gain access to the copper side of the module).
3. Locate the copper pad for TP67 and solder a short piece of
wire onto it.
4. Connect a jumper lead to this test point and connect the
other end to ground.
5. Connect a Frequency Counter to Test Point TP38.
6. Turn On the set and adjust R902 to obtain a reading of
15.734kHz on the counter.
7. Disconnect test equipment and remove the short from TP67.
Note: Some Frequency Counters may be too sensitive at one
attenuation level and not sensitive enough at the other level. In
this case, an oscilloscope may be used. Adjust R902 to obtain
a 63.5uSec delay from the leading edge of the first main vertical
pulse to the leading edge of the second main vertical pulse.
Video Level Alignment (this adjustment requires the use of
equipment not normally carried into the home)
1. Apply an NTSC Color Bar Pattern Signal to the antenna ter-
minals.
2. Tune the receiver to the applied signal in step 1.
15

3. Connect an Oscilloscope to the emitter of Q200 (Test Point
TP1) and adjust the Video Level Pot (R244) until the video
signal observed on the Oscilloscope is 2Vp-p +/-50mV.
Vertical Height Adjustment (this adjustment requires the use
of equipment not normally carried into the home)
1. Apply a crosshatch pattern to the antenna input terminals.
2. Adjust the Vertical Height Control (R551) to obtain a slight
underscan of the raster at the top and bottom of the screen.
3 Adjust the Vertical Height Control (R551) to obtain a slight
overscan at the top and bottom portions of the screen
(approximately 8% overscan total or near 3/4 inch).
Vertical Blanker Adjustment
Some television stations transmit additional information such as
Vertical Interval Test Signals (known as VITS), on video lines 20
and 21. VITS, Closed-Captioning, and other information may
occupy these lines. Normally, this additional information causes
no objectional distortion on the screen as it is transmitted during
the vertical blanking period. When distortion from this additional
information does appear on screen, it usually shows up as a
bright white line at the very top of the screen. The Vertical
Blanker Control (R802) eliminates this type of distortion by
adjusting the vertical blanking time to eliminate this white line
from the top of the screen. In order to properly adjust this con-
trol, you must first tune to the channel exhibiting this type of dis-
tortion on the screen. Adjust R802 to just eliminate the white
line. Increasing the blanking time any further will cause a loss
of standard video information and appear as though the screen
is being under-scanned. Attempting to compensate for an over-
adjustment by increasing the vertical height (size) will cause
geometric distortion. Therefore, adjust this control no further
than what is required to eliminate the white line distortion.
130Vdc Adjust
Upon replacement of the Power Supply Module, or if you sus-
pect possible problems with the 130Vdc Source, check and
adjust in the following manner:
1. Connect the positive lead from a Digital. Voltmeter (accuracy
of .1%) to the top end of L418 (end nearest the edge).
2. Connect the negative lead to the bottom end of the R-TEST
Resistor (this resistor is located at the top corner of the
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board nearest you).
3. Adjust R455 (also located in the top corner of the board) to
achieve 130Vdc +/-.5Vdc).
Stereo Decoder Alignments (this adjustment requires the use
of equipment not normally carried into the home)
Note: Several of the adjustments below require a Leader Model
LMS-238P MTS Stereo Alignment Generator or equivalent.
Composite Input Level Adjustment
1. Connect the LMS-238P Generator to the Antenna input.
2. Set the Generator as follows: Mode Switch set to L+R,
Internal Frequency set to 300Hz, SAP Off, Pilot Off, and
Level Control pushed In.
3. Connect an AC Millivolt Meter to Test Point 61.
4. Adjust R237 to obtain a reading of 245mV +/-5mV RMS.
Stereo DBX Filter
1. Connect an Audio Frequency Generator to Test Point 61.
2. Adjust the Audio Frequency Generator for 97.55kHz, at
250mV RMS.
3. Connect an AC Millivolt Meter to Test Point 54 (Pin 42 of
IC120) and adjust R123 for a minimum (null) reading on the
meter.
Note: This null voltage is less than 35mV RMS (typically about
20mV RMS).
Pilot VCO Adjustment
1. Apply a 4.5MHz sinewave at 20mV +/-5mV RMS to Test
Point 15. When pilot input is required, apply 15,734Hz, 5kHz
deviation, 4.5MHz carrier to Test Point 15.
2. Connect a DC Voltmeter to Test Point 64.
3. With only 4.5MHz (no pilot) applied, read and record the DC
voltage at Test Point 64.
4. Apply pilot input and adjust R122 until the DC voltage differ-
ence between the pilot and no-pilot condition is 0Vdc +/-
25inV.
5. Read the DC voltage at Test Point 59. If the DC voltage is
less than 1V, proceed to Separation Adjustment. If the volt-
age is more than 1V, adjust R122 until DC voltage at Test
Point 59 is less than 1Vdc, then go back to step 1 of this pro-
cedure and begin again. 17

300Hz Separation
1. Connect the LMS-238P Generator to the Antenna input.
2. Set the Generator as follows: Mode Switch set to L
Channel, Internal Frequency set to 300Hz, SAP On, Pilot
On, and Level Control pushed In.
3. Connect an AC Millivolt Meter to Test Point 66.
4. Adjust R107 for a null reading on the meter.
3kHz Separation
1. Connect the LMS-238P Generator to the Antenna input.
2. Set the Generator as follows: Mode Switch set to L
Channel, Internal Frequency set to 3kHz, SAP On, Pilot On,
and Level Control pushed In.
3. Connect an AC Millivolt Meter to Test Point 66.
4. Adjust Rl16 for a null reading on the meter.
Focus Adjustments (Electrical and Optical)
Control Preset Positions
1. Picture setting at mid-range.
2. Sharpness setting at mid-range.
3. Brightness setting at mid-range.
4. Color setting at minimum.
5. "lqnt setting at mid-range.
Electrical Focus
1. With the set tuned to a crosshatch pattern, this adjustment
can be made from the back of the set (with the light shield
removed). The pattern will appear clearer if the front of the
screen is covered with a dark cloth.
2. Observe the magnified reflections of the individual picture
tubes on the back side of the viewing screen.
3. Adjust the respective focus controls (top row on the
Focus/G2 Distribution Block) for the sharpest raster image.
Optical Focus Adjustment
1. This adjustment can be made through the back of the set
(with the light shield removed) while viewing a crosshatch
pattern on the back of the screen. The pattern will appear
clearer if the front of the screen is covered with a dark cloth.
2. Cover 2 of the CRT Output Lenses with. 7 inch square pieces
of cardboard.
3. Loosen the lens retaining wing nuts on the CRT Output Lens
and Housing Assembly.
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4. Move the wing nut in the slot of the uncovered Lens to locate
the optimum optical focus point (viewing the picture from the
back side of the screen), re-tighten the wing nut.
5. Repeat steps 2 through 4 for the 2 other Output Lenses.
Screen (G2) Adjustment Procedure
Control Preset Positions
1. Picture, Sharpness, Brightness, and lqnt set to mid-range.
2. Color setting at minimum.
3. Tune the set to unused input (AUX-1 with nothing connected
is good).
4. Turn all G2 Controls (Bottom Row on the Focus/G2
Distribution Block) to minimum (fully CCW).
5. Set the Hi-Lite Controls (on the Signal/Deflection Module) to
their full clockwise positions.
6. Set the Lo-Lite Controls (also on the Signal/Deflection
Module) to their full counter-clockwise positions.
7. Connect a DC Voltmeter to the cathode of the Green CRT
(Pin 8 of the CRT Socket or either end of R210).
8. Adjust the Sub-Brightness Control (R776) to obtain a read-
ing of 195Vdc on the meter.
9. Remove the DC voltmeter from the Green cathode.
10. Looking directly into the Tube Lens, bring up each of the G2
(Screen) Controls (bottom row on the Focus/G2 Distribution
Module) for just barely visible light in each tube.
11. Proceed to the Gray Scale Tracking and Sub-Brightness
Adjustment.
Alternate Method
1. Picture, Sharpness, Brightness and -Iqnt set to mid-range.
2. Color setting at minimum.
3. Tune the set to unused input (AUX-1 with nothing connected
is good).
4. Turn all G2 Controls (Bottom Row on Focus/G2 Distribution
Block) to minimum (fully CCW).
5. Set the Hi-Lite Controls (On Signal/Deflection Module) to
their full clockwise positions.
6. Set the Lo-Lite Controls (also on the Signal/Deflection
Module) to their full counter-clockwise positions.
7. Short Pins 1 and 6 of the J-Test ConneCtor together.
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