Page 1
NTDPJTV06
REV 1297
QUICK REFERENCE GUIDE
N5SS CHASSIS
PROJECTION TELEVISION
TW40F80
©1997 TOSHIBA AMERICA CONSUMER PRODUCTS, INC.
NATIONAL SERVICE DIVISION
TRAINING DEPARTMENT
1420-B TOSHIBA DRIVE
LEBANON, TENNESSEE 37087
PHONE: (615) 449-2360
FAX: (615) 444-7520
www.toshiba.com/tacp
Page 2
Contents
DISASSEMBLY............................................................3
1. Front....................................................................................................................................................... 3
2. Rear........................................................................................................................................................ 5
CRT ADJUSTMENTS ................................................6
1. Template Instructions........................................................................................................................... 6
2. Optical and Electrical Focus................................................................................................................ 6
3. Mechanical Tilt ................................................................................................................................... 7
4. User Convergence ................................................................................................................................ 8
5. Magnetic Centering ............................................................................................................................. 8
6. Electrical Centering............................................................................................................................. 8
7. Green Geometry................................................................................................................................... 9
8. Red Convergence ............................................................................................................................... 10
9. Blue Convergence .............................................................................................................................. 11
10. White Balance ................................................................................................................................... 11
11. WID, HIT, & VLIN.......................................................................................................................... 12
BLOCK DIAGRAMS.................................................13
1. System .................................................................................................................................................. 13
2. Power Supply ...................................................................................................................................... 14
3. Video .................................................................................................................................................... 15
4. Audio.................................................................................................................................................... 16
5. Deflection............................................................................................................................................. 17
TROUBLESHOOTING FLOW CHARTS ..............18
1. Shut down............................................................................................................................................ 18
2
Page 3
1. Front
DISASSEMBLY
3.Retract the two screws located near
the bottom of the x-ray shield. Loosen the top
two screws. Slide the shield to the right and
downward, then pull it away from the cabinet.
1.Retract the two screws located at the
bottom of the speaker grill. Then, remove the
speaker grill from the cabinet.
2.Retract the two screws located on the
front service panel. Remove the panel by
lifting up and pulling the bottom out and away
from the cabinet.
4.Retract the four screws located at the
bottom of the Front-LED panel. This panel will
still be attached to the cabinet via the FrontLED board’s wiring harness.
5.Retract the two screws located near
the Front-LED P.C. board. Remove the FrontLED P.C. board from the panel and pull the
panel away from the cabinet.
3
Page 4
6.Retract the four screws located at the
bottom of the bezel. Pull the bezel away from
the cabinet while lowering the top of the bezel
to the floor. The bezel will still be attached to
the cabinet via the Front-control board’s wire
harness.
8.Pull the two brass clips up and away
from the screen. Then, remove the lenticular
and fresnel screens by lifting them up and
away from the cabinet.
7.Retract the two screws located near
the Front control PC board. Remove the PC
board from the bezel. Pull the bezel away
from the cabinet.
This completes the front disassemby
procedure.
4
Page 5
2. Rear
1.Remove seven (7) wood screws and
four (4) brass screws on the back panel and
remove the back panel.
2.Remove the five (5) screws that secure
the PC board chassis to the cabinet.
4.Partially slide both PC board chassis
out from the cabinet. Release the wires from
thier harness clips located at the bottom front
of the cabinet. Slide both chassis to approximately 50% of the way out from the cabinet.
5.Lift the corner of each chassis frame
while sliding both chassis completely out of
the cabinet.
3.Release the wires from their harness
clips. Remove the brass screw securing the
grey plastic tray to the inside of the cabinet
and remove the tray.
6.Stand both chassis frames up on end
with the solder sides of the PC boards facing
outward. The TW40F80 is now in the proper
service position.
5
Page 6
CRT ADJUSTMENTS
1. Template Instructions
CAUTION: Use only water and a
damp cloth to clean an overlay. Any
other cleaning substance may cause
damage.
Both the TW40F80 and TW56F80 are
converged at four separate screens. In order
to reduce the number of times a template
must be installed and centered, two screens
have been printed on each template.
On PSOL4001, the SOLID lines are for
the FULL crosshatch and the DASHED lines
are for the WIDE#1 crosshatch.
On PSOL4002, the SOLID lines are for
the WIDE#2 crosshatch and the DASHED
lines are for the WIDE#3 crosshatch.
2. Optical and Electrical Focus
Always allow the set to warm up for at
least 15 minutes before making CRT
adjustments.
The TW40F80 and TW56F80 should be in the
WIDE 1 picture size for these adjustments.
1. Follow the appropriate disassembly
instructions to gain access to the CRTs.
2. If the wing nuts on the lenses are
pointed toward the screen, reverse the lenses
on each tube so the wing nuts are facing the
back of the set. Leave the lenses in this
position after servicing. Put the screen assembly back on.
The 56” templates are manufactured the
same way. PSOL5601 contains the FULL and
WIDE#1 crosshatch patterns. PSOL5602
contains the WIDE#2 and WIDE#3 crosshatch
patterns.
The templates for the TW40F80 are
centered by aligning the four corner brackets
(located on each template) with the inner
border that outlines the screen’s viewing
area.
For the TW56F80, temporarily install the
template on the screen. Locate the center of the screen by stretching two pieces of
string diagonally across it, corner to corner.
Align the template’s center crosshairs with the
center point of the screen.
Secure each template to the bezel with
low tack tape. To reduce parallax error, place
the template as flat against the screen as
possible.
3. Enter the service mode by pressing
MUTE on the remote control. Press and hold
the MUTE key a second time, while pressing
the MENU key on the set’s front control panel.
An “S” appears in the upper right corner of the
screen, indicating the set is in the Service
Mode. Press the MENU key again to enter
the service adjustment mode, and “RCUT”
appears in the upper left corner of the screen.
Press the 7 key to display the convergence
cross hatch pattern.
6
Page 7
4.Select the WIDE 1 picture size with the
PIC SIZE key on the TW40F80 and TW56F80.
12. Push the RTN key to turn on the blue
tube, and the 100 key to turn off the red tube.
5.Push the 100 key to turn off the red
tube, and the RTN key to turn off the blue
tube.
6.Move around to the rear of the set.
Loosen the wing nut on the green lens. Rotate the lens while looking up at the back of
the screen at the reflected image. Adjust the
lens for the best focus in the center area of
the screen. It helps to have the room dark. If
the room is not dark enough, place the
speaker grill, or a similar dark object, in front
of the screen.
7.Move around to the front of the set and
adjust the electrical focus for best focus in the
center of the screen.
13. Adjust the blue optical and electrical
focus. However, defocus the blue slightly with
the electrical focus control to maintain uniform
brightness.
14. Select the FULL picture size with
the PIC SIZE key on the TW40F80 and
TW56F80.
15. Push the 7 key two times to exit the
convergence mode and call up the built in test
patterns. There should be no connection to
the Video 1 Input.
3. Mechanical Tilt
Make sure there is no connection to
the VIDEO 1 input.
8.Repeat the optical focus, then tighten
the wing nut.
9.Repeat the electrical focus.
10. Push the 100 key to turn on the red
tube, and the 0 key to turn off the green tube.
11. Adjust the red optical and electrical
focus.
1. With the set still in service adjustment mode, push the TV / VIDEO key until the
white cross bar on black background test
pattern is displayed. Check each CRT’s tilt. If
a CRT’s cross bar pattern is tilted, loosen the
appropriate yoke with a non magnetic screw
driver and rotate the yoke until the cross bar
pattern is aligned vertically and hor izontally.
On the TP50F50/51, the notches in the
screen bezel can be used as a guide.
For the TW40F80 and TW56F80, place
the FULL / WIDE 1 template on the screen
and use the FULL (solid lines) center cross
hairs as a guide.
2. Turn the power off to exit the service
mode.
7
Page 8
4. User Convergence
5. Magnetic Centering
1.Tur n the power on.
2. Put the TW40F80 and TW56F80 in the
FULL picture size.
3.Enter the customer convergence
screen:
a) TW40F80 and TW56F80: Press the
menu key. Using the left or right arrow keys,
select the PICTURE icon. Use the down
arrow key to select CONVERGENCE. Use
the right arrow key to start the customer
convergence screen. The ENTER key selects
RED or BLUE. The arrow keys move the
selected color up, down, left, and right.
b) TP50F50/51: Press the setup ke y until
CONVERGENCE is highlighted. Press the +
or - key to start the customer convergence
screen. The + and - keys then select RED or
BLUE to converge. The 2 and 8 keys move
the selected color up and down, the 4 and 6
keys move the selected color left and right.
1.Enter the service adjustment mode.
Use the TV/VIDEO key to select the white
cross bar on black background test pattern.
2.Rotate the centering rings on the green
CRT to center the green cross bar. If the
rings won’t turn, remove the locking glue with
a small knife. On the TP50F50/51, use the
center cross hairs of the convergence template or the center notches in sides of the
screen bezel.
There are no center notches on the
screen bezels of the TW40F80 or TW56F80.
Use the FULL center cross hairs of the FULL /
WIDE 1 convergence template. The red and
blue CRT centering rings may be misadjusted
to make it easier to center the green cross
bars.
3.Center the red and blue cross bars
using the green cross bars as a guide.
4.Lock the centering rings with a pliable
adhesive.
4.Move the red vertical cross bar as far
as it will go to the right. Note the location.
Move the red vertical cross bar as far as it will
go to the left. Note the location. Set the red
vertical cross bar to the center of the two
extremes.
5. Move the red horizontal cross bar as
far as it will go towards the top of the screen.
Note the location. Move the red horizontal
cross bar as far as it will go toward the bottom
of the screen. Note the location. Set the red
horizontal cross bar to the center of the two
extremes.
6. Switch to the blue cross bars and
repeat the entire process.
7.Exit the customer convergence screen.
5.Exit the service adjustment mode.
6. Re-install the CRT x-ray shield.
6. Electrical Centering
1.Disconnect any input at the Video 1
input.
2.Select the FULL picture size on the
TW40F80 and TW56F80. Put the set in the
service adjustment mode.
3.Push the TV/VIDEO key on the remote
until the white cross bar pattern on a black
background is displayed.
8
Page 9
4.Check the centering of the cross bar
pattern with the centering notches in the bezel
on the TP50F50/51. For the TW40F80 and
TW56F80, use two pieces of string stretched
diagonally, corner to corner, to find the center
of the screen, or use the FULL center cross
hairs of the FULL / WIDE 1 convergence
template.
5.If the horizontal position is off, push the
channel up or down key until the “HPOS”
register appears. Use the volume key to
center the pattern.
flat as possible against the screen to reduce
parallax errors.
NOTE: If the microcomputer memory IC
(QA02) has been reset or replaced, or the
crosshatch pattern is not reasonably close to
the template pattern, make the adjustments in
section 11 (WID, HIT, & VLIN Adjustments).
Then proceed with step 5.
5.Push the 3 key on the remote until the
blinking cursor in the upper left corner of the
screen turns green.
6.If the vertical position is off, push the
channel up or down key until the” VPOS”
register appears. Use the volume key to
center the pattern.
7.Push the TV/VIDEO key until no test
pattern is displayed. Turn the power off.
7. Green Geometry
1. Put the set in the service adjustment
mode and bring up the convergence cross
hatch pattern. Select the FULL picture size
for the TW40F80 and TW56F80.
2.Push the 100 key to turn off the red
tube, and RTN to turn off the blue tube.
6.Move the blinking cursor to the right
with the 6 key, then down with the 8 key until
it’s one line to the right of center. The 4 key
moves the cursor to the left, and the 2 key
moves it up.
7.Push the 5 key to lock the cursor in
place.
8.Use the 2, 6, 8, and 4 keys to align the
lines of the cross hatch with those on the
template.
9.Push the 5 key to unlock the cursor.
10. Move the cursor to another location
and repeat steps 7 and 8.
There are two common methods for
accomplishing digital convergence:
3. Place the convergence template on the
screen and align the center cross hairs with
the center of the screen. Start with the FULL /
WIDE 1 template on the TW40F80 and
TW56F80. The solid line crosshatch is for
FULL. The dashed line crosshatch is for
WIDE 1.
4.Use low tack masking tape to attach
the template to the bezel. Get the template as
A. The first method begins in the center
of the screen and moves in a counter-clockwise spiral outward to the various adjustment
locations on the crosshatch pattern.
At each adjustment location the crosshatch line is pulled vertically and horizontally
to align with the template.
9
Page 10
B. The second method starts at the
center of the screen and adjusts all vertical
lines working outward to the right side.
Then, starting back at the center of the
screen, adjusts all vertical lines working
outward to the left side.
The process is then repeated for the
horizontal lines.
From the center of the screen, adjust all
horizontal lines working upward to the top.
Go back to the center and adjust all
horizontal lines working downward to the
bottom.
Usually, either process will need to be
repeated in order to fine tune the adjustments. Choose the method that is most
comfortable for y ou.
12. Repeat steps 5 through 10 for the
WIDE 1 picture size.
13. Press the PIC SIZE key to save the
WIDE 1 settings and change to the WIDE 2
picture size.
14. Remove the FULL / WIDE 1 overlay.
Put the WIDE 2 / WIDE 3 overlay in place
and center it on the screen. The solid line
crosshatch is for WIDE 2. The dashed line
crosshatch is for WIDE 3.
15. Repeat steps 5 through 10 for the
WIDE 2 picture size.
16. Press the PIC SIZE key to save the
WIDE 2 settings and change to the WIDE 3
picture size.
17. Repeat steps 5 through 10 for the
WIDE 3 picture size.
After completing the Green Geometry for
the FULL picture size, press the PIC SIZE key
to change the picture size to WIDE 1. The
crosshatch pattern does a one second distortion, indicating the FULL convergence settings have been saved.
NOTE: This completes the green geometry for
the TP50F50/51, however, the TW40F80
and TW56F80 require green geometry
adjustments for 3 additional picture
sizes:
11. Press the PIC SIZE key to change the
picture size to WIDE 1. The cross hatch
pattern does a 1 second distortion, indicating
the FULL convergence settings have been
saved.
NOTE: If the WIDE 1 cross hatch pattern
is not reasonably close to the WIDE 1 template, you may need to make the adjustments
in section 11 for WIDE 1 only. WIDE 1 has its
own WID, HIT, and VLIN registers.
NOTE: The Red and Blue must be
converged to the green. The Red and Blue
convergence steps must be repeated for all
picture sizes on the TW40F80 and the
TW56F80.
8. Red Convergence
1.On the TW40F80 and TW56F80,
change the Picture Size to FULL.
2.Remove the template and press the
100 key to turn on the red tube.
3.Press the 3 key until the red cursor
appears.
4.Align the red cross hatch pattern to the
green cross hatch pattern, using the same
procedure used to align the green cross hatch
pattern to the template.
10
Page 11
5.On the TW40F80 and TW56F80, repeat these steps for the WIDE 1, WIDE 2, and
WIDE 3 picture sizes.
9.Check the White balance and adjust, if
needed.
9. Blue Convergence
1.On the TW40F80 and TW56F80,
change the Picture Size to FULL.
2.Push the 100 key to turn off the red
tube, and RTN to turn on the blue tube.
3.Push the 3 key until the blue cursor
appears.
4.Align the blue cross hatch pattern to
the green cross hatch, using the same procedure used to align the green cross hatch
pattern to the template.
5.On the TW40F80 and TW56F80, repeat these steps for the WIDE 1, WIDE 2, and
WIDE 3 picture sizes.
6.Push the 100 key to turn on the red
tube and check the convergence with all three
tubes on. The cross hatch pattern should be
white with no red, green, or blue present.
Howeve r, depending on how much you
defocused the blue tube, a slight blue halo
may show. Check all four picture sizes on the
TW40F80 and TW56F80.
7.Push the 7 key to exit the convergence
mode, push the 7 key again to exit the adjustment mode, then turn the power off to save all
settings and exit the service mode.
8. Turn the set back on and check the
overall picture quality with a live video signal.
Check all the picture sizes on the TW40F80
and TW56F80. If all the picture sizes look
good, put the set back together. If any picture
sizes are not acceptable, recheck the convergence for that picture size.
10. White Balance
Perform the white balance procedure in a
darkened room.
1. Install the screen assembly and select
the FULL picture size.
2. Press the RESET key on the remote
control to set the customer controls to their
default values.
3. Enter the Service Adjustment mode
and adjust registers RCUT, BCUT, GCUT,
RDRV, and BDRV to a value of 40H.
4.Turn the power off to exit the Service
Adjustment mode, then turn the TV back on.
5. Select Video 3. Remove any inputs to
the Video 3 input jacks.
6. Remove the screen assembly.
7. Turn the RED, GREEN, and BLUE
screen controls completely counter-clockwise.
8. Look down into the lens of each CRT
and rotate the screen control clockwise until
the raster is just visible.
9.Install the screen assembly.
10. Input an NTSC color bar signal or
staircase from a color bar generator.
11. From the on screen menu, turn the
customer color control to minimum.
11
Page 12
12. Adjust the following registers for
proper gray scale tracking from white to black:
a) RDRV and BDRV for light gray and
white areas of the screen.
b) RCUT and BCUT for dark gray and
black areas of the screen. Leave GCUT set at
40H.
11. WID, HIT, & VLIN
NOTE: See the NOTES in Section 7,
before performing the following procedure.
1. Push the 7 key to exit the convergence mode and display the RCUT register.
If the WIDE 1 picture size is to be adjusted,
select WIDE 1 picture size.
13. Set the customer contrast to zero and
the customer brightness to 40%.
14. Adjust the sub-brightness register,
BRTC, until there is a slight difference in
brightness level between the two darkest bars
on the right side of the screen. Then, increase this value by six.
15. Generally, the subcolor register,
SCOL, and the subtint register,TNTC, do not
need to be adjusted. However, if adjustment
is necessary, first reset the customer brightness and contrast to normal. Connect an
oscilloscope to test point TP501 on the main
board. Connect the ground lead of the scope
to signal ground. From the Service Adjustment mode, select the SCOL register.
16. With the NTSC color bar pattern
input, adjust the SCOL register for an amplitude of 1.0 vp-p.
17. Decalibrate the oscilloscope so the
1.0 vp-p- is 3 divisions high.
18. Select the TNTC register. Adjust the
register until the amplitude of the 2nd bar is 2
divisions high (2/3 the amplitude of the SCOL
setting.)
2.Push the channel up or down key until
the WID register appears.
3.Adjust the WID register with the volume
key until the vertical lines are close to those
on the appropriate template.
4.Push the channel up or down key until
the HIT register appears.
5.Adjust the HIT register with the volume
key until the horizontal lines are close to those
on the appropriate template.
6.Push the channel up or down key until
the VLIN register appears.
7.Adjust the VLIN register with the volume key until the horizontal lines are close to
those on the appropriate template.
8.If needed, repeat both the HIT and
VLIN adjustments for the best results.
9.Push the seven key twice to return to
the convergence mode. Continue with step 5
(or step 12, if in WIDE 1) of Section 7, Green
Geometry.
19. Recalibrate the oscilloscope and set
the SCOL register to 1.8 vp-p.
Check the overall picture quality with a
live video signal.
12
Page 13
1. System
13
KEY
PAD
17
KEY A
REMOTE
SENSOR
KEY B
18
35
QA01
MICRO-
COMPUTER
RMT OUT
3
SCL0 SDA0
11 12
65
QA02
EEPROM
MEMORY
38
SDA1
SCL1
37
IC501
V/C/D
PROCESSING
27 28
40 39
QK06
AUTO LIVE
CIRCUIT
3
2
QB90
SDA2
5
SCL2
6
H002
IF/MTS/A.PRO
21
25 24 44
20
QV01
AV
SWITCHING
QZ01
3D-Y/C
COMB FILTER
20
60
19
59
H001
MAIN
TUNER
6
Q302
DPC CIRCUIT
DOLBY PRO
47 49
7
109
56" ONLY
QX01
WAC
CIRCUIT
DUAL
CIRCUIT
TUNER/IF
PROCESSOR
IC D12
LOGIC
16
QY91
HY01
POP
Q701
CONV.
17
34
43
14 15
40"
UM01
NEW OSD/EDS/CC
RGB SW.
-------------
AND
STARSIGHT
56"
P507
3
4
BLOCK DIAGRAMS
Page 14
2. Power Supply
120VAC
POWER
ON/OFF FROM
MICROCOMPUTER
T840
POWER
TRANS
RELAY
POWER
OFF
REGULATOR
FEEDBACK
Z801
16
CONTROL/PROTECTION
STANDBY
SWITCH
MODE
(SUB)
SWITCH
MODE
(MAIN)
3
+5VDC
RESET
+12VDC
TO MICROCOMPUTER
REG
+30VDC
REG
+15VDC
-15VDC
REG
+12VDC
+38VDC
+125VDC
125V B+ MONITOR AND
125V OVERCURRENT
1
PROTECT
+5VDC
+9VDC
-9VDC
X-RAY
SENSING
1413
OVERCURRENT,
OVERVOLTAGE, &
UNDER VOLTAGE
SENSING
14
Page 15
VIDEO - 1
VIDEO - 3
ANT 1
OUT
ANT 2
VIDEO - 2
15
VIDEO- 2
(DVD)
MAIN VIDEO
FROM
QV01-36
MAIN VIDEO
FROM
QV01-34
RF
TEST
CV/Y
C
CV/Y
C
RF
SWITCH
CONTROL
FROM
QA01
CV/Y
Cr
Cb
---------
+9v
COMPONENT VIDEO
DETECTION
15
Y
Q501
13
V/C/D
C
HY01 POP
TUNER/IF
H001
MAIN
TUNER
TO QV01-21
4
5
6
Y
(R-Y)
(B-Y)
Y
Q
I
IF
2
PW03-1
PW02-1
PW02-3
13
8
10
15
H002
IF/MTS
A. PRO
DVD
SWITCH
UNIT
PW01
CV TO VIDEO OUT JACK
12
38
14
CV
DG
3D - Y/C
COMB
AND NEW OSD EDS/CC BOARD
3. Video
FILTER
16
18
28
CV
7
CV
7
30
32
36
Y
34
C
Y
C
DC
DD
EO31Z
9
RED CRT
DRIVE
EO32Z
3
GRN CRT
DRIVE
RED CRT
GREEN CRT
QV01
EO33Z
9
BLUE CRT
DRIVE
Q501
BLUE CRT
43
R
42
G
41
B
SWITCHING
10
CV
Y
2
4
6
PX01-6
Q
PX01-5
I
PX01-4
AV
SUB-V
WAC
PX02-5
PX02-7
PX02-6
42
Q
TO Q501
2
Y
I
ZY01
WINDOW
PICTURE
Y/C SEP.
5
Y
PY01-8
PYO2-3
PY02-1
PY02-2
DUAL
3
C
PY01-15
PY01-5
PY01-4
PY01-6
53
Y
52
Q
51
I
TEST
SIGNAL
TO VIDEO-1
QA01
MICRO
COMPUTER
CONTROL FROM QA01
FROM QV01-38
CV
9
I2C
UM01
OSD
EDS/CC
RGB SW.
P507B-6
P507B-1
P507B-5
P507B-2
FROM
DIGITAL
CONVERGENCE
YS
R
G
B
32
YS
35
34
G
33
36
39
38
37
R
B
V/C/D
Page 16
TEST SIGNAL
S
R
L
S
FROM QA01
AUDIO 1
MONO AUDIO FROM HY01
POP TUNER
IF
FROM H001
MAIN TUNER
23
SURROUND
TW56F80 ONLY
16
L
R
14 12
H002
IF/MTS/A. PRO
L R
26 24 22 17 16 18
SURROUND OUT
11
QV01
13
29
31
5
6
6
L
5
R
10
SBS (SUB BASS SYSTEM)
AV
SWITCHING
37
L
3 2
FRONT SURROUND
---------------------------------
DOLBY PRO LOGIC
35
R
40"
56"
8
9
15
17
11
CENTER OUT
L
AUDIO 2
R
L
AUDIO 3
R
QV14
QS04
2
4
Q621
CENTER AMP
TW56F80 ONLY
12
7
L
TO AUDIO
OUT JACK
R
4. Audio
5
L
3
R
QS101
7
1
3
Q690
R
TO VARIABLE AUDIO
L
1
OUT JACK
+
+
5
2
Q601
7
INT/EXT
L
SWITCH
11
R
REAR AMP
2
4
Q641
FRONT O
CENTER
SPEAKER
R L
EXTERNA
SPEAKER
12
REAR
7
SPEAKER
Page 17
5. Deflection
T400
DYNAMIC FOCUS
AFC
AC TO HEATERS
+22V DC TO X-RAY
PROTECT
+125V DC FROM
MAIN POWER
Q501
VIDEO
CHROMA
DEFLECTION
PROCESSING
48
SVM
+12V DC
+35V DC
-27V DC
+200V DC
HD
23
VD
31
HORIZ.
DRIVE
WAC
B0ARD
10
9
7
6
5
3
2
4
T461
FLYBACK
TRANSFORMER
1
13
CIRCUIT
HORIZ.
DRIVE
Q302
DPC
HV
2
8
HV
DIST.
BLOCK
FOCUS
BLOCK
TO ABL
R
G
B
R
G
B
TO CRT
ANODES
FOCUS &
SCREEN DRIVE
TO CRTs
30.7KV
CIRCUIT
TO HORIZ.
YOKES
Q301
4
8
VERT.
DRIVE
2
TO VERT.
YOKES
2
SVM
CIRCUIT
1
TO SVM
COILS
17
Page 18
UNIT POWERS UP
MOMENTARILY THEN
SHUTS DOWN
TROUBLESHOOTING
SHUTDOWN CIRCUITS
1. Shut down
Z801-16 GOES FROM
HIGH TO LOW?
MONITOR Z801-14.
DOES VOLTAGE GO
ABOVE 1.5 V?
ANODE OF D7701
ABOVE APPROX.
ZERO VOLTS?
18
Q768
COLLECTOR
ABOVE APPROX.
ZERO VOLTS?
THE +30V SOURCE
HAS AN OVER
CURRENT CONDITION.
CHECK AND REPAIR.
YES
YES
NO
YES
ANODE OF D863
ABOVE APPROX.
ZERO VOLTS?
THE +30V SOURCE
CHECK AND REPAIR.
YES
NO
NO
YES
IS TOO HIGH.
NO
COLLECTOR
ABOVE APPROX.
ZERO VOLTS?
THE +15V SOURCE
CURRENT CONDITION.
CHECK AND REPAIR.
THE PROBLEM MAY
NOT BE A SHUTDOWN
CONDITION.
NO
ANODE OF D861
ABOVE APPROX.
ZERO VOLTS?
YES
THE +15V SOURCE
IS TOO HIGH.
CHECK AND REPAIR.
Q759
NO
YES YES
HAS AN OVER
NO
ANODE OF D866
ABOVE APPROX.
ZERO VOLTS?
YES
THE +15V SOURCE
IS TOO LOW.
CHECK AND REPAIR.
Q762
COLLECTOR
BELOW APPROX.
ZERO VOLTS?
THE -15V SOURCE
HAS AN OVER
CURRENT CONDITION.
CHECK AND REPAIR.
MONITOR Z801-13 .
DOES VOLTAGE GO
ABOVE APPROX.
25 V?
YES
T-461 IS PRODUCING
EXCESSIVE HIGH
VOLTAGE. CHECK
AND REPAIR.
NO
ANODE OF D867
ABOVE APPROX.
ZERO VOLTS?
YES
THE -15V SOURCE
IS TOO LOW.
CHECK AND REPAIR.
NO
VOLTAGE ACROSS R470
ABOVE 1.7V?
YES
THE +125V SOURCE
HAS AN OVER
CURRENT CONDITION.
CHECK AND REPAIR.
NO
ANODE OF D315
ABOVE APPROX.
ZERO VOLTS?
YES
THE +200V SOURCE
IS TOO LOW.
CHECK AND REPAIR.
NO
Q370 COLLECTOR
ABOVE APPROX.
ZERO VOLTS?
YES
THE +35V SOURCE
HAS AN OVER
CURRENT CONDITION.
CHECK AND REPAIR.
NO
JUNCTION OF
R888 AND R887
ABOVE 39V?
YES
THE +38V SOURCE
IS TOO HIGH.
CHECK AND REPAIR.
*ALL VOLTAGES MUST BE MEASURED
WITH A PEAK RESPONSE METER.
TROUBLESHOOTING FLOW CHARTS
Loading...