Sony D99 CHASSIS User manual

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TRINITRON®COLOR COMPUTER DISPLAY
OPERATIONMANUAL
TROUBLESHOOTING MANUAL
CIRCUITDESCRIPTION
DBoard(PowerSupplySection)............. 2
DBoard(DeflectionSection) ................... 9
ABoard .................................................. 20
GENERALTROUBLESHOOTING .............. 26
PARTSLEVEL BOARD REPAIR................ 37
D99 CHASSIS
TABLE OF CONTENTS

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CIRCUIT DESCRIPTION
D BOARD POWER SUPPLY SECTION
Power Supply Electrical Circuit
The power supply is located on the D Board. It has three modes of operation that are controlled by a microprocessor. The
topology is a discontinuous mode flyback converter with photocoupler feedback for regulating the secondary voltages.
Circuit operation and troubleshooting are explained in the following sections:
OperationModes SecondaryCircuitry
AC Input ProtectionCircuits
Degauss Circuit Troubleshooting
Primary Circuitry
OperationModes
The power supply has four modes of operation, ‘off’, ‘active off’, ‘suspend/standby’ and ‘active on’. These modes are
related to power savings and are indicated by the front panel LED. Additional indications are failure diagnostics and aging
mode. The table below lists operation mode, condition and LED status.
Except for power switch off, all modes of operation are controlled by the microprocessor located on the D Board. The
failure modes are detected by the microprocessor and the power supply is forced into active off mode. These functions are
discussed later (Deflection).
With the AC cord attached to the monitor and connected to an AC source, the monitor will be off until the power switch is
turned on. When the power switch is turned on, the power supply starts and is in active off mode. The next step is active on
mode. The power saving modes are activated by the microprocessor based upon the presence of either H or V sync. If no
sync signals are present, the power supply is set to active off mode. If only horizontal sync is present the power supply
moves to suspend mode. If only vertical sync is present the power supply enters standby mode.
Power supply operation control signals are “Remote On/Off” and “Heater On/Off”. Remote On/Off is digital low for active
off and suspend/standby modes. Heater On/Off is digital low for active off mode. To enter active on mode, the micropro-
cessor must set remote on/off to digital high. Heater on/off is also made digital high and the heater is turned on.
Output Off Active Off Suspend/Standb
y
Active On
B+ 0V 13V 180V 180V
80V 0V 10V 77V 79V
+15V 0V 1V 14V +15V
-15V 0V -1V -14V -15V
+12V 0V 0V 0V +12V
5V 0V 0V 0V +5V
Heater 0V 0V 4.6V 6.3V
H. Centerin
g
0V +7V +10V
STBY 5V 0V +5V +5V +5V
Mode Syncs Condition LED
Off N/A Power Switch Off Off
Active Off No H and V Low Power, Heater Off Amber
Suspend/Standby No H or V Low Power, Heater On Amber 0.5s<- ->Green 0.5s
Active On H and V Present Phase Locked, Normal Operation Green
Failure 1 NA HV or +B Failure Amber 0.5s<- ->Off 0.5s
Failure 2 NA H Stop, V Stop, Thermal Failure Amber 1.5s<- ->Off 0.5s
Failure 3 NA ABL Failure Amber 0.5s<- ->Off 1.5s
Aging/Self Test No H and V Aging Raster or Test Pattern Green 0.5s<- ->Off 0.5s

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1. AC Input Section
The AC input section provides EMI filtering, input protection, surge limiting and CRT degauss operation.
EMI Filter
The EMI filter comprises CN600 (inlet with filter), X-capacitors C604 and C605,Y-capacitors C606, C638, C660 and
C643 and the line filter transformer, LF602. Input protection is provided by F601and VA601; surge current limiting by
thermistor TH600 and resistor R600. Degauss is explained in the next section.
Degauss Circuit
The degauss circuit is used to demagnetize the CRT. After power on, the microprocessor located on the D Board sets the
degauss signal to digital high and Q601 turns on relay RY601. This allows AC current into the degaussing coil through
posistor TH601. The current heats up the posistor and its affective resistance increases, this dampens the current in the
degauss coil to nearly zero. Duration time is approximately 5-6 seconds and the microprocessor then shuts off RY601,
which disconnects the degauss coil from the AC line. This operation should sufficiently demagnetize the CRT.
2. Primary Circuitry Section
IC601
The heart of the primary section is the TEA1504/N2 power supply controller, IC601. The following describes the functions
of each pin.
Pin 1 – Vin: This is a MOSFET drain connection internal to IC601, which is connected directly to the DC mains voltage rail.
The startup current source derives power from the DC mains via the Vin pin. It supplies current to charge the Vaux (IC
supply) capacitors C616 and C617 and also provides current to the IC601 control circuitry.
Pin 2 – HVS: High voltage safety spacer pin is a no connection.
Pin 3 – NC: Connected to primary side DC mains return.
AC Input and Degauss

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Pin 4 – Driver: Outputs the pulse width modulated gate drive for switching transistor Q602. Maximum duty cycle is set
internally at 80%.
Pin 5 – Isense: Provides cycle by cycle over current protection by turning off pin 4 driver output when Q602 current exceeds
the current limit corresponding to 500mV at pin 5. This pin typically provides 425nS of leading edge blanking time. The
threshold voltage for switch over to low frequency (low power) operation is sensed by pin 5. When the voltage sensed at pin
5 is below 165mV, IC601 transitions from operating at high frequency (56.5KHz) to low frequency (23.5KHz).
Pin 6 – Vaux: IC601 supply pin. An internal current source from IC601 charges the Vaux capacitors C616 and C617 for
startup. Once the Vaux capacitors are charged to the startup voltage level (11V), then IC601 starts switching pin 4 driver
output.TheVaux is also supplied by an auxiliary winding from T601 on the primary side once the secondary output voltages
attain their nominal operating voltage values. Pin 6 also provides under voltage lockout detection (8V) and over voltage
protection (14.7V).
Pin 7 – DS: Provides the power supply for the driver output (pin 4).
Pin 8 – Iref: Controls IC601 internal bias currents, which determines the pulse width modulated switching frequencies.
High frequency is 56.5KHz during active on mode. Low frequency is 23.5KHz during suspend/standby mode.
Pin 9 – Vctrl: Feedback voltage for duty cycle control.
Pin 10 – NC: No connection.
Pin 11 – Gnd: Connected to primary side DC mains return.
Pin 12 – NC: No connection.
Pin 13 – Dem: Guarantees discontinuous conduction mode operation for the power supply. Verifies that T601 is demagne-
tized by not activating the next gate drive pulse until the primary side auxiliary winding of T601 is lower than the threshold
level of 65mV as detected at pin 13.
Pin 14 – OOB: On/Off/Burst mode input signal. A voltage greater than 2.5V enables IC601.
Operation
The power supply is a discontinuous-mode flyback converter with photocoupler feedback for regulating the secondary
voltages. The PWM controls the pulse width of the gate drive.
WhenAC is applied to the power supply and IC601 pin 14 is greater than 2.5V, start up current is supplied though IC601 pin
1 to IC601 pin 6. Startup voltage is approximately 11V. After start up, the voltage to pin 6 and pin 7 of IC601 is supplied
through D620 connected to T601 pin 2. The first mode of operation is active off mode. The output drive pulse frequency will
be in burst mode operation.
When the power supply enters active on mode, the switching frequency will be 56.5KHz. The Vaux level will be approxi-
mately 12.5 volts. OVP threshold is 14.7 volts and UVLO is 8.0 volts. Therefore, if theVaux voltage is not correct, the power
supply will not operate properly.
Feedback from the secondary side comes through IC603 and IC604, which is connected to IC601 pin 9. (See diagram on
page 5.)
3. Secondary Circuitry Section
The secondary section consists of the following circuits. Rectifier diodes and filters for all output voltages, horizontal
centering, +5/12 volt regulators, +5 standby regulator, heater voltage regulator, voltage feedback circuit, active off mode
feedback, and protection circuits. This section will describe each circuit and its function.
SecondaryRectifiers
The secondary rectifiers supply the following voltages, 180V (B+) deflection and video, 80V video, ±15V deflection and
regulators, 6.3 volt heater regulator, +5V standby regulator, horizontal centering voltages.

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Horizontal Centering
This circuit supplies IC503, which is used to adjust horizontal raster position on the CRT. The horizontal centering circuit
consists of fusible resistors R638 and R639, diodes D615 and D616 and filter capacitors C630 and C631. In respect to the
secondary ground, the horizontal centering ground is floating and connected to –H DY line. The voltages in reference to this
floating ground are ±10 volts. Care should be taken to not short the floating ground to the secondary ground.
+5/12Volt Regulator
IC605 is the 12 volt regulator and IC608 is the 5 volt regulator. The output voltages are supplied to the microprocessor,
deflection and video circuits. The +15 volt line provides the input voltage for +12V regulator; the +12V line provides the
input voltage for +5V regulator. During active off or suspend/standby mode, the 12 volt regulator is disabled via remote on/
off and subsequently the 5V regulator is disabled.
+5V Standby Circuit
IC607 is the standby 5V regulator. In the active on mode and the suspend/standby mode, the input to the regulator is supplied
from T601 winding 14-13. During the active off mode, the regulator input is supplied from T601 winding 10-13 via D612 and
D613. Typical input voltages to the regulator are active on mode: 9.5V; suspend/standby mode: 7.4V; active off mode: 11.5V.
HeaterVoltage Regulator
Heater filament voltage is supplied by T601 winding 14-13 and is regulated by IC602. IC602 output is turned on and off by
the heater on/off control line at pin 1, CTL. The output is off during active off mode.
Feedback Circuit
The feed back circuit is divided into two sections. One is for active on and suspend/standby modes; the other for active
off mode. The following two sections explains the theory and operation.
Active On and Suspend/Standby Mode Feedback
Shunt regulator IC604 regulates the B+ line to 179.2V by sinking current through the opto coupler 1C603 to ground. The

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reference voltage at IC604 pin 1 determines the sink current into pin 3. The reference voltage is set to 2.50 volts by
resistor divider R608, R650, R648, and R609. Since the B+ is connected to the resistor divider, any change in B+ voltage
is detected at the reference terminal. The shunt regulator will either increase or decrease the current into pin 3 in order to
decrease or increase the B+ voltage respectively and try to maintain the reference voltage to 2.50 volts. IC603 biases it's
phototransistor accordingly and drives IC601 pin 9 (Vctrl) which changes the duty cycle at IC601 pin 4 (driver) to
regulate the B+ voltage at 179.2V.
Active Off Mode Feedback
Heater control line is low (heater off) during active off mode and respectively Q603 is off. Voltage pulses from T601 pin 10
flow through C620, R636, and R660 triggering the gate of thyristor D613. D613 turns on effectively shorting the B+ rail to
the standby 5V regulator input; current flows from T601 pin 10 through D612 and D613 to the standby 5V regulator input.
When the standby 5V regulator input is increased to approximately 12.7V it forward biases zener diode D605 turning on
Q604 and sinks current through IC603 to ground. The standby 5V input supplies this current to IC603 pin 1. IC603 biases it's
phototransistor and drives current through D609 into IC601 pin 14 (OOB) triggering burst mode operation. IC601 pin 4
(driver) is pulled low turning off switching transistor Q602. T601 pin 2 (auxiliary winding) feedback pulses are discontinued
and IC601 pin 6 (Vaux) decreases to 8V. IC601 internal current source then charges pin 6 (Vaux) to the startup voltage level
(11V) which starts switching pin 4 driver output. The feedback cycle is then repeated. The burst repetition rate is approxi-
mately every 110mS and when IC601 pin 4 is switching its frequency is 23.5KHz.
Feedback Circuits

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4. Protection Circuits
The following are protection circuits: OCP, OVP, UVLO and secondary short circuits. OCP is pulse by pulse and is performed
on the primary side. OVP detects excessive output voltages. UVLO detects output under voltages. The following will explain
the operation of these functions.
OCP
OCP is activated if there is too much current passing through the power MOSFET, Q602. This condition will occur if either
the B+ line or 80 volt line is shorted.
R614 and R654 are the current sense resistors. Current through these resistors will produce a positive voltage reference to
ground. R623, R624 and C650 provide a voltage divider and filter to IC601 pin 5 (Isense). If the voltage level exceeds 0.5
volts, the IC does pulse by pulse current limit and the output voltages are reduced. This condition can be audible and
characterized by a ‘chirping’ sound.
OVP and UVLO
The OVP and UVLO functions are detected by IC601 pin 6 (Vaux). Vaux is mornally 12.5V. In the event the regulation
control loop were to fail, the output voltages would either increase or decrease; then Vaux would increase or decrease
respectively via T601 transformer coupling. IC601 pin 6 will detect an OVP at 14.7V and UVLO at 8V turning off the driver
output and initiating a low dissipation safe-restart mode.
Secondary Short Circuits
Safe operation during secondary short circuits is provided by the demag function of IC601 pin 13. Demag protection
decreases the switching frequency to a very low level, thereby reducing the input power level and providing safe opera-
tion. Demag also provides a soft start function during startup gradually increasing the switching frequency until fixed
frequency operation is attained.
5. Troubleshooting
Warning
Before attempting to fix the power supply, safety should be considered first. Never connect test probes to the primary side
circuits, unless proper isolation has been installed. If isolation for the AC mains is not present, serious harm can occur.
Never assume you are safe.
Protection Circuits

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No Power
In the event that the monitor does not turn on, first verify input power is applied to CN600 and the front panel power switch
is turned on; then check F601 and R605. If these parts are blown, the primary side circuitry should be checked. If the fuses
are not blown, then check the secondary side circuitry, especially the protection circuits. If these circuits are causing a no
power symptom, the problem can be more readily found.
AC Input and Degauss CircuitTrouble Shooting
For no power or nonoperating power supply, the AC input circuitry should be checked. Open or short circuit elements will
cause non-operation. F601, CN600, and R605 on the D Board should be checked first. Check the front panel power switch
for continuity.
If all elements are correct, check whether F601 breaks when power is applied and the power switch is closed. If the fuse
does blow, there may be problems with the primary circuitry or a component short.
The degauss will malfunction if CN601 is not connected. One problem could be loss of degauss signal from the micropro-
cessor. This can be verified by using the manual degauss command found in the OSD menu. If the signal does not appear at
Q601 base, then it is possible that the microprocessor does not function correctly or standby 5V is not functioning.
The second step is to place a short across theAC terminals of RY601 for less than two seconds. If degauss operates then
check Q601 and RY601. If degauss does not work, check TH601 for an open condition and VA600 for a short condition.
PrimarySection
Three main areas can diagnose primary circuit failures. These are IC601, Q602 and Feedback system.
Visible checks of these areas will aid in finding problems. The following will discuss each section.
IC601
First apply AC to the monitor and check IC601 pin 4 output. If the output on pin 4 is not present, there could be problems
with Q602 and related parts or pin 14 could be less than 2.5 volts. Further, check Vaux level at pin 6. If it less than 11
volts, the IC could be in safe-restart mode. If the voltage is very low, there could be a short on any of the IC pins. In
reference to ground, check the impedance of pin 1, 8 and 14. If any of these pins are shorted, replace the IC and check
components connected to the related pins. Take care that C617 and C616 are fully discharged before replacing the IC.
Q602
The switching transistor can be damaged in various ways. These are related to voltage, current and temperature.
Check whether the transistor is shorted across drain and source terminals. If there is a short, F601, R605, R614, R654,
R623, R624 and C650 should be checked. Additional components to check are D608, R612 and IC601. If Q602 is
shorted, all these parts should be replaced.
Failure of a secondary rectifier diode can also cause Q602 to fail. Check 180V and 80V diodes for open or short condi-
tions. There is also a clamp circuit, which is used to clip the turn off spike found on Q602 drain. If the clamp circuit is
broken, it can cause Q602 failures. Check D606, C612 and R635. Also check the snubber circuit components C613,
D607, R619 and R656.
SecondaryCircuit
Failure in the secondary circuits can be categorized by rectifier diodes, fusible resistors, regulators, feedback loops and
protection circuits. These sections are interrelated and failure in one can affect another. Consequently, some failures will
also affect the primary circuitry.
RectifierSection
Rectifier diode failures are not common, but do occur. Deflection, video and high voltage circuitry failures contribute to
diode damage. In the event a voltage is not present, check for shorts to ground, open or short diodes. Also check fusible
resistors found on the voltage lines.
HorizontalCentering
Loss of horizontal center adjustment can be affected by the rectifier diodes, fusible resistors, IC503 and related circuitry.
Measure the voltages in reference to the horizontal centering ground. Typically, the voltages are ±10 volts. However, the
adjustment setting can reduce the voltages. If there are no problems found with the diodes or fusible resistors, the next
step is to check the adjustment signal at Q506. If the adjustment signal is not present check the IC901 pin 4. Otherwise,
check IC503 and related components.

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+5/12 Volt Regulator
Loss of voltage due to shorts or device failures on either +12 or +5 volt output lines can occur. Consequently, IC605
or IC608 can be damaged and need replacing. Before replacing either IC, check for shorts or damaged parts along the
output lines. If +12 volt does not appear, check the remote on/off signal from IC901 pin 6.
Standby 5V Circuit
Failure of this circuit can be affected by IC607. In case the circuit does not work properly, check D605, D614, R634,
R611 and Q604. If these components are good, check the remaining circuit parts.
HeaterVoltage Regulator
This circuit may be affected by fusible resistor R634 or D619. If these parts are good, check the regulator output for a
short to ground. Shorts can occur on the video board. In the case of an output short, IC602 may have been damaged.
If the IC appears to have no damage, check for any problems with the heater on/off signal.
Feedback Circuit
Problems with feed back can cause power supply shut down or low voltages. First determine whether the power
supply is operating in active off, active on modes or not at all.
The power supply can be stuck in active off mode. The remote on/off signal, Q603, Q604, D605 and IC603 can affect
this condition. Likewise, if the power supply is always in active on mode, the same items should be checked.
Checking for voltages at IC603 pins 1 and 2, IC604 pins 1 and 3 can solve more difficult problems. Additionally,
IC603 pins 4 and 5, and IC601 pin 9 should be checked. If there are problems with these devices, 180V or standby
5V line, the feedback systems will not work correctly. Also check the protection circuits.
ProtectionCircuits
OCP occurs when there is excessive current through Q602. Failures with Q510, Q507 or the video section could
cause this condition. These areas should be checked. OCP condition can also occur if R614 or R654 are open; if
R623 is shorted; or if R624 is open.
OVP usually occurs when the feedback loop is open, or loss of standby 5V. Isolate the OVP trigger condition, by first
checking the operation of the feedback loop.
D BOARD DEFLECTION SECTION
1. Horizontal Deflection Circuit
Overview
These circuit drive the DY (DeflectionYoke) for Horizontal Deflection. The H size and H shape control (IC501 and
around) is included in this page as well.
H Drive, H Out, Feedback
+12Vp-p HD pulse is generated by the inverter Q903 using the Jungle IC902 H. out pin #17. And switch Q511
through A push-pull amplifier (Q501 and Q502) buffers. The drive current which introduced in HDT (T504) by this
switching will drive Q507 (H out Tr) and 1000V pulse appears on collector. D506 is the "Damper Diode" which avoid
the negative pulse and discharge the energy for next Horizontal Drive. Q508 is the buffer for the "H BLK" feed back
to Jungle IC 902 H. FLY pin #14 and it will be the reference of phase / jitter control of Jungle. HST (T505) is to sense
the deflection current through DY. The voltage appeared on secondary side will be the feed back for H Size/Shape
control.
H Size/Shape control
HD pulse also triggering the H Size/Shape control IC501 pin #8. IC501 is "PWM IC" and it controls H and HV B+
chopper duty. H Shape and H size information is already included and coming from Jungle IC902 E/W pin #9. It will
be supplied to IC501 pin #2. H reg output pin #20 is switching pulse of Q520 (B+ chopper). The energy supplement
from 180V to H Def circuit (through L503 HOT) is controlled by the duty of this pulse. The H Shape input and
feedback voltage from T505 are compared by error amp (in IC501) and H Reg out pulse duty is controlled to keep the
level of these two the same.

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H Deflection Circuit
R553
R569
CN801 H BLK
TO IC901 #32 pin
IC902 #14 pin
TO:
H Lin and
Ringing Circuit
E/W PIN #9
IC902
HD output pin #17
IC902
1
H DY+
2
HDY-
4
3
H DY+
HDY-
320
R551
R586
Q903
12V 12V
Q501
Q502
Q511
R511
T504 HDT
1
46
D502
-16V
Q507
H-OUT
D506 C518 Q508
Q518
12V
180V
R582 Q520
B+CHOP
D518
C575
D516
H Def
IN H Reg Out
H SHAPE
IN HD IN
PWM IC501
L503
HOC
T504
2
5
21
28
C543
C563
R933 R506
R594
C502
R508
R508
D501 R513
C510
R517
R518 C521
C522
HST
FB506
R581
FB504
C574
C582
R583
C576
8
3
1
2

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Troubleshooting
See attached “FLOW CHART” and confirm if it’s really H Deflection issue.
No H Deflection / No Power
Check Q507, Q520 and D506 first. In case any of these shorted, check T504, Q511, R511 and D502.
Those parts might have been damaged.
If both of Q507, 520 were not broken, check the HD pulse at the gate of Q511.
If no pulse, check Q501, Q502, Q903.
Otherwise, check R582, D518 or try changing IC501.
Bad Distortion
Check pin#2 of IC501 and confirm that proper DC level and AC waveform.
If the distortion is on only right side, check all above (“No H Deflection”).
Otherwise, refer to the Troubleshooting of next section (“H Lin and Ringing Correction”).
2. H Linearity and Raster/Distortion Ringing Correction Circuit
This section includes HLC Control circuit, S cap switching and HLC/S-Cap Damping circuits. These circuits are placed
directly on the “cool side” of DY which is in series with deflection current line.
H Centering circuit will be explained in next section.
HLC Switch Control and HLC Damping
There is HLC switch circuit. In case that Q519 is on, RY500 turn on then, L509 is shorted. Q519 is controlled by Micro-
processor (IC901). D505, R577 and C581 are damping circuit to avoid the raster Ringing (mainly on left side of picture)
caused by HLC, DY and S-caps.
S-Cap switching and S-cap Damping
H Def current is distorted by resonance between S-Cap and DY to correct the linearity. Since the resonance frequency has
to be changed for each fH, S-Cap switching is controlled by MICRO
S-Cap Switch - FETs (Q512, Q513, Q514, Q515, Q516) are "On" when its gate is Hi(5V) and that moment, drain voltage
should be grounded (0V).
L506, R578 and C573 is damping circuit to avoid Distortion Ringing (mainly on top of the picture) caused by S-caps and
H Control loop gain. L505, R575 and C572 is also the same purpose as above but only works when Q519 (Switch for the
Biggest S-Cap) is “On”.
Troubleshooting
See attached “FLOW CHART” and confirm if it’s really H lin issue.
Bad Linearity
Confirm that Raster is approximately in the center of the Bezel. If not, refer to next section (Raster Centering Circuit).
Check S-cap switches (Q512, 513, 514, 515, 516, HLC switch (Q519)) and confirm that H Linearity changes proportional
to the value of “S-Cap”.
Bad Top Distortion/ Left side Raster Ringing
Check damping circuits explained above.
3. H. Raster Centering Circuit
Overview
H Centering is changed by supplying DC current to DY. D99 is taking the common level on DY cool(-) side and +/- 8V from
power supply transformer(T601 PIN#16, 17, 18. #17 is the common).
H Center Circuit
The DC current is outputted by powered OP-amp (IC503). This circuit is making “invert amp” with the gain of R573/R579
and input 1S Q518 collector. The level is controlled by MICRO”H CENT" pin #4 through Q506(buffer).

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3
1
4
5
2
R577
33
3w
C507
0.19
400V
C512
0.01
B:CHIP
Q514
2SK3332
R519
56k
:RN
C515
0.01
B:CHIP
R524
56k
:RN
C520
0.01
B:CHIP
R523
56k
:RN C536
0.01
B:CHIP
R535
56k
:RN
R536
1k
:FPRD
C538
0.01
B:CHIP
R537
56k
:RN
R533
1k
:FPRD
R525
1k
:FPRD
R521
1k
:FPRD
R515
1k
:FPRD
R512
4.7
C511
0.22
250V
:PP
C568
0.047
400V
:PP
C516
0.3
250V
:PP C531
0.068
250V:PP
C523
0.12
250V C525
0.047
400V
:PP Q516
2SK3332 STBY
5V
C529
0.047
400V
:PP
S4
S0
S1
S2
S3
S4
:DFT
T503
SSSSS
Q515
2SK3332
Q512
2SK3332
Q513
2SK2098
C530
0.12
250V
2
1
5
4
3
+
+
R593
#L508
HLC
TH502
#
R516
150
1/2W
:RN
R591
150
1/2W
:RN
R592
150
1/2W
:RN
T505
C517
0.01
:PT
R590
22k
:RN Q521
2SA1309A
C583
0.1
:PT
L509
HLC
12V
R589
4.7k
C581
#
D505
ERB91-02TP1
RY500
12V
Q519
DTC114TSA
D512
1SS119
D519
1SS119
R576
47k
C514
0.82
250V
:PP
R575
68
1/2W
:FPRD
L505
2.2mH
R578
39
2W
:RS
C573
4.7
250V
H CENTERING CIRCUIT
CN501
HDY - #5.6 pin
C572
4.7
250V
L506
820µH
(BOARD)
D
H. LINEARITY AND RASTER/DISTORTION RINGING CORRECTION CIRCUIT
H SIZE/Shape Feedback

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FROM D615 IN P.S.
FROM PIN #17 T601
FROM D616 IN A.S. C631
C670 HC+
HC N
HC-
R570
D511
R529 Q518
Q506
H CENT
R571
R573
R572
C509 R580
HC+
C580
R579 HC+
IC502 R538
R539
HC-
L510
TO H. DY(-) VIA L510
TO H. DY(-) VIA L503
(DRAIN OF Q520)
!!! IMPORTANT !!!
CENTER VOLTAGE
COMMON (ISOLATED)
(BOARD)
(19D99 H. CENTERING CIRCUIT)
2
1
3
4
5
D
=
R500
T120
C506
R514 C559
C570

- 14 -
Trouble Shooting
See attached “FLOW CHART” and confirm if it’s really H Center Circuit issue.
No Raster Centering Control
Check R638, 639 (Right next the SRT) first. If it’s open, change IC503.
Confirm that voltage of Q5l8 base is changing accordingly to “HCENT _MINFH, HCENT_LO_FBFH,
HCENT_HI_FBFH, HCENT_MAXFH” register.
If not, change Q506.
CAUTION!!
The heatsink of IC503 is connected to the H center(-) level, not GND! It could have up to 150V and should not be
touched to any other metals.
4. Rotation Circuit
Rotation is a PWM waveform at approximately 125kHz measuring 5Vp-p at pin #3 of the micorprocessor IC901. Then
filtered by R560 and C547 combination. The DC current is outputted by powered 0P-amp (IC502). The output current from
pin #4 of IC502 flows through R563 and the rotation coil and returns to ground through R566. The feedback is sensed at
R566 and sent back to the amplifier through R562.
No Rotation Control
Check the waveform pin #3 of microprocessor IC901 if it is 5Vp-p PWM and approximately 125kHz. Otherwise, check
around IC502.
5. Dynamic Focus Circuit
Overview
Both H and V Dynamic Focus are combined through DFT (T503).
Rotation/Vertical Key Circuit
V-
V++
-
5
3
41
2
STBY
5V
3
Rotation Coil (CN701)
+15V
-15V
ROTATION
IC901
R562
R566
R563
IC502
R558
C547
R560
R559
C549
C513
#1, 2 PIN

- 15 -
H DF
Horizontal Parabola is injected into the secondary side of the focus transformer (DFT:T503). In order to keep the amount of
parabola constant over the horizontal frequency range the values of the AC coupling capacitors are changed by the transis-
tors, which switch the s-caps. This signal is amplified by the turns-ratio to the primary side of the transformer.
V DF
V DF waveform is buffered by Q505 and amplified by Q504 to about 150vp-p. VDF is controlled by Jungle IC902 pin #12.
300v Vcc is made by FBT through D515. This voltage is also used for HV Protector.
Troubleshooting
See attached “FLOW CHART” and confirm if it is reallya DF issue.
Bad H DF
Check H. Linearity. If it's no problem, change T701, T503 (DFT).
Bad V DF
Confirm that waveform is around 1Vp-p. If it’s more than 2.0Vp-p, change Jungle IC902.
Check 300v from FBT from Jungle pin 12 IC902.
6. High Voltage Protect Circuit
This circuit generates the High Voltage supply for the anode and G2 (1000V) of the CRT. It consists of a high voltage driver
and regulator similar to a switching power supply function. In addition, there are High Voltage and Beam Current protection
circuits. All those circuits are similar to D1 chassis circuits.
HighVoltage Regulation and Output Circuit
The HV Drive pulse is generated by IC501 and synchronized with Horizontal drive pulse. It is supplied to the Gate of Q510
the HV Out FET.
The HV Out Pulse approximately 700V, is generated by Q510 switching with the peak voltage being controlled by the
switching duty of Q503 (B+ chopper). Internal resistors and R540 and RV501 divide HV generated in the FBT. Since this
voltage is the feedback for HV Regulation control. Adjusting RV501 will result in changing the HV Regulation level(= HV
level). HV Feedback voltage is returned to IC501 at pin#12 to be compared with an internal reference voltage of IC501 at
pin#13. According to this feedback level, IC501 changes the pulse duty cycle. This pulse is felt at pin #18 of IC501 thereby
controlling the output of B+ chopper drive Q503.
G2 Voltage
G2 voltage at approximately 1250vdc is produced by the HV Out Pulse rectifying through D510, C528, D520, D521, C578
and C577. This voltage will be supplied to A board via CN 510, which contains the G2 control circuit.
HV Protect Circuit
HV Protect circuit will be activated by the Microprocessor when the signal at HV DET, Microprocessor pins#18 reaches a
+5vdc level. HV DET indicates the level of the primary current developed by the 300V winding of the FBT through R543,
D515.
Beam Current Protect
Beam Current Protect will be activated when ABL DET at microprocessor pin#16 reaches a level of 0V when operating in
main mode. ABL DET level is corresponding to the Beam Current which is supplied to FBT through R596, R550 and R548.
The voltage current relationship is inversely proportional Voltage (down) Current (up).
Troubleshooting Hints
See attached FLOW CHART to confirm if is really an HV/Protect Circuit issue.
No HV / No Power
Perform basic checks of Q510 and Q503 first. If both Q510 and Q503 were not broken, check the HV Drive pulse at the gate
of Q503. If no pulse, check R534 and D509. Otherwise, check R520, D504 or try changing IC501.
No G2 Voltage
Check R532 and D510, D520 and D521.

- 16 -
Dynamic Focus Circuit
3
1
4
5
7
8
2
12V
7
6
R543 D515
C540
FBT
FBT
VDF PIN #12
IC902
R502
180k
:RN-CP
R505
10k
Q504
2SC3941A-QR
R506
330k
:RN
C505
15pF
2kV
R565
330k
:RN
C507
0.19
400V
C512
0.01
B:CHIP
Q514
2SK3332
R519
56k
:RN
C515
0.01
B:CHIP
R524
56k
:RN
C520
0.01
B:CHIP
R523
56k
:RN C536
0.01
B:CHIP
R535
56k
:RN
R536
1k
:FPRD
C538
0.01
B:CHIP
R537
56k
:RN
R533
1k
:FPRD
R525
1k
:FPRD
R521
1k
:FPRD
R515
1k
:FPRD
R512
4.7
C511
0.22
250V
:PP
C568
0.047
400V
:PP
C516
0.3
250V
:PP
C531
0.068
250V
:PP
C523
0.12
250V
C509
100p
500V
B
Q506
2SA1309A
C525
0.047
400V
:PP Q516
2SK3332 STBY
5V
C529
0.047
400V
:PP
S4
S0
S1
S2
S3
S4
C503
0.01
B:CHIP
D529
MTZJ-T-77-18
Q505
2SA1309A
R503
10k
:RN-CP R507
2.7k
:RN
R501
100
CHIP
+
C501
10
:DFT
T503
TO FBT
PIN #15
6
SSSSS
Q515
2SK3332
Q512
2SK3332Q513
2SK2098
C530
0.12
250V
-15V
C504
330p
500V
B

- 17 -
Protect Malfunction
To see if HV Prot or ABL Prot are suspect check the Shutdown Log data at the Shutdown Log register. Refer to Shutdown
Log Table below.
When an HV Shutdown is indicated, check R917, R921 and D905 or, replace T501 (FBT).
Where ABL Shutdown is indicated, check the voltage T901 pin#11.
If it is higher than 0.5v immediately prior to shutdown, check connections all the way to N board. Should the voltage reach
and remain at the 0 volt level, even after the first 2.0 seconds of Power On, check D909 and 904 or check White Balance.
SHUTDOWN LOG TABLE
Bit Register value Shutdown Mode Comment
bit7 128 N/A N/A
bit6 64 N/A N/A
bit5 32 Thermal Explained later
bit4 16 ABL Shutdown Hardware Controlled
bit3 8 HV Over Hardware Controlled
bit2 4 HV U Shutdown Not Used
bit1 2 No Vertical Scan Explained later
bit0 1 No H Scan Explained later
7. Protection Circuitry Overview
Overview
The D99 chassis was developed with protection circuits other than HV/ABL.These protection circuits are controlled by
Microprocessor (IC901);
- Thermal Shutdown: Activates when S-Cap Switch in FET are broken (especially Q513 and Q514).
- V Scan Shutdown: Activates when Vertical Deflection signal is absent or of insufficient level or of a distorted nature.
- H Scan Shutdown: Activates when Horizontal Deflection signal is absent or of insufficient level or of a distorted nature.
Troubleshooting Hints
S Cap Switch Shutdown
In the event of failure of any S-Cap Switching FETs, the Microprocessor detects temperature of FETs (Q513 and Q514) by
TH501 and goes into shutdown mode. For these conditions, refer to the section of H Linearity Circuit.
Vertical Scan Shutdown
If the V FLY feedback at pin #19 the Microprocessor doesn't get pulse around 1.5 second, a Shutdown will be initiated.
Power Supply problems may also produce a similar type failure. For these conditions, refer to the V Deflection Circuit or
the Power Supply section.
Horizontal Scan Shutdown
If the H BLK feedback at pin #32 of the Microprocessor doesn't get pulse around 500mSec, Shutdown will be initiated.
Some power Supply problems may also produce a similar type failure. For these conditions, refer to the H Deflection
Circuit or Power Supply sections.
8. Vertical Deflection Circuit
Theory of Operation
The negative input of amplifier IC401 is driven by VSAW signal generated by Jungle IC902 pin #8. The positive input of the
amplifier is Vref Signal generated by IC701 (Convergence IC) pin #5. VSAW is centered on 5. 0V, and sawtooth waveform
that controls VSIZE. Vref is a reference that is compared to VSAW at IC401. VCENTER is controlled by the shift of VSAW.
IC401 serves as a transconductance amplifier (it amplifies a low level voltage into a high level current) for VSAW and the
DC difference between VSAW andVref. The current gnerated by IC401 is feed to the Vertical Deflection Coil.At the return
point of the Vertical Deflection Coil the current flows through R403 and R405 which generates a voltage across them which
is feed back to the amplifier via R404.
V FLY is generated by flyback pulse generated at pin 3 of IC401. If the flyback generation at IC401 does not work, then the

- 18 -
9
7
5
12V
ANODE OF CRT
10
12
11
FV2
14
15
FV1
16
13
HV
7
1
2
R534 C527
D509
180V
R527
D513
Q503
HV REG DRIVE
PIN # 18 IC501 R561
R530
R531
C526
T501
:FBT
Q510
HV OUT
R520
FB502
R574
D504
C578 D510 R532
C528
D520
D521
C577
G2 1ku
CN510
HV DET PIN # 18
IC901
D517
C544 R552
C542 R595 R547
300V
D515 R543
C540
R549
R510
C519
L502
L501
B+ CHOPPER HV
R597 R541 R568 IC501 PIN #12
"HV FEEDBACK"
C556
R540
RV501 C539
R544
C532
C534
CRT VIA
RED FV LEAD
H DF OUT
H&VDF OUT
CRT VIA
BLK FV
LEAD
SG501
R548 R550 R596
D514 C535
R546 C541 C928
ABL DET PIN #16
IC901
R934
D
BOARD
19 D99 CHASSIS HV/PROTECTOR CIRCUIT
R545 ABL DET PIN #1
S
S
HV DRIVE PIN # 19
IC501
6
R542

- 19 -
R406
R401 C402
C401
0
-15V
R404
C406
R405R403
0
RL LVDY
R402
V-
V++
-
62
0
+16V
3
5417
Flyback Generator
TDA8177
V-DY through CN501
IC401 C403 D401 C404
D-BOARD
8
VSAW
IC 902
(Jungle)
5
Vref
IC 701
(CONV)
C409 R409
R410
9
+15V

- 20 -
monitor goes to be shutdown as aV scan failure by microprocessor after wait around 1.5sec w/oVFLY.
TroubleshootingHints
Vertical Scan Failure
The first step is to check the shutdown log of the monitor and make sure the microprocessor has detected a loss of VFLY.
Once this has been verified the output of IC401 should be checked. If a normal output exists after the remote on/off bit is
turned on but the monitor still shuts down then the VFB detection circuit is malfunctioning. If no output exists signal
tracing should begin at IC902 pin #8 (VSAW) and IC701 pin 5 (Vref). In shutdown mode both of these levels should be
5.0V DC. If the remote on/off bit is turned on a sawtooth waveform of about 1Vpk-pk should appear on VSAWN while
DCC2 stays at 5.0V this should last about 1.5 seconds until a loss of VFLY is detected and the monitor shuts down again.
If the signals make it this far, the problem is likely in the IC401 area.
VIDEO "A" BOARD ELECTRICAL CIRCUIT
The Main function of the A Board is to receive incoming video signals and then process them into the RGB video drives
necessary for proper CRT biasing. The input signals (RGB, Separate & Composite Syncs and DDC) are received with the
conventional 15 D-sub connector. The RGB signals (0.7Vpp) are sent to the preamplifier (IC001) where they are amplified
with Contrast gain and Brightness offset. Next they are sent to the Video Driver for final amplication to drive the cathodes.
The Horizontal Sync pulse is buffered and then sent to the Microprocessor along with the Vertical Sync pulse. DDC is no
longer handled on the A Board. It passes through the A board directly to the micorprocessor.
IC003 is the On Screen Display (OSD) generator. OSD mixing is performed in IC001. Additional functionalities of the A
Board include processing of all the CRT cathodes operating voltages; heater, G2 control, cathode DC bias, and focus.
- Sync Timing Buffering.
- RGB video signal amplification and adjustment according to white balance requirements, contrast and
brightness settings.
- On Screen Display mixing.
- D/A conversion for RGB CRT cathode cutoff G2 levels control.
G2,Cutoff
OSD Generation
Video
Process
D/A Conv
CRT
J001
Heater and Focus Voltages
from D Board
Front Input
I
2
C Communication
V Sync and H fly
G2 Voltage
RGB Cathode Drv
Cuttoff
Voltage
D/A Level
17 D99 Chassis A
Board Block Diagram