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ORDER No. ETD: 96-304
Technical Information
Colour Television
Model:- TX-21S1T/B TX-21S1TL/B TC-21S1R/B TC-21S1RL/B TX-21S1T/BN TC-21S1R/BN
TC-21S1M/B TC-21S1R/BH TX-21S1T/BH
Date:- 23-11-96
Subject:- Horizontal Oscillations (Ringing).
Background:- Possibility of chopper transformer causing interference on 12V line causing the above
phenomenon.
Remedy:- Fit capacitor Part No. (ECKR1H102 ) across D856 on component side of P.C.B.
Method:- 1. Remove diode from PCB, position capacitor across diode body and solder to top
of diode legs.
2. Replace diode/capacitor in PCB checking polarity is correct.
3. Re-solder diode to PCB.
Warning:- Do not fit capacitor on copper side of PCB side as there is a possibility of capacitor
touching HOT SIDE of Power Supply.
Panasonic
Document No. QUA0011 Issue: 1
ORDER No. ETD: 96-283
Technical Information
Colour Television
Model:- TC-14S1R/BH TX-14S1T/BH
TC-14S2R/BH TX-14S2T/T
TC-14S1R/B TC-14S1T/B
TC-14S1M/B TC-21S1M/B
TC-21S1R/B TC-21S1R/BN
TC-21S1R/BH TC-21S1T/B
TX-21S1T/BN TX-21S1T/BH
Date:- 14-10-96
Subject:- Change of part types on E-PCB
Background:- The following change of parts on the E-PCB require them to be changed together.
Note:- Please refer to Parts Change Notice ETD:-96-284
14" Models
T551 R551 IC1205 JC43
OLD TLH15460M ERDS1TJ1R8 X24C0502A NIL
NEW ETH19Z169AZ ERDS1TJ1R5 X24C0503A ERJ6GEY0R00
When replacing OLD version F.B.T. with NEW version R551 must
be changed at the same time.
When replacing IC1205 with NEW version JC43 must also be changed.
21" Models
T551 R517 IC1205 JC43
OLD TLH154601M ERG3SJS101 X24C0502AC NIL
NEW ETH19Z169AZ ERG3SJS151 X24C0503AC ERJ6GEY0R00
When replacing OLD version F.B.T. with NEW version R517 must
be changed at the same time.
When replacing IC1205 with NEW version JC43 must also be changed.
Monitors 14"
T551 R551 IC1205 JC43
OLD TLH15460M ERDS1TJ1R8 X24C0501AK NIL
NEW ETH19Z169AZ ERDS1TJ1R5 X24C0502AK ERJ6GEY0R00
When replacing OLD version F.B.T. with NEW version R551 must
be changed at the same time.
When replacing IC1205 with NEW version JC43 must also be changed.
Monitors 21"
T551 R517 IC1205 JC43
OLD TLH15461M ERG3SJS101 X24C0501AK NIL
NEW ETH19Z169AZ ERG3SJS151 X24C0502AK ERJ6GEY0R00
When replacing OLD version F.B.T. with NEW version R517 must
be changed at the same time.
When replacing IC1205 with NEW version JC43 must also be changed.
Panasonic
Document No. QUA0011 Issue: 1
TechInfo Sheet fax: 01344 853689
Audio Visual email: [email protected]
Product Group: Colour Television Model: TX-21S1T
Date: 29/10/98 Revision No: 01 Document No: 07
Subject: Elusive Parts
Description Part Number
TV Stand Base Casting TZS9EW105
Cabinet Screws XTBT964Z
AV Terminal Cover TKK8E020
Panasonic CS U.K. Document No: 07
Model: TX-21S1T
1
TechInfo Sheet fax: 01344 853689
Audio Visual email: [email protected]
Product Group: ColourTelevision Model: TX-21S1T
Date: 19/10/98 Revision No: 01 Document No: 03
Subject: Power Supply Circuit Operation
1. Outline
Low power consumption (Use of small size power transformer) circuit. Both main power and remote
power are provided by one circuit.
2. Construction
The power supply circuit consists of:-
a) Full wave rectifier (D801, D802, D803, D804 and C807)
b) Switching transformer (T801)
c) Control IC (IC801)
d) Power ON/OFF control circuit (D813 and Q803)
e) Standby control circuit (D811, D812, C813, D817 and Q807)
f) Sub power supply circuit (D820, D806 and C818)
3. Operation
Standby
(1) AC voltage is passed to the bridge rectifier D801, D802, D803 and D804 where it is full wave
rectified and smoothed by C807.
Panasonic CS U.K. Document No: 03
Model: TX-21S1T
1
TechInfo Sheet fax: 01344 853689
Audio Visual email: [email protected]
Product Group: Colour Television Model: TX-21S1T
Date: 15/10/98 Revision No: 01 Document No: 02
Subject: Horizontal Oscillations
Models: TX-21S1T TC-21S1R TC-21S1M TC-21S1R/BH TX-21S1T/BH
Subject: Horizontal Oscillations (Ringing)
Background: Possibility of the chopper transformer causing interference on 12V line causing the above
phenomenon.
Remedy: Fit capacitor (part no ECKR1H102) across D856 on component side of P.C.B.
Method: 1. Remove diode from PCB, position capacitor across diode body and solder to top of diode
legs
2. Replace diode/capacitor in PCB checking polarity is correct.
3. Resolder diode to PCB.
Warning: Do not fit capacitor on copper side of PCB side as there is a possibility of the capacitor
touching the HOT SIDE of the power supply.
SECTION OF POWER SUPPLY SECONDARY
C855
L854
Q851
D852 D856
ADD
C856 D851 CAPACITOR
C851
S3 S1 S2 S4 NC
CHOPPER TRANSFORMER
Panasonic CS U.K. Document No: 02
Model: TX-21S1T
1
TechInfo Sheet fax: 01344 853689
Audio Visual email: [email protected]
Product Group: Colour Television Model: TX-21S1T
Date: 19/10/98 Revision No: 01 Document No: 06
Subject: Low Output from Power Supply
Symptom: Low output from power supply
Cause: Q803 breaking down under load
Remedy: Replace Q803 (2SD1272QLB)
Panasonic CS U.K. Document No: 06
Model: TX-21S1T
1
TechInfo Sheet fax: 01344 853689
Audio Visual email: [email protected]
Product Group: Colour Television Model: TX-21S1T
Date: 19/10/98 Revision No: 01 Document No: 04
Subject: Power Supply Tripping
Symptom: Power supply tripping
Remedy: Check to see if the coupler is o/c & replace R813, R821
Description Part No
PARTS: Opto coupler (if faulty) D813 PC120FY
Resistor R813 ERDS1TJ334
Resistor R821 ERDS1TJ334
Panasonic CS U.K. Document No: 04
Model: TX-21S1T
1
TechInfo Sheet fax: 01344 853689
Audio Visual email: [email protected]
(2) The DC voltage produced by this (approx 300V) is passed to pin 3 of IC801 through the primary
windings of T801 (P1 - P2).
(3) The startup supply current is fed via R818, R802, L804 to pin 2 of IC801, the internal circuit of the
IC shows that this will cause Q1 to switch on and collector current (Ic) will flow.
(4) DC voltage is also applied to base of Q803 via R813 and R821 and causes Q803 to switch on. This
is because during standby mode the power ON/OFF voltage from the microprocessor (IC1202) is low
and photo-transistor in D813 is off.
(5) With Q803 turned on Ic flows to ground via D810 and R812 so that voltage at pin 4 of IC801 (+B4)
becomes approx. +1V. (Q1 operates as an A class amplifier and the level Ic is very small).
(6) The rising Ic through the primary windings P1-P2 of T801 will induce a feedback voltage via
windings B1-B2. This negative feedback voltage charges C813 via D811 and R809. However,
because the positive pin of C813 is conected to the +B2 line (approx. 1 volt) the voltage
of the negative pin falls to approx. -2V.
(7) Folowing this Q804 turns on and the voltage between the anode and the cathode of D817 becomes
3V causing D817 to turn on (Anode: -2V, Cathode +1V).
(8) D817 and Q2 inside IC801 control the base current of Q2 to prevent Q2 having full drive applied.
Therefore the voltage at pin 4 of IC801 is kept to a constant level of approx. 2V.
Panasonic CS U.K. Document No: 03
Model: TX-21S1T
2
TechInfo Sheet fax: 01344 853689
Audio Visual email: [email protected]
(9) In addition to this, the voltage induced at windings B1-B2 of T801 is also applied to the base of Q1
as a trigger via D816, R803, L804 and pin 2 of IC801.
(10) Q1 amplifies this trigger voltage and outputs from its collector a phase inverted signal.
Because of this amplification, the Ic changes and so the induced voltage at the secondary
windings will also change. This change is fed to the base of Q1.
(11) Therefore this circuits operates as an oscillator.
Note
Q2 in IC801 does not operate during standby mode.
(12) The induced voltages at S2, S4-S1 of T801 are rectified by D851 and D856 and the +B4 supply
(approx. 8.5V) is created.
(13) +B4 is passed to IC851 and this creates the +B10(5V) line which is used to supply the
microprocessor (IC1202) and its peripheral circuitry.
(14) However, with he power ON/OFF output from pin 24 of Ic1202 low, then Q1203, Q853 and Q851
are turned off and the +B9 supply line is not available.
Power On
Panasonic CS U.K. Document No: 03
Model: TX-21S1T
3
TechInfo Sheet fax: 01344 853689
Audio Visual email: [email protected]
(1) When power is on, pin 24 of IC1202 goes high. This high is applied to pin 1 of D813 via
buffer transistor Q1203.
(2) With Q1203 on then pin 4 of D813 (the opto isolator) goes low, and Q803 is turned off.
(3) The voltage at the gate of D820 becomes high (because Q803 is cut off) and D820 turns on.
(4) With Q803 turned off the voltage supplied from R810 and R819 passes via R811 and charges
C814 and the +B2 voltage increases.
(5) C818 is charged during standby mode to approximately 90 volts and this is supplied to +B2
line via D820.
At the same time, the +B9 (+8V) also appears because Q851 is turned on by the power on
high from pin 24 of the microprocessor which is applied to the base of Q851 via Q1203 and
Q853.
(6) With these supply lines available, IC601 and the horizontal output circuits operate. With
the horizontal output stage operating, a horizontal pulse (H-pulse) is fed from pin E54 of
the flyback transformer (FBT) via R806 and D809 to pin 2 of IC801.
Panasonic CS U.K. Document No: 03
Model: TX-21S1T
4
TechInfo Sheet fax: 01344 853689
Audio Visual email: [email protected]
(7) This pulse causes Q804 to turn off because the +B2 line rises to a voltage higher than the
voltage potential of C813, and the voltage at the negative pin of C813 becomes positive.
Because of this positive voltage, the emitter voltage of Q804 becomes higher than the
base voltage and Q2 in IC801 is also turned off.
(8) However, Q1 base voltage is kept below 0.6V of its emitter voltage by D808. This means
Q1 turns off.
(9) When the H-pulse from the FBT enters the base of Q1 then Q1 turns on fully and Ic
increases.
(10) Q1 base voltage is kept higher than its emitter voltage by the voltage induced from B1-B2
which is passed via D816 and R803.
(11) When the Ic saturates, the B1-B2 induced voltage disappears and Q1 turns off.
(12) When the H- pulse is applied to Q1 base again Q1 turns on. At this point the cycle starts
again. This ensures that the switching frequency of the power supply is synchronised with
the horizontal output frequency.
(13) When Q1 is turned off, C814 is charged by the current from F2-F1 winding via D806 and
D820. By doing this, the efficiency of this switching circuit is improved.
(14) In this way, the +B2 supply is generated with control being provided by the error correction
circuit in IC801 which consists of Q3, D1, R1 and R2.
This circuit is used in both 14 inch and 21 inch models with the +B2 supply stabilised to
+103 volts for 14 inch models and +124 volts for the 21 inch models.
N.B. IC801: 21 inch models use STR51224-M for 124V
14 inch models use STR51203-M for 103V
Panasonic CS U.K. Document No: 03
Model: TX-21S1T
5
TechInfo Sheet fax: 01344 853689
Audio Visual email: [email protected]
The previous pages are a synopsis of the circuit explanation for the Z5 chassis. A complete explanation
of these circuits may be obtained by ordering the technical guide from our Spares Department.
PART NUMBER .Z5 TECH GUIDE
SPARES TEL NO. 01344 860133
Panasonic CS U.K. Document No: 03
Model: TX-21S1T
6
TechInfo Sheet fax: 01344 853689
Audio Visual email: [email protected]
Product Group: Colour Television Model: TX-14S1T
Date: 19/05/99 Revision No: 01 Document No: 05
Subject: Elusive Parts
Description Part Number
TV Stand Base Casting TZS9EW105
Cabinet Screws XTBT964Z
Panasonic CS U.K. Document No: 05
Model: TX-14S1T
1
TechInfo Sheet fax: 01344 853689
Audio Visual email: [email protected]
Product Group: ColourTelevision Model: TC-21S1R
Date: 19/10/98 Revision No: 01 Document No: 03
Subject: Power Supply Circuit Operation
1. Outline
Low power consumption (Use of small size power transformer) circuit. Both main power and remote
power are provided by one circuit.
2. Construction
The power supply circuit consists of:-
a) Full wave rectifier (D801, D802, D803, D804 and C807)
b) Switching transformer (T801)
c) Control IC (IC801)
d) Power ON/OFF control circuit (D813 and Q803)
e) Standby control circuit (D811, D812, C813, D817 and Q807)
f) Sub power supply circuit (D820, D806 and C818)
3. Operation
Standby
(1) AC voltage is passed to the bridge rectifier D801, D802, D803 and D804 where it is full wave
rectified and smoothed by C807.
Panasonic CS U.K. Document No: 03
Model: TC-21S1R
1
TechInfo Sheet fax: 01344 853689
Audio Visual email: [email protected]
Product Group: Colour Television Model: TC-21S1R
Date: 19/10/98 Revision No: 01 Document No: 04
Subject: Power Supply Tripping
Symptom: Power supply tripping
Remedy: Check to see if the coupler is o/c & replace R813, R821
Description Part No
Parts: Opto coupler (if faulty) D813 PC120FY
Resistor R813 ERDS1TJ334
Resistor R821 ERDS1TJ334
Panasonic CS U.K. Document No: 04
Model: TC-21S1R
1
TechInfo Sheet fax: 01344 853689
Audio Visual email: [email protected]
Product Group: Colour Television Model: TC-21S1R
Date: 29/10/98 Revision No: 01 Document No: 05
Subject: Elusive Parts
Description Part Number
TV Stand Base Casting TZS9EW105
Cabinet Screws XTBT964Z
AV Terminal Cover TKK8E020
Panasonic CS U.K. Document No: 05
Model: TC-21S1R
1
TechInfo Sheet fax: 01344 853689
Audio Visual email: [email protected]
Product Group: Colour Television Model: TC-21S1R
Date: 15/10/98 Revision No: 01 Document No: 02
Subject: Horizontal Oscillations
Models: TX-21S1T TC-21S1R TC-21S1M TC-21S1R/BH TX-21S1T/BH
Subject: Horizontal Oscillations (Ringing)
Background: Possibility of the chopper transformer causing interference on 12V line causing the above
phenomenon.
Remedy: Fit capacitor (part no ECKR1H102) across D856 on component side of P.C.B.
Method: 1. Remove diode from PCB, position capacitor across diode body and solder to top of diode
legs
2. Replace diode/capacitor in PCB checking polarity is correct.
3. Resolder diode to PCB.
Warning: Do not fit capacitor on copper side of PCB side as there is a possibility of the capacitor
touching the HOT SIDE of the power supply.
SECTION OF POWER SUPPLY SECONDARY
C855
L854
Q851
D852 D856
ADD
C856 D851 CAPACITOR
C851
S3 S1 S2 S4 NC
CHOPPER TRANSFORMER
Panasonic CS U.K. Document No: 02
Model: TC-21S1R
1
TechInfo Sheet fax: 01344 853689
Audio Visual email: [email protected]
Product Group: Colour Television Model: TC-21S1R
Date: 29/09/98 Revision No: 01 Document No: 01
Subject: Faulty Display
When switched on, some of the above receivers display C.H.K.
In order to cancel this, the following procedure must be followed:
C.H.K. Z5 CHASSIS
1. Press the F button on your television so the volume control shows.
2. Press the volume down button on the TV and the timer off button on the remote control
simultaneously. The screen should go to self check mode.
3. Switch the TV off then on again to confirm C.H.K. is gone.
Panasonic CS U.K. Document No: 01
Model: TC-21S1R
1
TechInfo Sheet fax: 01344 853689
Audio Visual email: [email protected]
(2) The DC voltage produced by this (approx 300V) is passed to pin 3 of IC801 through the primary
windings of T801 (P1 - P2).
(3) The startup supply current is fed via R818, R802, L804 to pin 2 of IC801, the internal circuit of the
IC shows that this will cause Q1 to switch on and collector current (Ic) will flow.
(4) DC voltage is also applied to base of Q803 via R813 and R821 and causes Q803 to switch on. This
is because during standby mode the power ON/OFF voltage from the microprocessor (IC1202) is low
and photo-transistor in D813 is off.
(5) With Q803 turned on Ic flows to ground via D810 and R812 so that voltage at pin 4 of IC801 (+B4)
becomes approx. +1V. (Q1 operates as an A class amplifier and the level Ic is very small).
(6) The rising Ic through the primary windings P1-P2 of T801 will induce a feedback voltage via
windings B1-B2. This negative feedback voltage charges C813 via D811 and R809. However,
because the positive pin of C813 is conected to the +B2 line (approx. 1 volt) the voltage
of the negative pin falls to approx. -2V.
(7) Folowing this Q804 turns on and the voltage between the anode and the cathode of D817 becomes
3V causing D817 to turn on (Anode: -2V, Cathode +1V).
(8) D817 and Q2 inside IC801 control the base current of Q2 to prevent Q2 having full drive applied.
Therefore the voltage at pin 4 of IC801 is kept to a constant level of approx. 2V.
Panasonic CS U.K. Document No: 03
Model: TC-21S1R
2
TechInfo Sheet fax: 01344 853689
Audio Visual email: [email protected]
(9) In addition to this, the voltage induced at windings B1-B2 of T801 is also applied to the base of Q1
as a trigger via D816, R803, L804 and pin 2 of IC801.
(10) Q1 amplifies this trigger voltage and outputs from its collector a phase inverted signal.
Because of this amplification, the Ic changes and so the induced voltage at the secondary
windings will also change. This change is fed to the base of Q1.
(11) Therefore this circuits operates as an oscillator.
Note
Q2 in IC801 does not operate during standby mode.
(12) The induced voltages at S2, S4-S1 of T801 are rectified by D851 and D856 and the +B4 supply
(approx. 8.5V) is created.
(13) +B4 is passed to IC851 and this creates the +B10(5V) line which is used to supply the
microprocessor (IC1202) and its peripheral circuitry.
(14) However, with he power ON/OFF output from pin 24 of Ic1202 low, then Q1203, Q853 and Q851
are turned off and the +B9 supply line is not available.
Power On
Panasonic CS U.K. Document No: 03
Model: TC-21S1R
3
TechInfo Sheet fax: 01344 853689
Audio Visual email: [email protected]
(1) When power is on, pin 24 of IC1202 goes high. This high is applied to pin 1 of D813 via
buffer transistor Q1203.
(2) With Q1203 on then pin 4 of D813 (the opto isolator) goes low, and Q803 is turned off.
(3) The voltage at the gate of D820 becomes high (because Q803 is cut off) and D820 turns on.
(4) With Q803 turned off the voltage supplied from R810 and R819 passes via R811 and charges
C814 and the +B2 voltage increases.
(5) C818 is charged during standby mode to approximately 90 volts and this is supplied to +B2
line via D820.
At the same time, the +B9 (+8V) also appears because Q851 is turned on by the power on
high from pin 24 of the microprocessor which is applied to the base of Q851 via Q1203 and
Q853.
(6) With these supply lines available, IC601 and the horizontal output circuits operate. With
the horizontal output stage operating, a horizontal pulse (H-pulse) is fed from pin E54 of
the flyback transformer (FBT) via R806 and D809 to pin 2 of IC801.
Panasonic CS U.K. Document No: 03
Model: TC-21S1R
4
TechInfo Sheet fax: 01344 853689
Audio Visual email: [email protected]
(7) This pulse causes Q804 to turn off because the +B2 line rises to a voltage higher than the
voltage potential of C813, and the voltage at the negative pin of C813 becomes positive.
Because of this positive voltage, the emitter voltage of Q804 becomes higher than the
base voltage and Q2 in IC801 is also turned off.
(8) However, Q1 base voltage is kept below 0.6V of its emitter voltage by D808. This means
Q1 turns off.
(9) When the H-pulse from the FBT enters the base of Q1 then Q1 turns on fully and Ic
increases.
(10) Q1 base voltage is kept higher than its emitter voltage by the voltage induced from B1-B2
which is passed via D816 and R803.
(11) When the Ic saturates, the B1-B2 induced voltage disappears and Q1 turns off.
(12) When the H- pulse is applied to Q1 base again Q1 turns on. At this point the cycle starts
again. This ensures that the switching frequency of the power supply is synchronised with
the horizontal output frequency.
(13) When Q1 is turned off, C814 is charged by the current from F2-F1 winding via D806 and
D820. By doing this, the efficiency of this switching circuit is improved.
(14) In this way, the +B2 supply is generated with control being provided by the error correction
circuit in IC801 which consists of Q3, D1, R1 and R2.
This circuit is used in both 14 inch and 21 inch models with the +B2 supply stabilised to
+103 volts for 14 inch models and +124 volts for the 21 inch models.
N.B. IC801: 21 inch models use STR51224-M for 124V
14 inch models use STR51203-M for 103V
Panasonic CS U.K. Document No: 03
Model: TC-21S1R
5
TechInfo Sheet fax: 01344 853689
Audio Visual email: [email protected]
The previous pages are a synopsis of the circuit explanation for the Z5 chassis. A complete explanation
of these circuits may be obtained by ordering the technical guide from our Spares Department.
PART NUMBER .Z5 TECH GUIDE
SPARES TEL NO. 01344 860133
Panasonic CS U.K. Document No: 03
Model: TC-21S1R
6