Toshiba TP43H60 Service Training
Main power supply & complete shutdown guide
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Also See for TP43H60:
- Owner's manual (64 pages) ,
- Service manual (4 pages) ,
- Owner's manual (64 pages)
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TOSHIBA
Service Training
PROJECTION
TELEVISIONS
Main Power Supply
Shutdown Guide
TP43H60
TP43H95
TP50H15
TP50H50
TP50H60
TP50H64
TP50H95
TP55H60
Copyright 1999
TOSHIBA AMERICA CONSUMER PRODUCTS, INC.
NATIONAL SERVICE DIVISION
1420-B TOSHIBA DRIVE, LEBANON, TN 37087
& Complete
NTDMOD02
TP55H64
TP55H95
TP61H60
TZ43V61
TZ50V51
TZ50V61
TZ55V61
TZ61V61
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Table of Contents
Related Manuals for Toshiba TP43H60
Summary of Contents for Toshiba TP43H60
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Page 1: Main Power Supply
TELEVISIONS Main Power Supply & Complete Shutdown Guide TP43H60 TP55H64 TP43H95 TP55H95 TP50H15 TP61H60 TP50H50 TZ43V61 TP50H60 TZ50V51 TP50H64 TZ50V61 TP50H95 TZ55V61 TP55H60 TZ61V61 Copyright 1999 TOSHIBA AMERICA CONSUMER PRODUCTS, INC. NATIONAL SERVICE DIVISION 1420-B TOSHIBA DRIVE, LEBANON, TN 37087... -
Page 2: Table Of Contents
Contents Main Power Supply....3 Overall Block Diagram ..................4 Operation......................5 Surge Protection Relay ................... 6 Start-up and Over Voltage Protect ..............7 Logic and Drivers..................... 8 Oscillator ......................8 Oscillator Control ..................... 9 Latch ........................9 Thermal Shock Detection Block ..............9 Over Current Protection................. -
Page 3: Main Power Supply
Main Power Supply... -
Page 4: Overall Block Diagram
Overall Block Diagram When the relay closes, the AC line input is applied directly to the main power supply. The supply starts Figure 1 is the overall block diagram of the main to operate and turns ON the television. D801 is switching power supply and the standby power the full-wave bridge rectifier for the main power supply. -
Page 5: Operation
Operation rent, the oscillator frequency decreases and oper- ates closer to the LC resonant frequency. The closer The main power supply is a current resonant switch- the switching frequency is to resonance, the higher ing power supply. Figure 2 is a basic block dia- the current flow through the primary windings of gram for this supply. -
Page 6: Surge Protection Relay
R810 first. If R810 is open, replace it, voltages, one of these voltages is applied to the using Toshiba part number 24007061, and look for base of transistor Q846. This voltage turns Q846 cold solder joints around Q846 and R846. -
Page 7: Start-Up And Over Voltage Protect
Start-up and Over Voltage Protect The positive cycle of the AC line input supplies a 16V start-up pulse to pin 8 of Q801 via resistor R861. Figure 5 is the block diagram for this cir- cuit. After start-up, a drive circuit consisting of a secondary winding of T862, diode D864, and ca- pacitor C868 supply 16-20Vdc to pin 8 of Q801 to maintain its operation. -
Page 8: Logic And Drivers
Logic and Drivers Oscillator As shown in Figure 6, the logic block controls the Refer to Figure 7. Q801’s internal Oscillator de- MOSFETs’ switching frequency. The outputs of velops the power supply’s switching frequency by the logic block feed two drivers that are powered generating a ramp waveform internally. -
Page 9: Oscillator Control
Oscillator Control Latch If the load current drawn from the 125Vdc line in- The latch block stops the operation of Q801 until creases, the 125Vdc voltage begins to drop, de- the voltage on pin 1 of Q801 is removed by turn- creasing the current through Q862’s LED side. -
Page 10: Over Current Protection
Over Current Protection 165V from D801 Figure 10 is the schematic diagram for the over R872 current protection and soft start circuits. The over Q801 current detect (OC) senses excess current in the LC series resonant circuit. As current in the LC series resonant circuit increases, a voltage devel- Control ops at the over current protect (OC) terminal pin... -
Page 11: Additional Information On Q801
Additional Information on Q801 Caution: Different input signals may cause a variance in voltage readings. The Voltages and waveforms below were recorded while displaying a color bar signal. Block Diagram of Q801 (STR-Z4117) From R861 to VB DRI Vcc 15 VB DRI Vcc Q801 Start... -
Page 12: Waveforms
Waveforms Q801 Internal Oscillator 1.5Vpp Dead Time Internal Q801 Internal Q801 MOSFET (A) Internal Q801 MOSFET (B) Pin 14, Q801 160Vpp 140Vpp Across C870... -
Page 13: Troubleshooting Flowchart
Troubleshooting Flowchart Start Caution: Before removing or adding fuses, remove all power from the Open fuse F470. television and always use an Isolation transformer when troubleshooting. Does relay SR81 close when the Power button is pushed? Check R810 Check the relay drive, microprocessor and standby power supply circuits. - Page 14 Continued from the Caution: previous page. Before removing or adding fuses, remove all power from the television and always use an Isolation transformer when troubleshooting. With fuse F470 still open, check the voltage on the power supply side of F470 when the television is first turned on.
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Page 15: Shutdown Guide
Shutdown Guide... -
Page 16: Summary Of Shutdown Circuits
In this scenario, the blink- ing LED indicates that the problem is related to the Toshiba incorporates an elaborate shutdown cir- microprocessor’s serial clock and data lines. If the cuit in every projection television for customer relay doesn’t energize or remains closed and the... -
Page 17: Peak-Response Meter
Peak-Response Meter The second input to Z801 is an x-ray protect be- tween pins 11 and 13. Pin 11 is the reference volt- The main component in the shutdown circuit is age and pin 13 monitors a dc voltage developed by Z801. -
Page 18: No Peak-Response Meter
NOT an answer to all situations. Warning!! Toshiba does not recommend disconnecting the shutdown circuit for troubleshooting. Disconnect- ing the shutdown increases the possibility of a fail- ure damaging the television. -
Page 19: X-Ray Protect
However, this is very uncommon age is most likely the cause of the shutdown. An- with Toshiba televisions. other way the x-ray protect can trigger shutdown, is by a loss of the 25V reference on pin 11. This •... -
Page 20: 125V Over Current Protect
• The over current sensing resistor R470 can increase +125V Over Current Protect in value and cause a false shutdown. R470’s value Figure 4 shows the over current protect (OCP) for may increase only slightly and cause a shutdown con- the main 125V B+ line. -
Page 21: Over Current Protect
+36V Over Current Protect Troubleshooting Tips: Figure 5 is the circuit diagram for the +36 over • If excess current is pulled from the power supply, current protect. Resistor R7782 is the over current check the convergence output ICs (Q752 and sensing resistor. -
Page 22: And - 18V Over Current Protect
+18V and – 18V Over Current Protect The +18V and –18V over current protect operates in a similar fashion as the +36V over current pro- tect. Refer to Figures 6 and 7 for the circuit dia- grams. +18V R7750 Load R7749 R7751 Stand by... -
Page 23: Over Current Protect
+35V Over Current Protect Troubleshooting Tips: As outlined in Figure 8, +35V develops at the cath- The vertical output Q301 and the high voltage regu- ode of diode D302 during normal operation. That lation IC Q483 are located on the deflection PC voltage is a supply for the vertical output Q301, board. -
Page 24: Under Voltage Protect
+ 9V Under Voltage Protect +200V Under Voltage Protect Figure 8 also shows the +9V and +35V Under The flyback transformer T461 produces about 200V Voltage protect circuits. An under voltage protect at the cathode of D406 (not shown). A voltage (UVP) circuits monitors the +9V line which is regu- divider drops it to 6.8V and applies it to the base of lated from the 12V supply. -
Page 25: Troubleshooting Flowchart
Troubleshooting Flowchart Notes: Start Caution: This flow chart is to help isolate Before removing or adding the cause of shutdown. Refer fuses, remove all power from to the circuit explanations for the television and always use additional information. an Isolation transformer when troubleshooting.