Hisense plasma TPW4218P power board principle and maintenance (Samsung V3 screen power supply) - android - Phones Developers

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Since the launch of the TPW4218P series plasma TV in 2005, Hisense has conquered a large number of customers with its excellent image and sound. The society is very large. As time goes by, the series gradually enters the maintenance period. The motherboard and AV board on the plasma TV are familiar because they are often in contact, so I won't introduce them here. The following mainly introduces the working principle of the Samsung V3 screen plasma power supply for this series of models and the troubleshooting of common faults.

1. Incoming line anti-interference circuit and VSB (standby 5V) voltage forming circuit

After entering the socket CN8001, the AC220V enters the overvoltage protection circuit composed of SA8001, R8005, C8004, C8096, L8002, RA8001, R8004, C8003, C8008, C8006 and the anti-interference circuit of the pre-stage line through F8001. The AC voltage after filtering out the interference signal is divided into two paths, one is sent to the next-stage anti-interference circuit composed of L8003 and other components, and the other is rectified and filtered by F8002, D8007, C8017 to form an unstable 300V DC voltage. This voltage is applied to the 5 pin of IC8003 (TOP223PN) via the 2/1 winding of T8001. IC8003 enters the working state. The VSB (+5V) voltage is formed from the secondary winding rectification filter (D8014, C8018) of the T8001 to supply power to the motherboard CPU. After the voltage is also isolated by D8015, the F/B-VCC voltage is generated to supply power to the voltage regulator of the subsequent stage circuit. At the same time, the VSB voltage is lit by R8035 (LED). The signal induced by the other set of windings of T8001 is rectified and filtered by D8006 and C8016 to form a voltage of 18V applied to the emitter of Q8012, and Q8012 is in the off state.

Second, the logic board requires 5V and 3.3V voltage generation

When we issue the second power-on command, the RELAY signal changes from high level to low level. At this time, Q8009 turns on, Q8013 turns on with saturation, and the collector of Q8013 goes low. All the way to the HIC8002 as a PS-ON detection signal. The other way is isolated by the iris (IC8005). After R8058, the base of Q8012 is turned to low level, Q8012 is saturated to pass, and the controlled 18V voltage is output. This voltage is regulated by IC8009 (7815A) to generate 15V PFC-VCC voltage to supply power to PFC diaphragm HIC8001. The other way to the Q8010's emitter is pending. At the same time, the Q8013 collector voltage is reduced, and the Q8004 and Q8006 are saturated, the relay RLY8001 is connected, and the LED8002 is lit (green). AC220V is sent to D8003 through C8006, C8007, L8003, RLY8001, R8009, R8010, C8001, C8009, L8004, C8002, C8010, C8005 secondary and tertiary incoming anti-interference circuit, and gets 100H2 pulsating DC power to PFC. Circuit. At this time, the detection signals are supplied to the PFC film block HIC8001 through R8037, R8038, R8039, and R8044 and R8045. The PFC circuit starts to work and outputs the PFC-OK signal and the RELAY-ON signal. The PFC-OK signal turns on the Q8010, generates a controlled DC-VCC signal to power the circuit on the sub-power board and the main power board, and then generates a VCC-S voltage of 17V through the Q8011, which is the switch of the VS part and the VA part. Integrated circuit power supply. After the RELAY-ON signal is isolated by the optical IC8002, the Q8005 and Q8008 are saturated and turned on, the RLY8002 is pulled in, and the R8009 and R8010 are short-circuited, which reduces the power consumption of the whole machine. At the same time, LED8001 is illuminated. The PFC circuit is fully operational. A PFC voltage of about 400V is output.

The PFC voltage is divided into three ways, one way is sent to the sub-power board through the socket CN8009 to generate a tuning voltage of 32V and a sound power amplifier voltage of 12V. The second PFC voltage is applied to the drain of Q8016 via F8003. The third PFC voltage is applied to the 1/pin of IC8023 via F8003 and the 16/11 winding of T8005. At this time, the VCC-S voltage generated by Q8011 is also applied to pin 3 of IC8023. The IC8023 enters a normal working state. The secondary winding of T8005 is rectified by D8040, and C8059 is filtered to generate 70V VA voltage. Used for powering the X board. The other path is rectified and filtered by D8042 and C8063 and divided into three paths. A VCC voltage of 15V is generated after passing through the regulator block IC8022. The second path (IC8024) DC/DC conversion produces a 3.3V D3V3 voltage. The third path (IC8026) DC/DC conversion produces a 5V D5VL voltage. D3V3 and D5VL are mainly used to power the logic board and supply small signals to other boards.

Third, the generation of other voltages of the whole machine

After the logic board is powered by D3V3 and D5VL, the internal CPU enters the working state and sends corresponding signals to the Y driver board, the maintenance board, and the X board. At this time, the indicator LED2000 on the logic board flashes. At the same time, return a high level (3.3V) VS-ON signal to the power board. The high-level VS-ON signal saturates the Q8023. The isolation of the optical IC8017 causes the 4 pin of the HIC8003 to go low, and the HIC8003 enters the working state. The forward drive signal is output from pin 15 to put Q8019, Q8020, and Q8016 into operation. The negative driving signal is output from the 9-pin to make the Q8021, Q8022, and Q8018 enter the normal working state. At this time, the resonant switch circuit composed of Q8016, Q8018, C8031, and T8002 works normally. The secondary winding is filtered by D8021, D8022, D8029, D8030 bridge rectifier and HIC8004, L8005, C8032, C8033 to generate a VS voltage of 160V-185V, which supplies power to the Y driver board of the plasma screen. At the same time, the VS voltage is divided into three ways.
All the way to F8004 to the 5 feet of T8003, after the internal winding of T8003, output from pin 3 to pin 2 of IC8012, the starting voltage is filtered by R8094, C8041, C8042 and added to pin 3 of IC8012. The switching power supply consisting of IC8012 and T8003 works normally. From the secondary D8023, C8034 rectification and filtering to get the VSET voltage of 135-165V. The other way is rectified by D8032, C8037 is filtered, and D8033 is isolated to form F/B-VCC voltage.

The second pass is added to the 2/3 pin of IC8019 via the 6/3 winding of F8004|T8004. The startup voltage is filtered by RC8116, C8057, C8054 and added to pin 3 of IC8019. After the secondary D8034, C8052 negative rectification and filtering, the VSCAN voltage of -70V is obtained. The other channel is rectified and filtered by D8039 and C8055 to supply power to the voltage regulator circuit.

The third path is applied to the 1/pin of IC8027 via the 5/3 windings of F8005 and T8006. The startup voltage is filtered by R8131, C8075, C8076 and added to pin 3 of IC8027. The switching power supply consisting of IC8027 and T8006 enters the normal working state. The secondary D8044, C8071 rectified and filtered to obtain a VE voltage of 125V-155V to supply power to the sustaining board. The other way is rectified and filtered by D8049 and C8077 to supply voltage to the voltage regulator.

Fourth, the whole machine voltage regulator circuit

The voltage regulator circuit of this machine is relatively simple. It is sampled by the resistor and sent to the control pin of the precision voltage regulator TL431. Then, the polarization information of the secondary circuit is sent to the power supply adjustment pin of the switching power supply through the isolation of the diaphragm. Thereby controlling the output of the secondary voltage, a stable output of the secondary voltage is achieved. For example, the VSB voltage regulator part: After the D8014 and C8018 rectified and filtered, the VSB voltage is added to the voltage regulator circuit in two ways, and the diode inside the R8049 and the optical IC8004 is applied to the regulated output pin of the IC8006 (TL431). The other way is divided by R8055, R8061/VR8002, and then added to the control pin of IC8006 via R8060. When VSB falls: (VSB↓) → [IC8006 (TL431) control pin] → [IC8006 (TL431) regulated output ↑] → [Optical third pedal] → [IC8003 (TOP223PN) 4 Ankle] → The duty cycle of the IC8003 internal output ↑ → VSB↑. When the VSB voltage rises: VSB ↑ → [IC8006 (TL431) control pin] → [IC8006 (TL431) regulated output ↓] → [Optical third pedal] → [IC8003 (TOP223PN) 4 Ankle] → IC8003 internal output duty cycle ↓ → VSB ↓. This achieves the regulation of VSB. The other part is the TL431 plus light, but the controlled IC is not the same, here is not analyzed one by one.

Fifth, the protection circuit

The protection circuit of this machine is mainly used by HIC8002. The output voltage of each group will be sent to HIC8002 for detection, when one of them is not normal. HIC8002's 1 pin FA1L1 will output a high level to make the thyristor Q8017 saturated, LED8004 (red) is lit, after the isolation of the optical IC8017, the base voltage of Q8006 is 0V, Q8006 is cut off. The RLY8001 trips open, causing the PFC power supply of the latter stage to be disconnected. Subsequent circuits of the PFC are all stopped. At the same time, the 27 pin of the HIC8002 also outputs a low-level PANEL-POWER signal to turn off the Q8015, and the Q8011 is turned off by the isolation of the optical IC8018. Disconnect power to the VS and VA part of the switching power supply IC. The switching power supply integrated circuits of the VA and VS sections are taken out of operation.

When the overcurrent of a certain channel causes the stability of Q8001 and Q8002 to rise, after the abnormal temperature is detected by the TC8001 on the same heat sink, Q8024 is cut off by the isolation of the optical IC8018, and the collector of Q8024 becomes high. Ping, the "K" pole of Q8017 becomes high level through the isolation of D8035, and the thyristor Q8017 is turned on. As before, LED8004 lights up and the whole machine enters the protection state.

As we all know, the timing of the supply of voltage to the plasma screen is very strict, and the order in which each voltage is established is strictly required. But this can be ignored for maintenance. We only need to know what conditions are generated by each voltage. For Samsung V3 screen power supply, we only need to look at the indicator light on the power board and the indicator light on the logic board to determine which voltage forming circuit has a problem: after plugging in the power, LED8003 will point. bright. If it is not lit, it indicates that there is a problem with the power supply of the whole machine or the VSB forming circuit. After the power-on command is issued, LED 8002 lights up. If it is not lit, directly check whether the RELAY signal is normally sent to the motherboard. Followed by LED8001 lit. If it is not lit, check if the AC220 is sent to the PFC circuit or the PFC circuit is working properly. When LED8001 is lit, the indicator LED2000 on the logic board will follow the flash. If it is not lit, it indicates that D5VL and D3V3 are bad. After the LED2000 is lit, the voltage of each group of the power board should be output normally. If it is not normal, check the VS voltage forming circuit and the VSET, VSCAN, and VE voltage forming circuits. In order to facilitate the repair and maintenance of the board. This power supply provides multiple sets of short-circuitable sockets to simulate or disconnect a portion of the circuit. Such as: J8005, when it is shorted, it can simulate the motherboard to send back the power-on signal. J8004, when it is disconnected, the protection detected by TV8001 can be released. J8003, when it is disconnected, the PANEL-POWER protection starts and the whole machine enters the protection state. J8002, when shorted it, can simulate the VS-ON signal returned after the logic board is working properly. J8001, after disconnecting it, it disconnects the power supply of PFC and subsequent circuits, and it is convenient to judge whether the VSB part or the PFC part circuit is short-circuited. In order to make it easy for everyone to repair. Attached to the measured voltmeter of each major IC.

Measured data:


1, TPW4218P plasma color TV after the second boot, no light, after a while to protect the shutdown.

After disassembling, it was found that the machine is a Samsung plasma V3 screen. In order to judge the fault location, first check the plasma screen, the result is no light, the screen should be a uniform white grating during normal self-test. The description is that the plasma screen assembly is defective. At the time of self-test, it was found that LED8001, LED8002, and LED8003 were all lit. There is no voltage for measuring VS, VSCAN, VSET, VE, etc. The indicator light on the visual logic board is on and off after a while. The logic board is also working. The VS-ON control signal sent by the logic board is normal. The output voltage of the power board should be normal. When VA is measured, it is found that the voltage is more than 90V when it is energized, and gradually drops to OV after burning, and the voltage should be 70V when it is normal. The VA circuit is poorly regulated. Looking closely at the circuit, it is found that the VA voltage regulator is composed of a diaphragm IC8025 and a three-terminal precision voltage regulator block (IC8029) TL431 and peripheral resistors R8129, R8133, R8134, R8135R8138, R8142 and capacitors C8074, C8079, C8070. The R8134 has a voltage that is sent from the VA section. The positive terminal voltage of the photodiode is -0.24V. According to the normal circuit, this should be a positive voltage. It is estimated that this is not normal. Check the resistor R8129 supplied to the diaphragm for no positive voltage at both ends. Explain that there is a problem with the F/B-VCC forming circuit. After inspection, R8129 is connected to VSB (+5V) which is rectified by D8014 through D8015, and the indicator of the power of this unit is lit, indicating that VSB has voltage. The VSB was measured to be 5.2V. Guess is good. The negative end of D8015 is not short-circuited to the ground. In the road detection D8015 open circuit, after replacing with a new IN4148, the fault is eliminated.

2, TPW4218P plasma color TV after the second boot, no light, after a while to protect the shutdown

After disassembling, it was found that the machine is a Samsung plasma V3 screen. In order to judge the fault location, first check the plasma screen, the result is dim with purple grating, the screen should be a uniform white grating during normal self-test. The description is that the plasma screen assembly is defective, and has nothing to do with the motherboard and the AV board. Suspected that the power board or the maintenance board is defective. At the time of self-test, LED8001, LED8002, and LED8003 are all lit, and LED2000 on the logic board is also blinking. VS, VSC, etc. are measured normally, and VE voltage is 0V, VE voltage is not normal, VE is shorted to ground in the road detection, CN8002 socket is removed, the VE load on the board is not shorted to the ground, and the VE on the power board Short-circuit to the ground, carefully look for the components on the VE, only D8044 and C8071 (resistance generally does not cause a short circuit) may cause a short circuit, after disconnecting C8071 or short circuit, indicating that D8044 is damaged, replace it with a new RU3C after troubleshooting.

3, TPW4218P [Samsung V3] screen plasma color TV indicator light, after the second boot, the light turns yellow and the whole machine is dull. After a while, the protection stops.

Disassemble the machine and observe that the indicator LED8003 is lit. After the second boot, LED8002 and LED8001 are lit, and the relay has a sound. But the screen is not bright, after a while the red LED8004 lights up, the whole machine protection stops. In order to facilitate the maintenance, the self-checking machine determines that the components on the screen are defective. The voltage supply timing of the machine is as follows: After the power is plugged in, the switch circuit composed of T8001 on the power supply board works, VSB (+5V) is generated, the working voltage is supplied to the CPU on the main board, the CPU enters the working state, and the standby command is issued. At the same time, the green LED 8003 lights up. When we issue the power-on command, the CPU sends a low-level RELAY signal to the power board. At this time, the relay RLY8001 and RLY8002 pull in, the L8001 and the PFC circuit composed of the peripheral circuit work, and the PFC boost is about 400V. The voltage, at the same time, the green indicator LED8002 and LED8001 are lit one after the other. The switching circuit composed of T8005, IC8023 and peripheral circuits generates VA (+70V) voltage, VCC (+15V), D3V3 (3.3V) and D5VL (+5V). Among them, D3V3 and D5VL are sent to the logic board, the circuit on the logic board enters the working state, (at this time LED2000 will flash) sends a logic normal VS-ON (high level) signal to the power board. The VS-ON signal causes the VS voltage generating circuit composed of the T8002 and the peripheral circuit to enter the working state, and outputs an adjustable VS voltage of 160V~185V, and the voltage forms a VSE voltage through the T8003 and the peripheral circuit, and the voltage forms a VSC voltage through the T8004 and the peripheral circuit. This voltage forms a VE voltage via T8006 and peripheral circuits. The generated voltages are sent to the various components on the screen, and the components on the screen are electrically operated, so that the plasma screen is illuminated. If any of the voltages generated above are abnormal or overcurrent and are detected by the CPU on the power board, the CPU will issue an instruction to put the power into standby mode and illuminate the red LED 8004.

After the machine is turned on twice, the relay has a sound of suction, and LED8001/LED8002 lights up, indicating that the motherboard has been working normally and a power-on command is issued. The indicator LED2000 on the observation logic board is not lit, indicating that the logic board does not get the working voltage or the operation is not normal. Test the D3V3 at F2000, which is normal. The D5VL at F2001 was measured, 1.34V, which was abnormal. Disconnect the logic board power supply connector and measure the voltage of the D5VL test point on the power supply board to 1.34V. It is still abnormal. Check the ground resistance and there is no abnormality. The D5VL DC/DC converter IC8026 has 1 foot of 17.5V, which indicates that the front stage power supply has arrived and should be normal. Debug the VR8009 adjustable resistor, the voltage gradually drops from 4.2V to 1.34V when starting up. Abnormal, check external resistors R8143, R8145 and D8050, C8099, etc. No abnormalities. After replacing IC8026 (LM2576T-ADJ), D5VL voltage output is normal, VE, VSE and other voltages are also generated normally, and all lines are connected and restored to normal state. The whole machine returned to normal. (D5VL and D3V3 are both generated with LM2576T-ADJ, the only difference is that its external resistance is not the same)

4, TPW4218P [Samsung V3 screen] plasma color TV indicator is not bright, three no.

The indicator light is off, indicating that the motherboard is not receiving power or the CPU on the motherboard is not working properly. Unpack the rear cover and find that the indicator LED8003 is not lit, indicating that the power supply is poor or the power supply is overloaded. Disconnect the power supply to the motherboard. Still not bright, indicating that there is a problem with the VSB voltage forming circuit. With the previous experience of repairing, we are much easier to fix. First check the fuse F8001 is good, visually found that the capacitor C8017 has a bulging phenomenon. The C8017 is just the filter capacitor of the primary part of the VSB voltage forming circuit. The test fuse F8002 is open circuit, the rectifier bridge stack D8007 is intact, and the drive block IC8003 has no abnormality in the road resistance. After replacing C8017 (450V/33UF0 and F87002 (1A), it is still not bad. After replacing IC8003 (TOP223PN), the fault is eliminated.

5, TPW4211PH [Samsung V3 screen] plasma color TV indicator light, after the second boot, can not hear the relay sound.

The indicator light is on, indicating that the motherboard has been powered. The fault may be caused by poor operation of the motherboard. The power-on test RELAY signal can change from high level to low level, indicating that the motherboard CPU has been working normally. To determine whether the motherboard's RELAY signal is sent to the main power board, directly short J8005, turn on the visual indicator LED8002/LED8001 or not Bright, indicating that RELAY has been normally generated, but it does not normally control the pull-in of relays RLY8001 and RLY8002. The fault should be on the circuit composed of Q8009/Q8013/Q8004/Q8006/Q8005/Q8008. Check the triode in the road. It was found that Q8009 was not normal. Remove the Q8009 (KTN2907A) test and found that B/C is extremely unreachable. After replacing with a good triode, LED8002 and LED8001 will be lit after power on, and the whole machine will return to normal.

6, after the TPW4218P plasma TV is turned on, the indicator light is off and the screen is blank.

After disassembling, it was found that the machine is a Samsung plasma V3 screen. In order to judge the fault location, first check the plasma screen, the result is no light, the screen should be a uniform white grating during normal self-test. The description is that the plasma screen assembly is defective. LED8003 does not light when the screen is self-testing. The description is that the switching power supply consisting of T8001 and IC8003 is defective. The F8002 (250V/1A) open circuit is detected, and the forward and reverse resistances at C8017 are normal. The forward resistance of the D8007 (S1WBS60) bridge stack is normal, but the AC input pin is shorted to the DC negative terminal, indicating that the diode in D8007 has a set of short circuits. After replacing the D8007 bridge stack and F8002, the whole machine returned to normal.

7, Hisense TPW4218P (Samsung V3 screen) lights up after booting, the lamp can change after the second boot, but the screen is not bright

First check the plasma screen and find that the LEDs 8003 and LED8002 on the plasma power supply are on, but the LED8001 is not lit. The description is that the PFC circuit part or the circuit part composed of Q8005 and Q8008 is defective. Test the PFC boosted test point T-VPFC point voltage is 0V. Not normal, it should be 400V when normal. Indicates that the PFC is partially damaged or not powered. The second three anti-jamming circuits and D8003 are detected on the road. Found that R8010 is open. After the R8010 is replaced, the LED8001 is still off. Both Q8005 and Q8008 are in the off state. There is no voltage at the positive terminal of the IC8002 internal diode. It indicates that the PFC diaphragm HIC8001 is defective, and there is no RELAY-ON signal that outputs a high level. Troubleshoot after replacing the PFC diaphragm HIC8001.

8,8, Hisense TPW4211PH [Samsung V3 screen] plasma color TV is turned on after the indicator light is on, after the second boot, the light can change but the screen is not bright

At the time of self-test, LED8001, LED8002 and LED8003 were all lit, but LED2000 on the logic board was not lit. Note that D5VL and D3V3 may have problems. Test D5VL and D3V3 without voltage, VA also has no voltage. The T-VPFC test point voltage is measured to be 400V. In the circuit detection resistor, it was found that F8003 is open circuit, and Q8018 and Q8016 are short-circuited. The BC8054 (1KV/222) capacitor on the secondary HIC8004 of VS was visually burned through a hole. The description is that the BC8054 on the component HIC8004 causes the VS load to be aggravated, and the Q8016 and Q8018 are damaged. After removing the Q8016 and Q8018, the symmetric drive triodes Q8019, Q8020, Q8021, and Q8022 are detected. No problems found. To prevent the Q8016 and Q8018 from being damaged again. It was decided to replace the Q8019, Q8020, Q8021, and Q8022 together. After replacing the damaged components mentioned above, the fault is eliminated. In the later overhaul. I also encountered damage to Q8016 and Q8018 caused by a hole in the BC8052 (1KV/222) on the HIC8004.