when i turn on, Philliips TV is not on
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Re: when i turn on, Philliips TV is not on
I can't make it out but there is likely another number before the "G", try looking at different angles to see if you can see anything else.
The number on the schematic UDZSTE-17, SHOULD have the voltage after this number (ie: UDZSTE-1722, 22v zener)
Some of the zeners that I looked at that end in G, like WG are only 10~11 volt which is normally too low a voltageLast edited by R_J; 01-25-2020, 01:43 PM.Comment
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Re: when i turn on, Philliips TV is not on
I can't make it out but there is likely another number before the "G", try looking at different angles to see if you can see anything else.
The number on the schematic UDZSTE-17, SHOULD have the voltage after this number (ie: UDZSTE-1722, 22v zener)
Some of the zeners that I looked at that end in G, like WG are only 10~11 volt which is normally too low a voltageComment
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Re: when i turn on, Philliips TV is not on
Without a number or voltage rating, it is a guess, Too high a voltage and you will exceed the ic's VCC (which we don't know without a datasheet) and without the full number from the diode its a guess. I would try around a 20 volt zener diode.
A lot of the infineon ic's (which this is but likely custom) have a max vcc of 22vComment
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Re: when i turn on, Philliips TV is not on
I can't make it out but there is likely another number before the "G", try looking at different angles to see if you can see anything else.
The number on the schematic UDZSTE-17, SHOULD have the voltage after this number (ie: UDZSTE-1722, 22v zener)
Some of the zeners that I looked at that end in G, like WG are only 10~11 volt which is normally too low a voltage
When I lift the zener diode and I have 6.4v at C951AComment
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Re: when i turn on, Philliips TV is not on
But did they actually install this ic in the board and check that it worked properly? Did anyone confirm that the DNP005 operates at 65khz vs 100khz?
Most of the Infineon icexbrxxx ic's have a max vcc of around 25v thats why I suggested the 20v zener.Last edited by R_J; 01-25-2020, 10:15 PM.Comment
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Re: when i turn on, Philliips TV is not on
Last edited by will62; 01-25-2020, 11:47 PM.Comment
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Re: when i turn on, Philliips TV is not on
C912 = 11v to 16v fluctuation
C906 = 8v to 21v fluctuation
I will order 20v zener diodeComment
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Re: when i turn on, Philliips TV is not on
PC901 pin1 = 6.60v
PC901 pin2 = 6.60v
ZD951 and C951A are gets hotComment
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Re: when i turn on, Philliips TV is not on
So you have no feedback to control the primary so it is trying to output more than the 5 volts on the secondary, That's why the ZD951 is getting hot. It is trying to clamp the voltage to 6.2 volts and thats why it gets hot.
First check that D950,951 &952 are not bad or leaky (they are likely ok)
Next check R954,R955, if they are ok IC951 could be bad
What is happening is IC951 is NOT regulating and bringing pin 2 of PC901 low. Check that PC901 pins 1&2 are not shorted. If the optocoupler is ok, I suspect the apl431 regulator is bad. If you don't have one, check an old switching power supply, they almost all use them but it might be a to-92 case but it would work to test.
PC901 has the same voltage on both pins so the internal led is not turning on, If the led does not turn on, the photo detector (pins 3 & 4) does not conduct, lowering the voltage across zd907. and regulating ic901Last edited by R_J; 01-28-2020, 04:46 PM.Comment
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Re: when i turn on, Philliips TV is not on
So you have no feedback to control the primary so it is trying to output more than the 5 volts on the secondary, That's why the ZD951 is getting hot. It is trying to clamp the voltage to 6.2 volts and thats why it gets hot.
First check that D950,951 &952 are not bad or leaky (they are likely ok)
Next check R954,R955, if they are ok IC951 could be bad
What is happening is IC951 is NOT regulating and bringing pin 2 of PC901 low. Check that PC901 pins 1&2 are not shorted. If the optocoupler is ok, I suspect the apl431 regulator is bad. If you don't have one, check an old switching power supply, they almost all use them but it might be a to-92 case but it would work to test.
PC901 has the same voltage on both pins so the internal led is not turning on, If the led does not turn on, the photo detector (pins 3 & 4) does not conduct, lowering the voltage across zd907. and regulating ic901
D950 = 0.2 ,951= 0.2 & 952 = is not populate
R954 =10k ,R955 = 2.976k
PC901 : when I do continuity test no beep. I checked diode mode pin 1(+) to pin 2(-) = 0.596 and pin 1(-) to pin 2 (+) = 0.608
Unsolder those two pin and measure diode mode pin 1(+) to pin 2(-) = 0.998 and pin 1(-) to pin 2 (+) = OL
But when I measure on the pad of PC901 pin 1 and 2 same voltage at diode mode.
I do not have apl431 regulator now. Once I get new I will update.Comment
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Re: when i turn on, Philliips TV is not on
The shunt regulator should be pulling pc901 pin 2 close to ground, When it is working you should have about 2~3 volts on PC901 pin2 and around 4~5 volts on pin 1. with about 1.5 volt difference across pins 1&2 the led would be lit and pin 4 would be closer to 1~2 volts, controlling the ic901Comment
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Re: when i turn on, Philliips TV is not on
The shunt regulator should be pulling pc901 pin 2 close to ground, When it is working you should have about 2~3 volts on PC901 pin2 and around 4~5 volts on pin 1. with about 1.5 volt difference across pins 1&2 the led would be lit and pin 4 would be closer to 1~2 volts, controlling the ic901
PC901 pin1 = 6.60v
PC901 pin2 = 6.60v (use C951A negative for ground)Comment
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Re: when i turn on, Philliips TV is not on
What are the voltages on IC951? something is wrong in that circuit, that is why there is no regulation happening. Maybe shorted C955,C954? I guess it might be PC901? if you don't have one try exchanging PC902 with PC901.Comment
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