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    Thermaltake 750W ATX power supply

    This is output section of Thermaltake 750W ATX power supply.

    Can somebody explain what is the role of this ckt in +5V rail ?



    - - - Updated - - -

    Two transistor forward topology is used here in the primary. I don't have the whole schematic, also looking for it :(

    •   Alt8th July 2012, 12:40

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    Re: Thermaltake 750W ATX power supply

    Dear MAXPAYNE
    Hi
    Which section is your problem ? can't you understand all of it ? or perhaps a bit of it ?
    Best Wishes
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    When you sensed that i can help you , feel free to ask me .
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    The only thing that i couldn't understand yet , is why humans should fight together ? why not helping each other to have a better world ?



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    Re: Thermaltake 750W ATX power supply

    My problem is in +5V section. Whenever I connect load on this rail the power supply shuts off itself. other two rail +12V and +3.3V is quite ok.

    - - - Updated - - -

    My problem is in +5V section. Whenever I connect load on this rail the power supply shuts off itself. other two rail +12V and +3.3V is quite ok.



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    Re: Thermaltake 750W ATX power supply

    Hi again
    Is your mean that when you put the load across the 5 volts out put , it's out put will be zero ?

    - - - Updated - - -

    Hi again
    Is your mean that when you put the load across the 5 volts out put , it's out put will be zero ?
    When you sensed that i can help you , feel free to ask me .
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    The only thing that i couldn't understand yet , is why humans should fight together ? why not helping each other to have a better world ?



    •   Alt8th July 2012, 16:51

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    Re: Thermaltake 750W ATX power supply

    yes. all other output is also 0 then...



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    Re: Thermaltake 750W ATX power supply

    Hi again
    can you show me the values of components , i think they are not proper .
    By the way , why you have used a 1 ohms resistor in parallel with the out put ? how much should be the maximum value of current ? is that a flyback converter ? did you design it yourself or perhaps it is derived from a source ? can you show me the compete circuit ? why the reference pin of tl 431 is not connected to the out put via a voltage divider ? more informations needed if you want the best answer .
    When you sensed that i can help you , feel free to ask me .
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    •   Alt8th July 2012, 20:38

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    Re: Thermaltake 750W ATX power supply

    I have not designed this ckt. This ckt is designed and made by CWT, and available as brand Thermaltake. Ignore the 1 ohm resistor and consider the dot line, as this is not present there. The max value of current is 28A in +5V rail. They have used two transostor forward topology here.

    chk the lower portion of secondary, this is used for +12V

    chk the upper inductor L7. this is for +3.3V output. i.e. +5V and +3.3V is derived from the same secondary coil.

    I didn't find the whole ckt diagram as mentioned before.

    I do need to understand this tl431 ckt. that is my main point as I said in the first post.



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    Re: Thermaltake 750W ATX power supply

    Hi again
    Check these parameters :
    1- be sure that TL431 is intact
    2- i think one of the diodes that shown in path of A928A , should be LED of an opto coupler . did you checked it ever ? if yes , be sure that it is intact . if my prediction is correct and you have an opto coupler in your circuit , i can describe all of circuit for you .
    Best Wishes
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    The only thing that i couldn't understand yet , is why humans should fight together ? why not helping each other to have a better world ?



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    Re: Thermaltake 750W ATX power supply

    Diodes that shown in path of A928A is not LED of an optocoupler. I have chcked it and found everything ok. There is a separate optocoupler-tl431 arrangement for feedback, which goes from +12V line. +5V is not connected to any feedback arrangement.

    Unfortunately don't have the feedback ckt part apart from this :(

    - - - Updated - - -

    U can have look inside from here ...

    http://www.hardwaresecrets.com/article/Thermaltake-Toughpower-750-W-W0116RU-Power-Supply/369/3

    - - - Updated - - -

    U can have look inside from here ...

    http://www.hardwaresecrets.com/article/Thermaltake-Toughpower-750-W-W0116RU-Power-Supply/369/3



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    Re: Thermaltake 750W ATX power supply

    Hi again
    Unfortunately don't have the feedback ckt part apart from this
    You should mention it at first ! not after creating many confusion .
    which page in that link has the full schematic ?
    When you sensed that i can help you , feel free to ask me .
    ************************
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    The only thing that i couldn't understand yet , is why humans should fight together ? why not helping each other to have a better world ?



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    Re: Thermaltake 750W ATX power supply

    To be honest I'm having a lot of trouble figuring out what's going on in the circuit.

    I'm pretty sure that L4 must be a saturable reactor, and the circuitry around QX is the controllable feedback circuitry for it. The components surrounding Q24 also seem to be part of the reset circuitry, but it's a variation I've never seen before, and can't quite make sense of.... But in normal saturable reactor feedback, the base of QX should be connected to a zener (which defines the setpoint for the regulator) while the emitter is connected to the output voltage. This isn't the case here. The function of the TL431 is the real mystery here. It's really hard to tell without knowing what the "+5T" node is. Does the rest of the schematic show what that node connects to?

    - - - Updated - - -

    Quote Originally Posted by MAXPAYNE View Post
    Diodes that shown in path of A928A is not LED of an optocoupler. I have chcked it and found everything ok. There is a separate optocoupler-tl431 arrangement for feedback, which goes from +12V line. +5V is not connected to any feedback arrangement.

    Unfortunately don't have the feedback ckt part apart from this :(
    The +12V line must be the main regulated output voltage for the flyback. The 5V rail (and probably the other derived voltages) have saturable reactor regulation, which doesn't require optocouplers, but they do require a voltage reference. But where that reference is generated isn't clear. A more complete schematic is necessary.


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    Re: Thermaltake 750W ATX power supply

    Quote Originally Posted by goldsmith View Post
    Hi again

    You should mention it at first ! not after creating many confusion .
    which page in that link has the full schematic ?
    I again ask you to read my first post. Why u r asking full schematic in spite of I have mentioned couple of times that I don't have it....
    Last edited by MAXPAYNE; 10th July 2012 at 05:02.



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    Re: Thermaltake 750W ATX power supply

    Quote Originally Posted by goldsmith View Post
    Hi again

    You should mention it at first ! not after creating many confusion .
    which page in that link has the full schematic ?
    I again ask you to read my first post. Why u r asking full schematic in spite of I have mentioned couple of times that I don't have it....

    - - - Updated - - -

    Quote Originally Posted by mtwieg View Post
    To be honest I'm having a lot of trouble figuring out what's going on in the circuit.

    I'm pretty sure that L4 must be a saturable reactor, and the circuitry around QX is the controllable feedback circuitry for it. The components surrounding Q24 also seem to be part of the reset circuitry, but it's a variation I've never seen before, and can't quite make sense of.... But in normal saturable reactor feedback, the base of QX should be connected to a zener (which defines the setpoint for the regulator) while the emitter is connected to the output voltage. This isn't the case here. The function of the TL431 is the real mystery here. It's really hard to tell without knowing what the "+5T" node is. Does the rest of the schematic show what that node connects to?

    - - - Updated - - -

    The +12V line must be the main regulated output voltage for the flyback. The 5V rail (and probably the other derived voltages) have saturable reactor regulation, which doesn't require optocouplers, but they do require a voltage reference. But where that reference is generated isn't clear. A more complete schematic is necessary.

    Thanks mtwieg for your reply. At last I have found some light ... :)

    I don't have any idea about saturate reactor. Can you provide some appropriate link so that I can study it and understand what is actually happening here.

    +5T is connected to GND, I have physically checked it.....

    - - - Updated - - -

    Quote Originally Posted by mtwieg View Post
    To be honest I'm having a lot of trouble figuring out what's going on in the circuit.

    I'm pretty sure that L4 must be a saturable reactor, and the circuitry around QX is the controllable feedback circuitry for it. The components surrounding Q24 also seem to be part of the reset circuitry, but it's a variation I've never seen before, and can't quite make sense of.... But in normal saturable reactor feedback, the base of QX should be connected to a zener (which defines the setpoint for the regulator) while the emitter is connected to the output voltage. This isn't the case here. The function of the TL431 is the real mystery here. It's really hard to tell without knowing what the "+5T" node is. Does the rest of the schematic show what that node connects to?

    - - - Updated - - -

    The +12V line must be the main regulated output voltage for the flyback. The 5V rail (and probably the other derived voltages) have saturable reactor regulation, which doesn't require optocouplers, but they do require a voltage reference. But where that reference is generated isn't clear. A more complete schematic is necessary.

    Thanks mtwieg for your reply. At last I have found some light ... :)

    I don't have any idea about saturate reactor. Can you provide some appropriate link so that I can study it and understand what is actually happening here.

    +5T is connected to GND, I have physically checked it.....



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