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  1. #1
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    tda4605-3

    At the startmoment it shall give pulse out on pin 5 to a CMOS-transistor,
    what frequence and amplitude should the pulse have??
    It is lokated in the P.S.U of a Beko TV-chassis 11.1,and the
    transistor 2SK2545 goes S/C direct with a try to start.

    •   Alt2nd May 2006, 20:43

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  2. #2
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    tda4605

    hello my friend
    TDA4605-3.pdf SpecSheet : Control IC for Switched-Mode Power Supplies using MOS-Transistor TDA 4605-3 Bipolar IC Features q Fold-back characteristics provides overload protection for q q q q q q q q external components Burst operation under secondary short-circuit condition implemented Protection against open or a short of the control loop Switch-off if line voltage is too low (undervoltage switch-off) Line voltage depending compensation of fold-back point Soft-start for quiet start-up without noise generated by the transformer Chip-over temperature protection implemented (thermal shutdown) On-chip ringing suppression circuit against parasitic oscillations of the transformer AGC-voltage reduction at low load P-DIP-8-1 Type TDA 4605-3 Ordering Code Q67000-A5066 Package P-DIP-8-1 The IC TDA 4605-3 controls the MOS-power transistor and performs all necessary control and protection functions in free running flyback converters. Because of the fact that a wide load range is achieved, this IC is applicable for consumer as well as industrial power supplies. The serial circuit and primary winding of the flyback transformer are connected in series to the input voltage. During the switch-on period of the transistor, energy is stored in the transformer. During the switch-off period the energy is fed to the load via the secondary winding. By varying switch-on time of the power transistor, the IC controls each portion of energy transferred to the secondary side such that the output voltage remains nearly i

    here's the data sheet for this IC and hope it'll help u in that :)
    Kind Regards



    •   Alt2nd May 2006, 21:40

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    tranzistor 2sk2545

    I shall try to explane more in my bad english.
    At the start moment there are a startpulse generator in the TDA4605
    to output pin 5.What frequensey and amplitude shall it be.
    I have to start the TV without the cmos 2SK2545.
    I have two guesses why the mosfet goes S/C at start.
    1.There are wrong output pulses on pin 5.
    2.The transformer are defective(I have no good way to test it)



    •   Alt5th May 2006, 20:27

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  4. #4
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    tda4605 application circuits

    hello my friend
    well , first of all check and replace C409,IC401 TDA4605 and T401 BUZ90 but before replacing them make sure to Discharge C410 and main filter capacitor otherwise u will have a defective TDA and BUZ again , so please make sure to Discharge C410 before Replacing them , also check and replace D406 1N4148 .
    if this doesn't make any changes , check and replace R413,R414,R415
    if u still have the same problem , try to connect a 15V or 18V Zener between the source and gate terminals of the mos fet BUZ 90 to prevent spikes from damaging the the mosfet again.
    if u still suffering the problem again that means u have a shorted chopper transformer , try another one or ring it using ur scope .
    here's the best service manual i could get for this chassis hope it'll help u .
    Kind Regards



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    test tda4605

    I cant download the file:to few points is the message.
    Thanks for the tips.
    I would anyway be grateful to know what the starting pulse
    at pin 5 of TDA4605 should be without the mosfet connected.
    The pulse I messaure with the scope is between 0 volt and 0.25 volt
    with a frequensy of 1 Hz.I dont think that is correct.I have changed
    the IC.I will try to avoid blowing another mosfet if possible.
    Best regards



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    tda4605-3 replacement

    hello my friend
    here's some beko chassis repair tips that may help u :)
    well, i've sent u a message asking for ur email to send u the service manual , so please answer me .
    Kind Regards



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    TDA 4605-3 functionexplanation help

    I also have a problem with a philips chassis Anubis SDD run by this little pwm controller: The B+ rises well above 95v to say, 145-150v in standby and still too high when running(110-115v). The cpu goes into protective mode and puts the tv into standby with the power LED flickering. Is it the TDA4605 faulty or the external circuit components?

    Tendi...



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