Regulator STR-58041 will this selfdistruct if

Discussion in 'Electronic Repair' started by Jim Lazzaro, Jul 29, 2004.

  1. Jim Lazzaro

    Jim Lazzaro Guest

    On TV Orion model S21 (which does not start) the power supply
    regulator STR-58041 has 329 volts on pin 3. The schematic shows it
    should have 280 volts.
    Since I haven't been able to solve this start up failure, I am now
    wondering if:
    1) the 329 volts apllied to it is sensed by the regulator as out of
    specs and therefore it does not turn itself on.
    or 2) the 329 volts is just higher because there is no current flowing
    due to the regulator being defenitely faulty.
    Note- all other checks have been done and also there are no shorts
    found, resistors have been checked etc., new caps installed.
    Please pass on your thoughts on this.
    Thanking you
    Jim
     
    Jim Lazzaro, Jul 29, 2004
    #1
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  2. Jim Lazzaro

    Franc Zabkar Guest

    On 28 Jul 2004 19:56:11 -0700, (Jim Lazzaro)
    put finger to keyboard and composed:

    >On TV Orion model S21 (which does not start) the power supply
    >regulator STR-58041 has 329 volts on pin 3. The schematic shows it
    >should have 280 volts.
    >Since I haven't been able to solve this start up failure, I am now
    >wondering if:
    > 1) the 329 volts apllied to it is sensed by the regulator as out of
    >specs and therefore it does not turn itself on.


    Pin 3 is the collector of the chopper transistor and is connected to
    the rectified 240VAC via the primary winding of the switching
    transformer. As such it should measure 240 x 1.414 = 340VDC if the PSU
    is in the no-start state.

    >or 2) the 329 volts is just higher because there is no current flowing
    >due to the regulator being defenitely faulty.
    >Note- all other checks have been done and also there are no shorts
    >found, resistors have been checked etc., new caps installed.
    >Please pass on your thoughts on this.
    >Thanking you
    >Jim



    - Franc Zabkar
    --
    Please remove one 's' from my address when replying by email.
     
    Franc Zabkar, Jul 29, 2004
    #2
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  3. Jim Lazzaro

    mo Guest

    Franc Zabkar <> wrote in message news:<>...
    > On 28 Jul 2004 19:56:11 -0700, (Jim Lazzaro)
    > put finger to keyboard and composed:



    Filed this reply in the wrong pigeon hole,but here goes anyway.
    It is possible that there are 2 resistors of about 120 kOhm in series
    from large capacitor to where you are supposed to find that 0.4 Volts
    on your ic.
    Isolate one end of resistors and measure resistance.
    Good luck.
     
    mo, Jul 30, 2004
    #3
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