SMPS for RCA 32V434T CRT tv

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  • cmj21973
    Badcaps Veteran
    • Feb 2010
    • 267
    • USA

    #1

    SMPS for RCA 32V434T CRT tv

    Need some help/guidance trouble shooting SMPS for this tv set.

    https://www.badcaps.net/forum/showpo...51&postcount=5
  • cmj21973
    Badcaps Veteran
    • Feb 2010
    • 267
    • USA

    #2
    Re: SMPS for RCA 32V434T CRT tv

    I blew the fuse while test voltage.
    Probe slipped, analog meter fine. Unfortunately, when I replaced the fuse it blew again. Must have shorted something out.

    How screwed am I.. uhh, I mean is this SMPS?

    Am I or am I ?

    Comment

    • Evil Lurker
      Warranty Voider
      • Feb 2011
      • 454

      #3
      Re: SMPS for RCA 32V434T CRT tv

      Be glad you didn't

      Anyhoos...

      Comment

      • cmj21973
        Badcaps Veteran
        • Feb 2010
        • 267
        • USA

        #4
        Re: SMPS for RCA 32V434T CRT tv

        My bad, forgot thread link.
        https://www.badcaps.net/forum/showthread.php?t=16914

        Comment

        • cmj21973
          Badcaps Veteran
          • Feb 2010
          • 267
          • USA

          #5
          Re: SMPS for RCA 32V434T CRT tv

          Found RT860 blown.
          It's a thermistor marked 5, 5D210, D V

          Will this one from Digikey be an equivalent?
          http://search.digikey.com/scripts/Dk...63658373885660

          Could this also be the cause of the 5VDC STBY to measure about 42VDC?
          Attached Files
          Last edited by cmj21973; 11-08-2011, 04:32 PM.

          Comment

          • Th3_uN1Qu3
            Believe in
            • Jul 2010
            • 6031
            • Romania

            #6
            Re: SMPS for RCA 32V434T CRT tv

            That thermistor is a PTC type so it *may* be used to limit voltage... Are you sure you're using the right ground for measuring? I've heard of high standby rails but that's out of the norm by too much.

            Are the other rails good that come from the same transformer? If they're also very high there's probably something wrong with the opto IC804 or the transistor driving it.
            Originally posted by PeteS in CA
            Remember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.
            A working TV? How boring!

            Comment

            • cmj21973
              Badcaps Veteran
              • Feb 2010
              • 267
              • USA

              #7
              Re: SMPS for RCA 32V434T CRT tv

              Originally posted by Th3_uN1Qu3
              That thermistor is a PTC type so it *may* be used to limit voltage... Are you sure you're using the right ground for measuring? I've heard of high standby rails but that's out of the norm by too much.

              Are the other rails good that come from the same transformer? If they're also very high there's probably something wrong with the opto IC804 or the transistor driving it.
              Photo #1:
              I used the "RED" circled points (photo #1) to measure the 5VDC on the main board. Guess I should have used the "YELLOW" circled points to prevent a probe short.

              Photo #2:
              I used the "RED" circled points (photo #2) to measure the 5VDC on the Controlboard.

              I was retest the 5VDC, with anaolog meter, when I caused a probe short. RT860 PTC could have just finally failed on it own, but I don't think so.

              I did remove RT860 and it measures 5.5 Ohms. It also has a chunk if it's encasement blown off.

              I didn't get other voltages. Hopefully when I replace RT860 it won't blow fuse, when power is applied, and I can get the other voltage readings.

              I thought the tv set had bad caps. Sometimes when it was turned on, it would take a few second to get a pic. Sometimes it would have sound and no picture, but cycling power would correct it till now. I thought it was the flyback until I found the RCA ATC010 Training Manual and start shutdown troubleshooting by testing the voltages.
              Attached Files
              Last edited by cmj21973; 11-09-2011, 01:04 AM.

              Comment

              • cmj21973
                Badcaps Veteran
                • Feb 2010
                • 267
                • USA

                #8
                Re: SMPS for RCA 32V434T CRT tv

                Status:

                With a 40watt bulb, across the fuse holder, I determine that D861; D862; D863; & D864 were bad.

                I replaced them and retested. IC860 tested bad.

                Will be order these to replace RT860 and IC860.
                http://search.digikey.com/scripts/Dk...66952994897708
                http://search.digikey.com/scripts/Dk...66952994897708

                Comment

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