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Rca rlc3255a-b doa

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    Rca rlc3255a-b doa

    So I picked this up yesterday, no indicator lights.
    No SBV
    Fuse ok, no shorts and ~165vdc out from bridge.
    Looking for SCH, no luck yet...
    Attached Files

    #2
    Re: Rca rlc3255a-b doa

    Closer pic of PSU? Does 5V come back when you pull the power to main board connector out? Any ticking/pulsing sound from power board?
    Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
    For service manual, schematic, boardview (board view), datasheet, cad - use our search.

    Comment


      #3
      Re: Rca rlc3255a-b doa

      No ticks or hums or clicking don't see any relays anyway..
      Tested SBV voltage with main board disconnected.
      165v at main cap as well.
      Attached Files
      Last edited by Fwrothy; 03-09-2014, 06:41 PM. Reason: Add cap

      Comment


        #4
        Re: Rca rlc3255a-b doa

        Better psu pic...
        Attached Files

        Comment


          #5
          Re: Rca rlc3255a-b doa

          Is it MAGMEET MP118A? Pictures is not well focus.
          Try heating those two caps with hair dryer to see if the 5VSTBY will start up or replace them.
          Attached Files
          Last edited by budm; 03-09-2014, 09:09 PM.
          Never stop learning
          Basic LCD TV and Monitor troubleshooting guides.
          http://www.badcaps.net/forum/showthr...956#post305956

          Voltage Regulator (LDO) testing:
          http://www.badcaps.net/forum/showthr...999#post300999

          Inverter testing using old CFL:
          http://www.badcaps.net/forum/showthr...er+testing+cfl

          Tear down pictures : Hit the ">" Show Albums and stories" on the left side
          http://s807.photobucket.com/user/budm/library/

          TV Factory reset codes listing:
          http://www.badcaps.net/forum/showthread.php?t=24809

          Comment


            #6
            Re: Rca rlc3255a-b doa

            Just found it @sj- it's a mp116a.
            Attached Files

            Comment


              #7
              Re: Rca rlc3255a-b doa

              Originally posted by budm View Post
              Is it MAGMEET MP118A? Pictures is not well focus.
              Try heating those two caps with hair dryer to see if the 5VSTBY will start up or replace them.
              Thanks Bud I'll give that a try!
              Ya under the magnifying glass the 100uF looks bulged(bigger blue )-didn't notice before...
              Last edited by Fwrothy; 03-09-2014, 09:35 PM. Reason: Additional info

              Comment


                #8
                Re: Rca rlc3255a-b doa

                No luck with the hair dryer. Did pull out both capacitors(100mF 35v & 10mF 100v),no shorts,charged them with ohmmeter and drain back with voltmeter idk.
                No luck with SCH either, so resorted to fishing.

                Did notice short across octo didn't seem right; lifted it it seem ok. There's a sot 6 pin IC in area no idea what it is???
                Found N MOSFET (F2HNK60Z) seems shorted , will pull next...
                All these components are associated with primary of low voltage transformer.

                Comment


                  #9
                  Re: Rca rlc3255a-b doa

                  MOSFET F2HNK60Z shorted D-S ....gate seemingly not shorted.

                  SOT6? PWM controller?
                  Last edited by Fwrothy; 03-10-2014, 03:24 PM. Reason: Clarification

                  Comment


                    #10
                    Re: Rca rlc3255a-b doa

                    Originally posted by Fwrothy View Post
                    MOSFET F2HNK60Z shorted D-S ....gate seemingly not shorted.

                    SOT6? PWM controller?
                    Yes looks to me like a FAN6862...



                    Seems fried; Vdd,gate,FB all shorted to ground. That explain fault at octo.
                    Can bad caps cause this?!
                    Last edited by Fwrothy; 03-10-2014, 04:13 PM. Reason: Correction

                    Comment


                      #11
                      Re: Rca rlc3255a-b doa

                      Blown FET can damage IC.
                      Replace IC, FET, and nearby resistors and diodes.
                      Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                      For service manual, schematic, boardview (board view), datasheet, cad - use our search.

                      Comment


                        #12
                        Re: Rca rlc3255a-b doa

                        Thanks Tom, just repaired a similar situation but found some white residue on trace side of board oddly enough. Could that be leaked electrolyte?

                        Comment


                          #13
                          Re: Rca rlc3255a-b doa

                          So I got off my butt and found my camera, iPad doesn't seem to be cutting it.
                          Got a pic of the afore mentioned residue, looked like something I saw in 'worst soldering' thread (somebody had a go at it already I think), but what a difference, been squinting through the magnifying glass and camera lens for too long now I can see discrete component markings and ICs way better than naked eye! Would like to get an inexpensive USB microscope/camera...

                          Anyways, trying to get a parts list together and dunno how to spec PWM controller -mentioned a FAN6862 or similar a while back but there seems lots to choose from and I don't know anything about cross compatibility...

                          Any suggestions? Pic at least show package marking if that's any help.
                          Attached Files

                          Comment


                            #14
                            Re: Rca rlc3255a-b doa

                            Decided since I didn't have a SCH I'd try my hand at drawing one...at least the part that seems bad.
                            So here goes, most of it seems to make sense...any feedback would be appreciated on the plausibility of the circuits I've tried to interpret.
                            Btw q9 is the bad/ shorted MOSFET and there are various resistors hi-lighted that look damage as well as no reading/OL.
                            Attached Files
                            Last edited by Fwrothy; 03-14-2014, 12:31 PM. Reason: Add info

                            Comment


                              #15
                              Re: Rca rlc3255a-b doa

                              R80/R81 will likely be low ohms. Are they through hole? Completely unreadable?
                              R73: typically 2~3x R74 value non-critical
                              R74: around 22 to 56 ohms check IC2 datasheet
                              Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                              For service manual, schematic, boardview (board view), datasheet, cad - use our search.

                              Comment


                                #16
                                Re: Rca rlc3255a-b doa

                                Originally posted by tom66 View Post
                                R80/R81 will likely be low ohms. Are they through hole? Completely unreadable?
                                R73: typically 2~3x R74 value non-critical
                                R74: around 22 to 56 ohms check IC2 datasheet
                                I think the last pic shows them, r80/81 look like 4 digits.
                                They are all SMDs... Biggest issue is I don't know what IC2 IS...just guessing by pin layout .

                                Comment


                                  #17
                                  Re: Rca rlc3255a-b doa

                                  Looks like 2R20 i.e. 2.2 ohms which is about right.
                                  Couldn't find any info on that IC either.
                                  Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                                  For service manual, schematic, boardview (board view), datasheet, cad - use our search.

                                  Comment


                                    #18
                                    Re: Rca rlc3255a-b doa

                                    Ya it's a bugger... There are a few in the Fairchild roster that seem like they could work but idk how pick or compatibility issues. It's a $40 psu and available, plus the trace is lifting a bit (probably my fault when re&re ec7)-just trying to challenge myself.
                                    Thanks for the input appreciated as always
                                    Better pic..
                                    Attached Files

                                    Comment


                                      #19
                                      Re: Rca rlc3255a-b doa

                                      If you do not get any where with it, replacement is not too bad.
                                      http://www.shopjimmy.com/megmeet-mp1...upply-unit.htm
                                      Never stop learning
                                      Basic LCD TV and Monitor troubleshooting guides.
                                      http://www.badcaps.net/forum/showthr...956#post305956

                                      Voltage Regulator (LDO) testing:
                                      http://www.badcaps.net/forum/showthr...999#post300999

                                      Inverter testing using old CFL:
                                      http://www.badcaps.net/forum/showthr...er+testing+cfl

                                      Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                                      http://s807.photobucket.com/user/budm/library/

                                      TV Factory reset codes listing:
                                      http://www.badcaps.net/forum/showthread.php?t=24809

                                      Comment

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