Magnavox 42MF230A/37 no picture no sound!!

Collapse
X
Collapse
 
  • Page of 1
  • Time
  • Show
Clear All
new posts
Previous template Next
  • RJR
    New Member
    • Sep 2010
    • 2
    #1

    Magnavox 42MF230A/37 no picture no sound!!

    Hello I have a Magnavox 42MF230A/37 its a plasma. When I turn it on the red standby LED turns blue and I hear the relay click and that's it. After I turn it on at the controls on the TV, the only way I can get it to turn off is by unplugging it.

    I found and replaced 4 bad caps three on the power supply board and and 1 on the Y main board. still no picture or sound.

    If anyone can help that would be amazing.
    Thanks RJR
    Tags: None
    • PlainBill
      Badcaps Legend
      • Feb 2009
      • 7034
      • USA
      #2
      Re: Magnavox 42MF230A/37 no picture no sound!!

      Originally posted by RJR
      Hello I have a Magnavox 42MF230A/37 its a plasma. When I turn it on the red standby LED turns blue and I hear the relay click and that's it. After I turn it on at the controls on the TV, the only way I can get it to turn off is by unplugging it.

      I found and replaced 4 bad caps three on the power supply board and and 1 on the Y main board. still no picture or sound.

      If anyone can help that would be amazing.
      Thanks RJR
      The service manual is here. Dowmload it, study it, then test the output voltages of the power supply. If they are good, the fact that you cannot turn the TV off from either the power button or the remote indicates a problem on the Small Signal Board or one of the sub-boards. Those boards should be well documented in the manual.

      I would question if it is worth putting a great deal into that TV unless you are sure it has very low hours. That uses a very early plasma panel.

      PlainBill
      For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

      Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

        Comment

        • RJR
          New Member
          • Sep 2010
          • 2
          #3
          Re: Magnavox 42MF230A/37 no picture no sound!!

          Well I've got good voltage going to and coming out of the sub power supply board and good voltage going to my main power supply but nothing coming out of it. So that sounds like a good place to start. The TV was free got it from a friend so I've got nothing in it but some time and a few caps.

          Thank you sooo much for your help!! I'll be posting again if that fixed it or not.

          RJR

            Comment

            • dzooem
              New Member
              • Oct 2010
              • 3
              #4
              Re: Magnavox 42MF230A/37 no picture no sound!!

              "Hello I have a Magnavox 42MF230A/37 its a plasma. When I turn it on the red standby LED turns blue and I hear the relay click and that's it. After I turn it on at the controls on the TV, the only way I can get it to turn off is by unplugging it."
              I just fix my TV today.same model # and same problem You have .I found bad diode on Power supply board supply 155V/VE voltage for driving X board

                Comment

                • jeffescortlx
                  Member
                  • May 2011
                  • 40
                  #5
                  Re: Magnavox 42MF230A/37 no picture no sound!!

                  Originally posted by dzooem
                  I just fix my TV today.same model # and same problem You have .I found bad diode on Power supply board supply 155V/VE voltage for driving X board
                  I have the same modle with the same problem. I went over the power supply 3 times, "155V/VE" does'nt seem to be a part number, or a location.

                  Could you give me a hint on what kind of diode I'm looking for, or it's location?
                  I back tracked the X sus board plug and could'nt find any bad diodes. Then I checked every diode on the PS.

                    Comment

                    • jeffescortlx
                      Member
                      • May 2011
                      • 40
                      #6
                      Re: Magnavox 42MF230A/37 no picture no sound!!

                      Looks like my problem is different but same "LED goes blue, get a click, but no picture or sound"

                      My Y main has two open burnt resisters. There fairly high wattage, 3-5 watts or so, lifted off the board.
                      I backed pinned what I could get to and identify on the power supply. It seem's to have power where it should. So the Y board must be keeping the TV from powering up. Does this sound right?

                        Comment

                        • jeffescortlx
                          Member
                          • May 2011
                          • 40
                          #7
                          Re: Magnavox 42MF230A/37 no picture no sound!!

                          Y sustain board LJ92-01200A has a shorted D5009 Diode, and R5028 & R5090 are burnt open. It looks to be tired into a 7815 voltage regulator.
                          I checked all the cap's and fuses and looked for shorted semiconductors, fet's, diodes, 7815 and looked for bad solder joints on the Y board and power supply and any thing else I could find. I cant find any other bad parts on this board.
                          I replaced the bad diode and resisters. They just burnt up again.
                          Any one know how to check that big STK under the heat sink? Thats the only thing I did'nt meter. But the parts that are frying dont seem to be related to the STK pack.
                          Last edited by jeffescortlx; 02-17-2012, 04:11 PM.

                            Comment

                            • PlainBill
                              Badcaps Legend
                              • Feb 2009
                              • 7034
                              • USA
                              #8
                              Re: Magnavox 42MF230A/37 no picture no sound!!

                              This plasma panel is very problematic. Google the Coppell TV Repair Blog for information on locating shorts on the Y-Sustain and Y Buffers.

                              PlainBill
                              For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

                              Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

                                Comment

                                Previous template Next

                                Related Topics

                                Collapse
                                • Tynan Dill
                                  Vizio e601i-A3 - Has Sound and Display, But No Backlight - Bad Power Supply Board or Bad LED Bulbs ?
                                  by Tynan Dill
                                  I was given this TV from my great uncle. He said it just wouldn't turn on one day out of nowhere, replaced the TV, and gave it to me to possibly fix and use for myself.

                                  Upon bringing it home and plugging it up, it showed a standby light.

                                  I powered it on and without a flashlight, the display showed the "V" but the lighting is very dim, but visible.

                                  The screen seems to blackout and stay black, but with a flashlight I can see the display.

                                  With my Playstation 4 connected via HDMI, and running a game I can hear sound.

                                  Assuming...
                                  ORIGINAL POWER SUPPLY BOARD
                                  7 Photos
                                  11-22-2024, 01:46 PM
                                • TR103
                                  Samsung TV model UE50TU: rebooting, backlight, sound, but no picture
                                  by TR103
                                  Hi, I have a Samsung UE50TU with:
                                  - sound and backlight, but no picture
                                  - when it arrived, it had a picture for a few seconds
                                  - it keeps rebooting
                                  - without ribbon cable between the two panel boards, it does not reboot but I have no picture
                                  - without cable between mainboard and lcd panel, it does not reboot (but obviously i have no picture)
                                  - when i try a tape fix, its keeps rebooting, unless I tape off pin 1 (the innermost pin). In that case it does not reboot but I have no picture.

                                  - without cable between mainboard and lcd panel and with a jumpered...
                                  01-22-2025, 04:12 PM
                                • jord4231
                                  Toshiba 37AV500A Regza TV good power supply no sound no picture
                                  by jord4231
                                  Hi Everyone,

                                  I'm working on a Toshiba 37AV500A Regza TV.

                                  The issue:
                                  TV was working picture and sound went out. Green stand by light stayed on, It will respond to the power button being pressed (goes in and out of standby)
                                  The TV will very intermittently work for around 40 mins then stop. This doesn't seem to matter if its hot/cold unplugged for a while etc.


                                  I checked the PSU voltages and everything looked good.
                                  No bulging caps or signs of heat.

                                  24v aud = 24.41v
                                  12v = 11.98v
                                  5v = 5.062
                                  p_o/f = Goes high...
                                  03-29-2022, 09:21 PM
                                • Mgiffune
                                  Samsung UN60EH6000F Black Screen, Backlight and Sound Good. Power Cycle Returns Picture
                                  by Mgiffune
                                  I have a 60 inch Samsung UN60EH6000F flatscreen TV. The screen went black a few months ago Sound is good, backlight is good, no menu. I replaced the TCon board with a used board purchased from Ebay. It worked fine for a 3-4 months, then the screen started ‘fading' back. Once again, sound is good, backlight is good, no menu. However, this time the picture looks fine for about 10-15 minutes, then fades back. If I power cycle the TV, the display reappears, for another 10-15 minutes, then fades black again. Repeatable ever time.

                                  I ordered a supposedly ‘new' Tcon board this time, and                                  ...
                                  06-09-2024, 10:28 AM
                                • Ierwin
                                  Samsung UE60KU6079 backlight okay mainboard responsive, no picture, no sound
                                  by Ierwin
                                  Hello everyone,
                                  Ive got a UE60KU6079 on the workbench that is giving me some headaches trying to troubleshoot.
                                  The previous owner stated that there had been white dots on the screen which from the description sounded like some lenses fell of the backlight LEDs.
                                  He had opened the TV from the back, trying to get to the backlight, supposedly gave up, reassebled everything and gave the TV to me.
                                  I expected the worst like ripped COF cables or a cracked panel but could not find anything like that yet.
                                  Anyway I still fully expect that there has been something seriously damaged...
                                  05-13-2025, 03:31 PM
                                • Loading...
                                • No more items.
                                Working...