Announcement

Collapse
No announcement yet.

Anyone familiar with the Akai LCD3701AD?

Collapse
X
Collapse
 
  • Page of 5
  • Filter
  • Time
  • Show
Clear All
new posts
Previous 1 2 3 4 5 template Next
    #1

    Anyone familiar with the Akai LCD3701AD?

    Hello,

    I got a customer's TV. It's an Akai LCT3701AD. I get the standby light and when I hit power, it turns green then red again. I'm thinking it's something with the PSU.

    I pull the cover off and look at the PSU and don't physically see any swollen caps. I pull off the cover for the video board and see a swollen 470uF 16V cap near one of the tuners. I'll replace that but I don't think that's causing the issues.

    I'll post pictures later, maybe tomorrow. Just wanted to know if anyone knew of any common failures with this board. The caps on the PSU are all glued. The cables on the video board, they're all glued as well. It's gonna be a pain to pull those caps and check them on the PSU. Was hoping someone might have a suggestion. I know some boards are known to fail for one reason or another. I was hoping this one of those boards. Like yeah! Check out cap c108! That always seems to fail on these boards!

    Thanks.
    Last edited by Spork Schivago; 09-19-2016, 07:47 PM.
    -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full
    Tags: None
    #2
    Re: Anyone familiar with the Akai LCD3701AD?

    The only 470uF 16v cap I have right now are polymers. Do you guys think I could switch out the bad 470uF 16v electrolytic for the 470uF 16v polymer and be okay? I know that caps bad, and although I doubt it'd fix the TV, I'd like to get it fixed first, just in case.
    -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

    Comment

      #3
      Re: Anyone familiar with the Akai LCD3701AD?

      Maybe a mod can fix the title of this thread? I accidently typed LCD3701AD instead of LCT3701AD. Thanks.
      -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

      Comment

        #4
        Re: Anyone familiar with the Akai LCD3701AD?

        Images of the boards ?
        Please Do Not PM My Page Asking For Help Badcaps Is The Place For Advise, Page Linked For Business Reasons Only. Anyone Doing So Will Be Banned Instantly !

        https://www.facebook.com/Telford-Tel...7894576335359/

        Comment

          #5
          Re: Anyone familiar with the Akai LCD3701AD?

          I'll post them.

          These are the best I can get right now. It's still a bit dark here. We're still unpacking and haven't found the flashlights yet. They're not the brightest.

          My wife found my ESR meter last night, so I can finally test caps again. I'm going to replace the 470uF 16V with a used (but good) 470uF 16v electrolytic cap on the main board, just to see if the TV powers on. I doubt it though. I think that bad cap next to the one tuner (there's two tuners) won't affect whether the TV powers on or not, but maybe.

          The PSU looks fancy but none of the connectors are really labeled like they usually are. I don't see an PS_ON or STDBY like I normally do. A few have some volts written next to them, like 5v and 24v, so I can check those. What sucks also is almost every connector is glued. And on the power supply board, a lot of the caps are glued to each other. What a mess!
          Attached Files
          -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

          Comment

            #6
            Re: Anyone familiar with the Akai LCD3701AD?

            very hard to say in those pictures but by the tuner theres a small heat sink then a large capacitor it looks like the outer plastic sleaving has shrunk so certainly worth testing all the capacitors for correct uf and esr.If this was my set and i was working on it for a customer i would certainly fully re cap the psu too.

            Comment

              #7
              Re: Anyone familiar with the Akai LCD3701AD?

              Originally posted by vinceroger69 View Post
              very hard to say in those pictures but by the tuner theres a small heat sink then a large capacitor it looks like the outer plastic sleaving has shrunk so certainly worth testing all the capacitors for correct uf and esr.If this was my set and i was working on it for a customer i would certainly fully re cap the psu too.
              I know the caps you're talking about with the shrunken plastic sleeves. I've never seen that before. I pulled them and tested but they're good. I replaced the bad 470uF and I'm gonna see if it powers on, if not, I'll probe the PSU with my multimeter and see if I'm missing any voltages (at least where they're labeled). If I'm missing them, I'll start pulling caps on the PSU and testing them.

              It's definitely an odd TV. I've never seen one from the factory that had jumper cables wired onto it. This main board has two. One on the front side, one on the back.
              -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

              Comment

                #8
                Re: Anyone familiar with the Akai LCD3701AD?

                As I suspected, the 470uF 16v cap didn't fix the issue. The caps on the power supply are CapXon. At this point, I'm not even sure one of the caps on the power supply unit is bad. Maybe it's one of the six transformers? Or maybe one of those 3 pin chips on the heatsinks. There's 9 of those 3-pin chips.
                -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

                Comment

                  #9
                  Re: Anyone familiar with the Akai LCD3701AD?

                  Megmeet MLT386X (MLT386Y) Power Supply Unit.
                  http://www.shopjimmy.com/megmeet-mlt...pply-unit.htm#

                  Pictures provided by shojimmy.
                  So what dcv did you test on the power supply output connectors so far?
                  Attached Files
                  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

                    #10
                    Re: Anyone familiar with the Akai LCD3701AD?

                    This might be a tough one. I'm testing the MOSFETs now. The few caps that I pulled (because of the glue) tested fine. It takes a while to cut away the glue. I figured maybe the MOSFETs might be something I should concentrate on first. What are the chances of them failing or causing this problem?

                    My DCA meter can successfully identify them. I'd think if one was broken, my DCA meter wouldn't detect them or say faulty component or something. Do you think that's a safe assumption or is there a better way to test MOSFETs? Thanks.
                    -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

                    Comment

                      #11
                      Re: Anyone familiar with the Akai LCD3701AD?

                      Originally posted by budm View Post
                      Megmeet MLT386X (MLT386Y) Power Supply Unit.
                      http://www.shopjimmy.com/megmeet-mlt...pply-unit.htm#

                      Pictures provided by shojimmy.
                      So what dcv did you test on the power supply output connectors so far?
                      None Budm. I replaced the bad cap on the main board and then just started pulling caps. Then after I pulled two, I went and pulled one of the MOSFETs and tested it. It looked like some of the words had disappeared on it, so I thought maybe it was bad. Do you want me to test the connectors that have the voltages labeled on them?
                      -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

                      Comment

                        #12
                        Re: Anyone familiar with the Akai LCD3701AD?

                        test all the voltages on the psu connectors test with set on standby and in the switched on condition also if possible test the voltage across the large filter capacitor on the hot side of the psu (be carefull as high volts) do this in standby and set switched on condition and write down all voltages and any printing by the connectors so we know what pins the voltage relates too.

                        Also check on the underside of the psu for any burnt parts/dry joints etc
                        Last edited by vinceroger69; 09-21-2016, 11:23 AM.

                        Comment

                          #13
                          Re: Anyone familiar with the Akai LCD3701AD?

                          Now that it's brighter outside, I got better pictures. Also, after removing the cables, I noticed they are labeled (thankfully!). Here's new up-close images of the connectors with their various labels.
                          Attached Files
                          -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

                          Comment

                            #14
                            Re: Anyone familiar with the Akai LCD3701AD?

                            Originally posted by vinceroger69 View Post
                            test all the voltages on the psu connectors test with set on standby and in the switched on condition also if possible test the voltage across the large filter capacitor on the hot side of the psu (be carefull as high volts) do this in standby and set switched on condition and write down all voltages and any printing by the connectors so we know what pins the voltage relates too.
                            Even though the TV doesn't turn on? Measure them, record them, then hit the on button, have the red light turn green real quick like, then back to red, and repeat?
                            -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

                            Comment

                              #15
                              Re: Anyone familiar with the Akai LCD3701AD?

                              sorry forgot it dosnt turn on just do the one test and see what voltages you have at the minute then we might have to force the psu on.

                              Comment

                                #16
                                Re: Anyone familiar with the Akai LCD3701AD?

                                Let use see what DCV you have on all those pins of the power supply connector first.
                                We know that you must have at least the standby power supply otherwise you will not see the LED indicator lights up.
                                Make sure to put the pin names and follow by the DCV readings.
                                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

                                  #17
                                  Re: Anyone familiar with the Akai LCD3701AD?

                                  Have you checked the power supply disconnected from the main board to see if you have all the voltages come up when you jumper 5VSTB to PS_ON using a 1K resistor.
                                  Willing to help but I'm no expert.

                                  Comment

                                    #18
                                    Re: Anyone familiar with the Akai LCD3701AD?

                                    Originally posted by dick_barton View Post
                                    Have you checked the power supply disconnected from the main board to see if you have all the voltages come up when you jumper 5VSTB to PS_ON using a 1K resistor.
                                    No, I haven't.

                                    Yesterday, I had to get up at 4:00AM and when I posted last, I had to leave for an appointment. My wife's pregnant and we had to go to Birth and Beyond. When we got back, people came over to bring her some gliding rocking chair and afterwards, I just went to bed. I got some vaccines yesterday and now I got a fever. It's not a bad one. Last time I checked, it was 100.3F. I believe the flu vaccine I received contained an inactive version of the virus, so there's no way I caught the flu from it or anything. Maybe I was going to get sick anyway, or maybe it's just a side effect.

                                    I got the flu vaccine and then the tdap one (the tetanus / whooping cough combo).

                                    I'll test the voltages and report back soon. I didn't know about the 1K resistor trick. So, when PS_ON received 5V, it turns on the power supply?
                                    -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

                                    Comment

                                      #19
                                      Re: Anyone familiar with the Akai LCD3701AD?

                                      Originally posted by budm View Post
                                      Let use see what DCV you have on all those pins of the power supply connector first.
                                      We know that you must have at least the standby power supply otherwise you will not see the LED indicator lights up.
                                      Make sure to put the pin names and follow by the DCV readings.
                                      I don't have to check the 24DCV ones, right? They're just for the inverter, right?

                                      Thanks.
                                      -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

                                      Comment

                                        #20
                                        Re: Anyone familiar with the Akai LCD3701AD?

                                        Okay, I got the voltages.
                                        Code:
                                        (left most connector in pic one)
GND -> PS_ON: 0.084VDC
GND -> +5VSB: 5.18VDC and 5.19VDC (more than one hot)

(left most bottom connector in pic one)
GND -> 8V: 0VDC

(2nd to left most connector in pic one)
GND -> 5V: 0.35VDC
GND -> 12V: 0.25VDC

(last two remaining right connectors)
all GND -> 24V: 0VDC
                                        -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

                                        Comment

                                        Previous 1 2 3 4 5 template Next
                                        Working...