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    #1

    SmartVision LCD Monitor/TV

    Hi everyone , I have SmartVision LCD Monitor/TV , model : 9005L-TD , power supply : AC 100-240V 50/60Hz 1.5A.

    So I'm here becouse it's obiously not working well .
    It was 3 times on some service repairings and when i get my monitor back home it works for 2-3 days and then turns off by itself.
    Man from service told me that he changed capacitors and that monitor was working normally for him.

    I tried several times to unplug its power cable , sometimes monitor works for few minutes , sometimes doesnt shot any signs of working (no green or red LED lights) etc..

    First of all I looked for bad capacitors but they all look good (from physical aspect).

    You can see some pictures of my monitor:

    http://*************/photo/my-images/600/sam1767.jpg
    http://*************/photo/my-images/696/sam1770a.jpg
    http://*************/photo/my-images/600/sam1771v.jpg

    http://*************/photo/my-images/694/sam1773l.jpg
    http://*************/photo/my-images/200/sam1774.jpg

    Then I tried to check voltages from 12-pin connector (with multimeter) on power supply output and got this :

    http://*************/photo/my-images/818/sam1772u.jpg

    Is it ok !?

    I would be thankful for your help .
    Last edited by SmartVision; 06-06-2011, 12:00 PM.
    Tags: None
    #2
    Re: SmartVision LCD Monitor/TV

    For several reasons we prefer you attach the images to your post using 'Manage Attachments' (below the text entry area).

    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

      #3
      Re: SmartVision LCD Monitor/TV

      Hm , why i can't edit post ?

      Comment

        #4
        Re: SmartVision LCD Monitor/TV

        Originally posted by SmartVision View Post
        Hm , why i can't edit post ?
        Original posts have a 30min time limit. After that you cannot edit. Just attach the pics as per PlainBill.
        --- begin sig file ---

        If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post.

        We respectfully ask that you make some time and effort to read some of the guides available for basic troubleshooting. After you have read through them, then ask clarification questions or report your findings.

        Please do not post inline and offsite as they slow down the loading of pages.

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        Comment

          #5
          Re: SmartVision LCD Monitor/TV

          Your submission could not be processed because a security token was missing.

          If this occurred unexpectedly, please inform the administrator and describe the action you performed before you received this error.

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            #6
            Re: SmartVision LCD Monitor/TV

            My sig file in post #4 explains the photo/jpg restrictions.
            --- begin sig file ---

            If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post.

            We respectfully ask that you make some time and effort to read some of the guides available for basic troubleshooting. After you have read through them, then ask clarification questions or report your findings.

            Please do not post inline and offsite as they slow down the loading of pages.

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            Comment

              #7
              Re: SmartVision LCD Monitor/TV

              Here they are .

              And sorry for those unnecessary questions..
              Attached Files

              Comment

                #8
                Re: SmartVision LCD Monitor/TV

                First I'm going to get a few things off my chest. The pictures are a big help, but they could have been a lot better. Here are some comments on the major issues.

                1. A picture of the front of the TV/ Monitor is of little use.

                2. The picture of the back with all the cards in place is good; it could have been better if the cables were in place, even if they were only loosely plugged into their connectors. This helps identify the function of connectors.

                3. Conversely, I would prefer that pictures of the individual cards NOT have cables obscuring anything.

                4. Quite often valuable information can be found at the ends of boards, don't crop too closely.

                5. The overall sharpness could have been much better; still I have been able to identify one likely problem.

                6. I REALLY like the way you identified voltages on the power supply. One question - were those measurements made with the main board connected? If not, please repeat them with the main board connected, and ideally when the monitor is working and again when it is not working.

                You mentioned the technician had indicated he replaced some capacitors. Do any stand out as having been replaced?

                I have circled a number of caps on both the power supply board and the main board, what are the brand and series (Series is often a two letter designation next to the temperature rating) of these caps? (I don't need an exhaustive list, just a summary.)

                On the main board I have circled two voltage regulators. For each regulator, what is the part number, and what is the voltage on each pin? Use the mounting screw in the lower left corner as ground; the pins on the regulators should be numbered 1-3 with the pin closest to the bottom of the picture being 1.

                There is some discoloration around the voltage regulator toward the bottom of the board (IC102?). What is that?

                On the main board, I have circled an 8 pin IC in white. It appears some of the pins are poorly soldered. What is the part number of that IC, and does it appear to have been replaced?

                What country are you in? That information may help us make recommendations for parts suppliers.

                PlainBill
                Attached Files
                Last edited by PlainBill; 06-07-2011, 06:31 AM.
                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

                  #9
                  Re: SmartVision LCD Monitor/TV

                  First of PlainBill , big thanks for you time and help .

                  1.[[ You asked about measurements , they were taken without mainboard connected.
                  Now I connected everything to power supply and measured voltages on pins (picture 1) :

                  First I did with monitor not working (red light):

                  "5 V - 5 V - 5 V - GND - GND - GND - 10.65 V - 0.04 V - 13.17 V - 13.17 V - GND - GND "

                  Second one , monitor working (green light):

                  "5V - 5 V - 5 V - GND - GND - GND - 0.06 V - 0.75 V - 12.86 V - 12.86 V - GND - GND"

                  To get monitor working I needed to reconnect power cable , and it worked for 1 minute and then turned off by itself. ]]


                  2.[[ I really don't know what capacitors were changed. I took pictures of back side of power supply and mainboard .
                  I must admit that power supply looks very bad , I don't know is it done manufactured like that or that tehnician did it like that.

                  Mainboard looks very clean , like new.

                  Pictures 2 , 3 and 4. ]]


                  3.[[ Capacitors on power supply : First those two on left , bigger one is Chang - CD288H - 0804 , the smaller one is KSC - GL - 0746 .

                  Those on right side , 2 bigger are Antel (there's no serie letters) , this 4 smaller are KSC (no series) and Chang - CD288H - 0745.

                  Capacitors on mainboard are all Sancon - CD268.

                  Looking your 2 pictures. ]]


                  4. [[ Voltage regulators - left one is A1 AS1117L-33 B0739 H9.
                  Right one is A1 AS1084R K0734 . In this AS1084R regulator I can see that middle leg (pin) is not connected , it's like broken (I dont know is it normal) , you can see it one some new pictures that i put .

                  You also asked me to check voltage on each pin , well I'm not really sure how to do it but I think I measured something like 37.5 mV !? ]]


                  5. [[Discoloration at the bottom is nothing , just bad picture quality I think , you can see on new pictures. ]]


                  6. [[ It is 7ACLH8M NE5532P , I am pretty sure that it's original , it's not changed , you can see on picture 4 those 8 pins in the left bottom. ]]


                  7. [[ And the last one , I'm from Croatia ]]
                  Attached Files
                  Last edited by SmartVision; 06-07-2011, 09:08 AM.

                  Comment

                    #10
                    Re: SmartVision LCD Monitor/TV

                    Originally posted by SmartVision View Post
                    In this AS1084R regulator I can see that middle leg (pin) is not connected , it's like broken

                    You also asked me to check voltage on each pin , well I'm not really sure how to do it but I think I measured something like 37.5 mV !? ]]
                    The packaging for the AS1084R regulator is not broken. It is suppose to be like that.

                    Check the voltage regulators by putting your multimeter on DC V (20V DC if manual). Put your black probe on a ground screw on the logic board. Put your red probe on each pin of the voltage regulator and report your findings.
                    Last edited by retiredcaps; 06-07-2011, 12:44 PM.
                    --- begin sig file ---

                    If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post.

                    We respectfully ask that you make some time and effort to read some of the guides available for basic troubleshooting. After you have read through them, then ask clarification questions or report your findings.

                    Please do not post inline and offsite as they slow down the loading of pages.

                    --- end sig file ---

                    Comment

                      #11
                      Re: SmartVision LCD Monitor/TV

                      Awesome pictures. I can even follow traces.

                      This thing is amazing. It's got a very clean design, and they even label parts. I see another voltage regulator was hidden under the wire. Measure the voltage as retiredcaps suggested on U102, U103, and U104. I'm especially interested in the voltages after it shuts down.

                      I'm not enthusiastic on the caps in this TV. You are right, the work done on the power supply is pretty bad. It looks like something I did when I built my first Heathkit.

                      Croatia. Well, no point in suggesting DigiKey.

                      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

                        #12
                        Re: SmartVision LCD Monitor/TV

                        Here there are :

                        First monitor not working :

                        First (red) : 0 V -- 3.29 V -- 5.36 V
                        Second (yellow) : 0.67 V -- 1.92 V -- 4.10 V
                        Third (pink) : 0 V -- 3.32 V -- 5.36 V

                        Monitor working :

                        First (red) : 0 V -- 3.29 V -- 5.16 V
                        Second (yellow) : 0.67 V -- 1.87 V -- 3.37 V
                        Third (pink) : 0 V -- 3.32 V -- 5.16 V


                        You can see colors on picture .
                        Attached Files

                        Comment

                          #13
                          Re: SmartVision LCD Monitor/TV

                          Originally posted by SmartVision View Post
                          Here there are :

                          First monitor not working :

                          First (red) : 0 V -- 3.29 V -- 5.36 V
                          Second (yellow) : 0.67 V -- 1.92 V -- 4.10 V
                          Third (pink) : 0 V -- 3.32 V -- 5.36 V

                          Monitor working :

                          First (red) : 0 V -- 3.29 V -- 5.16 V
                          Second (yellow) : 0.67 V -- 1.87 V -- 3.37 V
                          Third (pink) : 0 V -- 3.32 V -- 5.16 V


                          You can see colors on picture .
                          We have identified a possible problem. 'Red' and 'pink' are 3.3 volt regulators and the output is stable. 'Yellow' isn't. Also, that input voltage is very low - the regulator is rated to provide up to 5 Amps with as little as 1.5 volts between input and output. With the TV on it's down to 1.2 volts; on the verge of dropping out.

                          Hmm, what is U101?

                          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

                            #14
                            Re: SmartVision LCD Monitor/TV

                            It is AS1084R

                            Comment

                              #15
                              Re: SmartVision LCD Monitor/TV

                              I don't know if this is voltage of that regulator but you can see 1.8 V under that regulator which is suspicious.

                              Red circle on Picture.
                              Attached Files

                              Comment

                                #16
                                Re: SmartVision LCD Monitor/TV

                                Originally posted by SmartVision View Post
                                I don't know if this is voltage of that regulator but you can see 1.8 V under that regulator which is suspicious.

                                Red circle on Picture.
                                There are a number of things going on here that require exploration. I'd seen that '1.8V' before, then lost sight of it. That is significant.

                                1. The `'1084' family of parts are rated for .1% load regulation and .015% line regulation. The regulation here seems to be way out of specs, you shouldn't be able to measure any variation in the output voltage.

                                2. I'd noticed this yesterday, but had a 'junior' moment and forgot to mention it. The entire area seems rather discolored - as if it had been running warm.

                                3. Where does U102 get it's power?

                                4. What is with D101 and D102, C105, and C106? That looks like the output of a bucking regulator.

                                5. R104, R105 set the output voltage.

                                And now to find something for you to check:

                                1. In the picture you attached to the latest post, the upper end of R105 should be ground. Remeasure the voltages on U102 using that as ground. That will eliminate errors due to ground resistance.

                                2. What are the part numbers of D101 and D102?

                                3. Again, referring to the last picture you attached, the left hand pin of U102 is the input. Can you trace it back to the power connector or other source of voltage?

                                What is the part number of U101?

                                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

                                  #17
                                  Re: SmartVision LCD Monitor/TV

                                  1.Results look same by puting black probe of multimeter on upper end of R105.

                                  2.It's hard to see but i think those are fr0 !?

                                  3.What do you mean , how to trace it ?

                                  4.U101 is ME9435 6737.

                                  And what you need to know of those questions from above (2,3,4 and 5) ? Here is bigger picture if it can help you.
                                  Attached Files
                                  Last edited by SmartVision; 06-08-2011, 12:01 PM.

                                  Comment

                                    #18
                                    Re: SmartVision LCD Monitor/TV

                                    OK, I've put my inconsiderable talents to work on this and came up with some answers that lead to more questions. On the top view I've traced out the current flow to U102. D101 and D102 drop the voltage to U102 so U102 generates less heat. And I take back some of the things I said about the design. This is a REALLY poor way to do it. U101 appears to be a red herring - it's a mosfet at appears to be used to switch power to something - probably whatever is connected to CN301.

                                    Crude analysis of the circuit design: 5.4 volts comes from the power supply, through the fuse, down the trace, and into D101. There should be about a 1 volt drop across D101 and again a 1 volt drop across D102. This results in 3.4 volts into U102, which is wired to provide 1.8 volts. Note that the input voltage is 1.6 volts higher than the output - just about perfect for minimum dissipation in U102.

                                    What went wrong? There are several possibilities. Ordinarily U102 maintains regulation to within .2%. Even with the monitor not working the output (1.92V) is much higher than that. If R104 and R105 were 5% tolerance it would explain some but not all of that error. THAT suggests U102 may be damaged. Another possibility is the output capacitors of the power supply or C106 (the input cap for the 1.8 volt regulator) and the output cap of U102 (I can't see a designator) are allowing excessive ripple, and U102 is on the ragged edge of dropping out of regulation. ANOTHER possibility is D101 and D102 have a slightly high voltage drop, reducing the input voltage to U102. And ANOTHER possibility is that U403 is drawing excessive current.

                                    My suggestions:

                                    1. Measure the voltage at the anode of D101. This SHOULD be 5.4 volts.

                                    2. Measure the voltage across D101, and the voltage across D102. If the voltage drop across either is more than .1 volt higher that the the other, consider replacing the one with the higher voltage drop.

                                    3. Consider replacing C106 with a name brand low ESR cap.

                                    4. Consider replacing U102 if you have the equipment and skills to do so.

                                    5. A REALLY desperate test - jumper across either D101 or D102. This will increase the input voltage to U102. It could also kill U102 and even U403.

                                    PlainBill
                                    Attached Files
                                    Last edited by PlainBill; 06-08-2011, 08:45 PM.
                                    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

                                      #19
                                      Re: SmartVision LCD Monitor/TV

                                      1. Voltage on anode of D101 is 5.36 V.

                                      2. Now I measured voltage on D101 - on anode is 5.36 and on cathode 4.73 V.

                                      On D102 on anode is 4.73 V and on cathode is 4.10 V.

                                      3. Do I need to replace C106 with same voltage or I can take some litlle higher.

                                      4. I'll try to change U102 .

                                      Comment

                                        #20
                                        Re: SmartVision LCD Monitor/TV

                                        Originally posted by SmartVision View Post
                                        1. Voltage on anode of D101 is 5.36 V.

                                        2. Now I measured voltage on D101 - on anode is 5.36 and on cathode 4.73 V.

                                        On D102 on anode is 4.73 V and on cathode is 4.10 V.

                                        3. Do I need to replace C106 with same voltage or I can take some litlle higher.

                                        4. I'll try to change U102 .
                                        You can use a cap with a higher voltage rating. I'd like to emphasize that it must be a low ESR cap.

                                        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

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