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    #1

    Hanns-G 281D -- No power, Replaced Powerboard

    Hi guys,

    I've read a couple Hanns-G threads for this very same monitor (281D) on this site, and I concluded that I had a problem relating to bad capacitors (a common problem for this monitor), where the capacitors dry out, causing a high ESR condition. I couldn't get the monitor to turn on at all, and no "Standby" mode either. It was as if the monitor wasn't plugged in at all/

    A fine gent was nice enough to post the needed capacitors to do a full replace of the board (on this forum), and I ordered them from Digikey. However, I was a bit too eager in the removal process and "messed up" a couple of the capacitors copper tracks & figured all was lost.

    Anyways, I ordered a replacement power supply, supposedly tested from an online site. The part number is PSM217-404-H-R. It replaces several different monitors, from 26-38 inches in size (viewsonic, hannspree, hanns G, etc). I put the monitor back together with the new supply, and still is having the same issue. For trouble shooting they told me to do this:

    "We have test the item before we send out it.
    Can you Please test below:

    +5SB 5V
    PSON 5V
    connect +5SB and PSON test 24V 12V normal or not

    Please don't connect dirver board. just test power board
    independently."

    Where exactly would I test for this? It's definitely getting voltage from the wall... Could this trouble shooting the company is reccomending pan out, and the monitor would still refuse to turn on? That's where the capacitor issue could come in, however I don't trust my skill to do the job, especially after screwing up last time :-(

    Thanks for any suggestions any of you guys have...

    Tyler
    Tags: None
    #2
    Re: Hanns-G 281D -- No power, Replaced Powerboard

    The initial fault you had,totally 'dead',does not mean that the Power Supply Board is the problem,and the Logic board may well be faulty.
    What they have asked you to do,is plug the Board into the mains supply with NO other board connected,switch on and measure the 5v Standby voltage ,which should be indicated on the connector going to the Logic board(this is where photos, are a necessity ) if you need further help.If you have the 5v then connect that to the pin that says PSON(Power Supply On) and then measure the 12v and 24v outputs of the Board, if you have them then the Board is fine, and the fault is probably on the Logic Board.

    Comment

      #3
      Re: Hanns-G 281D -- No power, Replaced Powerboard

      The initial fault was that the monitor became harder and harder to turn on -- sometimes it would turn on right away, other times it would take 20-30 presses of the ON switch to get it to "catch". My friend who gave me the monitor said that it started doing it a year ago, and he just put it in the closet and let it sit.

      I could get the monitor to turn on for about 2 weeks, then it got worse and worse, then nothing at all.

      Here are some pictures of my powerboard. None of the capacitors are bulging or anything like that. there is a logic board on ebay now. Any ideas on how i could test it for functionality?

      https://dl.dropbox.com/u/24984984/po...er%20board.JPG

      https://dl.dropbox.com/u/24984984/po...20Heatsink.jpg

      https://dl.dropbox.com/u/24984984/po...%20Removed.jpg

      I could post a picture of the previous board, which i de-capped, and started re-capping when i ran into the problem of getting the solder to stick.

      Comment

        #4
        Re: Hanns-G 281D -- No power, Replaced Powerboard

        I will steal this from retiredcaps :

        __________________
        --- 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.

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        _________________________


        That said, you have in the picture of the bottom side of the powerboard marks of 12V, 24V, GND , 5V, 5V Stand By, etc.

        First, measure with black probe in GND, red probe in +5VSB.

        If there is 5V in it, use a 1K resistor to connect it to PSON. Then with red probe in the other voltages ( +12V, +5V and +24V ) see if there are voltages present.

        Inform your findings.

        Comment

          #5
          Re: Hanns-G 281D -- No power, Replaced Powerboard

          You cannot test the functionality of the Logic Board,all you can test on there are the Voltage regulators,but as there is no photos of them,cannot point them out...ALSO please use the photo software which comes under Advanced.

          Comment

            #6
            Re: Hanns-G 281D -- No power, Replaced Powerboard

            sorry for the crummy photos -- here are some high res ones, which i borrowed from a couple different threads on this site.

            In measuring 12v & 24v, does that mean the voltage at the pins will default to 12v and then go to 24v once the power button is pressed? or are there two separate terminals that I should probe, one for 12v and one for 24?
            Attached Files

            Comment

              #7
              Re: Hanns-G 281D -- No power, Replaced Powerboard

              Once you have connected the 5v to the PSon then that is all you need,you were already advised that NO other Boards need to be attached...ONLY the Power Board itself.

              Comment

                #8
                Re: Hanns-G 281D -- No power, Replaced Powerboard

                Originally posted by tylerwerrin View Post
                sorry for the crummy photos -- here are some high res ones, which i borrowed from a couple different threads on this site.

                In measuring 12v & 24v, does that mean the voltage at the pins will default to 12v and then go to 24v once the power button is pressed? or are there two separate terminals that I should probe, one for 12v and one for 24?
                Look at the underside of the power board. The pins of the connectors have marks like "+12V", "+24V", etc.

                The voltages in these pins should measure near the values marked on them.

                First, measure the 5VSB one. And inform if it is ok.

                Comment

                  #9
                  Re: Hanns-G 281D -- No power, Replaced Powerboard

                  Hi guys,

                  I took the readings with my multimeter.

                  5SB -- 0V
                  PSON -- 0V
                  all the 12v -- 0V
                  all the 24v -- 0V

                  I tested the power board without any other cables connected but the AC plug. I used several different verified ground points, and no change. All measurements were taken with the AC function on my multi meter, as well as DC (just to make double sure.)

                  What should I do next? Should I try connecting other cables to the powerboard (like the inverter, motherboard, etc.?)

                  Comment

                    #10
                    Re: Hanns-G 281D -- No power, Replaced Powerboard

                    Originally posted by tylerwerrin View Post
                    I took the readings with my multimeter.

                    5SB -- 0V

                    I tested the power board without any other cables connected but the AC plug. I used several different verified ground points, and no change. All measurements were taken with the AC function on my multi meter, as well as DC (just to make double sure.)
                    Since I have no idea if you are experienced in using a multimeter or not, let's try this.

                    1) Post a picture of it.

                    2) Measure a fresh new AA battery. Report your reading.

                    3) The 5V SB pin is DC volts. Your red probe should be on that pin. Your black probe should be on the chassis or ground screw. Do not connect any other boards. Just plug in the AC plug.

                    4) If you have no 5V SB and we are sure you are measuring it right, then you might have a blown fuse.

                    5) My fellow Canadian afrotechmods makes an excellent multimeter tutorial (less than 5 minutes)

                    http://www.youtube.com/watch?v=bF3OyQ3HwfU
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                    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: Hanns-G 281D -- No power, Replaced Powerboard

                      "Measure a fresh new AA battery. Report your reading."

                      1.53v

                      "The 5V SB pin is DC volts. Your red probe should be on that pin. Your black probe should be on the chassis or ground screw. Do not connect any other boards. Just plug in the AC plug."

                      I probed all the pins. Got nada, although sometimes i can get a flutter in the MV ratings -- it will start at .8~mv or so and then drift down to 0.00v.

                      "multimeter tutorial vid on youtube"
                      I watched this, its very informative. I've used multimeters for mostly automotive applications, but I've got a pretty decent handle on how to work them.

                      "may have a blown fuse"
                      Where on this board would the fuse be? Could you direct me to it? I'm leaning towards the heat shrunk wrapped "thing" by the large brown capacitor (the big 420v one.)
                      Attached Files
                      Last edited by tylerwerrin; 09-07-2012, 12:31 AM.

                      Comment

                        #12
                        Re: Hanns-G 281D -- No power, Replaced Powerboard

                        Originally posted by tylerwerrin View Post
                        Where on this board would the fuse be? Could you direct me to it? I'm leaning towards the heat shrunk wrapped "thing" by the large brown capacitor (the big 420v one.)
                        1) Your fuse is likely in the top right hand corner. It is red and square. On the board, it should say something like F100. "F" stands for fuse.

                        2) A good fuse should measure less than 1.0 ohms. Always measure resistance with power off and lcd unplugged.

                        3) One retiredcaps' point or a picture of your multimeter.

                        4) Do know that you have the red probe on the negative terminal and black probe on the positive terminal in the picture? While it may not matter for an AA battery, it will matter when taking more advanced voltages because there is a hot and cold ground. Getting the 2 confused will cause readings that are hard to interpret.
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                        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

                          #13
                          Re: Hanns-G 281D -- No power, Replaced Powerboard

                          5) Since I can't see how you have things connected, I have to ask the obvious.

                          a) Do you have the AC cord plugged into a known working outlet?
                          b) Do you have the cable connected to the power board that is connected in green?

                          PS. Your fuse is circled in red.
                          Attached Files
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                          Comment

                            #14
                            Re: Hanns-G 281D -- No power, Replaced Powerboard

                            Thanks retiredcaps --

                            Yep, I got an AC plugged in from a working wall socket. I have the plug which connects the powerboard to the AC plug connected to the board (the one circled in green.)

                            I measured the ohms on the "new" board for the fuse...it reads 9.04 Mohms (M and the ohm symbol, i''m guessing mega ohms, which is a huge number).

                            I then measured the ohms for the fuse on my "old" board (the one which I tried to re-cap, and kinda messed it up) and got around .4 ohm (which is about what you said it should be, for a good fuse)

                            Sooo maybe my problem is just a fuse on the "new" board? I'll have to check RadioShack if they have a new fuse, or I can just pinch the fuse from my other board to test with in the meantime. Thanks for your help so far --

                            Comment

                              #15
                              Re: Hanns-G 281D -- No power, Replaced Powerboard

                              Originally posted by tylerwerrin View Post
                              Anyways, I ordered a replacement power supply, supposedly tested from an online site.
                              Call them up and tell them the fuse is blown on their "tested" board. A blown fuse could be masking other problems on the board namely a shorted power mosfet or bridge rectifier.
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                              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.

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

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                              Comment

                                #16
                                Re: Hanns-G 281D -- No power, Replaced Powerboard

                                sadly they are in china somewhere, so i can't call em up. Their emails are hard enough to understand as it is. In the meantime I will try another fuse and see if it blows. If it holds, I'll test the voltages again and update the thread with what I come back with.

                                Comment

                                  #17
                                  Re: Hanns-G 281D -- No power, Replaced Powerboard

                                  I got the new fuse installed -- the voltage at 5VSB now fluctuates in the 4.75 range. It is never stable at any point.

                                  Comment

                                    #18
                                    Re: Hanns-G 281D -- No power, Replaced Powerboard

                                    Originally posted by tylerwerrin View Post
                                    I got the new fuse installed -- the voltage at 5VSB now fluctuates in the 4.75 range. It is never stable at any point.
                                    If the standby voltage is fluctuating, then you likely have bad caps like Mishannya

                                    https://www.badcaps.net/forum/showthread.php?t=11329

                                    It sounds like you got completely ripped off on a "tested" and working board. First the fuse is blown and now you have unstable 5V SB power.

                                    I would file a complaint and try to get your money back.
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                                    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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                                      #19
                                      Re: Hanns-G 281D -- No power, Replaced Powerboard

                                      Thanks for the help with the diagnosis, retiredcaps. I wrote to the company -- we'll see what they say. I still have the other board, which i completely de-capped, however getting it re-capped has proven to be challenging for me. Hopefully I'll get a working replacement board.

                                      One last question, from an engineering standpoint, does the fluctuating 5v SB voltage tell the monitor that it can't turn on because it hasn't met it's 5V requirement? what if the SB had reached 5V, but other voltages were fluctuating? would that cause a similar "no on" problem? Just curious.

                                      T

                                      Comment

                                        #20
                                        Re: Hanns-G 281D -- No power, Replaced Powerboard

                                        Now that you have some SB Voltage, and you may have faulty caps, what happens when you now plug everything in and switch on ???????/

                                        Comment

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