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    #81
    Re: Getting started with troubleshooting [Samsung 245BW]

    You are probably narrowing down on the original issue, which caused the switching MOSFETs to fry in the first place. Do you get 24v with the inverter board disconnected? Keep the light bulb in circuit for the time being, it may save your bacon.
    Originally posted by PeteS in CA
    Remember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.
    A working TV? How boring!

    Comment

      #82
      Re: Getting started with troubleshooting [Samsung 245BW]

      Originally posted by Th3_uN1Qu3 View Post
      You are probably narrowing down on the original issue, which caused the switching MOSFETs to fry in the first place. Do you get 24v with the inverter board disconnected? Keep the light bulb in circuit for the time being, it may save your bacon.
      Even with the inverter board disconnected, I get 0V on the "24V" pins. I traced those pins back to the "+5.3V" pins on the connector on the left side of the board (using the continuity feature), and those +5.3V pins also measure 0V. I made sure the monitor was "on" and not in "standby" when measuring the voltages.

      I don't know if it's relevant, but I also took measurements on the smaller cable on the left hand side, above the cable that has the S_B pin. They also measured 0V. The labels of those pins are, from top to bottom:

      DET
      ST/PWM_DIM
      ANA_DIM
      SOS
      BL
      Attached Files

      Comment

        #83
        Re: Getting started with troubleshooting [Samsung 245BW]

        If 5.0V standby is now steady, let's make sure it is reaching the logic board. The logic board tells the power supply to start.

        See picture (one person in another thread questions why pictures are needed and implies that I'm an idiot for even asking).

        List the part number and DC voltages each pin, of the red and yellow circled component (the two components that are designated IC on the PCB - one is IC703).

        Measure each pin (except the big tab) with respect to ground. Use a ground screw on the logic board for ground.
        Attached Files
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          #84
          Re: Getting started with troubleshooting [Samsung 245BW]

          Originally posted by retiredcaps View Post
          If 5.0V standby is now steady, let's make sure it is reaching the logic board. The logic board tells the power supply to start.

          See picture (one person in another thread questions why pictures are needed and implies that I'm an idiot for even asking).

          List the part number and DC voltages each pin, of the red and yellow circled component (the two components that are designated IC on the PCB - one is IC703).

          Measure each pin (except the big tab) with respect to ground. Use a ground screw on the logic board for ground.
          The red circle is IC705, and the part number is AnaChip 1501-33. Here is the data sheet:
          http://www.alldatasheet.com/datashee...IP/AP1501.html

          The measurements for the 1501-33 are:

          Pin 1: 5.18V
          Pin 2: 3.30V
          Pin 3: 0V
          Pin 4: 3.23V
          Pin 5: 0V

          From what I can understand from the datasheet, it seems that Pins 1 through 4 have the correct values, but I'm not sure about Pin 5?

          The part number on IC703 is "J412 953-18". I wasn't able to find a datasheet for this one. The measurements are:

          Pin 1: 2.93V (3.18V if I turn the monitor off)
          Pin 2: 0V
          Pin 3: 1.78V (regardless of on or off)

          The pins were counted from left to right using RetiredCaps' picture.
          Last edited by nerdbot; 05-20-2011, 08:00 PM.

          Comment

            #85
            Re: Getting started with troubleshooting [Samsung 245BW]

            Ok, now this is weird. I searched other threads for "953-18" to see if anyone else had measurements I could compare against (which I did find, and I guess my readings are normal). I then checked the voltage across the main capacitor, that previously measured 160V. It now reads 384V!

            Comment

              #86
              Re: Getting started with troubleshooting [Samsung 245BW]

              Originally posted by nerdbot View Post
              The measurements for the 1501-33 are:

              Pin 1: 5.18V
              Pin 2: 3.30V
              Pin 3: 0V
              Pin 4: 3.23V
              Pin 5: 0V
              The suffix in part numbers like the one above indicate the output voltage. So -33 denotes 3.3V DC. So pin 2, it spot on at 3.30V DC.

              The part number on IC703 is "J412 953-18". I wasn't able to find a datasheet for this one. The measurements are:

              Pin 1: 2.93V (3.18V if I turn the monitor off)
              Pin 2: 0V
              Pin 3: 1.78V (regardless of on or off)
              -18 indicates 1.80V DC should be the output. Most of these parts should be with 1% of the output rating. That is 1.80 x 0.99 = 1.782. Let's say this voltage regulator is working properly because most multimeters are +/- 0.5% accuracy on DC V.
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                #87
                Re: Getting started with troubleshooting [Samsung 245BW]

                Originally posted by nerdbot View Post
                I then checked the voltage across the main capacitor, that previously measured 160V. It now reads 384V!
                Monitors bigger than 19 inch "normally" have 2 power supplies. 384V DC is "normal" when a PFC is involved. That is good news. The power supply is trying to start.
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                  #88
                  Re: Getting started with troubleshooting [Samsung 245BW]

                  1) What are the part numbers for each of the 4 colored transistors?

                  2) Test each of the above for shorts.

                  3) If there are no shorts, measure each pin for DC voltage with respect to ground. Use a ground screw for your black probe.
                  Attached Files
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                    #89
                    Re: Getting started with troubleshooting [Samsung 245BW]

                    Regarding the 384V DC and PFC, see PlainBill's post at

                    https://www.badcaps.net/forum/showpo...&postcount=171

                    the other Samsung245BW thread.

                    Some of the suggestions are now relevant to you now.
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                      #90
                      Re: Getting started with troubleshooting [Samsung 245BW]

                      Originally posted by retiredcaps View Post
                      1) What are the part numbers for each of the 4 colored transistors?

                      2) Test each of the above for shorts.

                      3) If there are no shorts, measure each pin for DC voltage with respect to ground. Use a ground screw for your black probe.
                      Red - EN210A 8222EN
                      Green - EN210A 8222EN
                      Couldn't find a datasheet for these 2

                      Light blue - N 8A FCQ10A04 S255K


                      Magenta - SIK (i think) 8008HFE


                      I tested them using the same method I used for the other MOSFETs, though I think the "light blue" transistor is a Schottky Barrier Diode, so I'm not sure if that's the proper way to test it.

                      Red transistor -
                      Black Pin 1, Red Pin 2 - 19.7 ohms
                      Black Pin 1, Red Pin 3 - 0.3 ohms
                      Black Pin 2, Red Pin 3 - 21.0 ohms

                      Green transistor -
                      Black Pin 1, Red Pin 2 - 19.7 ohms
                      Black Pin 1, Red Pin 3 - 0.3 ohms
                      Black Pin 2, Red Pin 3 - 21.0 ohms

                      Light blue transistor -
                      Black Pin 1, Red Pin 2 - 21.4 ohms
                      Black Pin 1, Red Pin 3 - 0.4 ohms
                      Black Pin 2, Red Pin 3 - 22.6 ohms

                      Magenta transistor -
                      (From the data sheet, it looks like pin 3 is the ground pin, so I used that for my black probe and measured the resistance between the other 4 pins)
                      Black Pin 3, Red Pin 1 - 19.5 ohms
                      Black Pin 3, Red Pin 2 - 21.4 ohms
                      Black Pin 3, Red Pin 4 - 700 ohms
                      Black Pin 3, Red Pin 5 - 590 ohms

                      Comment

                        #91
                        Re: Getting started with troubleshooting [Samsung 245BW]

                        Originally posted by nerdbot View Post
                        Red transistor -
                        Black Pin 1, Red Pin 2 - 19.7 ohms
                        Black Pin 1, Red Pin 3 - 0.3 ohms
                        Black Pin 2, Red Pin 3 - 21.0 ohms

                        Green transistor -
                        Black Pin 1, Red Pin 2 - 19.7 ohms
                        Black Pin 1, Red Pin 3 - 0.3 ohms
                        Black Pin 2, Red Pin 3 - 21.0 ohms

                        Light blue transistor -
                        Black Pin 1, Red Pin 2 - 21.4 ohms
                        Black Pin 1, Red Pin 3 - 0.4 ohms
                        Black Pin 2, Red Pin 3 - 22.6 ohms

                        Magenta transistor -
                        (From the data sheet, it looks like pin 3 is the ground pin, so I used that for my black probe and measured the resistance between the other 4 pins)
                        Black Pin 3, Red Pin 1 - 19.5 ohms
                        Black Pin 3, Red Pin 2 - 21.4 ohms
                        Black Pin 3, Red Pin 4 - 700 ohms
                        Black Pin 3, Red Pin 5 - 590 ohms
                        Hmm, all the above readings would suggest that all those 4 components are possibly shorted.

                        Given how QM802 andQM803 were bad, it is possible that this board got some severe damage?

                        I would desolder just one transistor (say the red circled one) and retest it for a short. There could be something "in circuit" that gives these 4 transistors a "false" reading?

                        If you want to minimize the work involved in desoldering the red circled transistor, try to just "lift one leg" of the transistor and retest.
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                          #92
                          Re: Getting started with troubleshooting [Samsung 245BW]

                          Originally posted by retiredcaps View Post
                          Hmm, all the above readings would suggest that all those 4 components are possibly shorted.

                          Given how QM802 andQM803 were bad, it is possible that this board got some severe damage?

                          I would desolder just one transistor (say the red circled one) and retest it for a short. There could be something "in circuit" that gives these 4 transistors a "false" reading?

                          If you want to minimize the work involved in desoldering the red circled transistor, try to just "lift one leg" of the transistor and retest.
                          I guess anything's possible... I recall saying earlier how I was surprised I didn't screw up something bigger sooner Could it be that when I tried those first two resistors (before fixing the QM802/803 mosfets) that it caused damage to the other 4 transistors? When the resistors blew, I didn't turn off the power immediately, but maybe 15-20 seconds later.

                          I'll desolder one of them in the morning. If it does turn out that they are shorted, I believe Th3_uN1Qu3 said they were kinda hard to find. I guess at that point I'd be looking at just buying a new power board?

                          Comment

                            #93
                            Re: Getting started with troubleshooting [Samsung 245BW]

                            If it's the 5 pin ones, yes, you're going to have a hard time locating them. They are custom parts that go out of production soon after they're released. A new power board would be a good idea.
                            Originally posted by PeteS in CA
                            Remember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.
                            A working TV? How boring!

                            Comment

                              #94
                              Re: Getting started with troubleshooting [Samsung 245BW]

                              If the 5 pin IC is bad, I use findchips.com

                              http://www.findchips.com/avail?part=8008HFE

                              However, the cost of replacing all the shorted ICs may only be the beginning. Other components may be shorted after replacing these.

                              If you want the satisfaction of potentially fixing your board, then you may want to replace whatever ICs are shorted.
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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.

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                                #95
                                Re: Getting started with troubleshooting [Samsung 245BW]

                                I attached pictures of the red, green (both marked "EN210A 8222EN", and light blue ("FCQ1A04") transistor .

                                When I pulled out the red transistor and measured it again, I got the following readings (counting pins from left to right using the attached pictures):

                                Black Pin 1, Red Pin 2 - Out of range
                                Black Pin 1, Red Pin 3 - Out of range
                                Black Pin 2, Red Pin 3 - 140.8 Ohms

                                Since the little icons on the transistor looked like diode symbols, I also tried:

                                Black Pin 2, Red Pin 1 - 140.7 Ohms

                                And just for kicks:

                                Black Pin 3, Red Pin 1 - Out of range
                                Black Pin 3, Red Pin 2 - Out of range

                                Because these readings looked better than when in-circuit, I pulled all the transistors and tested them. Out of circuit, the green transistor tested similarly as the red above:

                                Black Pin 1, Red Pin 2 - Out of range
                                Black Pin 1, Red Pin 3 - Out of range
                                Black Pin 2, Red Pin 1 - 141.5 Ohms
                                Black Pin 2, Red Pin 3 - 141.3 Ohms
                                Black Pin 3, Red Pin 1 - Out of range
                                Black Pin 3, Red Pin 2 - Out of range

                                Light blue transistor:
                                Black Pin 1, Red Pin 2 - Out of range
                                Black Pin 1, Red Pin 3 - Out of range
                                Black Pin 2, Red Pin 1 - 116.5 Ohms
                                Black Pin 2, Red Pin 3 - 116.4 Ohms
                                Black Pin 3, Red Pin 1 - Out of range
                                Black Pin 3, Red Pin 2 - Out of range

                                Magenta transistor:
                                Again, I tested using the black on pin 3, since the datasheet indicates that is the ground pin. Sadly, after pulling this one out, I could see what looked like a blister on the front (picture attached), and it tested similarly to when it was in-circuit

                                Black Pin 3, Red Pin 1 - 20.1 ohms
                                Black Pin 3, Red Pin 2 - 21.4 ohms
                                Black Pin 3, Red Pin 4 - Out of range
                                Black Pin 3, Red Pin 5 - 604 ohms

                                So I'm thinking, of course, the one that is broken is the one that's hardest to find?

                                Originally posted by retiredcaps View Post
                                If the 5 pin IC is bad, I use findchips.com

                                http://www.findchips.com/avail?part=8008HFE

                                However, the cost of replacing all the shorted ICs may only be the beginning. Other components may be shorted after replacing these.

                                If you want the satisfaction of potentially fixing your board, then you may want to replace whatever ICs are shorted.
                                Well, in the course of troubleshooting my 245BW, I have fixed 3 other monitors - my smaller and older Samsung 204B, and 2 for friends, so I have felt the deeply satisfying feeling of bringing back monitors from the dead with my own 2 hands I won't lie though, it would've been nice to get the 245BW working w/ just a few replaced parts - but I see that one of the suppliers RetiredCaps' provided that can ship to the US has a $20 handling fee for a $4 part. Similarly, I can get a "non-working" (as in they don't know exactly what's wrong with it) BN44-00195A from eBay for $20 + shipping, but who knows if the transistor I'd need is working on that one either.

                                While I'd like to go 4 for 4 with revived monitors, $24 is about 30% of the way towards a brand new power board. So, sadly, I think I'll cut my losses here

                                Regardless, it's been a great learning experience for me, and I had a lot of fun learning how to solder and fix these monitors. Prior to this, I knew enough to just buy the replacement boards for dead monitors, which was still a better deal than replacing them completely. Now I know I can often fix them for far less than that! I really appreciate everyone's help with educating me along the way.

                                A few remaining questions:

                                1.) Currently, I can either get the BN44-00195A board from eBay (as a board pulled from a previously working monitor, supposedly working and not the same as the "non-working" one I mentioned above) or from partstore.com brand new. Has anyone had any experience with partstore.com?

                                2.) I tried searching the forums but I didn't have much luck - what's the proper way to dispose of the capacitors I've removed? My company has an electronics recycling bin, but that's usually filled with larger electronics (computers, monitors, motherboards, etc), and I hear those just get sent off to China to be scrapped for parts.
                                Attached Files

                                Comment

                                  #96
                                  Re: Getting started with troubleshooting [Samsung 245BW]

                                  Originally posted by nerdbot View Post
                                  1.) Currently, I can either get the BN44-00195A board from eBay
                                  The ebay one for $20, if you look closely at the picture, has at least one bloated cap (near top right hand corner). The auction does state "The monitor was starting up after a long wait." so it could be a simple recap to fix this power board?

                                  My company has an electronics recycling bin, but that's usually filled with larger electronics (computers, monitors, motherboards, etc)
                                  Are there are any dead monitors in the bin that you can get?
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                                    #97
                                    Re: Getting started with troubleshooting [Samsung 245BW]

                                    Originally posted by retiredcaps View Post
                                    The ebay one for $20, if you look closely at the picture, has at least one bloated cap (near top right hand corner). The auction does state "The monitor was starting up after a long wait." so it could be a simple recap to fix this power board?
                                    Yeah, I did notice that, though it still is a gamble. Maybe I'll wait until closer to the end of the auction. If I can get get it for closer to $20 (instead of the buy it now of $34), I might be inclined to try it (I did buy twice as many caps as I needed when I originally ordered the replacements caps for the 245BW...)


                                    Originally posted by retiredcaps View Post
                                    Are there are any dead monitors in the bin that you can get?
                                    The monitors that are in there are often either dead KVM LCD panels or CRTs.
                                    Last edited by nerdbot; 05-21-2011, 08:04 PM.

                                    Comment

                                      #98
                                      Re: Getting started with troubleshooting [Samsung 245BW]

                                      Farnell,UK 509 in stock:-
                                      http://uk.farnell.com/allegro-sanken...Ntt=SI-8008HFE

                                      Comment

                                        #99
                                        Re: Getting started with troubleshooting [Samsung 245BW]

                                        Well, I'm back. I ended up getting that used power board off of eBay for $20, and I replaced all the caps on it. I plugged it in to the logic board, connected the front bezel, and plugged everything into the current limiter power strip. I turned on the power switch on the power board, and the light bulb flashed momentarily then went dark. I then turned on the monitor and again, the light bulb flashed momentarily, then went dark, while the blue power LED stayed lit. From what I understand, this is correct behavior.

                                        I then unplugged the monitor, connected the power board to the inverter board, and plugged the monitor into a regular outlet and turned it on. The power LED came on, the backlight came on, but it is solid white. Also, as soon as the backlight came on, something on the logic board popped. I attached a picture. It's labeled D701. Even after D701 popped, the backlight remained on.

                                        When I connect a VGA cable to my laptop and set it to use the 245BW, the backlight comes on, the screen is white like before, but it flickers often, but with a random pattern.

                                        I'm guessing something else is bad on this different power board that caused D701 on the logic board to blow?
                                        Attached Files

                                        Comment

                                          #100
                                          Re: Getting started with troubleshooting [Samsung 245BW]

                                          Originally posted by nerdbot View Post
                                          I'm guessing something else is bad on this different power board that caused D701 on the logic board to blow?
                                          I don't think so. I think that unfortunately the main processor (the Genesis chip) is bad, and its excess current draw blew the diode.
                                          Originally posted by PeteS in CA
                                          Remember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.
                                          A working TV? How boring!

                                          Comment

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