Gateway FPD1975w SMPS

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • alexanna
    Member
    • Mar 2010
    • 1346

    #1

    Gateway FPD1975w SMPS

    This Monitor does not have any secondary voltages. And the power supply is different than other FPD1975w monitors
    I measure 164v DC across the large capacitor.
    The SMPS controller is an NPC1337.
    There are two 25v 47UF capacitors in the area of the SMPS that have been replaced with Nichicon PW series.
    The pin voltages of the NPC1337 are
    1= .9v
    2=0v
    3=0v
    4=0v
    5=.2v
    6=8v
    8=25.5v
    I am still not familiar with the start up process,But I feel pin # 1 may be a cause for concern.
    I have attached a data sheet.
    Al.
    Attached Files
    Whatever I do, I consider it a success, if in the end I am breathing, seeing, feeling and hearing!
  • jetadm123
    Badcaps Legend
    • Feb 2010
    • 2169

    #2
    Re: Gateway FPD1975w SMPS

    Replacing the 47uf startup caps eliminated one possible source of problems. Pin 6 is the VCC. The NCP1137 stays off at under 10V and starts at 12V. You have 8V. Pin 6 voltage is provided by a diode fed off the main transformer. Check this diode for a short. There may also be additional caps or resistors connected to pin 6 or the diode. Check these for shorts/proper values. Also check the mosfet on the heatsink above the large 450V cap for shorts.

    Comment

    • PlainBill
      Badcaps Legend
      • Feb 2009
      • 7034
      • USA

      #3
      Re: Gateway FPD1975w SMPS

      And one point not yet mentioned, the NPC1337 may be bad.

      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

      • alexanna
        Member
        • Mar 2010
        • 1346

        #4
        Re: Gateway FPD1975w SMPS

        Ok this thing came back to life. It most likely was a poor solder joint on the SMPS coil although I did re solder other things on the hot side of the board.
        Some of the voltages changed on the NPC1337
        Pin 1 is now 1.09v
        #2 is .13v
        #6 is reading 11v
        And pin #8 came up to 128v
        I have not hooked up the logic board yet but I do have a good 5v going to the connector.
        Looking at the rest of this power supply it's probably a good candidate for a lot of fresh solder.
        Al.
        Whatever I do, I consider it a success, if in the end I am breathing, seeing, feeling and hearing!

        Comment

        • alexanna
          Member
          • Mar 2010
          • 1346

          #5
          Re: Gateway FPD1975w SMPS

          I spoke to soon on this monitor, after verifying I had a good 5 volts going to the logic board I did a total recap of the P/S inverter. Putting everything back together I had a really nice picture, and everything was working as it should. When I woke up this morning it is dead again.
          I was really hoping I could boost my average of problems that I have posted in the forum,
          I think so far I'm batting close to .000
          Am I thinking correctly of a poor solder connection causing the problem?
          Whatever I do, I consider it a success, if in the end I am breathing, seeing, feeling and hearing!

          Comment

          • PlainBill
            Badcaps Legend
            • Feb 2009
            • 7034
            • USA

            #6
            Re: Gateway FPD1975w SMPS

            Originally posted by alexanna
            I spoke to soon on this monitor, after verifying I had a good 5 volts going to the logic board I did a total recap of the P/S inverter. Putting everything back together I had a really nice picture, and everything was working as it should. When I woke up this morning it is dead again.
            I was really hoping I could boost my average of problems that I have posted in the forum,
            I think so far I'm batting close to .000
            Am I thinking correctly of a poor solder connection causing the problem?
            Poor solder, or a component overheating.

            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

            • alexanna
              Member
              • Mar 2010
              • 1346

              #7
              Re: Gateway FPD1975w SMPS

              There was a huge difference on pin #8,the high voltage pin.On the schematic of the NPC1337 it shows pin 8 being fed voltage through a resistor and the SMPS coil,with a Mosfet involved and through another resistor to pin 4 of NPC1337 which is a ground.
              And I am guessing there are some diodes involved although it doesn't show them in the simple schematic.
              Is that a good description of the circuit? Or is something else involved?
              Al.
              Whatever I do, I consider it a success, if in the end I am breathing, seeing, feeling and hearing!

              Comment

              • PlainBill
                Badcaps Legend
                • Feb 2009
                • 7034
                • USA

                #8
                Re: Gateway FPD1975w SMPS

                Originally posted by alexanna
                There was a huge difference on pin #8,the high voltage pin.On the schematic of the NPC1337 it shows pin 8 being fed voltage through a resistor and the SMPS coil,with a Mosfet involved and through another resistor to pin 4 of NPC1337 which is a ground.
                And I am guessing there are some diodes involved although it doesn't show them in the simple schematic.
                Is that a good description of the circuit? Or is something else involved?
                Al.
                The drawing in the datasheet is incomplete. Here's the usual design. The rectified line voltage goes to pin 8 of the IC. There is a filter cap connected to pin 6. The IC contains a constant current regulator which charges the cap from the rectified line voltage. When the voltage at pin 6 reaches about 12 volts the SMPS controller starts driving the gate of the FET. It also turns off the constant current regulator, as a result the voltage at pin 8 will rise. The FET of course drives the primary of the transformer; secondary windings are rectified to produce the output voltages, typically 5V and 12V. The 5V output is monitored and fed back to the SMPS controller through the opto-isolator to maintain a constant 5V at the output.

                There is a tertiary winding on the transformer that is connected to pin 6 through a diode and sometimes a resistor. That provides the run power for the IC.

                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

                • alexanna
                  Member
                  • Mar 2010
                  • 1346

                  #9
                  Re: Gateway FPD1975w SMPS

                  Well my hair has developed a lot more gray ones; I know this should be very simple.
                  This has failed in a different way there is only 180MV showing on pin 6 of the NPC1337
                  What I have found is pin 6 of the NPC1337 is grounded. If I place the red lead of the DMM on the positive lead of the large cap I am reading 164VDC with the negative of the DMM hooked to pin 6 of the NPC1337.The small 25v 47uf cap is not shorted and there are some poly caps that appear to be in the circuit also, these are not shorted. So I don’t think that pin 6 should be grounded.
                  If I check resistance of pin 4 to pin 6 I am reading 380 ohms.
                  Last edited by alexanna; 03-31-2011, 08:31 PM.
                  Whatever I do, I consider it a success, if in the end I am breathing, seeing, feeling and hearing!

                  Comment

                  • PlainBill
                    Badcaps Legend
                    • Feb 2009
                    • 7034
                    • USA

                    #10
                    Re: Gateway FPD1975w SMPS

                    Originally posted by alexanna
                    Well my hair has developed a lot more gray ones; I know this should be very simple.
                    This has failed in a different way there is only 180MV showing on pin 6 of the NPC1337
                    What I have found is pin 6 of the NPC1337 is grounded. If I place the red lead of the DMM on the positive lead of the large cap I am reading 164VDC with the negative of the DMM hooked to pin 6 of the NPC1337.The small 25v 47uf cap is not shorted and there are some poly caps that appear to be in the circuit also, these are not shorted. So I don't think that pin 6 should be grounded.
                    If I check resistance of pin 4 to pin 6 I am reading 380 ohms.
                    D804 is the diode for Vcc. C807, C810, R813, and IC 801 are other possible suspects.

                    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

                    • alexanna
                      Member
                      • Mar 2010
                      • 1346

                      #11
                      Re: Gateway FPD1975w SMPS

                      Originally posted by PlainBill
                      D804 is the diode for Vcc. C807, C810, R813, and IC 801 are other possible suspects.

                      PlainBill
                      Thanks PlainBill,I had found all the components except IC801 octocoupler.Removing it from the circuit causes the resistance of pins 4 and 6 to increase to about 1.5K ohms.
                      I am unable to prove IC 801 shorted with an ohmmeter test. If I use the diode function I read 1.04v on pins 1 and 2,pins 3and 4 show open.
                      I have enough spare parts around here I should be able to find another one to substitute and see if it makes a difference.
                      Al.
                      Whatever I do, I consider it a success, if in the end I am breathing, seeing, feeling and hearing!

                      Comment

                      • alexanna
                        Member
                        • Mar 2010
                        • 1346

                        #12
                        Re: Gateway FPD1975w SMPS

                        Replacing the octocoupler with a new one, I have very high resistance between pins 4 and 6 of the NCP1337.Upon Appling power to the circuit I still have very low voltage on pin 6, and it is still indicating that pin 6 is grounded when voltage is checked with the positive lead of the large capacitor.
                        Is there anything else I can check, or is it time to replace the NPC1337?
                        Al.
                        Whatever I do, I consider it a success, if in the end I am breathing, seeing, feeling and hearing!

                        Comment

                        • PlainBill
                          Badcaps Legend
                          • Feb 2009
                          • 7034
                          • USA

                          #13
                          Re: Gateway FPD1975w SMPS

                          Originally posted by alexanna
                          Replacing the octocoupler with a new one, I have very high resistance between pins 4 and 6 of the NCP1337.Upon Appling power to the circuit I still have very low voltage on pin 6, and it is still indicating that pin 6 is grounded when voltage is checked with the positive lead of the large capacitor.
                          Is there anything else I can check, or is it time to replace the NPC1337?
                          Al.
                          I'd replace the NCP1337. This design frequently fails. You HAVE verified the diodes on the secondary are not shorted, haven't you?

                          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

                          • alexanna
                            Member
                            • Mar 2010
                            • 1346

                            #14
                            Re: Gateway FPD1975w SMPS

                            Originally posted by PlainBill
                            I'd replace the NCP1337. This design frequently fails. You HAVE verified the diodes on the secondary are not shorted, haven't you?

                            PlainBill
                            The schotty barrier diodes have been removed from the circuit and tested; they are not showing short with ohmmeter. Diode testing they are showing a voltage drop of .145v on the 40a and .225v on the 100a one.
                            Question to be sure something weird is not happening, could I safely apply power to the board with these diodes removed from the circuit,and see if anything changes on pin6 of the NPC1337?
                            Al.
                            Whatever I do, I consider it a success, if in the end I am breathing, seeing, feeling and hearing!

                            Comment

                            • alexanna
                              Member
                              • Mar 2010
                              • 1346

                              #15
                              Re: Gateway FPD1975w SMPS

                              ^Typo on diode amprege 10a 40v and 10a 100v is corect
                              Whatever I do, I consider it a success, if in the end I am breathing, seeing, feeling and hearing!

                              Comment

                              • PlainBill
                                Badcaps Legend
                                • Feb 2009
                                • 7034
                                • USA

                                #16
                                Re: Gateway FPD1975w SMPS

                                Originally posted by alexanna
                                The schotty barrier diodes have been removed from the circuit and tested; they are not showing short with ohmmeter. Diode testing they are showing a voltage drop of .145v on the 40a and .225v on the 100a one.
                                Question to be sure something weird is not happening, could I safely apply power to the board with these diodes removed from the circuit,and see if anything changes on pin6 of the NPC1337?
                                Al.
                                Ordinarily I would say no. The SMPS controller will keep increasing the drive pulse duration to the fet until something overloads. In this case, the smps controller shuts down if Vcc rises above 17 volts. It may not tell you much, but you can.

                                HOWEVER, I would suggest you reinstall the schottky diode for the 5 Volt supply and test it that way.

                                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

                                • alexanna
                                  Member
                                  • Mar 2010
                                  • 1346

                                  #17
                                  Re: Gateway FPD1975w SMPS

                                  Originally posted by PlainBill
                                  Ordinarily I would say no. The SMPS controller will keep increasing the drive pulse duration to the fet until something overloads. In this case, the smps controller shuts down if Vcc rises above 17 volts. It may not tell you much, but you can.

                                  HOWEVER, I would suggest you reinstall the schottky diode for the 5 Volt supply and test it that way.

                                  PlainBill
                                  I replaced the schottky’s from I used board I had, to rule them out as being a problem.
                                  The voltage stays very low on pin on pin 6 of the NPC1337, I guess it’s time to source a controller.
                                  Thanks for the help, I will update when I find the part
                                  Last edited by alexanna; 04-01-2011, 03:15 PM.
                                  Whatever I do, I consider it a success, if in the end I am breathing, seeing, feeling and hearing!

                                  Comment

                                  • alexanna
                                    Member
                                    • Mar 2010
                                    • 1346

                                    #18
                                    Re: Gateway FPD1975w SMPS

                                    I received the NPC1337 yesterday and while I was installing it, I removed this resistor to make sure I did not create a solder bridge. Its colors are Brown- Black-Black it is tied to pin 5 of the NPC1337 and then the circuit goes to a schottky diode. The resistor disintegrated removing it. I know it's 10 ohms,but would this be a metal oxide resistor?
                                    Attached Files
                                    Whatever I do, I consider it a success, if in the end I am breathing, seeing, feeling and hearing!

                                    Comment

                                    Related Topics

                                    Collapse

                                    • dkneyle
                                      Onkyo DX-V500 Laser Disc Player - weird SMPS fault
                                      by dkneyle
                                      This relic from a technology path that came to a dead end (but still has historical interest) was brought in with a dead SMPS, which is based around a MK1210 device. I got it going after a battle. It seems to have a strange design - if it's not getting feedback that the secondary is OK it cause the big FET to go into full conduction and overloads resulting in a blown fuse at best or something worse! I'm using a Dim Bulb Tester (70W/230V) which thankfully has saved the day a number of times whilst repairing.

                                      Now, it loads a CD OK. The motor voltage output (which is built onto the SMPS...
                                      02-01-2022, 02:08 AM
                                    • abhishekkumar1902
                                      Huntkey HK340-72FP SMPS shut on load above 2 amps
                                      by abhishekkumar1902
                                      I have this Huntkey HK340-72FP PC SMPS where I am facing a strange problem where the SMPS shuts down when the load on any of its 12v output rails goes above 2 amps while the rating of each 12v rail is above 10amps capable.

                                      I have checked the following:
                                      1. All output caps are OK, and all output rails read correct voltages at no load
                                      2. All output diodes are OK
                                      3. NTC is ok
                                      4. Hi voltage cap on input correctly reads 150uF on LCR meter per the spec, also the bridge rectifier is OK
                                      5. No short in main switching MOSFET
                                      6. All other components...
                                      12-18-2022, 09:52 AM
                                    • madan1
                                      Mackie Th15 SMPS low Vout
                                      by madan1
                                      Hello,
                                      I'm troubleshooting a PA speaker Mackie Th15 (schematics attached).
                                      It is basically a smps with amp and some dsp.
                                      The issue is that on the secondary side I read +/- ~23V instead of the expected +/- 38V. Indeed all secondary side and feedback/aux rails are like 1/2-3/5 of the expected values.
                                      Q2, Q3, C35, C40, C33, C36, C41 and C42 were tested out of circuit with a component tester and read fine. Most of the other components on the primary were tested in circuit and seem to be fine. +HV to -HV on primary is ~330V.
                                      By the way, the ferrite core of L10 is broken,...
                                      02-16-2025, 04:15 PM
                                    • rewease
                                      Replacement for the Siemens Bakelite caps in an early 1980s SMPS
                                      by rewease
                                      Hi everyone,

                                      There actually was a time when early SMPS and late bakelite housed electrolytic caps coexisted in high end industrial gear. A friend of mine just got himself a CNC milling machine form that time with its first set of now 41 year old caps still installed in the PSU... and it's malfunctioning.

                                      Two of the caps have already leaked slightly onto the board. I have not desoldered or measured any so far but they should qualify for replacement.

                                      Now I'm wondering what to put in there as a replacement. First idea was state of the art low-ESR Nippon KY,...
                                      09-17-2023, 12:53 AM
                                    • dkneyle
                                      MK1210 chip SMPS based supply - can I fire this up?
                                      by dkneyle
                                      Power supply used in an Onkyo laser disc player, circa 1995?

                                      Came into the Repair Cafe after another tech had a go and gave up. Only evidence I could see of a repair was C22 (2200uF) cap had been changed and D25 was missing. The power plug had been left disconnected so I figured I wasn't going to apply power until I'd checked everything out. I replaced the usual suspects: the SMPS chip ML1210, all the electros except the main charge caps, the 33V zener, replaced the missing high-frequency rectifying diode. I meticulously checked over remaining components with my meter and all seem...
                                      01-30-2022, 01:44 AM
                                    • Loading...
                                    • No more items.
                                    Working...