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    DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

    Hello Folks,
    i have one DC Power Supply (DF1730SB-5A), where power supplier is Programmable and i can adjust output voltage and it was working fine before one month, i had not use it for a while & last time when i power it on, it show on both LCD display VOLT/AMP (LO BAT -1.8:88) as show on attached pics, i can test out-put voltage with multi meter & it working fine, i can adjust volt, amp & put load and all working fine, seems like LCD display have some problem, both LCD show same error, i try to open power supply and check if any where short or any cap got shorten or burn but not found any thing with physical inspection,
    not sure where need to start to find fault & fix it, any help shall highly appreciated,
    Below DC Power Supply (DF1730SB-5A) link
    https://www.elfa.se/en/bench-top-pow...-5a/p/16984742

    Thanks.
    Attached Files

    #2
    Re: DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

    Unless it has a power supply problem that powers the meter circuits and is locking the meter chip up or ( the meter chip is bad but for both of showing the same exact thing probably not )

    I do have a question for what is the part number on the ic chip that is doing the voltage and current measurements

    If it is a ICL 7106 or ICL 7107 or something similar then see if you unhook the input leads to the meter ic chip and see if it will show 00.00 volt or 00.00 amps with the wires shorted together

    If it has this type of meter chip they can be powered two different ways either one power supply rail or a “ + “and “-“ power supply rails if has the last type of power supply and you do not have the “-“ power supply it might cause this problem

    Unless this power supply is using some type of controller to do the voltage and current measurements and it has a chip something like this chip

    https://www.ebay.com/itm/Eventide-H3...-/322273446880

    If has something like this chip then you could have some problem getting this to work again unless you have have a way to get the parameters back into the controller
    Last edited by sam_sam_sam; 02-09-2020, 09:48 PM.
    9 PC LCD Monitor
    6 LCD Flat Screen TV
    30 Desk Top Switching Power Supply
    10 Battery Charger Switching Power Supply for Power Tool
    6 18v Lithium Battery Power Boards for Tool Battery Packs
    1 XBox 360 Switching Power Supply and M Board
    25 Servo Drives 220/460 3 Phase
    6 De-soldering Station Switching Power Supply 1 Power Supply
    1 Dell Mother Board
    15 Computer Power Supply
    1 HP Printer Supply & Control Board * lighting finished it *


    These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%

    1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
    2 Hem Saw Computer Stack Board

    All of these had CAPs POOF
    All of the mosfet that are taken out by bad caps

    Comment


      #3
      Re: DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

      Thank Sam for reply & help, i am not sure which ic chip that is doing the voltage and current measurements, i had take few more pictures of power supply board, seems like IC is N7CC1LK (LM324N) (Pic-6 in attachment)
      appreciated your further help to sort-out fault,
      Thanks.
      Attached Files

      Comment


        #4
        Re: DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

        I would think it is something that is common to both meter display boards, It looks like all segments are being turned on, including the LO BAT, Do the modules have numbers on them?
        Last edited by R_J; 02-11-2020, 05:10 PM.

        Comment


          #5
          Re: DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

          i try to unhook the input leads to the meter ic chip and display gone, so this trick not working,

          @R-J yes but where is that LO BAT part? i mean is that some IC?
          i have update high resolution pictures in this post
          Attached Files

          Comment


            #6
            Re: DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

            The LO BAT is just part of the display, likely not used in this case. The modules seem to be DX61030A with ICL7106 ic's?
            The power supply looks a bit water damaged (on controls) I suspect the display ic's may have some corrosion as well.
            Last edited by R_J; 02-11-2020, 07:03 PM.

            Comment


              #7
              Re: DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

              those chipsockets are a writeoff,
              need a pair of machined-pin sockets and clean the chip legs with a small wire brush and some IPA

              Comment


                #8
                Re: DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

                Originally posted by Ali101 View Post
                Thank Sam for reply & help, i am not sure which ic chip that is doing the voltage and current measurements, i had take few more pictures of power supply board, seems like IC is N7CC1LK (LM324N) (Pic-6 in attachment)
                appreciated your further help to sort-out fault,
                Thanks.
                What is the ic chip part number for meter display board there are two of them but I can read the number
                9 PC LCD Monitor
                6 LCD Flat Screen TV
                30 Desk Top Switching Power Supply
                10 Battery Charger Switching Power Supply for Power Tool
                6 18v Lithium Battery Power Boards for Tool Battery Packs
                1 XBox 360 Switching Power Supply and M Board
                25 Servo Drives 220/460 3 Phase
                6 De-soldering Station Switching Power Supply 1 Power Supply
                1 Dell Mother Board
                15 Computer Power Supply
                1 HP Printer Supply & Control Board * lighting finished it *


                These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%

                1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
                2 Hem Saw Computer Stack Board

                All of these had CAPs POOF
                All of the mosfet that are taken out by bad caps

                Comment


                  #9
                  Re: DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

                  @R_J its not water damage, Taiwan is humidity place that's why it might looks like this but i had check all over the Power supply & it don't have any rust or corrosion included display section,

                  @stj i did clean all boards of power supply with IPA using brush but nothing seems working,

                  @sam enclosed close pic of meter display,

                  i suspect issue belong to 2nd enclosed pic since that board is connected to display section,

                  Display wire connected to second pic board as mark in red circle, if i disconnected any of those wires then display gone,
                  Attached Files
                  Last edited by Ali101; 02-13-2020, 06:54 PM. Reason: edit pictures

                  Comment


                    #10
                    Re: DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

                    the chipsockets look like they are full of white stuff.

                    Comment


                      #11
                      Re: DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

                      @sam IC Chip Part Number for meter display board is CS7106AGP (IBAD1K3232L) Semic

                      hope can get help from your side to sort-out issue,
                      Thanks.
                      Attached Files

                      Comment


                        #12
                        Re: DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

                        Originally posted by Ali101 View Post
                        @R_J its not water damage, Taiwan is humidity place that's why it might looks like this but i had check all over the Power supply & it don't have any rust or corrosion included display section,
                        I was just looking at this white discoloration on the pots. does'nt look normal to me.
                        Did you ever check if you had proper voltage going to the lcd modules?

                        Comment


                          #13
                          Re: DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

                          @R_J how much is proper voltages?

                          Comment


                            #14
                            Re: DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

                            Originally posted by Ali101 View Post
                            @R_J how much is proper voltages?
                            I believe it is 9 volts, It should be marked on the module (+9V) and (-) Measure it where C3 would be.
                            Last edited by R_J; 02-14-2020, 07:36 PM.

                            Comment


                              #15
                              Re: DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

                              on module it marked 7.5 V and i am getting around 7.6 V,

                              Comment


                                #16
                                Re: DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

                                Originally posted by Ali101 View Post
                                on module it marked 7.5 V and i am getting around 7.6 V,
                                That voltage is on the input, There is a +9 Volt line that operates the ic
                                Attached Files

                                Comment


                                  #17
                                  Re: DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

                                  ah got it, let me check again & get back to you,

                                  Comment


                                    #18
                                    Re: DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

                                    Icl7106

                                    Look at section ( 5 )

                                    Some how it is in the test mode or the ic chip is damaged from something kind-a voltage spike or static electricity

                                    Look at the test pin ( 37 ) and see what it is hooked to this pin

                                    https://cdn.badcaps-static.com/pdfs/...ab8c44713c.pdf

                                    I have use these two meter module before ICL 7106 and the ICL 7107 both are covered in this data sheet
                                    Last edited by sam_sam_sam; 02-14-2020, 10:55 PM.
                                    9 PC LCD Monitor
                                    6 LCD Flat Screen TV
                                    30 Desk Top Switching Power Supply
                                    10 Battery Charger Switching Power Supply for Power Tool
                                    6 18v Lithium Battery Power Boards for Tool Battery Packs
                                    1 XBox 360 Switching Power Supply and M Board
                                    25 Servo Drives 220/460 3 Phase
                                    6 De-soldering Station Switching Power Supply 1 Power Supply
                                    1 Dell Mother Board
                                    15 Computer Power Supply
                                    1 HP Printer Supply & Control Board * lighting finished it *


                                    These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%

                                    1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
                                    2 Hem Saw Computer Stack Board

                                    All of these had CAPs POOF
                                    All of the mosfet that are taken out by bad caps

                                    Comment


                                      #19
                                      Re: DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

                                      Originally posted by Ali101 View Post
                                      on module it marked 7.5 V and i am getting around 7.6 V,
                                      No it has a 7.5 volt reference voltage for the ic chip

                                      Look at the voltage on PIN number ( 1 ) and ( 26 ) you should have 9 volts
                                      Is that Zener diode across the two pins if so then they doing it for a stable power supply

                                      This might be the low battery warning reference if you were running of a battery or used for something else

                                      ( Look at both Figure 7-1 [ A and B ] to see which set you have for the reference voltage and check to see if you have that voltage if it has a Zener diode ) if not then your voltage reference will 100 mill-volt and is adjustable ve-a trim pot
                                      Last edited by sam_sam_sam; 02-14-2020, 11:00 PM.
                                      9 PC LCD Monitor
                                      6 LCD Flat Screen TV
                                      30 Desk Top Switching Power Supply
                                      10 Battery Charger Switching Power Supply for Power Tool
                                      6 18v Lithium Battery Power Boards for Tool Battery Packs
                                      1 XBox 360 Switching Power Supply and M Board
                                      25 Servo Drives 220/460 3 Phase
                                      6 De-soldering Station Switching Power Supply 1 Power Supply
                                      1 Dell Mother Board
                                      15 Computer Power Supply
                                      1 HP Printer Supply & Control Board * lighting finished it *


                                      These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%

                                      1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
                                      2 Hem Saw Computer Stack Board

                                      All of these had CAPs POOF
                                      All of the mosfet that are taken out by bad caps

                                      Comment


                                        #20
                                        Re: DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

                                        Thank R_J & Sam, appreciated your help & support,

                                        @R_J it given me 7.8 V on C3 because it getting same voltages from back board,

                                        @Sam, i checked voltage on PIN number ( 1 ) and ( 26 ) and it given me same voltages, 7.8 V , Pin 35 (V Ref -) & Pin 36 (V red +) given me 0.98 V ,
                                        look at attach pic,
                                        Attached Files

                                        Comment

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