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If I replace with inferior capacitor, Is it No harm to other IC components at all?

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    If I replace with inferior capacitor, Is it No harm to other IC components at all?

    I replaced some capacitor which is located on optical pickup pcb which is shown in the table below(PCB #2).Because it have been out of order.
    Now,It works very well,But I just have found that all caps (6svpc100my and other part number as well) ,which is shown in the table below, has ultra-high ripple current spec.
    It is not able to obtain any capacitor which can be a substitute for this ultra-high ripple current nichicon capacitor.
    So I replaced it with samxon and rubycon's general capacitor(GP,YXA series).
    I know that these capacitor will not last as long as nichicon capacitor did,
    But I doubt that inferior capacitor really harms nearby IC components, So I dread that Not only It doesn't last long, it may also chip away at lifespan of nearby IC components.

    Click image for larger version  Name:	rik7f4o12gd21.png?width=760&format=png&auto=webp&s=238f01bb43f1cf9e1334ef86c91d383eccdca2e5.png Views:	0 Size:	15.5 KB ID:	3166505
    Last edited by chth96; 12-22-2023, 04:46 AM.

    #2
    nobody can say if it could cause damage unless they have a schematic

    Comment


      #3
      below link is a schematic for this pcb.
      https://www.acidmods.com/RDC/SEGA/Dr...OM%20XV779.pdf

      Comment


        #4
        so which cap is it? or is it all 7 100uf caps?
        who made that list btw? you should be fitting tantalum not more crap smd electrolytics.

        Comment


          #5
          Originally posted by stj View Post
          so which cap is it? or is it all 7 100uf caps?
          who made that list btw? you should be fitting tantalum not more crap smd electrolytics.
          I don't know who made this list for the first time.
          It was stumbled on when I browsed through reddit site.
          https://www.reddit.com/r/consolerepa...pacitors_just/
          and a schematic is came from acidmod.com
          https://acidmods.com/forum/index.php?topic=44892.0
          By the way,Can I replace all of cap with tantalum?
          And Is it okay to purchase tantalum capacitor from aliexpress?

          Comment


            #6
            firstly lets talk about cap lists.
            they should contain the board number - because there are different versions,
            the cap uf, volts and ideally esr & ripple and most importantly size (width / height)
            a lot of people forget that bit and people buy caps that either dont fit or are too tall for stuff to be re-assembled.

            so you can replace electrolytics with tantalums,
            the only reason they dont use them from the factory is they cost like 5x the priice.
            apple, sun & sgi always used tantalums though - because it's expensive stuff.

            the bi-polar caps are special, you cant use regular electrolytics or tantalum for those.
            you can use film caps but those are probably too big to fit

            as for ali - i have had no problems with ali tantalums when i was doing xboxes.
            remember to pay atention to sizes so they fit across the pads nicely.

            and i hope you have a fast scope because you may mess up the laser calibration.

            btw, because tantalum dont dry out you can salvage them from old boards
            Last edited by stj; 12-23-2023, 08:30 AM.

            Comment


              #7
              Thank you very much for your reply.
              I bent all of caps in order to fit the height of space between pcb and plate like below jpg attachment.
              It seems that all of caps narrowly fit to space,And I test its performance by comparing it with another intact laser pickup PCB which I never have soldered at all and works fairly well.
              I inserted some burned CD-R and It seems that It also able to recognize any burned CD-R which can be recognized in the intact laser pick up PCB and It also stuttered to read some CD-R which is stuttered to read in the intact laser pick up.
              It seems that performance of pcb, which I replaced capacitor, is almost the same with intact laser pickup pcb.

              I plan to replace this regular electrolytics,which I soldered, with tantalium caps if it fail to recognize all of CD-R again..

              As for the bi-polar caps in the list,I heard that It is audiograde capacitor, So I think it should not be replaced with common tantalum or film capacitor.

              And I don't know what fast scope is, and not have any osilloscope but I measured resistance of laser diode and It seems that it is still fine
              Attached Files
              Last edited by chth96; 12-23-2023, 07:04 PM.

              Comment


                #8
                bi-polar electrolytics are actually rare,
                they used to be used in crt tv's and monitors mostly.
                for audio-path the best caps to use are polypropylene film.
                the downside - if your converting from electrolytic anyway, is they are a lot bigger physically.

                Comment


                  #9
                  Originally posted by chth96 View Post

                  I plan to replace this regular electrolytics,which I soldered, with tantalium caps if it fail to recognize all of CD-R again..

                  As for the bi-polar caps in the list,I heard that It is audiograde capacitor, So I think it should not be replaced with common tantalum or film capacitor.

                  And I don't know what fast scope is, and not have any osilloscope but I measured resistance of laser diode and It seems that it is still fine
                  I would recommend that you put wire insulation or heat shrink tubing that is the right size on the the capacitors leads when you put capacitors across traces like that what you have is not a good practice to get into because if when you remount the circuit board and you just happen to move one of those capacitors and the wires lead bends upward you will not know that this has happened and things might not go as planned I have had this happen in the past

                  However putting kapton tape is a good idea to use however you need to put it underneath the the capacitor leads as well but it does not keep the capacitors leads from being pushed together and cause issues that is why using wire insulation is a better solution for mounting capacitors on the bottom of a circuit board if you have enough space to do so

                  One note you need to try to keep the capacitors leads as short as possible to prevent picking up noise interference from the rest of the circuit sometimes this is hard to do sometimes you might need to put heat shrink tubing on the capacitors themselves to keep from shorting out the shell of the capacitor to the circuit leads from the board

                  Good job figuring out what the issue was with CD rom drive one more item that did not end up in the landfill
                  Last edited by sam_sam_sam; 12-25-2023, 07:33 AM.
                  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

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