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Help. I shorted out my 5155's power supply.

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    #31
    Does your 5155 have a hard disk installed, or just floppies? If it's just a floppy system, you've got enough +5 for your board. Remember that the original 5150 PSU was only 63.5W. If you have a hard disk installed, try disconnecting it.

    Your motherboard uses parity, BTW. (4 banks of 8 data bit + 1 parity).

    Your motherboard is one of many variations of the basic ERSO XT board. I've got two variations here myself--an 8 and a 10 MHz one.
    Reach me: vcfblackhole _at_ protonmail dot com.

    Comment


      #32
      I've just calculated an approximate power consumption of the 5155's CRT unit. It's only about 15W. That's based on the fact that the unit is powered only by a dedicated 12Vdc wire pair from the PSU, the wire pair rated at 1.5A.

      So if we make some approximations:
      1. 5155 CRT unit = 15W
      2. 10MHz motherboard = 20W (based on fact that a 5160 motherboard draws about 15W)
      3. Various cards = 20W
      4. CF card = 2W (a wild guess)

      So Chuck is right. There's certainly enough power available.

      Maybe a dud PSU - defective component that only starts to fail above a certain current level.

      Originally posted by ibmapc View Post
      Yes, the combo seems to work but when Falcon AT is run, the video goes to EGA Mode(I'm using an ATI EGA Wonder)
      I should have picked this up before.
      The CRT unit will be connected to the composite video connector on your ATI EGA Wonder.
      What's the go there? It's set for CGA mode?
      If the composite video out is switching from CGA to EGA, I bet the CRT unit is being highly stressed.

      Comment


        #33
        Originally posted by modem7 View Post
        I should have picked this up before.
        The CRT unit will be connected to the composite video connector on your ATI EGA Wonder.
        What's the go there? It's set for CGA mode?
        If the composite video out is switching from CGA to EGA, I bet the CRT unit is being highly stressed.
        Yes the video on the internal CRT flickers alot in EGA mode, but this has not been a problem when using the original MB at 4.77mhz. Does the faster clock speed(10mhz) effect the composit out of the EGA Wonder in EGA mode? Anyone care to speculate what if any damage might be occuring with the internal monitor when the EGA Wonder switches to EGA mode? I believe it goes interlaced causing the flickering display. I was under the impression that the EGA Wonder was designed to operate in EGA mode without harming the 5155's monitor.

        Comment


          #34
          I think you're okay there. A composite monitor simply wouldn't sync, unlike a TTL mono monitor which most likely be turned into a crispy mess.
          Reach me: vcfblackhole _at_ protonmail dot com.

          Comment


            #35
            Originally posted by ibmapc View Post
            Here's a couple of pics of the 10 mhz MB. I can't see anything here but maybe a more trained eye might see something.
            Could be one of the blue capacitors. They are scattered everywhere on the board, and the one that made the pop (If one did, that is..) could just have a small crack in it making it hard to detect. On the other hand, as have been mentioned in this thread, if it works fine you should not worry too much
            Current machines:
            PCs: IBM PC XT 640K, IBM PC XT 256K ,IBM PC XT , 2x IBM PC AT, Compaq Portable I, Compaq Portable II, Compaq Portable I/286, Philips Logic Analyzer XT clone, IBM PS/2 Model 30 286 , HP 95X, HP200LX (2x),Compaq SLT/286.
            Apple: Macintosh 512k, Macintosh SE, Macintosh Classic, PowerBook 170, iBook Clamshell, iBook G3,iMac G4 , TiBook's, Apple IIc, Many newer machines (G4, G5, Intel..), 20th Anniversary Mac
            Others: Commodore 64C,Amiga A500, CCS S-100 System, SNES,

            Wanted: Macintosh 128k, Hard Disk 20, System disks and games for the Mac

            Comment


              #36
              Originally posted by QuantumII View Post
              Could be one of the blue capacitors. They are scattered everywhere on the board, and the one that made the pop (If one did, that is..) could just have a small crack in it making it hard to detect. On the other hand, as have been mentioned in this thread, if it works fine you should not worry too much
              Check out this close-up of a blue capacitor. I saw the small cavity in the top of it when I inspectected the board under magnification. This capacitor is right next to the slot where the EGA Wonder was plugged in. So, my guess is that when the video board was switched to EGA mode, this capacitor didn't handle it well and started arcing ind smoking.

              Now, I need to find a replacement. Printed on the side is the number 104. Anyone have any sugestions on a source for replacement.

              Comment


                #37
                It's what I said earlier--a 0.1uF bypass capacitor. Just about any type of this capacitor is suitable. I buy them by the 100s--they're cheap. You can use a film, ceramic...etc. type. It doesn't matter in this application.
                Reach me: vcfblackhole _at_ protonmail dot com.

                Comment


                  #38
                  Originally posted by Chuck(G) View Post
                  It's what I said earlier--a 0.1uF bypass capacitor. Just about any type of this capacitor is suitable. I buy them by the 100s--they're cheap. You can use a film, ceramic...etc. type. It doesn't matter in this application.
                  will one of these work?

                  Comment


                    #39
                    Probably; I'm assuming that its voltage rating is at least 10V.
                    Reach me: vcfblackhole _at_ protonmail dot com.

                    Comment


                      #40
                      It's rated for 50V

                      Comment


                        #41
                        You're fine, then.
                        Reach me: vcfblackhole _at_ protonmail dot com.

                        Comment


                          #42
                          I would like to thank everyone who helped me through this minor crisis!! You guys are really great!! I managed to un-solder the offending capacictor and re-solder the new one(note, I only burnt two fingers and now there's a funny brown spot on the dining room table). But, the system is running perfectly with no arcs or pops and no more smoke, even when worked hard in EGA mode running Falcon AT!! Now, if someone could help me find a V20 that will run at 10mhz and maybe an 8087 to go with it, that would be really cool.

                          Comment


                            #43
                            Cool! It's great that you got it repaired
                            Current machines:
                            PCs: IBM PC XT 640K, IBM PC XT 256K ,IBM PC XT , 2x IBM PC AT, Compaq Portable I, Compaq Portable II, Compaq Portable I/286, Philips Logic Analyzer XT clone, IBM PS/2 Model 30 286 , HP 95X, HP200LX (2x),Compaq SLT/286.
                            Apple: Macintosh 512k, Macintosh SE, Macintosh Classic, PowerBook 170, iBook Clamshell, iBook G3,iMac G4 , TiBook's, Apple IIc, Many newer machines (G4, G5, Intel..), 20th Anniversary Mac
                            Others: Commodore 64C,Amiga A500, CCS S-100 System, SNES,

                            Wanted: Macintosh 128k, Hard Disk 20, System disks and games for the Mac

                            Comment


                              #44
                              Originally posted by MikeS View Post
                              Maybe even remove the MB from the case and put everything back the way it was when it worked, in case there's a short at one of the mounting screws. And of course make sure that the connectors have the black wires in the middle, i.e. next to each other. It's pretty hard to catastrophically "short out" a PC PS.
                              You guy's are great! When I connected the original MB and flipped the switch, the fan came on and appears to run normal, so I turned it back off and connected the HDD with the LED and flipped the switch again and the fan came on, the LED lit and the drive spun up normally. So it would seam the PSU is fine. Just my trouble shooting methods were faulty. Glad I didn't buy that refurbished power supply from CODEMICRO!! Thanks everyone!!


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