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

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    #16
    Pic of Compaq Deskpro 386 load resistor...

    dummy-load.jpg

    dummy-load-face.jpg

    Comment


      #17
      Hehe, that was a cool looking dummy HDD. It's of the kind that can fool a seller into thinking "This PC has a HDD but it does not work". It could also be used as a decoration on a newer PC to give it a bit of a vintage look
      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


        #18
        I have several 3.5" to 5.25" hdd adapters that are like that but designed to hold a HDD - like using them in modern boxes.. I even found a beige one by some streak of luck that matches my latest case's beigeness. They even have little light holes, a few of them even having a proper LED and plug for the rare IDE disk that had a header for a HDD light right on it, or you could run it to the motherboard. Most of them just had a clear colored plastic piece for a light mounted on the odd IDE disk to shine through, though.

        One of them tricked me though, the first time I saw it.. It was a beige desktop case, and it looked like it had a 5.25" MFM disk. I expected some sort of cool XT or AT clone, but when I opened it it was a 486 and the HDD turned out to be an EMPTY adapter bracket, heh. The case was awesome on that machine, but unfortuantely had many broken clips making it fall apart.. I kept it so I can look out for another.
        More commonly known as "Yushatak" - www.yushatak.com
        Focused on 486 and Pentium Machines
        I collect All-In-One PCs and Keyboard PCs, especially Compaq.

        Comment


          #19
          OK, I got it working with the turbo 8088 MB. Thing is when I ran FALCON AT, I heard the what sounded like an arc and saw smoke so I powered it off immediatly and started taking things apart to see if the source of arcing could be found. I could not find any thing obvious, but the big transromer in the power supply looks funny.(see picture). Am I overloading the PSU with this 10mhz Turbo 8088 MB? Does that brown stuff on the transfomer look normal or has it been overheated? Am I risking PSU failure if I continue to use this MB?

          Comment


            #20
            Nothing obvious that I can see. I doubt that a 10MHz 8088 board would make a big difference (are you running an 80C88 or V20 to keep the power down?). But aging components can and do make smoke. Power it up again and watch carefully. Often the component giving trouble will give itself away by the smell.
            Reach me: vcfblackhole _at_ protonmail dot com.

            Comment


              #21
              The brown stuff is lacquer (what the wire in the transformer/filter gets coated with). It's not unusual to see lacquer there. It's quite a bit, but I wouldn't consider that to be an definite indicator of overheating.

              The 5155 PSU should be able to handle the 10mhz Turbo 8088 motherboard.

              The symptoms you describe could be caused by a ruptured line suppression capacitor. See the 'Line Suppression Capacitor' section of http://members.dodo.com.au/~slappanel555/failure.htm
              In your photo, the two blue things are line suppression capacitors. They look okay in the photo, but take a close look at them. In my 5155 PSU, there's also one wired directly to the contacts on the power switch.

              Of course, there are other components that can arc/smoke.

              One way of detecting the location of arcing is to operate the equipment in a dark room, being extra careful due to the greater risk of shock (e.g. difficulty seeing opened PSU).

              Comment


                #22
                I'll add that if what you heard was a loud "snap" then just a bit of smoke, but the system kept going, it's likely a popped bypass or decoupling capacitor somewhere on one of the boards, not in the power supply. This happens more than you'd think on old gear. If it's a bypass (value around 0.1uF, don't worry about it--just make a note to replace it when you have time. If it's a decoupling (usually tantalum), move it a bit higher on your priority list, but don't sweat it.
                Last edited by Chuck(G); July 10, 2010, 09:11 AM.
                Reach me: vcfblackhole _at_ protonmail dot com.

                Comment


                  #23
                  Originally posted by Chuck(G) View Post
                  I'll add that if what you heard was a loud "snap" then just a bit of smoke, but the system kept going, it's likely a popped bypass or decoupling capacitor somewhere on one of the boards, not in the power supply.
                  I second this. I have experienced the same multiple times. One snap, flying debris and some smoke. My S-100 backplane did this 3 times, one cap each time power was applied. The first "explosion" severed a PCB trace as well Look around the motherboard for signs of a broken small capacitor. Usually they are blue or light brown.

                  Might as well show us a large picture of the motherboard, so that we can help you look at it
                  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


                    #24
                    Originally posted by QuantumII View Post
                    Might as well show us a large picture of the motherboard, so that we can help you look at it
                    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. Also, on a side note, anyone have info on this board?
                    I have not been able to figure jumper settings or how to switch between turbo and slow speed. I've tried "cntrl+alt +/-", and "cntrl+alt+pgup/pgdwn" and a bunch of other keyboard manuvers with no luck, it remains in turbo mode.

                    Comment


                      #25
                      It sounds to me like your PSU/motherboard combination is working, but that you are trying to locate the component that arced/smoked. Is that the case?

                      Originally posted by ibmapc View Post
                      Also, on a side note, anyone have info on this board?
                      Your motherboard looks very much like a PIM-TB10. The manual for that is at http://members.dodo.com.au/~slappanel555/manuals.htm

                      Originally posted by ibmapc View Post
                      I have not been able to figure jumper settings or how to switch between turbo and slow speed. I've tried "cntrl+alt +/-", and "cntrl+alt+pgup/pgdwn" and a bunch of other keyboard manuvers with no luck, it remains in turbo mode.
                      When you tried "cntrl+alt +/-", did you try the "-" on the keypad (i.e. not the "-" on the main section of the keyboard).

                      Comment


                        #26
                        Originally posted by modem7 View Post
                        It sounds to me like your PSU/motherboard combination is working, but that you are trying to locate the component that arced/smoked. Is that the case?


                        Your motherboard looks very much like a PIM-TB10. The manual for that is at http://members.dodo.com.au/~slappanel555/manuals.htm


                        When you tried "cntrl+alt +/-", did you try the "-" on the keypad (i.e. not the "-" on the main section of the keyboard).
                        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) and since this game was meant to run on a 286, it pushes the system pretty hard and that's when I hear the arcing and see the smoke (happened on two separate occasions).
                        For now I've put the original MB back because the arcing noise made me nervous, but I'll probably try this MB agian soon. I've tried both "-" keys with cntrl+alt.

                        Comment


                          #27
                          Looks like you've got something very close to this turbo mainboard. If the jumpers line up, you may want to fool with jumpering/un-jumpering JP6 to alter the speed.

                          As far as software-controllable turbo mode goes, try Ctrl-Alt-keypad anything.
                          Reach me: vcfblackhole _at_ protonmail dot com.

                          Comment


                            #28
                            Originally posted by Chuck(G) View Post
                            Looks like you've got something very close to this turbo mainboard. If the jumpers line up, you may want to fool with jumpering/un-jumpering JP6 to alter the speed.

                            As far as software-controllable turbo mode goes, try Ctrl-Alt-keypad anything.
                            You're right Chuck, that board looks very close. The only difference I can see is my board doesn't have JP9 for parity enable/disable. I wonder if that means that it doesn't use parity. Or, maybe it does and can not be dissabled. How can I determine if parity is used? Sorry for wondering off topic but my mind tends to do that a lot.

                            ps The board that Modem7 mentioned in his post also looks very close. It's manual also specifies JP6 for turbo.
                            Last edited by ibmapc; July 10, 2010, 04:18 PM.

                            Comment


                              #29
                              According to Mueller's Upgrading & Repairing PCs book, the 5155 PSU is rated at 114W. Compared to a standard 5155, you're running a faster motherboard and you've probably installed a hard drive as well. Maybe you're right. Maybe Falcon AT use is indeed pushing the PSU loading to it's limits (but not enough to invoke the PSU's overload protection).

                              Re the component that smoked. Have you tried disconnecting the 5155 from the mains for a while (10 minutes should be adequate), then using your nose to home in on the component.

                              Comment


                                #30
                                Originally posted by modem7 View Post
                                According to Mueller's Upgrading & Repairing PCs book, the 5155 PSU is rated at 114W. Compared to a standard 5155, you're running a faster motherboard and you've probably installed a hard drive as well. Maybe you're right. Maybe Falcon AT use is indeed pushing the PSU loading to it's limits (but not enough to invoke the PSU's overload protection).

                                Re the component that smoked. Have you tried disconnecting the 5155 from the mains for a while (10 minutes should be adequate), then using your nose to home in on the component.
                                Yes, I've tried that but my nose can't find the source. And you're comment about pushing the PSU to it's limits is exactly what I'm afraid of. Maybe I'll put the Turbo board back in and see if I can kill it. At least at the moment I can still find refurbished PSU's. In the future, I'm sure they will be harder to find.

                                RE the hard drive. I have only a CF card connected to a Siliconvalley Computers IDE adapter.

                                Comment

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