Announcement

Collapse
No announcement yet.

BSD coil not working after TIP102 replacement

Collapse

Request help on Pinball repairs..

X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • BSD coil not working after TIP102 replacement

    Helping a mate out with a non working pop bumper coil on BSD. I don't have the machine here, but the following has been observed:

    Pop bumper switch works fine in switch test and game (ie: scores points and makes sounds, and tests fine 100%).

    75v at both sides of coil

    11 ohms resistance, same as other pop bumper coils

    This is driven by Q54 (TIP102), if the metal tab is grounded, the coil fires OK.

    He noticed one of the resistors (r92,93 or 94 from memory) was burnt, so he brought the board to me, and i replaced the TIP102, 2N5401 predriver, the diode and 4 associated resistors. These are driven by U4 on the power driver board, so i replaced this as well.

    However, he took the board home, and the coil still won't activate in test menu or game, however the same symptoms as above ie: coil voltage is present, switch works fine and the coil fires if you ground the TIP102.

    Ribbon cables have all been reseated

    I'm stumped.....any ideas?

  • #2
    Do all other coils work?

    Comment


    • #3
      Originally posted by Pinballer View Post
      Do all other coils work?
      Yep. It's the only thing not working

      Comment


      • #4
        Have you check continuity of from each component on the board. There maybe a damaged trace on the board. I came across this issue recently, where simply shot gunning the replacement parts into the board fix the problem.

        Comment


        • #5
          has the appropriate chip in u1-u5 been shot?

          Comment


          • #6
            I’m for the trace back to the relevant U chip as you’ve proven the continuity from transistor to coil, so must be upstream from there. If you’ve replaced chip then not much left

            Comment


            • #7
              Ok. I didn't buzz out each trace after I replaced it but visually I thought it looked ok. Can I earth out a leg on it to trigger it?

              Comment


              • #8
                It sounds like the logic signal from the CPU isn't making its way through to the IC that turns on the pre-drive transistor or beyond. It can look perfectly fine, but not test ok with a meter. I found this out the hard way lol

                Comment


                • #9
                  If you have a logic probe and schematics for the driver board you could plot the signal throughout the circuit. Or just use a multi-meter to confirm continuity from the legs of each component through the circuit.

                  Comment


                  • #10
                    or the pre transistor
                    Australian Distributors for Planetary Pinball, Chicago Gaming, American Pinball.
                    Your one Stop Shop For New Pinball & Arcade Games.

                    Comment


                    • #11
                      Ok. He has confirmed continuity from pin 5 of u4 to the resistor before the pre driver as well as continuity between all parts highlighted below. What do I look for upstream of u4? Click image for larger version

Name:	20200913_192922.jpg
Views:	48
Size:	142.0 KB
ID:	2163220

                      Comment


                      • #12
                        The inputs to U4 come directly from the header J113, which connects to the short ribbon cable between the Power Driver and the CPU board.

                        Comment


                        • #13
                          Ok. Ignore above. Apparently there was not continuity between the right leg of the tip102 and the tip102 above it. So he will inspect that track and report back

                          Comment


                          • #14
                            Ah that's good news!

                            Comment


                            • #15
                              Cheers for the help Rob and fellas, I'll let you know how it goes 👍

                              Comment

                              Users Viewing Topic: 0 members and 1 (guests)
                              Working...
                              X