Pinball: STTNG Star Trek The Next Generation

Bought 2016 sometime


  • The cleanest best condition machine I’ve ever seen, immaculate under the glass
  • ColorDMD display
  • Power driver board is a Rottendog replacement (full size, all through hole), laid out like original except BR’s are separate diodes.   It seems pretty nice
  • Firmware = LX-7
  • MCU board:
    • J120 has supplementary PCB:
      • KAHR.US Circuits
      • Looks to be the basic version as no monitoring MCU fitted & no LEDs
    • 62256 Ram, R93 not installed, W3 jumpered
    • Country DIP set to USA: W11-W18: Off, Off, Off, On, On, On, On, On

Reminder re ball locations/trough sensors on startup:

  • STTNG is a six ball game, BUT on startup it relocates the 6 balls so that:
    • 1 sitting in Left VUK trough
    • 1 sitting in Left Gun VUK trough
    • 1 sitting in Right Gun VUK trough
    • 3 in main trough
  • There a 2 switches each in both Left & Right Gun VUK troughs
  • There are 4 switches in Left VUK trough

Issue STTNG-20180120: F112 Fuse blown

A guest was playing and said balls had disappeared. They had.

Looked at Power Driver Board, has separate unlit 50V indicator LED as well as nice test points.  The 50V circuit is out.

From WPC Schematics manual

  • J102 supplies BR3 via F112
    Output of BR3 (50V DC) splits to pass through:

    • F101, F102 then flipper circuits via J109, J110
    • F103 (Continuous), F104 (Lo power pulse), F105 (High power pulse) then to solenoids via J106, J107, J108

Checked fuses:

  • F112 is blown, no others. It had a 5A fuse.  manual says 7A but some people do seem to put 5A in instead as thats what they have.  I won’t simply assume its under fused until I check for shorts

Trouble shooting step 1:

  • Reseated J102
  • Disconnected J106, J107 (J108 is NC on this machine)
  • Replaced F112 with 5A fuse
  • Powered up machine


  • 50V DC led is on
  • Did all Flipper tests no problems

Trouble shooting step 2:

  • Reconnected J106. Hmm I can’t see J106 in the solenoids table
  • Power up machine


  • fuse still good
  • Ran all solenoid tests.  No solenoids fired.  Still not sure what J106 is feeding

Trouble shooting step 3:

  • Reconnected J107
  • Power up machine
  • Machine plays ok

I will assume is underfused and takes a particular combination to blow F112 at 5A

Update (20180203) Machine is playing ok with regards to this issue)

Issue STTNG-20180203: Left VUK firing but not ball not sucessfully kicking out (Weak VUK)


  • This is a very busy VUK, in near constant use, so is a high wear assembly
  • The coil mounting bracket has a missing stud (Part = A-16858).  A fair indication that has been worked on previously
  • The plunger is sticking slightly when retracted fully (by the spring)
    • The coil sleeve on this coil extends longer than those on the Left & Right Gun VUK coils.  I suggest the coil sleeve has been replaced previously with a sleeve that extends far enough out the top of the coil that the slight mushrooming of the coil plunger is binding on the sleeve


  • Replaced the coil sleeve with one that extends less out the top of the coil (Part = 03-7067)
  • Trimmed (bevelled) the edge of the VUK plastic top extension (Part = Armature Assembly A-13270)
  • On assembly replaced missing coil bracket stud with bolt/lock nut

Issue STTNG-20220827 Multiple issues

  • Fuses blown on Rotten Dog DMD driver board board F103, F104, F105, F107, F111
  • Replaced fuses
    • 3A: F103, F104, F105, F107
    • 5A: F111
  • Start game, flipper button resets machine

Issue STTNG-20180303: Getting Air balls off stand ups either side of Beta Quadrant Ramp

  • New backing foam into these standups, also the Time Rift standups as a precaution

Issue STTNG-20190210 Broken Plastics

  • 31-1803-10-SP Ferengi set left side
  • 31-1803-32 cracked, not so necessary to replace