(Topic ID: 295751)

Star Trek TNG. Switch matrix faults

By Mervyn

3 years ago

Topic Stats

  • 7 posts
  • 3 Pinsiders participating
  • Latest reply 2 years ago by Mervyn
  • No one calls this topic a favorite


Linked Games

#1 3 years ago

With strange gameplay I have found plug J 5 on the 16 opto pcb A-16998 . Under the play field needs replacing. I have had this issue on 2 STTNG machines now. It’s easily diagnosed. Put in switch test mode and various switches will act up intermittently.
Moving the wires on plug J 5 will instigate the fault. New plug fixes the issue, I use the crimp on plugs instead of the push type which just cuts the insulation and does not make a great connection in any case. STTG seems to use a lot of these bad plugs.
This particular fault was causing the cannons to not find home,also initial ball loading sequence sometimes would not start and strangely enough Fuse 112 was blown, supplies power to fliptronic board, cold checks found no shorted rectifiers or transistors, I’m hoping the switch matrix fault activated the flippers wrongly and blew that fuse, it’s on test , time will tell.
Also the mod to the 8 driver pcb earthing fault mentioned in other threads, should always be carried out when these machines are in for service

#2 3 years ago
Quoted from Mervyn:

I’m hoping the switch matrix fault activated the flippers wrongly and blew that fuse,

Unlikely since the flipper switches are not part of the matrix. Will be interesting to hear what you find.

#3 3 years ago

Good point. When replacing the fuse F112 I used a current limiting resistor and a 12 volt halogen lamp in series,instead of a fuse and on power up I heard at least one coil somewhere lock on. High current went through the lamp which,as stated was in place of Fuse 112. So immediately switched off. Then removed the fliptronic pcb and driver board to do cold checks etc. no faults found. Refit and test and of course every thing works fine. I have now done the tie back wire mod on the 8 driver board.could that have blown F112? I have the operations manual . Do you know where I can download a copy of the Power driver board schematic? I want to prove if F112 only supplies the fliptronic PCB ? When things were running Thats when the switch matrix fault showed up but not blowing fuses etc so that was an ongoing problem , now fixed, thanks for your advice so far. I will keep this thread active with my findings. I really need the schematic at this stage.

#4 3 years ago

Keep in mind Fuse F112 powers every coil in the game, not just the flippers.

#5 3 years ago

@ Pin Guy .Keep in mind Fuse F112 powers every coil in the game, not just the flippers

Yes I have the schematic now and note that after the bridge rectifier there are multiple fuses going to other circuits. All run via F 112…What’s interesting or annoying is when I replaced the fuse with current limiting ,ie halogen lamp and resistor , I heard a couple of solenoids activating and high current flow, BEFORE the cpu had even booted, which lead me to think there was a shorted Transistor somewhere. Removing both PCBs for cold tests revealed no faults and the machine has been perfect since refitting and installing the correct fuse again. Still interesting that plug J 5 as stated was a definite problem but we can’t say that’s what caused the issue. Intermittent problems , great fun!

#6 3 years ago

#1 issue in a game of this age is cracked solder joints and worn plating on headers and connectors (max rating of these is 25 cycles) removing a connector and putting it back on is 2 cycles.

2 months later
#7 2 years ago

Update. This STTNG pinball had a new Homepin cpu board fitted some mths ago. On switch on from cold some solenoids would (kick) for a very short time. Perhaps next switch on, this would not occur, swapping the cpu pcb with an original cleared the switch on problem, The Homepin pcb suppliers seem to think it could be a blanking problem on the home pin boards, I have returned 2 of them to be checked and hoping this issue will be sorted. I believe the boards had this issue and eventually came back for repair because of the blown fuse as stated earlier. Disconnecting power to the cpu pcb or of course removing the pcb completely and powering up the driver board eliminated the solenoid pulse problem as well.

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