Thanks Thanks:  0
Likes Likes:  0
Results 1 to 5 of 5

Thread: Star Trek Next Generation technical help please.

  1. #1
    Join Date
    Jul 2007
    State
    Auckland, NZ
    Posts
    1,070
    Mentioned
    50 Post(s)
    Quoted
    274 Post(s)

    Star Trek Next Generation technical help please.

    Hi everyone

    I have a friend whose STNG cannon launchers kept moving after boot up. The test report showed 'LT LAUNCHER CAN'T FIND HOME ERROR'. Also RT LAUNCHER etc.

    20190816_111148[1].jpg

    The CPU board looked good (no corrosion) so I reseated all the cables on the CPU board with power off. No change upon boot up.

    Once in 'Switch Edges test', I manually triggered the microswitches underneath the cannon launchers but they both failed to register.
    These microswitch levers are triggered by the cams underneath the cannons.

    20190816_111630[1].jpg

    I didn't have a manual with me but I decided to change both microswitches even though there was slim chance of both failing at the same time.
    Once again the cannons keep searching for home and the new microswitches still didn't register in Switch Edges test.
    The old microswitches tested ok out of circuit.

    I had a known good CPU board so I fitted it and hey presto, no more faults.

    Once I got home, I looked at a STNG manual and a quick look at the switch matrix shows all the cannon launcher switches in column 9.
    I discovered that each launcher has two microswitches underneath, one MARK and one HOME

    20190819_124902[1].jpg

    Column 9 appears to be sensed by the 8 bit driver board but it was fixed by a CPU board replacement.
    How do I progress from here?

    20190819_124921[1].jpg

  2. #2
    Join Date
    Oct 2005
    State
    Redlands
    Posts
    19,365
    Mentioned
    169 Post(s)
    Quoted
    2008 Post(s)
    I'm pretty sure those switches only register in the specific cannon test.
    Is the ribbon cable attached to j204 and the right way around?

  3. #3
    Join Date
    Jul 2007
    State
    Auckland, NZ
    Posts
    1,070
    Mentioned
    50 Post(s)
    Quoted
    274 Post(s)

    The owner wouldn't have opened the back box to mess around with the cables, he's not technical. It was definitely fixed by changing the CPU board so that's where i suspect the fault is. I could fit it to another wide body with the 8 bit driver board, Twilight Zone and see what happens.

  4. #4
    Join Date
    Jun 2013
    State
    NSW
    Posts
    317
    Mentioned
    7 Post(s)
    Quoted
    101 Post(s)
    Looking at the diagrams, the home and mark switches go via the 8 Driver Board to the CPU on J204. Since all of column 9 is not registering look at U7 pin 9 74LS244 on CPU board which is data line D7 to the 8 Driver board.

  5. #5
    Join Date
    Jul 2007
    State
    Auckland, NZ
    Posts
    1,070
    Mentioned
    50 Post(s)
    Quoted
    274 Post(s)

    Quote Originally Posted by c_mario View Post
    Looking at the diagrams, the home and mark switches go via the 8 Driver Board to the CPU on J204. Since all of column 9 is not registering look at U7 pin 9 74LS244 on CPU board which is data line D7 to the 8 Driver board.
    Thanks a bunch, I'll just change U7 and stick it back in his game. I'll report back in about a week.

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Star Trek the Next Generation
    By Maxprofits in forum Common Problems listed by Machine/Manufacturer
    Replies: 6
    Last Post: 7th February 2017, 07:53 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •