Star Trek TNG: Cannon's problem

[Deleted member 2463]

Guys,
My ST:TNG on location at work has developed a problem. I've not had a chance to flip the play field but I thought I'd ask on here first. The game behaves as if the cannons have been deactivated and the machine gives three errors:

check Switch 36 under L.gun sw.1
check switch 37 under r.gun sw.1
check switch 38 left gun shooter

I went into the test and I can make the guns move.

anyone seen this? Hoping its not the dreaded looms!

Cheers,
Neil.

 

[pinballmania]

Well they're all in the same column so first check the rest of the switches in that column. If all out then suspect cpu fault or connection to it. If some work but others don't then break in the loom somewhere ? Unlikely to be the cannon looms as you have more than one sworn out.

 

[Deleted member 2463]

Andy - thanks - so the other stuff on that column was ok a checked the cabling and again looked ok - so I put a ball down the launcher and it detected it, did the same for the other and it was ok. Ball in the shooter all ok. Exited the menu and game A-OK. So not sure what triggered this but will keep an eye out - thanks for your help.

Cheers
Neil


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[pinballmania]

When next in there check the bunch of cables on the left hand side of the playfield. They get caught in the playfield hinges and are often damaged. If there are previous repairs then check that they are good. If someone has twisted wires together and put tape under them you could have a hidden intermittent connection.

 

[Deleted member 2463]

Thanks!


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[Deleted member 2463]

Has happened a couple of times since but I caught the start of it (before the machine was just turned off) - Machine working fine last night turn it on this morning and the coil that fires the ball up from the tunnel on the right hand side is firing constantly. So I'm guessing that there is a problem with Under Right Gun Sw. 1 (sw 37?)

Neil.

 

[aaronhicksuk]

That sounds like a dodgy opto to me Neil. You might get away with just cleaning it but if its weak it would be better to change it, generally the transmitter side is the problem. If you have trouble with lots of optos then it can be worth checking out the opto driver board for cold solder joints and reseat the connectors to improve continuity. Most of the problems that affect STTNG are opto related, I just replaced every opto on my game (transmitters and receivers) and its been 100% rock solid ever since. The ones under the 3 VUKs are actually pretty easy to work on, just disconnect the plugs, unscrew the mechs and drop them off the playfield.

They're cheap as chips (like 18p each) if you buy by the 100 from Farnell and cover you for any WPC game:

Transmitter (QED123): http://uk.farnell.com/fairchild-semiconductor/qed123/infrared-led-5mm-890nm-thd/dp/2453249
Receiver: (QSD124): http://uk.farnell.com/fairchild-semiconductor/qsd124/photo-transistor-npn-880nm-5mm/dp/2453253

Slotted Opto (OPB804): http://uk.farnell.com/optek-technology/opb804/slotted-switch-transistor/dp/2352217 (You won't need these for this problem but these are the other type of opto used on WPC games. A bit more money but used a lot less often. These are used for the flipper cabinet switches. Also used for a few bits on other games, Clock on TZ, POA on Indy etc)

 

[aaronhicksuk]

One more thing I forgot to mention. When you change these I've found the easiest way to get them installed the correct way round is remember "the big leg goes to the small letter."

Transmitter boards are labelled with an A (Anode - Long Leg) and K (Cathode - Short Leg)
Receiver boards are labelled with a C (Collector - Long Leg) and E (Emitter - Short Leg)

 

[Deleted member 2463]

Thanks, I had come to the same conclusion and was about to order the optos from Phil. I will give it a clean and see if that helps and then replace if need be.


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