sttng wont stop putting balls into play

[john bud]

hi guys, im having a bit of a problem with a sttng, it keeps putting balls into play. eventually it goes into multiball but just keeps going. whilst im happy to rack up huge scores, i could do with a break now and again. i have read the other thread on the plunger and think possibly its a similar fault. it seems to be a problem at the top of the machine. i have never worked on a pinball before so its new ground to me. jon will be coming over at some point to help out, but im impatient and want a few credits just now.



i can hear something like a ball plunger going ??? i.e. trying to load a ball into something. my head is saying its a switch somewhere that is stuck. this is a learning curve for me so be gentle. any advice would be great.



cheers.



john bud

 

[Rus121]

I would suspect the ball trough optos. A common fault on sttng (and others).



You will need to check your opto pcb that is connected to the ball trough (where the balls sit before they go into the shooter lane), Its at the front of the machine near the lockdown bar under the playfield. The transmitter board is the one facing you, so remove that board and turn it around so you can see the opto leds. Turn the power on the machine and look at the opto leds through a camera/camera phone (only a camera can see the infra red beam), if you see an led out, you have found your problem and will need to investigate futher. From my experience both the leds and the big blue resistors that are connested to the board can both fail.



If you find the pcb to be faulty, i happen to have a fully working one from an indiana jones that will fit it. £15 posted and its yours....Let me know via PM if this tickles your fancy...

 

[john bud]

if you can hold the board for a bit that would be superb

sent out the smoke signals and a couple of hours later, scotlands finest shows up,

great to see jon and nikki again. jon did all of the above even testing things by reversing wires etc. the logical fault lol, couldnt help that lol sorry. it seems to be pointing to a fault on a big board with lots of plugs he is going to bring a board out to swap it over, fingers crossed we can prove it. whilst here he also had a look at my dracula pinball it needs 3 coils and a fuse

its 1 of my faves so a bit of a bummer its blowing coils. on the plus side though i learned some things about pinballs on the repair side, so not all doom and gloom. i learned how to set the balls, both on 5 now

and set to easy, magic. its been great to meet some of you guys over the past couple of years, mostly through videos im looking forward to the pinball side, im pretty sure i have all the vids i need. i gotts to say thanks again to jon for popping over.





cheers.



john bud

 

[highjon]

Having had a look at it, it appears to be the opto at one of the left upkicker holes. The opto is changing state-11-12volts but not registering, the signal is getting to the underfield opto board but not registering after that.

I will pop back over with a spare opto board and a diode on a piece of wire, to check the board...

any other ideas guys?

 

[Moonraker]

A few ideas.... did you check that the transmitter led was lit (mobile phone), did you check the voltage on both the receiver and transmitter leds? did you diode test both leds? If all those are ok then try reflowing the solder to the connectors on the 16-opto PCB (J2 & J5). Good luck!

 

[highjon]

Yep, checked the Tx with a mobile camera, and the voltage on both. 12v at one side and 1.1v on the other side, changing to 12v when beam broken.

What do you mean by diode testing both leds? I was going to check the board in the backbox by using a diode fly lead to trigger the switch directly at the pins on the board to prove that board.

cheers

A few ideas.... did you check that the transmitter led was lit (mobile phone), did you check the voltage on both the receiver and transmitter leds? did you diode test both leds? If all those are ok then try reflowing the solder to the connectors on the 16-opto PCB (J2 & J5). Good luck!

 

[Moonraker]

LED's are light emitting diodes so you can test them using the diode test function on a multimeter... They sound ok though if you are seeing a voltage change when breaking the beam. I'd check that you get the same changes at J2 and J5 on the 16-Opto PCB before you check the backbox driver board, unless you're swapping that for a known good one.

 

[Judge Dreads]

I had same problem when I purchased my STTNG, said to the guy knock £50 off for a new pair of boards as we lugged it out of the house, (gees it was a heavy pig) me and my mate looked at each other gurning, the boards in there were well hacked so I thought easy fix ........... turned out to be nothing to do with the trough boards, it was acid damage on the CPU board, worth a look if everything else checks out.

 

[mufcmufc]

Possibly the LM339 on the (big) opto board, change and socket both

 

[john bud]

i dont know if its any use, but i took a ball out of play, it now wont fire the cannons or even load them but the game doesnt keep loading balls now. im thinking possibly the fault is linked to the cannons ??? or possibly the sensor that loads them. but at least we got a few credits on it.



cheers.



john bud

 

[pinballmania]

Take a close look around the bundle of wires on the left hand side of the playfield. They frequently get snagged in the hinge mechanism, and get snapped. If the opto is registering through the 8 opto board, but not getting to the cpu, then i bet one of the switch matrix wires is broken here.

 

[BigIan]

Having a similar problem on my ST:TNG. One of the opto leds is far dimmer than the others, ordering a couple from Andy.



Also the subway diverters fail testing so am guessing they have locked on and burnt out (only just bought the table).



John you can turn the cannons off in the menus which could help diagnose your problem..

 

[john bud]

i will try to have a look tonight at both the connectors and turning off the cannons. been too busy with paperwork. if i turn off the cannons should i then put the 6th ball back into the table ??? and if it plays ok without chucking balls into play, will this prove the fault lies with the cannon circuit ???



cheers.



john bud

 

[Lippy427]

Hi,

had similar faults on my STTNG over the years - caused by the following...



1) Under table diverter being locked on. Which means that the table can't load a ball under the right cannon. This happens at switch on and it will keep launching a ball which is then returned to the table/trough from the left up kicker - you can't start a game.

2) Connections to the trough boards being bad - meaning that the machine is never sure how many balls are in the trough, so it tries to adjust by firing balls out. This was fixed by getting a proper molex insertion tool and reseating the connections.

3) loose purple/yellow(?) wire that connects to the standup/drop down target at the top of the table. This also seemed to mess up the optos which resulted in balls being released from anywhere and everywhere. A visual inspection of the wire looked ok, but it was only fastened by a single thread - re soldering it cured it.



Hope this helps.

Geoff

 

[john bud]

yippee, had a visit from jon higgins ast night. he replaced 2 coils in the bsd, and its now running sweet. sadly the sttng is proving to be a bit of a job though. he tried replacing chips but its still gubbed. it will be getting uplifted to go over to his for a more indepth repair. but at least im flipping balls now. had a mate over last night, it was 12.57 when he left. i didnt know the time until i put a fray bentos pie in the oven. gotts to say though it went down a treat. so big thanks go to jon for getting the bsd fixed, and mr bentos for making such nice pies lol.