STTNG firing two balls - SOLVED!

[robm]

One of the opto transmitters on my ball trough (STTNG) is not lighting up when viewed through my digital camera screen.  I rang Jaycar and they said they need the specs to see if they have a replacement.  Can anyone help me with what they are? Otherwise i will order one through PSP or RTBB -  its just i want to get it going ASAP as we have a couple of kids here desperate to play, so if i can get it from Jaycar i will.

Thanks

Rob

See the last post for the new problem

[ktm450]

I was going to try these:

http://www.jaycar.com.au/productView.asp?ID=ZD1945&CATID=&keywords=ZD%2D1945&SPECIAL=&form=KEYWORD&ProdCodeOnly=&Keyword1=&Keyword2=&pageNumber=&priceMin=&priceMax=&SUBCATID=

But ended up using NOS leds

Cheap and worth a try, let us know how you go.

[AskJacob]

at the risk of opening a whole can of worms regarding nanometres and sensitivity, let me just say that ANY IR LED will be fine as long as it works. These are non-critical in their spec (the opto receivers on the other hand are a bit more finicky as substitutions may cause odd behaviour).

In a pinch I have pulled an IR LED from an old VCR remote for the ball trough in my IJ, it has worked fine for years now!

Cheers
Jacob

[pinballist]

I agree with Jacob, it's really a matter of just having an IR light source there in the first place, the specs for these are pretty much standard.

[robm]

Awesome - just grabbed an old IR LED off a remote and it works fine!!


BUT


The machine is still loading and firing two balls at the start of each ball - all six trough optos work fine in the switch edges test....any suggestions now?

[AskJacob]

Check, recheck then solder anyway all the pins on the connector on the trough PCBs. Both of them (receiver and transmitter boards). Also touch up the receiver legs on the PCB.

Cracked solder joints are a pain in the arse and often don't show up in tests, only when the solenoids fire and vibrate the boards.

Cheers
Jacob

[pinballist]

Yeah dry joints are the biggest pain because they may look nice and shiny but the components are loose inside them making an intermittently high resistance connection.  Sometimes applying a little new solder to existing joints does wonders especially as AJ pointed out around areas subject to shock & vibration.

[Marty Machine]

.....or, press "1" on the vcr remote for 1 ball hehehehehehe. 

[pinballist]

.....or, press "1" on the vcr remote for 1 ball hehehehehehe. 

ROTFL - now Marty that was funny!!!!!!

[robm]

I have pulled both boards out either side of the trough, and reflowed all soldering.  This did not fix the problem (ie: still shooting two balls at startup).

I then pulled each board out of my working indy and swapped them one at a time across to STTNG, neither fixed the problem.  So from this i assume the problem is definitely not the boards themselves.

I have also read that the trough itself can become a bit pitted where the balls sit, causing them to roll slowly to the upkicker coil.  I chocked one side of the machine to make it slope more and the balls roll down no worries.

From this i assume the problem is elsewhere, i see from the switch matrix, this column goes to pin 13 of U20 - could u20 be stuffed???

the only other bit of relevant info i can pass on is that this only occurred after the machine was shifted across a couple of metres.

Help please

[robm]

I have swapped a good U20 into the machine and this has not changed anything...i'm leaning towards a broken connection or wire somewhere while it was being moved but have no idea where to start looking.

[robm]

Some further testing has revealed that if i take one ball out (ie: only 5 installed) the machine only loads one ball into the shooter lane - the game works fine until it tries to use a ball stored under the playfield for a mode such as battle simulation - then it gets confused as there are only five balls instead of six.

So this sort of points back to the trough being the problem, yet when i put my indy trough boards in it still showed the same problems. 

As this game stores 2 balls under the playfield, i guess if there were any suspect optos they would be number 3 or 4 in the trough (as there are only ever 4 balls in the trough)???????????

[Strangeways]

Typical ST TNG problem

The trough will be slightly pitted, and what happens is that at least 2 - 3 balls will be in the subway before the game will work properly. So there CAN be 2 balls in the trough - which is fine, but, there will be a section of the ball trough that is so worn, that the timing of the first ball into the catapult switch is detected, but the second ball in the trough has not moved into the area of the first ball "in time" - so the game spits out the second ball. You can see this for yourself when you remove the apron and look down into the trough - the first ball is served and the second ball has not moved. There is no third or fourth ball to "push" the second ball.

I fix this issue by removing the trough, dismantling all the parts and then filing the trough until the pitted area is smooth. Re assemble and test.

I know I've seen this problem twice - one fix was the optos, the other was the pitted trough.

Make sure the target at the top of the playfield is working. The game gets VERY confused if it does not reset at the start of each ball.

[silverball]

Pitted trough (already mentioned) and vibration due to the balls constantly slamming into the trough on return are very common faults on this machine (as well as other pins using the same trough/opto setup). Dont go changing chips too quickly, stick the game in switches edges mode and manually throw balls in and observe all all optos "open and closures".

[robm]

I'm almost certain now the problem is not in the trough.

Reasons -

When i watch the balls in the trough run down after the 1st one pops up, it is almost instant - the others do not sit in any divots and take a while to roll down.

I swapped the whole trough (trough, coil and both opto boards) from my Indy into the ST TNG and it did the same thing - this indicates to me the problem is in the programming or wiring...maybe?



I also put three extra balls in the trough as soon as it popped the 1st one up - it then threw 5 into the shooter lane.... this tells me the machine does not like any more than 2 balls in the trough at any one time????? is this right? (there should be 4 in the trough at the start then 3 once one is in play)

Strageways; I Checked drop target - it resets OK

All opto's work perfectly on the switch edges test - both open and closed

I don't really know where to start looking elsewhere though.....