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Stern S.A.M ball trough issue - does a permanent fix exist?

NateG119

NateG119

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Aug 22, 2019
Messages
61
Location
Brantham
Hi all, wondering if there's a way to permanently quash the Stern S.A.M ball trough issue? I imagine most are aware of what I'm talking about, the ball troughs in Star trek/Iron Man/Tron/ACDC etc. thinking the ball has drained when it hasn't, causing flippers to die or multiballs to end or ball saves to activate. I've encountered it dozens of times.

Had Star Trek (Pro) since new and this issue resurfaces once or twice a year. So far:
- Replacing both of the boards in the ball trough fixed it for 6 months or so, but it came back (only did this once)
- Resoldering the board closest to the front (the receiver?) fixes it for several months (have done this alot)
- Simply unplugging the boards and then plugging them back in again tends to fix it for a couple of weeks

Is there a way to stop this for good? Or are all S.A.M owners constantly tweaking the ball trough boards? Cheers!
 
AlanJ said:
I’ve had a stern star trek pro for 6 years. never ever had this issue?
Click to expand...
Maybe it depends on the batch? I've seen this happen to 3 different Star Treks (LE at the Pinball office, one at Pinfest, my own), the Tron that used to be on Bournemouth pier did it, the ACDC from Walton pier did it, an Iron Man at a show did it to me once...suggests its part-specific perhaps.
 
Never had this issue on the few Sam games I’ve owned. Currently have Met & TWD and I’ve not seen this problem once.
 
Have ST and TWD also from new and not had a problem with them , but i do remember there is /was an issue regarding the trough , that issue was the connector and zip tiring the connector sorted that problem !
 
carl lawrence said:
that issue was the connector and zip tiring the connector sorted that problem
Click to expand...
Zip tieing the connector is something I haven't tried yet but makes sense...would also explain why the issue creeps back over time if it's gradually coming loose. I'll give it a go, thanks
 
There's 3 or 4 different things that cause this.

The main cause is the trough Z connector which can oxidise (so in theory zip tying should be pointless). Easiest long term fix is solder the trough wires directly to each other (cover bare wires with heat shrink) removing the Z connector. A short term fix is to lightly sand the Z connector pins. Reseating connectors works but only a few times before you need to sand. I once did a bodge fix on an AC/DC premium in a London & SE league game by rubbing the Z connector pins on exposed brick work which allowed the game to continue to the end of the league meet without further issue!

Not so common is a second Z connector in some games, which I think is at the bottom of the playfield on the right hand side.

Swapping both Z connectors for new can fix the issue for a period of time but you really can't beat the solder fix.

It can also be heat related with the fluorescent tube in the back box.

If the game has another mini trough then that can also be a cause.

Another cause is cracked solder joints on trough optos, oh and dirty optos.

Finally the trough switches can cause issues if the ball fails to sit on the properly this could be caused by poor switch adjustment, divots in the trough (WPC games also suffer from divots), balls catching on the top of the trough. In some games there is a rail to help protect the switches, then (I suspect) with Stern's cost cutting the rail is missing on more recent games causing issues with the ball resting on the switch (eventually bends the switch arm).

Basically, anytime the ball isn't where the game thinks it should be when in the trough can cause issues to happen.
 
I had a weird problem like this, changed the opto boards, looked at connectors etc
Turned out to be a diode on a trough switch became disconnected that you just could not see, was messing about in the trough test banging around and saw that switch flicker.
Was on Tron.
 
Any time I had this it was the connector to the loom. The poor plating oxidises and prevents contact, simply taking it off and on a few times fixes itso a permanent fix would be to either solder it or replace for a better quality part.
 
Thanks everyone, plenty more things for me to try there :) the 'glad it's not just me' feeling is a relief for sure
 
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