Trough Switch #4, SAM - Works but Won't Register

I'm having an issue with what I believe is trough switch #4 in a Stern SAM. During gameplay, a ball will drain but the trough switch won't register and the game will do an endless ball search rather than advance to the next ball.
I have tested the trough switches in the Diagnostic mode of the Service Menu and they check out fine. I tested them by loading four balls into the trough and then, through the open coin door, using a small screw driver to gently move the balls onto and then off of their respective switches. There is a narrow slot in the trough which allows access for this purpose. Why would the switch check out when tested but for some reason not alert the game to the presence of a ball in the trough? Do I replace the switch to begin with? Below is a link to the only trough switch I could find at Pinball Life. Marco does have a few more, but none that truly matches the Stern switch in my trough.

https://www.pinballlife.com/data-eastsegastern-ball-trough-microswitch.html
IMG_0545 (resized).jpg

#2 4 years ago

MJS

schudel5

Pinside member

20y 166K 6,392 27

Did you test the switch with a ball or your finger? If you used your finger, you are pressing the switch down farther than the ball can sitting in the trough. Test with a ball. Chances are the wire actuator needs to be bent up slightly so the ball can push it down.

#3 4 years ago

LER

Lermods

Are you sure its the switch and not the opto boards failing?

#4 4 years ago

J_G

Jason_Jehosaphat

Pinside+ Frequent

Quoted from schudel5:
Did you test the switch with a ball or your finger? If you used your finger, you are pressing down farther than the ball can sitting in the trough. Test with a ball. Chances are the wire actuator need bent up slightly so the ball can push it down.

Thanks, Schudel.
I amended my post to reflect how I tested the switch using balls, not my finger.
Failing opto board? I hadn't though of that, but the game is low-play HUO, so I would not suspect a failed board. Can the Diagnostic menu be used to evaluate an opto board? If not, now about a mult-meter? Such testing is nothing I've ever done before.

#5 4 years ago

LER

Lermods

OP
Quoted from Jason_Jehosaphat:
Thanks, Schudel.
I amended my post to reflect how I tested the switch using balls, not my finger.
Failing opto board? I hadn't though of that, but the game is low-play HUO, so I would not suspect a failed board. Can the Diagnostic menu be used to evaluate an opto board? If not, now about a mult-meter? Such testing is nothing I've ever done before.

Yes, put game in test mode and pass a piece of paper across the upper and lower optos to see if they register. Also, even if they test ok,.vibration during game play can cause them to have intermittent issues. The opto boards are the cause of almost all trough issues in Stern Sam games. It doesn't matter if it's huo and low play, these boards are notorious for failing.

#6 4 years ago

DAD

Thermionic

Inactive member

8y 54,300 750

Definitely check the opto boards, they fail often and that is highly likely possible; as above, it doesn't matter how old or new the game is, these things can fail at any time for any (or no) reason. In my experience, they can often be fixed by reflowing the solder joints at the connector and LEDs.

Could also be a case of magnetized balls. I have had this occur a couple of times in these troughs, and the symptoms were very similar to what you describe. The balls tended to "stick" to the trough, as a result they tended to roll down sluggishly and when they encountered the opening for the switch actuator they would stall just short of triggering the switch.

#7 4 years ago

ERW

chuckwurt

Pincinnati

10y 193K 31,343 16 13

This trough has physical switches. Not optos. My bet is on magnetized balls.

#8 4 years ago

J_G

Jason_Jehosaphat

Pinside+ Frequent

Quoted from chuckwurt:
This trough has physical switches. Not optos. My bet is on magnetized balls.

Thanks, Erik.
I loaded new balls in the game just today. They roll in the trough normally. No sluggish movement due to magnetization. Heck, I even have my magnets turned off.
Still, knowing there are no opto switches in my trough is helpful. I was wondering if there might be one at the entrance to the trough as I was sure the switches *in* the trough were simple, mechanical micro switches.

#9 4 years ago

J_G

Jason_Jehosaphat

Pinside+ Frequent

Quoted from Thermionic:
Definitely check the opto boards, they fail often and that is highly likely possible; as above, it doesn't matter how old or new the game is, these things can fail at any time for any (or no) reason. In my experience, they can often be fixed by reflowing the solder joints at the connector and LEDs.
Could also be a case of magnetized balls. I have had this occur a couple of times in these troughs, and the symptoms were very similar to what you describe. The balls tended to "stick" to the trough, as a result they tended to roll down sluggishly and when they encountered the opening for the switch actuator they would stall just short of triggering the switch.

Thank you, too, Thermionic.

#10 4 years ago

LTG

Pinside member

Hopkins, MN

12y 191K 56,943 24 7

OP
Quoted from Jason_Jehosaphat:
Why would the switch check out when tested but for some reason not alert the game to the presence of a ball in the trough?

Could have flux inside, causing it to work slow - fine in test but fail game play.

Also reseat connector right there for the ball trough switches, and shove the wire for switch #4 into the IDC connector for good connection.

LTG : )

#11 4 years ago

ERW

chuckwurt

Pincinnati

10y 193K 31,343 16 13

Try resetting the two white connectors right before the VUK that kicks the ball into the shooter lane. Not sure that’s your issue, but might as well.

#12 4 years ago

LER

Lermods

Quoted from chuckwurt:
This trough has physical switches. Not optos. My bet is on magnetized balls.

Wait, what? There are two optos, trough and jam that are on two boards at the end of the trough where the ball ejects. Here’s the switch matrix that shows them, 21 and 22. Unplug and plug back in first to see if that fixes your issue. If that doesn’t, replace them, they are like $8 each.
5F330D8D-3A42-4A29-8C8B-2A139CB467C8 (resized).jpeg

#13 4 years ago

ERW

chuckwurt

Pincinnati

10y 193K 31,343 16 13

The switch he is having issues with is trough #4. That’s a micro switch. See picture above. This tiny opto board could be the issue but usually when that goes nuts the game will end your ball mid ball. Not what was described. worth a shot though. Cheap part like you said.

#14 4 years ago

LER

Lermods