LOTR Mode Start Issue

[BigBoss]

I am having a problem with my LOTR where modes seem to start randomly.
It's very tough to place my finger on exactly what is causing it. It
is definitely not related to hitting any specific switch or anything.
I have seen it happen when the ball is in the middle of the field. At
first, I thought modes were starting randomly intentionally, like
random encounters in an RPG, but after reading the rule set, I see
this is not supposed to be the case. This occurs once or twice every
5-10 minutes of play. By the way, hitting the ring also works
correctly and starts modes as it should.

The closest I can put my finger on, seems that maybe using the flipper
intermittently starts it. It has also occurred when landing in the
left uptake area (Hobbiton). Perhaps intermittently on events that
require a large amount of power.

While in test mode, I have been unable to reproduce it or see any
indicator that switch 47 is firing when it should not. The ring
appears to work correctly when testing the ring, itself. I have pulled
up the play field and attempted to shake it and tap on it in various
places to see if the wiring on the opto board is loose. It's not. I
assume the two things that can cause a mode to start are triggering
switch 47 (opto ring sensors) and the bash balrog switch, in some
cases. I have had modes start when the ball is no where near these
areas.

I'm at a loss for next steps. Any suggestions on where to start?

[frenchy]

Most likely it's an iffy infrared receiver or emitting diode in the
ring. Dunno if bad connection of those sensors by itself could also
cause it to give false closures but u
should check any connections in the pf for that diode. Seems like if
the emitter connection failed that would cause a closure since it
would be the same as the beam being blocked. Can you hear the buzzing
of the ring coil when this happens? Possible that those diodes are
misaligned also and are barely maintaining an 'open' status. You
could check that with one of those infrared light testing cards, that
allows you to see the emitter light spot. Check the exit switch of
the ring trough too.

[DNO]

You are close...
I had the same problem with 2 different LOTRs.
Most likely the wires are failing on the bash balrog switch harness.
This is a normally closed switch, and the wires break within the
shrink tubing.
I've had to cut off the shrink tubing just to look, but you can
sometimes tell if the harness bends real easy in 1 spot.
It sucks to repair, but I would bet that this is your issue.
-DNO-

[BigBoss]

Thank you. My balrog light had bad wiring and I had to replace it
also. I will test this and report back. In fact, the wiring in this
machine has all been questionable. One of the flashers in the front
has an open in its wire somewhere.

Another bit of data is that when I bought this machine, the opto
amplifier board was dead (part 520-5239-00). I couldnt find a -00 and
had to get a 520-5239-01 instead. That board seems to be working
although I had to reverse the opto receiver input. The board looked
physically identical other than this. I wonder if that could be part
of the problem though.

[BigBoss]

I've been working on this all day and have the following additional
details to add:

Disconnecting balrog bash switch: no impact on the problem

Disconnecting spinner switch 52: no impact.

Disconnecting opto amp board power, problem gone but of course you
cannot start any ring modes in any method.

Swapping opto amp board with spiderman, problem stays with lotr so I
assume opto amp board is fine.

Cleaned both opto sensors, they still seem solid. No impact on
problem.

Removed both opto sensors and replaced all the wiring. Soldered them
to the opto board this time, no impact on problem.

Disconnected switch 48 in ball tube behind ring magnet and no impact.

Stern support says that the 520-5239-01 board is fine to use and
cannot be the cause.

It seems to happen a bit more frequently when something requiring
power occurs such as: flipper hit, path of the dead hit, the hole hit
next to Gimli where it upshoots onto the sword. But it's not
exclusive to that. Could it be a power issue? It seems to almost
always happen when hitting the path of the dead entrance if mode start
is lit. While this is not the only time it occurs, it has been about
10 out of 10 at that location. It also occurred once hitting the
spinner (switch 52) but not with enough power and the ball was on its
way out to drain.

[BigBoss]

I finally solved this by replacing the opto transmitter and receiver
in the ring. While the old ones appeared to work in tests, when I
installed the new ones, the first thing I noticed is that the red LED
in the ring looked hotter. My theory is that the LED transmitter was
weak. When power hit, it dropped enough voltage for the game to think
the opto switch triggered.

[Jawzzz]

I just had the same issue. Random mode starts. In my case, the problem was two-fold. The first thing I checked was the spinner switch. It seemed to register correctly when I'd roll a ball through the spinner, however upon closer examination, I found that every once in a while the spinner would get stuck in the closed-switch position. This was caused by the fact the post rubber was a little too tall and when the spinner would push the spring down it would hit the top of the post rubber and get stuck. I cut the post rubber down just a bit to give the switch spring the clearance it needed and that solved that problem.

The second part of the problem was with the opto switch in the ring. I started playing around in switch test interface (the one which shows all the active switches). Every once in a while I would see 47 flicker on the test screen. Even though when I would pass a ball through it would register correctly. I noticed once I opened the machine that the opto beam would flicker every once in a while. So, I jiggled the 2-pin connector which had come slightly loose and the opto started working again.

I think the problem for me was when the spinner switch would get stuck closed and the opto beam would cut out, it would trigger a mode start. When I fixed both of those issues, the ring modes started working again.