mth crossing gate test

Edit: I got this wrong before I knew I about the internal schematic of the gate crossing. The RED and Blue wires are connected together internally, so Yellow or White to Red is a valid trigger I was unaware of.

Your failure is, you do not connect the YELLOW or WHITE wire to positive.

You alternately connect one or the other to BLUE.

The manual https://www.mthtrains.com/site...ction/30as10200i.pdf

Again, Red and Black are the power source.

BLUE is a COMMON, and WHITE and YELLOW alternate which one is connected to BLUE.

Think of the ITAD shown as a relay- again with COMMON, NC (normally closed), NO (normally open) contacts.

Either yellow or white connects to blue (never both at the same time). One represents up, the other down.

Hello Vernon, I am always amazed at the resources here at the forum. This morning I spoke with my friend Pat Norcross on a tether issue on one of my Weaver I-5's. Now you have been very helpful on getting the gates tested before installing them. I certainly appreciate your help. Thanks . Bill Park

@Bill Park posted:

Hello Vernon, I am always amazed at the resources here at the forum. This morning I spoke with my friend Pat Norcross on a tether issue on one of my Weaver I-5's. Now you have been very helpful on getting the gates tested before installing them. I certainly appreciate your help. Thanks . Bill Park

To be fair, I had a local repair come in on one of these gate crossings about 2 weeks ago. Point being, I was very familiar with bench testing one.

In that repair case, it was a lost cause. The worm wheel gear on the gate arm shaft had been stripped beyond any chance of it ever working again.  It was no longer a viable repair when good working gate arm sets could be bought at roughly $80 for a pair ($40) each, it was just a loosing battle of labor cost and parts exceed the value of the item.

I hate not being able to fix something- but when to say when when $$$ are involved.

Hi Vernon, I followed your instructions and was able to get one of the gates to work pretty well. The other stutters and jerks a bit if you play with it. Do the limit switches play any significant role in the operation and should I be trying to adjust them to make the gate work? Also, do you apply and lubrication anywhere?

@Bill Park posted:

Hi Vernon, I followed your instructions and was able to get one of the gates to work pretty well.

The other stutters and jerks a bit if you play with it.

Do the limit switches play any significant role in the operation and should I be trying to adjust them to make the gate work? They control the limits, however, if it is jerking or problematic in the middle of movement between the up and down end limits- they have nothing to do with it- that's all the gear and motor system and likely problems in that mechanical area- not electrical and not adjustment.

Also, do you apply and lubrication anywhere? Yes, specifically to the tiny motor bushings, light oil, and the other big wear point, the worm gear to worm wheel gear- the one that was stripped and damaged in the one I was trying to repair. I used a plastic safe PTFE grease on the worm gear interface, and that required taking off the moving gate arm (2 screws one on each side) then the square shaft can be pressed through the gear enough to one side to allow it to come out the inspection hole cover.

Being honest, I do not see a good way to inject grease into the system just by removing the side cover plate and getting grease where it matters- on the teeth of the gear and the worm- without taking the arm off, pressing the square shaft out, and removing the gear from the housing to see the worm on the far side.

This is an extremely tiny mechanism and little room for error. Also, if that gear is chewed and damaged either from the force on the gate arm stripping it or just wear and tear, it's kind of a done deal.

Also, let me be clear here. Sure, you could have a split gear right on the motor. They have that part, that can be fixed. That would also cause problematic operation but is the classic small gear pressed on a motor shaft splitting from stress cracks.

https://ogrforum.com/...-gear-failure?page=1

What I'm talking about is greasing and inspecting the upper gear that is the final gear moving the arm. It's not even a full round gear, just a C shaped section of a gear that interfaces to the vertical worm gear and has little arms that hit the limit switches. That gear- if it strips or has problems is kind of a bigger deal.

Hi Vernon, The frustrating part of this is these were brand new gates. They had been in my basement in their standard packaging until several weeks ago. One Forum member weighed in here and said the limit switches play an important part in the operation. Is that a fact and is there any way to know how to set them, any procedures etc.?

FWIW, another great informational post on repairing one of these by @stan2004 https://ogrforum.com/...9#155716354510032309

Also, was just checking MTH parts and sales, the one gear (on the motor) that was in stock is no longer

@Bill Park posted:

Hi Vernon, The frustrating part of this is these were brand new gates. They had been in my basement in their standard packaging until several weeks ago. One Forum member weighed in here and said the limit switches play an important part in the operation. Is that a fact and is there any way to know how to set them, any procedures etc.?

Again, by all means read the post by Stan2004 made, there is excellent info in a lot of those replies in that topic https://ogrforum.com/...c/mth-30-11012-wires

My point was- you said this "The other stutters and jerks a bit if you play with it".

Now obviously interpretation and reading between the lines is everything, but I read that as describing the motion when it is moving.

Again, understand the limit switch function- to STOP movement at the END of position.

I don't know how good you are at reading or understand a schematic- but it pretty much says what I just said- The limit switch affects ONLY the limit of motion AFTER it starts moving (as intended). Now, you could in theory over adjust by screwing in too far and basically lock a limit switch closed- preventing that direction of travel. Again, the limit switch basically shorts that input into the motor drivers section when closed- so if the mechanical adjustment is out and closes it, or the device is just physically at the end limit- then the motor cannot move in one direction- but that sounds different than your symptom.

I'll also admit I was wrong. I did not know this schematic had been posted or existed, and I was only previously going off the instructions, and seeing that Blue was tied to common which I assumed was Black. So yes, sorry, my first reply, it appears the Red wire to either Yellow or White activates because Red and Blue are internally connected and I was unaware of that connection.

Again, I read this and think: you may have a split gear on the motor, and that could explain jerky movement because the motor is trying to overcome that split on each rotation so it acts jerky. The catch22 is, now, today, that gear is not in stock at MTH parts and sales.

EH5200001GEAR / DRIVE / PLASTIC / 3.5mm D x 4mm H / RAILKING O SCALE OPERATING CROSSING GATE (Out of Stock)

That said, this post talks about an alternate at NSLW

https://ogrforum.com/...79#80551019603897079

2 pics from that topic

I have no experience with the MTH crossing gate. I know in the smaller scales many use a Tortoise with some sort of bell crank under the table. I realize this isn’t a cheap fix and probably requires a bit of tinkering.  You need a Tortoise along with their signal activator. Around $40. Tortoises are pretty much bulletproof. Seems like it might be a long term solution as far as reliability. I’m only guessing the throw can activate the travel required in O.

@Vernon Barry posted:

Also, was just checking MTH parts and sales, the one gear (on the motor) that was in stock is no longer

Yes, but North West Short Line (NWSL) has a gear that works...p/n 37410-6.   And it's hobbed from brass.  I've repaired a couple dozen of these gates for the split motor gear with the NWSL gear.  Works perfectly and will never again split.  Yes, it's not as cheap as a plastic gear, but it's a one-and-done repair solution...IMHO.

The NWSL gear comes with a 1.5mm bore.  You may want to gently and slowly ream the bore with a very fine needle file to minimize the press fit to the motor shaft.  Check your fit frequently before the final press, supporting the terminal end of the motor shaft.

There are other 10-tooth plastic pinion gears available through the net that have been reported to work.  OTOH, if they are of nylon...a hygroscopic plastic (properties affected by ambient humidity)...they may end up cracking again in the future.  Nylon has always been an inexpensive OEM choice for molded gears, but other plastic resins...e.g., acetal...are a more durable choice, especially for small pinion gears having very thin stock between the bore and gear root diameters.

FWIW...

KD