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Tortoise point motor faulty internal switch


Natalie Porter
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I have had over 60 of these for several years and only had a problem with one.  According to Circuitron this problem most commonly happens if ballast from above slips through the tie-bar hole and gets into the mechanism. Even worse if the ballast still has sticky PVA attached.

 

In my case I was only using one of the internal switches so I was able to move the wires over to the other. Don't know why mine failed as I hadn't ballasted recently, and it was a while before I realized that locos occasionally stalling on the point was due to a dead frog. 

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34 minutes ago, RFS said:

I have had over 60 of these for several years and only had a problem with one.  According to Circuitron this problem most commonly happens if ballast from above slips through the tie-bar hole and gets into the mechanism. Even worse if the ballast still has sticky PVA attached.

 

In my case I was only using one of the internal switches so I was able to move the wires over to the other. Don't know why mine failed as I hadn't ballasted recently, and it was a while before I realized that locos occasionally stalling on the point was due to a dead frog. 

I’ve not ballasted yet, I’ve taken the point motors apart now and the issue is obvious, the copper contacts have come lose where they attach to the actuator arm, I’ve araldited them securely back in place, I’m quite certain I’ll have no further issues with them but the fact remains, they shouldn’t have come lose in the first place. I have about 40 of them yet to install, I just hope I don’t have a faulty batch, I will be checking the rest of them prior to installation.

Edited by Natalie Porter
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Never had a problem with mine. Don’t they come with a lifetime guarantee?

 

I always wire mine up using both switches for the frog so have an element of redundancy from the start.

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I have done the same using both switches for the frog, the ones I have repaired work great now. and, yes I believe they do come with a lifetime guarantee but sending them back could take a long time and I would really like to make progress.

Edited by Natalie Porter
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I've seen the switches fail, on a very large layout, running a 5A DCC system.   Solution is hard work, but does the job - external microswitches using essentially the same method as that described in a Model Railway Journal article a few years ago. 

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I've had over 50 of them. Some still running after nearly 18 years. The only 2 switches that ever gave me any grief were ones where some gunk got in under the wiper. The only real reason a switch will fail is if the wiper fails to make contact with the contact pad on the circuit board. There are 3 scenarios that will cause this. 

1: connection to the wiper or the contact and the solder pad has broken. Damaged trace usually. A small bit of wire as a bridge will suffice. 

2: the wiper has been bent and is no longer making contact. 

3: there is material between the wiper and contacts. 

 

This will void your 9 year warranty, but...... Open the unit. Gently clean the contacts and wiper with either isopropyl or contact cleaner. Very gently make sure the wipers are making good contact with the pads. Reassemble, test. The contacts are rated as 1a switching current and 5a continuous. Unless you have other wiring issues that cause a brief short while the point blades change over, or are changing the points under a large loco, the frog should never be drawing current when you switch. If you have fried the wiper and contacts, you need to look at the cause being in your wiring. 

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40 minutes ago, Nigelcliffe said:

I've seen the switches fail, on a very large layout, running a 5A DCC system.   Solution is hard work, but does the job - external microswitches using essentially the same method as that described in a Model Railway Journal article a few years ago. 

Not knowing what that was my method, if you need to by-pass the internal switches, would be a pair of microswitches on an L shape bracket with the actuating arms operated by the plastic bit that the wire screws to.

Edited by melmerby
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We had trouble with a number of our ones not switching properly. A friend of mine stripped and cleaned the switches and treated them to a special grease which has transformed reliabiliy. I will find out what he used and report back.

 

Martin

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20 hours ago, Taz said:

Never had a problem with mine. Don’t they come with a lifetime guarantee?

 

I always wire mine up using both switches for the frog so have an element of redundancy from the start.

Using both switches, I suspect will give you grief, if one of the pair does indeed go faulty. A multimeter may give results that appear fine, but isn't.

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2 minutes ago, kevinlms said:

Using both switches, I suspect will give you grief, if one of the pair does indeed go faulty. A multimeter may give results that appear fine, but isn't.

Maybe, but it will be obvious as any short will only occur when a loco crosses the V. I have wired them up into chocolate boxes so they are easy to swap out if one was to play up.

 

 

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As Martin said we had quite a few problems with Tortoise motor wipers on a large exhibition layout.  The motors were more than 10 years old and despite regular cleaning some still gave problems, which at an exhibition, was far from ideal.

 

After applying Electrolube SGB 2X contact grease the problems disappeared.  Apply sparingly.

 

It is available from Farnell RS and Rapid plus others.

 

Neale.

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7 hours ago, melmerby said:

Not knowing what that was my method, if you need to by-pass the internal switches, would be a pair of microswitches on an L shape bracket with the actuating arms operated by the plastic bit that the wire screws to.

 

Essentially that's it.   A bit of aluminium angle on each side of the tortoise, holding a microswitch with an extended arm,  the switch arm is moved by the plastic swinging bit of the Tortoise.  

 

In our case, the modifications included disconnecting the internal Tortoise PCB to break the tracks to the internal wipers, and fix the new microswitches onto the 8-pin header at the top of the motor (so switch change-over can't be in conflict).    Thus, the layout wiring was still "plug in a replacement Tortoise" at the header block when the next one to give problems appears.  There are ready-to-go motors with microswitches fitted in the layout spares box.    

 

- Nigel

 

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The biggest problem I have had was the push on edge connectors as most don't fit properly because the slot is too long, with the result that with vibration they can move causing a contact short, some have been modified with small piece of plastic to restrict end to end movement.

The few I had for later motors were a good fit.

If I was starting again I would just solder the wires!

Of 55 Tortoises only one was faulty from new (made a nasty ticking sound) and that was replaced by the vendor and i have had no problems with them in use

 

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12 hours ago, melmerby said:

The biggest problem I have had was the push on edge connectors as most don't fit properly because the slot is too long, with the result that with vibration they can move causing a contact short, some have been modified with small piece of plastic to restrict end to end movement.

The few I had for later motors were a good fit.

If I was starting again I would just solder the wires!

Of 55 Tortoises only one was faulty from new (made a nasty ticking sound) and that was replaced by the vendor and i have had no problems with them in use

 

 

I got over the problem by soldering small screw terminal blocks to the pcb fingers after drilling extra holes in the fingers to give a straight line (the existing holes in the fingers are staggered), see the photos below.

DSCN0956.JPG.86de061df0023369469bc8450a43b221.JPGDSCN0957.JPG.4f6ff1a98428bc750469c0b44ac309c7.JPGDSCN0958.JPG.36ce6b64e8e54aa96d4593c092838957.JPG

 

Mike

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I've noticed from the Tortoise motors on my plank is they sometimes have to be cycled to give a positive route indication when the layout is powered up. It's only an Inglenook+ plan with three motors, and the second set of contacts illuminate the green side of bi-colour LED to show which siding has been selected, the reds are on permanently but on a lower voltage and separate circuit and the brightness of the green overpowers them. 

 

The motors themselves are probably 15 years old but haven't been used until installed on the layout a couple of years ago. 

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  • 1 month later...

I have repaired some of our Club motors when the switch failed.

 

I have found that the PCB can move very slightly sometimes.

 

Strip down, clean contacts and then use slithers of plasticard to stop any movement of the PCB.

 

I have also noticed that where the arm pivots on the side of the body, this hole can wear. Simply find any piece of tubing that fits over the pivot arm, then fix this in the body to provide a new fulcrum.

 

Costs almost nothing.

 

 

Dave.

 

 

 

 

 

 

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  • 2 weeks later...
On 18/06/2019 at 08:35, Nigelcliffe said:

I've seen the switches fail, on a very large layout, running a 5A DCC system.   Solution is hard work, but does the job - external microswitches using essentially the same method as that described in a Model Railway Journal article a few years ago. 

When building a large club layout a decade or so ago, I recall fitting microswitches because the received wisdom was, that in time, we would have a reliability issue. On Houghton Street points are controlled from triple pole changeover switches. One set of contacts control the tortoise, the other two change frog polarity. 

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