Sounds like the Tortoise case will need to be opened to fix it unless you elect to return them under warranty. I have had three Tortoise contact failures over 7 years of layout use. The problem has been one of the two small contact assembly mounts failed, allowing one of the pairs of contacts to rotate out of position. This can be fixed and I did repair one but elected to replace the other two with new Tortoise machines.

This is likely not the problem with your new machines. They are easy to open, just one screw. Whatever the cause, it is likely repairable. Here are two pictures of the guts. The contacts near the pivot arm are rotated out of position, the set near the gear are correct. Hard to see in the picture but the pair of contacts nearest the gear have much less tension on them than the other three sets of contacts.

@cnwdon  The switch contacts are just that - 2 sets of normally open and normally closed contacts. If you are seeing the continuity change with position of the motor, then they are working properly. You have to put the contacts into a circuit in order to see voltage.  There is no electrical connection from the motor contacts to these contacts unless you put it there

In the image link below shows the Tortoise contacts.

circuit

There is no internal source for power inside them as they're presently set up.  Consequently, as @ScoutingDad has mentioned you won't read any voltages on the contacts -- not on either side of them.

You'll need to hook up, in your own way, power to feed the contacts.  In the easiest-to-implement form of this you would likely use an external power source.

Mike

@cnwdon Are you converting the 18v AC to DC using diodes?  The tortoise machine requires DC  current.

Marty

Thanks, all of you, for the effort to help.  The answer turned out to be “none of the above”.  The edge connectors I bought have such minimal traces from the Tortoise trace to screw terminal that they were burning out the very first time an O gauge loco passed over the switch throw rail they were powering via the SPDT Tortoise internal switches.  That’s why the circuit tested good at first with the ohmmeter, and then died soon after.

Here are the items, from a DCC (not DCS) accessory supplier, with their online description.  As you can see, the limited current capacity is not noted at all, so no way to expect it’s not matching Tortoise’s 4 amps for those switches when not switched under load.  A message to the supplier has not yet been returned.

SNAPS! 12 pack from ACCU-LITES, Inc.

$77.88

Photos below. Since we needed to keep moving on our layout project, we improved these by soldering short 20 ga copper jumpers between each pair of solder blobs so the current capacity is now at a minimum 4 amps.  Problem solved, but others should know these are not suitable for O gauge applications using those Tortoise internal switches for anything more than an LED indicator light or small bulb.

Problem solved. I am am not familiar with that product. My Tortoise machines have the 800-6601 Circuitron solderless connectors. They work up to 10A with no problems.

Ahh, just a wee, but key piece of info needed to trouble shoot. So nothing wrong with the tortoises. I use a similar connector for my tortoises, but made for higher amps.  Question is why is track voltage connected to the tortoises? Why not a separate power source?

Scouting Dad: the track voltage travels from the adjacent center rail through one of the Tortoise internal SPDT switches to power just the correct throw rail and not the one carrying wheels, depending on turnout position, so there is no dead spot for locos with short inter-roller distances.  For tiny locos it may carry the whole load; for larger ones or multiple units it will only carry the load of one roller at a time among two or several.  Thus far working OK with the "improved" connectors.  If any locations develop problems, the Tortoise switch can be made to power a SPDT relay coil instead.

Tom: Wish I had known to get Circuitron's own version of edge connectors, would have save us some time and aggravation!  Thanks for informing others so they can avoid my mistake.

Do we know what the current rating is for the Tortoise auxiliary contacts?

It may be the case that they are not rated to handle large traction currents.

As suggested it may be advisable to use these contacts to drive relays whose current ratings are robust enough to switch traction power. Small, inexpensive low-voltage relays with contacts rated at 10 amps are available for this purpose. Protecting the Tortoise contacts is advisable so that replacing the entire Tortoise machines when their contacts fail is avoided. It's much easier and quicker just to unplug and replace a failed relay.

According to the Tortoise instruction sheet the auxiliary switches can switch a maximum of 1A but can carry 4A. For higher current demands they advise using a relay or paralleling the two sets of contacts. I use the aux contacts to power a 12VDC relay coil.

All correct above.  Should contacts fail, one can simply use the other internal switch to drive a relay, would not have to junk the switch machine for it.

I agree with AmFlyer. You would think the tortoise contacts could handle the amperage for the short amount of time the wheels make contact with that short length of rail. But over time I have also had problems with burnt contacts.

I now use HiLetgo relays for all my turnouts and only use the tortoise aux contacts to trigger the relay.

This bank of relays (facia removed) controls the throat into my 4 track passenger terminal, 2 turnouts and 2 double slips.

Buy the way, Circuitron offers a repair kit for the tortoise that includes replacement contacts and updated circuit board.  The price was pretty cheap compared to a new tortoise.