NCE Switch8 and DC Problem

[JPD]

I am using an NCE Switch8 Mk2 and the Button Board to control Tortoise switch motors. It is wired for both DCC and DC. If I leave the DC switch on the Switch8 set to off, then when I turn on my Digitrax Evolution system everything works just fine. However, if I have the DC switch set to set to on when I power up my system, then the push buttons will not work. The light flashes on the Button Board, but nothing happens. I am still able to throw turnouts using my Digitrax throttle. If I turn off the DC switch, count to ten, turn it back on, then everything works just fine.

 

I know that it is not recommended to run the Switch 8 just on DC only and I am not doing so. It is also connected to my DCC bus. I have checked the voltage coming into the Switch8 of both the DC and DCC power and DC reads at 12 volts and DCC at 14 volts. The wall wart I am using to power the DC is rated at 12 volts (but I notice on my meter with no other charge on it, the voltage reads 17 volts).

 

Any idea what is going on?

[gregc]

JPD

The wall wart I am using to power the DC is rated at 12 volts (but I notice on my meter with no other charge on it, the voltage reads 17 volts).

you mean without any "load" on it, it reads 17V?

the output is at the rated voltage at the rated current

[rrinker]

 You may have simply uncovered the reason it is not recommended to use DC only. If it works with the switch set the way you are going to leave it...

 Actually, I don't see that in the instructions for the Switch8, but it really sounds like the power isn;t getting to the + and - connections going to the button board when the switch is in DC. If it works fine in DCC, then the power does get tehre from the rectifier and filter on board the Switch8. That is otherwise works in the DC mode though, sort of rules out the selector switch being bad.

 DCC Guy has a whole video on YouTube about Switch8 and button board issues - but I think most issues people have are from using too long a cable between the button board and the Switch8.

 

                           --Randy

[JPD]

That is correct, without a load, my meter shows the wall wart at 17 volts, but when it is connected to the Switch8 it shows 12 volts. On the wall wart it says it is 12 volts. Is this an issue with it being unregulated?

I tried a different wall wart, rated at 9 volts, and notice the same behavior with the Switch8.

gregc

 

JPD

The wall wart I am using to power the DC is rated at 12 volts (but I notice on my meter with no other charge on it, the voltage reads 17 volts).

 

 

you mean without any "load" on it, it reads 17V?

the output is at the rated voltage at the rated current

 

[JPD]

I watched the DCC Guy videos already. That is where I learned that one should not just run on DC. The Switch8 is always connected to DCC.

Agreed that the selector switch appears to be OK. I tested the DC connection with my meter and it shows that power is coming in from the wall wart and the positive is going to the center of the connector as it should.

Before I installed the Switch8 under my layout with my Digitrax system I tested it using a Sprog and I did not have this problem. I thought perhaps the wall wart was the issue because I used a 9 volt on the Sprog testing and 12 volt with the Digitrax. However, using the old 9 volt wall wart I see the same behavior.

 

rrinker

 You may have simply uncovered the reason it is not recommended to use DC only. If it works with the switch set the way you are going to leave it...

 Actually, I don't see that in the instructions for the Switch8, but it really sounds like the power isn;t getting to the + and - connections going to the button board when the switch is in DC. If it works fine in DCC, then the power does get tehre from the rectifier and filter on board the Switch8. That is otherwise works in the DC mode though, sort of rules out the selector switch being bad.

 DCC Guy has a whole video on YouTube about Switch8 and button board issues - but I think most issues people have are from using too long a cable between the button board and the Switch8.

 

                           --Randy

 

[JPD]

OK, I re-watched the DCC Guy's video on the DC problem with the Switch8 and tried adding a SPDT switch on the negative wire between the wall wart and the Switch8. This does work in the sense that I no longer have to reach under the layout and hunt for the tiny DC/DCC switch on the Switch8. I can leave that tiny switch set to DC and then flick on the SPDT switch, wait about ten seconds, and every thing works.

I have a 12 volt bus that I plan on using with the Tortoise motors and I will put the SPDT switch on that bus and connect the Switch8 to that bus thus removing the wall wort from the equation. I can then turn on the Tortoise bus from a central point. If I add more Switch8 boards, then I will not have to reset the DC on them at the boards but from a central location.

All that said, I still fail to understand why this is now necessary. According to the manual and DCC Guy, if I am connected to the DCC bus and have the DC/DCC tiny switch set to DC, then it should work without any need to reset it.

I wonder if the Switch8 board is bad. I have also sent a message to NCE support. If they can solve the problem, then I will post their solution here.

Frustrating day.

[BigDaddy]

JPD

I wonder if the Switch8 board is bad.

There is an NCE forum in Groups.io

[JPD]

I heard back from NCE support:

"If you are using external DC power on the SW8, you will need to leave that power supply plugged in and ON all the time. The DC / DCC switch will need to stay on DC."

I turn off all the power to my layout when I shutdown for the night. So this is not the way I want to operate. I will just add a toggle switch to the Tortoise machine bus and use it to reset the Switch8.