# TCS keep alive mother board with 21 pin loksound installed?



## Theamazingswal (Dec 14, 2017)

Maybe someone here may know this? I have a consist with 3 TCS decoders installed in Atlas locos with TCS keep alive mother boards. I don't like any of the horns choices that TCS provides. If I buy a loksound 21 pin decoder, which you can change the whole engine if you choose to, will that mate up with the TCS mother board and will the keep alive still work? 

George


----------



## ncrc5315 (Jan 25, 2014)

You can plug in the ESu 21 pin decoder, into the TCS mother board, with the keep alive, and the keep alive will keep the ESu decoder "alive". The problem is going to be programming the ESu decoder, as the TCS keep alive circuit will interfere with the programming, as the capacitor will absorb the programming "spikes", and attempt to smooth them out. This is why the ESu "keep alive", is soldered to the decoder, to prevent the capacitors from interfering with programming, as the capacitor is located after the signal has been stripped off. I think there is a procedure for programming with the keep alive, but the best way is to do the programming withe the decoder not installed, then after programming, install the ESu decoder. Or is the keep alive can be removed, then install it after programming.


----------



## Lemonhawk (Sep 24, 2013)

If the keepalive is installed before the DCC signal detect, would it not interfere with both programming and normal DCC signals?


----------



## ncrc5315 (Jan 25, 2014)

No, it has to do with how the programming signals are sent. I have read how there is a difference, but don't really remember the exact details, since it doesn't' affect me.


----------



## MatroxD (Jan 19, 2018)

Yes, you can do that (replace the decoder with an esu). The only thing is that with the keep alive, just make sure you give it time to drain all the juice out of the capacitors before you start it up again(such as a change that requires a power cycle).

I have keep alive in all my locomotives and decoders (including an esu), and the keep alive does nothing besides just that, keep it alive, with the exception of, if I need to do, say a reset or something that requires a power cycle (it has no effect on anything else). 

The easier way to do what your suggesting down the line is via jmri... 

Sent from my SM-N950U using Tapatalk


----------



## ncrc5315 (Jan 25, 2014)

MatroxD, thanks for your reply, I know there was a way to do it, just couldn't remember how.


----------

