ADDING A CAPACITOR TO SOUNDTRAXX PNP DECODER

[Kusojiji]

I bought an ECONAMI PNP8 decoder and would like to add a capacitor to it. I bought the wire harness for it so that I can plug it in. Question is can I just add a capacitor (electrolytic)? I don't want to use one of my super caps with the circuit board as this decoder is going into a Kato C44-9W and I don't think it really needs something to make it last a few seconds. I just need it for that quick hit that tends to shut sound decoders down.

I think I have some 1000 uF/25 Vdc caps.

 

[ctclibby]

Umm, why would there be any difference between this and any other cap you have added to whatever decoder? Am I missing something?

L8r

 

[Kusojiji]

My other installs, I either used a supercap system or tantalums behind a current limiter/resistor. This time, I just want to use a raw cap. The installation manual says that the BLU-1100, TSU-1100 and UK ECO-100 come with a 220 uF/25 vdc cap, but I don't know if the PNP has protection for the inrush.

 

[ctclibby]

Time = RC; 1 time constant gets you to 63% charge. Is there already a resistor in the circuit? If so, you may change its value somewhat. If no resistor, circuit is relying on the resistance of the DC [DCC] line. Have you checked the actual run time at s-l-o-w speed when power is bumped? You might be OkieDokie with the 220uF

L8r

 

[Kusojiji]

I haven't installed the decoder yet. Just doing some prep work. As for a resistor in the decoder, I don't know. I've been searching the interweb and so far nothing. I guess I could send soundtraxx an email and ask.

I have the TCS KA-N1 micro stay alive in a few of my UK 0-6-0s and while it doesn't provide any run time, it does work with that micro-second hit like going over switches. It's a 1000 uF tantalum. It has the circuitry on the board.