I think I have a Soundtrax decoder overheating and causing some weird operation. It's driving a Kato FEF with a brand new motor and it has a TCS KA2 Keep alive hooked up. I am wondering if the Keep Alive is keeping too much heat in the tender. It's pretty tight in there with weights, a sound enclosure on a 15 x 10 (or 8) speaker. I removed the shell and still acts up or sometimes even shuts down. The red light doesn't blink it just stops. This just started after the Keep Alive and new coreless motor. It's pulling 20 Reefers.
Which decoder? The only SoundTraxx decoder that I know of that had heating issues was the 750 Micro. It happened to me and others. Can you easily remove the keep alive? Rich
I was unaware of the overheating issue but I had to rerail the unit and the tender was warm to the touch. I removed the shell and it kept overheating so I put her up for the night. I am wondering if I can take a couple capacitors off the keep alive and reduce the heat? It needs some size capacitor to keep the decoder from resetting the sound, etc.
Capacitors do not create heat, there is something else going on there. Capacitors do not dissipate power.
From my 30+ years in the industrial controls business, capacitors do store up electricity and act as a "short life power source" otherwise they would have no affect on the performance of a decoder with respect to stalling. I am unsure as to where the excess heat is coming from with the decoder. I am only controlling the motor with it. No lights attached. I still have the shell off and will run some tests later today
I have even considered that it may be something with my auxiliary UTP from my old PowerCab not being compatible with the Pro Cab unit I just put in. I have the unit running now with 20 cars continuously. I will see how it does.
I think you might have the KA connected wrong. Capacitor wired backwards will get warm or hot. Did you connect the KA to the track power? Not good.
I think I hooked up to the original leads of the Soundtrax Capacitor. It does it's job as far as holding the power source when you shut the DCC systems down for about 15 seconds or so. Of course you can't change anything in the operation. The decoder just stays "lit" until the capacitors bleed off. It's neen running for 40 minutes just fine. I may have had a intermittent short in a switch or wire touching. I an going let it run for another hour before I shut it down or blow it off to Gremlins!
He was talking about keeping heat in the tender. No air circulation. Reversing wires would blow the keep alive and maybe ruin the decoder. Electrolytic caps do not like reverse voltage for even an instant. There are about seven caps in a keep alive module. Not to be separated. Google keep alive modules. Some vary. Rich
I took a spare Keep Alive and removed the wrapper last night to see if I could reduce the heat potential and there are 5 capacitors in series. I suppose if you wanted to reduce the time hold on the Keep Alive you could remove a couple capacitors and solder in a jumper to keep continuity. There are smaller Keep Alive style units than the one I bought. The TCS is so well known I figured I couldn't go wrong. The train has been running for 3 hours now with no sign of a hiccup. I must have had some stray trash in the tracks, an exposed wire somewhere some other anomaly in the system. GREMLINS IN THE SYSTEM!!!! I will try a smaller capacitor next time. The KA2 takes up a lot of space in N scale tenders.
Careful. Super caps have a lower voltage level than the average electrolytic. You could blow a cap or two. Last I knew, they were rated at about 5.5 volts. Check the rating before messing with them. It has been a few years since I looked into super caps used in keep alive modules. Maybe things have changed. Rich
Thanks Rich. I have been continuously running this loco since 10:00 this morning and it has not missed a beat all day. I am going to close this maintenance file until it happens again, if it does. I may need to take a look at my solder joint on the Cap to the decoder. It may very well be the issue.
I was wrong. It is less. Here is a link you might like. I am sure it is air circulation. Keep the link. This guy is really good. https://sites.google.com/site/markgurries/home/decoders/keep-alive-compatibility Rich
The caps in Keep Alives, Stay Alives, No Halt, etc, are 2.7 volts. 5 x 2.7 v = 13.5 volts... which is what you need for this use. If you remove one cap, you bring it down to 10.8 volts. Remove two caps, you bring it down to 8.1 volts. You are going to toast the caps. They will overheat and vent electrolyte. Not good, that is corrosive. The Keep Alive itself is not your heat problem. All it does is store energy and give it back when power from the track (frog, dirty rails, etc) is interrupted. Something else is going on to cause your decoder to overheat.
Here is a schematic of the Stay-Alives I make for my own locos. Each cap is 2.7 volts, which in series is 5 x 2.7 v = 13.5 volts. I do note that some manufacturers use only 4 caps.
