DIY Stay Alive Success!

[hornblower]

I had previously added TCS Keep Alive modules to a few of my locos and was rather impressed, not only in their ability to keep locos rolling smoothly over dirty track but also in their ability to help the locos crawl along even slower than before.  Thus, I want to add these modules to all of my locos.  However, even at the discounted street prices between $20 and $25, I would have to spend a small fortune to equip all my locos.  Thus, I decided to try my hand at "Do-It-Yourself" Stay Alive modules.  

Using the advice of the DCC columnists at both Model Railroader and Model Railroad Hobbyist magazines, I purchased enough electronic parts to assemble five (5) stay alive modules.  As I already had everything else I needed for assembling these modules, the unit price worked out to $5.24 each.  Assembly was pretty straight forward and if you can install a hard wired DCC decoder in an older loco, you can assemble a stay alive module.  My finished modules are simlar in size to a TCS KA2.  I installed the first two in a pair of Athearn Blue Box EMD F7 locos that I had previously remotored using Mabuchi FK-280SA 14200 motors.  Both of these locos now smoothly and quietly crawl around the layout at about 2 scale miles an hour without a hiccup.  Just to see how far these locos would travel without power, I laid a strip of blue painters tape about 14 inches long atop one rail of the main line. With the loco at speed step 10 of 128, the loco traveled the entire length of the tape and almost came to a stop before the two lead wheels rolled beyond the end of the tape and the loco resumed it's previous speed.  Not bad at all, especially for five bucks!

[rrebell]

hornblower

I had previously added TCS Keep Alive modules to a few of my locos and was rather impressed, not only in their ability to keep locos rolling smoothly over dirty track but also in their ability to help the locos crawl along even slower than before.  Thus, I want to add these modules to all of my locos.  However, even at the discounted street prices between $20 and $25, I would have to spend a small fortune to equip all my locos.  Thus, I decided to try my hand at "Do-It-Yourself" Stay Alive modules.  

Using the advice of the DCC columnists at both Model Railroader and Model Railroad Hobbyist magazines, I purchased enough electronic parts to assemble five (5) stay alive modules.  As I already had everything else I needed for assembling these modules, the unit price worked out to $5.24 each.  Assembly was pretty straight forward and if you can install a hard wired DCC decoder in an older loco, you can assemble a stay alive module.  My finished modules are simlar in size to a TCS KA2.  I installed the first two in a pair of Athearn Blue Box EMD F7 locos that I had previously remotored using Mabuchi FK-280SA 14200 motors.  Both of these locos now smoothly and quietly crawl around the layout at about 2 scale miles an hour without a hiccup.  Just to see how far these locos would travel without power, I laid a strip of blue painters tape about 14 inches long atop one rail of the main line. With the loco at speed step 10 of 128, the loco traveled the entire length of the tape and almost came to a stop before the two lead wheels rolled beyond the end of the tape and the loco resumed it's previous speed.  Not bad at all, especially for five bucks!

 

Wish you were closer, we could do some horse traiding, skills for parts. my skill level just not there yet.

[thomas81z]

yea i have 7 big boys i need to do so i might check that out & try it myself

[Overmod]

thomas81z

yea i have 7 big boys ... 

Now look here, is it 7 or is it 30?  Inquiring minds HAVE to know...

[wvg_ca]

glad that it worked out for you .. it's actually pretty easy to do ..

[hornblower]

I also discovered that its pretty easy to test your Stay Alive before you install it in a loco.  Simply charge the Stay Alive for a few seconds using a 9 volt battery.  Be sure to touch the blue wire to the positive post of the battery and the black wire to the negative post.  Remove the battery after a few seconds of charging.  Attach a 1K ohm resistor to the negative lead of an LED, then touch the blue wire of your Stay Alive to the positive lead of the LED and the black wire to the resistor lead.  If you assembled your Stay Alive correctly, the LED will light signifying it's ready to install in your loco.  That's all it takes.  Keep the 9 volt battery and the test LED handy on your workbench until you finish assembling all of the Stay Alive units you plan to make.  

[woodone]

OK, where is the list of parts used? Maybe explain how to make up the keep alive too.

[hon30critter]

Congratulations Hornblower! Well done!

If I am correct, one thing that you might want to consider adding to your home made keep alives is an isolation switch. Keep alives can interfere with programming your decoders. If you install an isolation switch to cut off the keep alive power to the decoder when needed you won't have any problems reprogramming your decoders.

Dave

[trainnut1250]

Model Railroad Control Systems sells a circuit board and has a parts list as well as DIY kits (all the parts) for stay alives for those of you who want a simpler DIY alternative and still save some money.

 

Disclaimer: I do know Seth (the owner) and was a beta tester for this product.

 

Guy

[hornblower]

woodone

OK, where is the list of parts used? Maybe explain how to make up the keep alive too.

I used the following parts for this project: 

 

Nichicon supercapacitors 2.7 volts, 1 Farad (use five per module)

            MFG P/N: JUWT1105MCD 

 

ON Semi - Zener diode, 13 volts, 5 watts (use one per module)

            MFG P/N: 1N5350BG 

 

Yageo Carbon Film Resistor - 110 ohm, 1/2 watt (use one per module)

            MFG P/N: CFR-50JB-52-110R 

 

Taiwan Semi Rectifiers - diode 1 amp, 1000 volts (use one per module)

            MFG P/N: 1N4007G-K ROG 

 

Blue and Black 30 awg wire (I had these on hand) 

 

1/16" and 3/4" shrink tubing (I had these on hand) 

 

There are useful step-by-step videos on YouTube including a video by Larry Puckett (DCC Guy) of Model Railroader Magazine fame.  Just look up "Build your own Stay Alive" to find this and several other videos. 

 

It is simplest to build a linear, flat module with the five supercapacitors side by side.  I used Larry Puckett's suggestion of using double sided tape to hold the capacitors in place while soldering.  Start by bending the negative lead of one capacitor 90 degrees away from the center of the capacitor and flat with the top of the capacitor.  Bend both leads of the second capacitor 90 degrees, flat to the top of the capacitor and away from the center of the capacitor.  Place the two capacitors side-by-side on the double sided tape with the negative side of the first capacitor (white stripe) against the positive side of the second capacitor and with the negative lead of the first capacitor parallel to and touching the positive lead of the second capacitor.  Solder the two leads together and snip off the excess wire using flush cutting pliers.  Repeat this process until all five capacitors are soldered together in a straight line.  Leave the positive lead of the first capacitor and the negative lead of the fifth capacitor pointing straight up.  Place a piece of electrical or Kapton tape over the soldered capacitor leads to protect them from short circuits. 

 

To ensure that my modules would be as flat as possible, I decided to position the other three components lengthwise and tight against the top of the capacitors (not on the side of the capacitors as Larry did).  I started by placing the anode end (no white stripe) of the Zener diode body close to the negative lead of the capacitor pack and tight against the top of the capacitors.  Once in position, I soldered the anode lead of the Zener diode to the negative lead of the capacitor pack.  The cathode end (with white stripe) of the Zener diode will be soldered to the positive lead of the capacitor pack.  However, to protect the resulting long cathode lead from potential shorts, I cut a piece of 1/16" shrink tube to fit over the cathode lead between the Zener diode body and the positive lead of the capacitor pack.  After heating the shrink tube, I soldered the cathode lead of the Zener diode to the positive lead of the capacitor pack. 

 

I next positioned the resistor and plain diode parallel to each other with the component bodies staggered so they would fit closer together.  I put 90 degree bends in one lead on each end of this assembly to aid soldering these components together.  After soldering, I snipped off the excess lengths from the two bent leads (leave the straight leads alone for now).  I then positioned this assembly close to the positive lead of the capacitor pack so these components would fit tight against the shrink tubing protected cathode lead of the Zener diode.  Be sure the cathode end of the plain diode (white stripe) is pointing away from the positive lead of the capacitor pack.  When correctly oriented and positioned against the top of the capacitor pack, solder the anode end of the resistor/diode assembly to the positive lead of the capacitor pack.  Trim off any excess leads.  Note that soldering the Zener diode directly across the leads of the capacitor pack and the anode end of the resistor/diode assembly directly to the positive lead of the capacitor pack eliminates the need for the "green" wire used in Larry Puckett's video.  This also places the soldering points for the blue and black wires on the same end of the module. 

 

Now solder a length of black 30 awg wire to the negative lead of the capacitor pack close to the top of the capacitor.  Use flush cutting pliers to trim off any excess lengths of negative capacitor and Zener diode leads.  Next, solder an appropriate length of blue 30 awg wire to the free end of the resistor/diode assembly and trim off any excess length of resistor/diode assembly lead.  Apply lengths of 1/16" shrink tube as needed to eliminate short circuits between the solder points of the blue and black wires.  

 

At this point, it is a good idea to test your Stay Alive circuit.  You will need a 9-volt battery and a 1,000 ohm resistor soldered to one lead of a 3 or 5 mm LED.  Charge the Stay Alive circuit by touching the end of the blue wire to the positive battery post and the black wire to the negative battery post.  After a few seconds of charging, remove the battery from the circuit.  Next, touch the end of the Stay Alive module's blue wire to the positive side of the resistor/LED assembly and the black wire to the negative side.  If the LED lights up, your Stay Alive circuit works.  If not, go back and check all your solder connections and make sure your capacitors and diodes are all oriented correctly.  

 

Finally, cut an appropriate length of 3/4" shrink tube and fit over your Stay Alive module.  I used a hair dryer to heat the shrink tubing as it produces a nicely even and smooth wrapper without burning the shrink tube as can happen when using a soldering iron to heat the tubing.  Trim the ends of the shrink tubing close to the ends of the capacitor pack to ensure the smallest module length.  Your module is now ready to install in your loco.  

 

Connecting the blue wire is easy as it can be attached to any of the existing positive function connections indicated by a blue wire.  The black wire should be connected directly to a negative ground location on the decoder.  In my case, the NCE D13SRJ decoders I use have an unused and clearly marked (-) negative ground solder pad as well as an equally convenient positive solder pad directly below the blue wire on the 9-pin connector, both on the underside of the decoder board.  

 

My finished Stay Alive modules worked out to dimensions similar to that of a TCS KA2 Keep Alive module and should fit most locos without much fuss.  However, I do own an Athearn Baldwin S-12 and two Bachmann Alco S4's that could require a different shape module to fit inside the end cabs since the area under the hoods are already pretty full.  I also need to find the appropriate connection points for the SoundTrax Sound Value decoders in the Bachmann locos. 

 

I hope my explanation helps and I'm sure Larry's video will answer any questions you might have.