Home Made Power Packs

Discussion in 'FAQs' started by Fred_M, Mar 5, 2004.

  1. Fred_M

    Fred_M Guest

    Well, Tuesday while running a triple header consist my DCC gave up its magic smoke and quit. The man at MRC was nice and told me to box it up and send it to him. That's OK, but how to run trains? First thing was to take my locos to a friends and program them to analog. With that being done I then needed to get some power. I gave away my MRC packs when I got my DCC (shortsighted) and all's I have are a Bachmann HO pack and a Lifelike N powerpack. Well, the N pack will run a loco, but I pull long trains and with a Walthers Dash8 40b it would pull 30 cars about 30 MPH. It wouldn't even start 2 locos. The Bachmann pack would pull a bit faster running an Athearns superpower, but when I doubleheader it actually slowed down the max. speed to about 1/2. This isn't going to work.

    So looking around the shop I decided to build a power pack from accumulated junk and parts. I started with a 18 VDC 25 watt power supply I took out of a HP printer that I junked because the paper feed was damaged. It was a 3820 I think. Any 12 VCD to 18 VCD pack should work. I then used a case from an old ethernet to fiberoptic network box for a case, a nice big aluminum case to use as the LM317T heatsink. I then added a LED and a 2K trimmer resistor for a power on light. All parts were fastened with cold melt glue in a hot melt gun. A note on the 2K trimmer, I got these for about the same price as regular 1/4 resistors and they are lots better for LEDs. You just set them at 2K, power up, and turn them up to the LED glows to suit you (don't blow them). Hey, no math needed! I then added a LM317T screwed to the case and wired it up the standard way. I use old LED holders and computer parts connectors as plugs for these little IC regulators and LEDs to make change outs easier. I then used a hook relay from an old 14.4 external modem and powered it with a 7805 regulator. Put a 1N4001 in anti-parallel with the relay coil for field collaspe spikes which can damage other stuff. I then hooked it up to a telephone modular wall jack and use 4 wire telephone modular cable to route power to my hand controller which is another wall jack with a 5K linear pot inside and the on-off switch from the modem glued to it. Just remember, telephone line have the pairs reversed, red is black at the other end, and green is yellow. Now I have a cheap tethered power pack that will work until I get my DCC back (or longer for a test supply). I used 6 new items, a 5k pot @ $.50, a LM317T @ $.50, two modular wall plugs @ $.50 each, a modular telephone cord @ $.10, and a 2k trimmer @ $.06. Total cost $2.16 USD. It runs the double header about 150 MPH now wide open. If I did another I would probably use a 12 VDC power pack. Notes, 1) this unit needs no fuses as both the 18VCD power supply I used and the LM317T have this function on-board (as well as overheat protection). 2) Max powers as built by me is 15.88 volts at 1.3 amps. 3) Also be aware that the lower the voltage the unit runs the more heat that is generated. Be sure to turn off (unplug) the unit when not in use as it can get hot with locos on the track not moving. 4) Unplugging the hand controller causes the unit to go to full power forward. 5) pushing the reverse switch reverses the polarity instantly which usually wrecks trains.

    Attached Files:

  2. Fred_M

    Fred_M Guest

    Here's a sketch. Blah Blah...build at you own peril. FRED

    Attached Files:

  3. DeaconF

    DeaconF Member


    I just visited your site from this post. I am impressed with your teaching methods. You make impossible stuff look a little easier. thanks for that and thanks for sharing your tips. Your tips on making cheap trees is again well done. You mentioned "Now if I only knew how to make ground foam." I have been experimenting with a recipe I saved a long time ago. Get an inexpensive blender (or do like me and steal the wife's) get some foam blocks, I have used cheap sponges, popcorn packaging and computer box packing stuff. the lighter the color the better. cut into smaller blocks, put some water and green paint, yellow paint and black, into the blender - turn it on and watch what happens. you may need to mix it up a little but so far it works for me. get a large cookie sheet, put newspaper on it and put the mixture out to dry. Maybe a day, or so. the biggest problem I have is matching the color - but this isn't a problem. you can make quit a bit with some cheap foam. Hope this helps. Thanks again Frank
  4. Fred_M

    Fred_M Guest

    I need to edit that site as I ran across how to make foam here on the gauge with the method you mention and it works fantastic. The best foam I found is seat cushion foam (or matress cover foam). "Foam Rubber" I use an old Oyster blender from a yard sale ($1) and made enough ground foam in a few hours to last a lifetime.:D Funny but when I first restarted the hobby in 99 I though "ground foam" meant foam to cover the ground, not literally foam that had been ground up.:) :) I guess it's one of them dual meaning names like DASH. :) :D But I really appreciate you taking the time to write a how to to me:thumb: :thumb: :thumb: . And seriously, them trees are easy to make. I taught my 7 year old granddaughter to make them and she makes them now, all but putting on the plastic hot melt trunks. An import note is watch the hot melt gun you buy/use. I purchased a new one and it's a hot hot melt gun and it blistered my fingers. Use a cool (low temp) hot melt gun. FRED
  5. Lightbender

    Lightbender Member

    Hello Dash,

    Your creativity and inventiveness is certainly to be admired but I am endeared with your obvious geeky, techno-junky, pack-rat side. I have a modest collection of ancient artifacts from the early years of computing. A couple of PETs, a motley collection of Atari 8bit's and much associated nonsense of equal value.

    Oh yeah, a light dimmer potentiometer thingy of the right rating will let you make your hot hot glue gun a warm one.
  6. Fred_M

    Fred_M Guest

    But a light dimmer costs more than a hot melt glue gun ($1.47) at hobby lobby. They sell both kind for the same price right next to each other and if you shop by color and "pretty" you buy the purple one (HOT) instead of the yucky looking green one (COOL) you burn your fingers. One benefit was if you use cool glue in a hot gun it goes on thinner, has more working time, can pump more before the gun cools off, and seems stronger when cool. :) Downs are the gun leaks a little when allowed to lay and stinks a bit after a few hours. FRED
  7. shaygetz

    shaygetz Active Member

    Kinda reminds me of the time I made my own tatoo gun...outta an eight track player motor, a sharpened guitar string and some junk box odds and ends. Yep, it worked and the tatoo is still there staring at me...small wonder I made it this far:rolleyes:

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