F
Fred_M
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.
FRED
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.
FRED
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.