I have always found that the Model Railroader faithful are a wealth of information and in my darkest hour I always turn to them. I am in the final stages of finishing my new layout wiring and have ran into a problem that I am sure entails a simple fix. My layout is divided into two electrical blocks, and my yard block seems to be where I'm currently held up. After plugging in the block's track bus into my MRC DCC power system to check for shorts I discovered I had a short which turned out to be two electric frog switches that were not properly insulated. So once I had solved that issue I turned the power back on and I had juice. I use two different loco's to test my track to insure I have sufficient feed around the layout. When I place a loco in this particular block I get sound on the loco and everything seems fine but once I put throttle to it it seems to loose electrical contact, almost as if there's just not enough juice to run the sound and the motor but if the sound is mute there is still no throttle control, the unit will simply move maybe half an inch or so and stop along with the sound cutting out. I have had similar result with a non-sound loco also. I can't fathom that my problem would be lack of feeders or lack of AMPS I have a 3.5 AMP power supply and only one loco in the block. I'm not to good with electricity, so this only makes it more difficult. If I had a major short I would expect my power unit to start buzzing at me but all indications are that I do not have a short in the block. Thanks everyone for your help!
This is where you run to the local hardware store and purchase a decent digital multimeter. They can be had for about $15-20 if you look around. Then check the voltage at the rails just in front of the engine before you get it to move. Just barely touch the tips of the probes to the rail sides, the webs. You may or may not show the proper 14-ish volts on the 20 volts AC setting. Suppose it does show the full voltage. You get the loco to move and you meter the rails immediately when it stops again. Closer now to the locomotive's front wheels, same thing...probe very gently to read the voltage without pressing on the rails. What is the reading? If zero, then your loco is heavy enough to press on a join somewhere under or just about behind it, and that joiner is losing contact.
One other thing to check and that is that the tether is fully seated into its socket. You can get sounds with many engines, but no movement if the tether isn't fully seated.
This assumes your base unit isn't sensing a short as soon as the lead tires cross a gap or a join and shutting down silently. If it is protecting itself and your decoders, then of course you will get a zero volts reading because it has cut power to the bus.
I doubt it is a short in the engine, but that is also possible. Ask cudaken about his troubles with a Y6b.
Crandell
I'm a little concerned by this:
"After plugging in the block's track bus into my MRC DCC power system to check for shorts I discovered I had a short which turned out to be two electric frog switches that were not properly insulated. So once I had solved that issue I turned the power back on and I had juice. "
How, exactly, did you resolve that problem?
I, too, strongly suggest that you buy a multimeter. Understand that inexpensive meters are calibrated to read a sine wave and DCC uses a square wave so the reading will not be exact, but it will be close enough for anything YOU need to measure. Take all the powered or lighted stock off the track and then measure the voltage at various places around the layout. There should be no significant differences. If you find low voltage somewhere then you have a wiring problem in that area.
When you think you have it resolved perform the "quarter test" around the layout.
Dave
Lackawanna Route of the Phoebe Snow
I have three meters from Harbor Freight plus a brick and mortar HF store about 15 miles away.
I check using the resistance scale first with the DCC controller disconncted.
I clip an auto light bulb, 1156 to the tracks for a load and check around the layout for voltage drops. Move the bulb to different parts of the layout.
These meters show about 13.7 VAC with my NCE Power Cab.
Rivet counters will insist on a $200.00 meter. I have used one and the cheap work just as well and cost very little to replace if you bust the meter. Rivet counters forget that.
I know this guy must have seen the link here before.
http://www.harborfreight.com/7-function-digital-multimeter-90899.html
Clip leads.
http://www.harborfreight.com/18-inch-low-voltage-multi-colored-test-leads-66717.html
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
Did the OP clean the tracks? Not looks clean, did the OP actually clean the tracks with lint free rag and alcohol? If no short, sounds like intermittent pickup. This is quite common with new DCC users.
I have cleaned my tracks carefully, and a month or two later, with no use at all, they develop a very pale greenish tarnish, like you get on real silverware. I'm sure it is there at the rail joiners too. After soldering many rail joints and leaving several unsoldered for expansion and contraction, I took a small screwdriver and slightly moved the rail joiners back and forth a milimeter or two, just to renew the contact with the rail. It made a very noticable improvement in my power pickup problems. Still, a few locos are determined to give me problems. So I am hard wiring them together in a consist. Since I keep many of my locos together in consists, I am wiring some of them together. I just wired an ABA F3 lashup together, and they run perfectly. Each loco has the benefit of 12 axle pickup, instead of four.
It sounds like you may have an intermittent connection that fails when current starts to flow.
I strongly recommend the 'quarter test' for all new track and wiring. When track and wiring are complete placing a quarter anywhere on the track will cause the booster or other short circuit protection to operate. This test will ensure you buss-feeder work is adequate, and that there is enough power to operate any loco (even the ones with 20W four channel sound)
The advice to employ a multimeter is also valid, however as an electrician and electrical engineer I've seen multimeters misapplied and misunderstood many times.
Good luck.
Dwayne A
I'm a rivet counter when it comes to electronics, since that is what my degree is in. I have an expensive benchtop meter, which I used when sitting at my workbench, usually. For 99.9% of the stuff I need a meter to check out though, those Harbor Freight ones can;t be beat. I have about 4 of them now, one in my train toolbox, one on the layout, one in my car, and another in my desk. When I see them on sale I usually pick one up. They are MORE than adequate for most anything you need on a model railroad. And for most things you'd need around the house. For some high-ened electronic projects (ie, commercial/lab stuff) maybe not.
The only reason I have the expensive desktop meter is because it was getting thrown out. With the sort of stuff I do, I'd NEVER need somethign that fancy. But when you get it for free...
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.