What about cheap loco's?

[mfm37]

Relatively simple with your RRampmeter.

Connect you DC supply to one side of the Rrampmeter. Positive to the red terminal, negative to the black terminal. Connect the other side of the Rrampmeter to a piece of track. Place the engine to test on the track and hold it so it won't move. Turn the throttle all the way up and read the current on the RRampmeter. That's the stall current.

Pick a decoder with a higher current rating than your engine's stall current.

 Martin Myers

[loathar]

Take a digital multi meter that reads DC milliamps. Wire it in line between one leg of your power pack and the track.(meter black lead to power pack DC and red lead to track) As you run your locos through their speed range, you will see the amps go up or down. Turning the power pack up all the way and holding your loco down on the track so the wheels can't spin will give you your stall current or the maximum amps that loco can draw. This # should not exceed the decoders stall amp specs.

Understand?

[donhalshanks]

Sorry to ask a novice question, but what do I have to do to determine the current draw by a locomotive? (I do have the DCC rampmeter, and a regular multimeter).

Thanks, Hal

[mikept]

I would agree.  I am new to the Forum (this is my first post/reply) and new to DCC, although I have been into model railroading since the late 50's. I, however, have been on the sidelines for the past 15 years and am just getting more active again since I've retired.

Anyway,  I have several older HO Rivarossi steam engines (old time 2-4-0, 4-4-0s) that were sitting in there original boxes since the early 80's.  I just finished converting one of the 4-4-0s to DCC using an NCE Z14SR.  The motor's max stall current was less than an amp and the one I converted ran well,to my surprise, on DC right out of the Box. It has the motor in the tender.  After conversion, with the decoder in the tender, The engine runs great under DCC, At least in MHO, since it is my first conversion.  I plan on converting the others after I investigate whether I will be able to put sound in them, possibly using a micro-tsunami.

As a side note, I have a MRC Prodigy wireless and, so far, I think it is great.

 

Mike

[jeffrey-wimberly]

One of the main things in DCC is to have the motor completely isolated from the frame. On many of the older locos that's impossible or close to it. Many Mantua locos had the motor built into one truck with a direct draw from that truck while the power was returned to the track through the other truck. If memory serves this is the description of the Mantua MU-2 drive which was also used in many Tyco locos as well as those of some other makers. Many Bachmann's had the motor built into the chassis with the brush on one side connected to the chassis and the brush on the other side connected to the rear wheels by a wire. I have one similar to that that I was able to remotor and keep the motor isolated so it could be converted to DCC, which I did. If the loco didn't mean so much to me I would have simply tossed it in the trash can. Converting it was a LOT of work and required much grinding and elbow grease, as well as a couple of shoehorns to fit a new Bachmann GP40 shell to it. Almost all my other old locos (pre 1980) have hit the trash can. The only other one I kept is a Bachmann 0-6-0 lettered for the L&A. I don't intend to run it.

[loathar]

My opiniion is if they run good on DC, don't draw alot of current (under 1 amp is my cutoff, less is even better) and have electrical pickup from all wheels, I'd spend the $20 for a TCS T-1 or NCE D13SR decoder.  Especially if you've spent a lot of effort detailling them.

Yeah. You should check how much current your old motors draw first. The NCE decoders would be a good choice for a cheap decoder. 1.3 amp continuous and 2 amp peak.
http://cgi.ebay.com/NCE-D13SRJ-HO-DCC-Decoder-9-Pin-plug-524-125-Athearn-GP_W0QQitemZ150279090798QQcmdZViewItem?_trksid=p3286.m20.l1116
I've even seen these for about $12/each in 4 packs if you keep an eye on E-Bay.

[NC&StL]

I appreciate the replys. It's just after getting a Rivarossi E properly attired in Southern Crescent green, with all the details, I hate to let it sit.  Of course it could be on the tracks waiting to leave with a consist I guess. Thanks everyone.

[Randall_Roberts]

cacole's answer is good.

The short answer is, yes a $20 decoder should work fine in your $10 locomotives.  

[mikebo]

My opiniion is if they run good on DC, don't draw alot of current (under 1 amp is my cutoff, less is even better) and have electrical pickup from all wheels, I'd spend the $20 for a TCS T-1 or NCE D13SR decoder.  Especially if you've spent a lot of effort detailling them.

[cacole]

As one who is old to the hobby and old to DCC, let me be quite frank: 

I started out in 1960 by building MDC and Tyco metal steam locomotive kits, and also have some of those old AHM, Rivarossi, Bachmann and Lima diesel engines.  I have not tried to convert any of them to DCC because their motors run too poorly and DCC would be a waste of time and money.  Some of them won't even run at all, anymore.  Many diesel models of that day had plastic wheels with traction tires and the motor mounted to one truck, and the other truck, which was not powered, had metal wheels to pick up current for the motor.

I would not plan on spending $20 or so on a decoder for a $10 engine when there are many on the market today that run so much better.  In my experience, the locomotives you have take off like a jackrabbit after the throttle is turned about half way up, and only know two speeds -- full throttle and stop.  Motors like that are not candidates for DCC.

If those older locomotives have sentimental value put them on a display shelf and buy yourself some new engines that are DCC equipped or at least DCC ready.  Mine sit in a locomotive museum on the club layout.

[NC&StL]

I am old to the hobby but I am new to DCC.  What about the older loco's that I have detailed out the wazoo, BUT they are like AHM GP-7's and F's that cost $10 - $20 when they were new.  If they run good on  D C will they run good on DCC? (Sounds like a dumb question but I have to ask).