riogrande5761I have been told the BEMF in decoders can cause issues when MU'd with other DCC loco's -
Don - Specializing in layout DC->DCC conversions
Modeling C&O transition era and steel industries There's Nothing Like Big Steam!
You need to test the stall current of the motor using an amp meter. This will tell you what size DCC decoder you need. Also you need to make sure your motor is isolated from the frame. (A common problem with older locos)
The average DCC decoder handles between .75 and 1.25 amps (1.00 being most common) But I've seen HO DCC decoders go up to 2.5 amps continuos. (Lenz I believe) Lenz even has a decoder setting for open frame motors.Remotoring will cost you about $20->$30 for a good can motor.
CGW121 What I wound up doing is one F7. I used a TCS t1 decoder. It worked ok but if I tried muing it or running it with another train the system would go wonky. I replaced it with a NCE D13srj. That worked fine can mu and run different trains etc. I have more but am in no hurry as of right now.
What I wound up doing is one F7. I used a TCS t1 decoder. It worked ok but if I tried muing it or running it with another train the system would go wonky. I replaced it with a NCE D13srj. That worked fine can mu and run different trains etc. I have more but am in no hurry as of right now.
I have been told the BEMF in decoders can cause issues when MU'd with other DCC loco's - apparently they try to adjust and end up causing bucking against the other loco. Decoders with BEMF such as the TCS T1 can be programmed to fade out the BEMF effects above slow speeds which my cancel out the bucking effect - thus giving you smooth slow starts and then removing the BEMF above the start speed since you don't need it. It may be the NCE decoder you put in place doesn't have BEMF and there fore the wonky effect was eliminated.
I installed TCS T4's in a couple of my RTR Athearn tunnel motors (same as the T1 but 4 functions) and they didn't buck but ran ok together. I'm not sure why but from what people have explained, it sounds like your F7 had some issues caused by the BEMF. That said, you can still use the T1 decoder, but just be aware if that happens in the next loco, it can be programmed to cancel it out. The BEMF is supposed to help older loco's like Athearn to run smoother, per Joe Fugate and others.
Rio Grande. The Action Road - Focus 1977-1983
I was just test running a gp-35 (from the late 70's) that I put a DH123 (or whatever) in and I don't think it's worth it to re motor...in my case. I got a new shell for it at a local train show to test out repainting it (spent a whole dollar for it) and was hoping dcc would make it run better...it doesn't. I might turn it into a sound only dummy (to try my hand at my first sound installation) but the hood width is distracting now that modern locos have scale width hoods. Most likely I'll wait until I can afford a modern loco in C&O scheme (yes, I'm aware of the MTH model)...they run so much better. My Blue Box loco needs to be at full throttle only to keep sputtering down the line.
Now I have to make the same decision about an old Atlas FP7...that one runs better than the GP35 ever did, but still not as good as the new Genesis locos. If only it was available in the low - wave freight paint scheme...oh well. :)
http://delray1967.shutterfly.com/pictures/5
SEMI Free-Mo@groups.io
MisterBeasleyHow old is old?
The OP is asking about blue box, so at least 20 years or more. Rubber band, well, most of us perfer not to go there - there is a reason rubber band drives have been out of production for a long long time.
CGW121 I would like to keep them cause they are good pullers, noisy but good! So the dillema is I have heard differing info, some say to get the modern stuff others say it can be done. I guess i hate to spend money on a decoder and find it wont work ( I tern to be cheap ) But I like the F units. I even read how one guy shortened the springs so the motor would draw less current. What I do not want to do is damage the dcc unit ( a DB 150 ). I will get more modern engines but if the Athearn engins can be converted I will, since I want a lot of f units like the CGW, but seems like running them under dcc control is not gonna happen until they are converted.
I would like to keep them cause they are good pullers, noisy but good! So the dillema is I have heard differing info, some say to get the modern stuff others say it can be done. I guess i hate to spend money on a decoder and find it wont work ( I tern to be cheap ) But I like the F units. I even read how one guy shortened the springs so the motor would draw less current. What I do not want to do is damage the dcc unit ( a DB 150 ). I will get more modern engines but if the Athearn engins can be converted I will, since I want a lot of f units like the CGW, but seems like running them under dcc control is not gonna happen until they are converted.
Bottom line is yes, they can be converted, but it will be up to you if they are worth the trouble and expense. Converting Athearn blue box requires a good deal of DIY work so it depends on how "handy" you are. You will have to remove the motor assembly from the metal frame, then insulate the cavity where the motor sits so it no longer comes into electrical contact - then wire the motor to the pickups separate from the frame and to the decoder. Digitrax used to make a decoder specifically adapted to blue box conversions to make it a little easier but you don't have to use them. You can use the original motors, and many will work fine - as others have suggested, it is good insurance to check the current draw at stall, just to give yourself the warm fuzzies you will minmize the chances of frying a decoder.
You it's your call - if you love to tinker and tear things apart, this is totally doable, but many of course, don't feel it is worth the effort for various reasons - which include they prefer the newer, more accurate models on the market. If fidelity to the prototype isn't important to you, and you are very sentimental over the old blue box Athearns, then maybe it's worth it to convert them to DCC.
Accidently hitting the direction switch while running forward will spike the motor to near the stall current. So will jerking the throttle wide open from a dead stop. While neither is the way we should be running our train, things happen. True that motor decoders are relatively cheap these days, unlike the early DCC days, but sound decoders are still $80+, the 'micro' type even higher. Don't want to be frying those.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Measuring the Amp draw of a motor at full stall is overkill -- how likely is it that you will EVER push down on a model until the wheels stop spinning? Not very likely.
A more accurate measure is to hook a string of rolling stock to the locomotive and see how much your current draw is pulling up a 2 or 3 percent grade. With the wheels spinning under load the current draw won't be as much.
The 'Stall Current' measure came about in the very early days of DCC when a single non-sound decoder could cost upwards of $75-$80 each, and the decoder manufacturers were looking for a sure-fire way to not be blamed for a burned up decoder.
Insuring that the lower motor brush is no longer picking up power from the frame is more important than worrying about stall current.
Hi Gang,
I know this is an older post, but that I might add a bit of test enough for everyone.
I purchase an Athearn BB SW1500 a couple of months ago, it's probably from the mid 90's era, but was brand new, unused. I purchased a Micro-Tsunami decoder to put into it. According to the instructions that came with the decoder, you should only use a motor that draws no more than 0.75 amps when stalled.
Now, here is an interesting part that I want to share with everyone, so those who're maybe a little new to this type of thing might learn something from this experience...
I've been using DCC for a long time now, so the only DC power pack I have laying around is an old Lionel 18v job that came in a pretty old Lionel HO scale train set. Anyway, I figured I could use that to check the current draw of the Athearn 5 pole open frame motor.
With the power all the way up (about 17.89 volts) and the motor stalled, my meter shows a current draw of only .57 amp! Wow, I was amazed, and did the test several more times and checked to make sure I had everything wired correctly, and sure enough, .57-.59 amp was the highest I could get out of it.
Well, I thought great, I can go ahead and use this motor after all. But as I sit there thinking, I knew I had read a few times that these things (Athearn open frame motors) normally draw somewhere around 1.2 to 1.8 amps, so I figured something had to be wrong in my readings or setup.
After thinking about it for awhile, I decided I had an old PC power supply I could use, and that it would be the best thing anyway, as PC power supplies are regulated to a pretty high standard, and I knew for sure that there would be plenty of amperage there for this test. (this power supply offered a max of 25 amps on the 12 volt circuit) So I hooked everything back up, grabbed the Athearn open frame motor, and ran the test again.
Wow, what a difference! I now realized that the old Lionel power pack simply could not supply anymore than about half an amp (0.50 amp) of power, and that's why my readings were so low! Now, using the PC power supply with plenty of amperage to back it up, I was getting a consistent reading of 1.34 amps at stall.
Thank goodness I decided to do these new tests, because it surely saved me the cost of a very expensive sound decoder!
So, hopefully this will be helpful to people who're looking for info on this subject. And make certain, if you're going to test any motor for current draw, that your power supply can provide plenty of amperage to give you good/true readings from your tests.
Hope this helps others,Patrick
I put a TCS-1 decoder in an Athearn GP38-2. It runs very nicely. The decoder has BEMF. Biggest problem with old Athearn BB locomotives is those sintered wheels. They seem to crud up pretty fast.
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
What do you mean when you say your Athearn DC engines "don't run". Are you trying to run them on the stretch zero or did you install a decoder and then try to run them..or what? Athearns are often converted to DCC but you have to get them to run smoothly on DC first and at a reasonably low current draw. Athearn tuning is not difficult and it doesn't cost much. Just Google Athearn "tune up". Some of those old Athearn diesels are quite nice and pull quite well.
Redvdub1
The blue box loco with gold colored flat can motor is not going to draw too much current. As I've stated, I have two F units consisted together that don't draw too much current for my Digitrax Zephyr, so don't be too concerned wit current draw.
NP 2626 "Northern Pacific, really terrific"
Northern Pacific Railway Historical Association: http://www.nprha.org/
I've done two, a D9-44CW, and a GP60. They work pretty well, and are not that hard to do. My D9 will pull anything i hook it up to, enough so that I thought about using it to help dig out my car last winter.... So long as current draw is measured, and the proper decoder chosen, it is very possible to do it.
Ricky W.
HO scale Proto-freelancer.
My Railroad rules:
1: It's my railroad, my rules.
2: It's for having fun and enjoyment.
3: Any objections, consult above rules.
CGW121,
Like I said I have converted 5 Athearn Blue Box locomotives to DCC: An SW1500, a GP-7 a GP 38-2 and an A and B set of F-7s. It boils down to people thinking they know that it's not worth it, to people who know it is! The choice would seem pretty simple to me. I would agree that you want to start with Athearn Blue Box locos with the gold colored motors!
Sorry if the post is rambling but I am just finishing my first cup of caffee.
rrinker Just don't mix and match or you will notice the obvious extra width of the old Athearn narrow hoods. The F units are fine, especially if you add a dress-up kit and put freestanding wire grabs on them. And maybe shave off the steam generator detail they all came with. If they are at least the gold-side motors, a proper tuneup (several websites have this info, including the NMRA), and a proper break in of the gears results in a fairly quiet loco that does not draw too much power for an HO DCC decoder. Replace the "fire in the cab" giant bulb with an LED fitted to the headlight lense and there's no reason to junk them. --Randy
Just don't mix and match or you will notice the obvious extra width of the old Athearn narrow hoods. The F units are fine, especially if you add a dress-up kit and put freestanding wire grabs on them. And maybe shave off the steam generator detail they all came with. If they are at least the gold-side motors, a proper tuneup (several websites have this info, including the NMRA), and a proper break in of the gears results in a fairly quiet loco that does not draw too much power for an HO DCC decoder. Replace the "fire in the cab" giant bulb with an LED fitted to the headlight lense and there's no reason to junk them.
Could not agree with you more, Randy!
And seriously, if you want to get rid of them, PM me and I'll give you my address so you can send them to me. I don't care if the hoods are too wide for the "rivet counters". I'll take them!
How old is old? The ones I turned into dummies were from the Eisenhower administration. They had those old sintered wheelsets, too, so power pickup was marginal. And, they had rubber band drive.
Here's an old GP9 on the left and a newer GP9m on the right. The GP9m was produced by retrofitting a GP9 with new insides and a low nose. I looked up the unit numbers and added the GP9's road number to make it the same engine that was "sacrificed" to create the GP9m.
With a cheap Soundbug decoder inside, Kadees and add-on railings, the old engine is still earning her keep, even if she's just being towed along.
For comparison, these are two new Proto GP9s.
It takes an iron man to play with a toy iron horse.
Seriously...buy modern. The details and paint job will be better too.
- Douglas
If you're really intent on keeping the old Athearn stuff, re-motoring might be fairly easy. Can motors from Kato/Atlas/Stewart mechanisms can be made to work, as can others. Locos which have damaged shells, undecorated, or unpopular roadnames often turn up at shows for reasonable prices. Some of these also have trucks that are direct substitutes for the Athearn originals, allowing the whole mechanism to be dropped in.
Sometimes remotoring requires machining the frame or modifying other parts of the drive, like the universals. If you're comfortable doing this, parts-built mechanisms can be fun projects, and the results can run as well as anything new. Unfortunately such conversions may not be cost-effective compared to buying newer models, so judge for yourself whether the effort is worth it.
Rob Spangler
I have had good results with older Blue Box Atherns with Digitrax DH123 and DH 126 decoders as well as one Tsuanami. I upgraded my motors to can units from Micro Mark. All run great.
Wow, all your findings and suggestions are so much different than mine. I have converted 5 Blue Box Athearns with Digitrax DH123 and DH126 without problems!
I still have an Athearn F-7 A and B powered unit consisted that is a very strong puller, even though I should probably re-motor them. I went to a lot of trouble to re-paint and super detail these locos for Northern Pacific Freight units and I love how they turned out. I guess if you've worn them out, maybe it makes sense to buy newer stuff! Also, my Athearn locos have pretty much the same motors as my older LLP2K motors.
I guess if you don't want them and don't want to use them as dummies, I'll take them and pay the freight for them!
It looks like it can be done but it seems like it is more effort than its worth. Time for new stuff!
I'm with David on this. Buy new stuff.
I have a number of old Athearn engines that I gutted and turned into dummies. Some have lights and sound-only decoders now. These were horn-hook era locomotives, and I didn't want to just toss them. Now, I consider them "honorary" engines and I can still enjoy them.
I don't run DCC, but I am remotoring my Athearn BB locomotives a few at a time to allow me to run multiple locomotives without overloading my power source. Athearn is currently making remotor kits for some BB using Genesis componets for around $48 per. I haven't done that yet...but I have remotored using the kits available from Micro Mark which are a Bachmann Kader motors with flywheels. They work well. NWSL work well also, but were a bit more involved to install...I've done a few of those. I haven't remotored with Kato yet, but I hear they are good.
The Micro Mark kits go for $30.
Mark H
Modeling in HO...Reading and Conrail together in an alternate history.
Most of my older Athearn stuff I gave away. The rest are "shelf queens." Besides the old motor you have dried up grease and old worn out gearing. They would work fine for DC where higher current draw can be tolerated but in DCC you can toast a $20+ decoder in a split second if your hi-amp engine were to stall.
Most are not worth the investment in new motors (or replacing the whole chassis with a newer one) you would spend almost as much as what you can get some of the Bachmann and Trainline stuff for.
Happy Modeling, Ed
I have just switched to dcc on my home layout. The club I belong to has Digitrax so I went with them. My dcc locos run fine as do my Bachmann FT GP30 and Doodlebug which are dc. My Athearn locos which are older bluebox open frame motors draw too much current and do not run and make the system go wonky. So is there an easy replacement for those motors or should I just wait and buy more modern stuff?