Thanks for all suggestions, I took a good look at the motor and gears and found a LOT of fiber wrapped around the motor. Removing didn't help much, but I clearly need to do a major disassemble. New motor may be the best solution.
Mike
Mike:
This a small point but I think an important one. You said that you would adjust the CVs first and then re-lube the motor. I think that is in the wrong order. If lubrication is a problem, no amount of CV adjustment will compensate for dried out grease or flash on the gears. I would suggest cleaning the drive line first and then inspecting it carefully under magnification. That will eliminate any issues related to dried out grease or gear flash before you start to play with the decoder settings.
I will suggest one more step after cleaning and re-lubing the engine. That is to run it for a while on DC to make sure it actually runs smoothly. I am currently working on a sound decoder installation where I apparently did not pay enough attention to the running charactaristics on DC which turned out to be poor. I thought I had given the engine enough time on DC to show its faults but a couple of minutes on a test track apparently wasn't enough to tell the truth.
Dave
I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!
Put a value of 50 in the starting voltage and see what happens.
I read the CV's and here is what I found. Decoder is a Lenz --does anybody know what a model #41 (cv-7) is?-- and the following is the readback from my MRC Wireless: Start Voltage -- 0; Acceleration Voltage-- 0; Decelleration Voltage--0; Top Voltage -- 255. I plan to do the maintenance over the weekend so if anybody has suggestions for CV settings, I'd like some feedback.
mreagant Thanks for the input. I don't have a history on performance before the decoder was installed--old story-- and frankly, that does not make any difference at this point since I want to solve the existing problem, not revisit the oughts and shoulds. I'll try a reprogram starting voltage just to see what happens although I'm uncertain where to start. Then, do the maintainence/lubrication/cleaning. Last resort will be to live with it. By the way. This is not just any old Athearn BB locomotive. It is a custom painted T&P GP-7 fully detailed and weathered and painted in a proto-typically accurate Swamp Holly Orange and Black. Try to find one of those in your LHS.
Thanks for the input. I don't have a history on performance before the decoder was installed--old story-- and frankly, that does not make any difference at this point since I want to solve the existing problem, not revisit the oughts and shoulds.
I'll try a reprogram starting voltage just to see what happens although I'm uncertain where to start. Then, do the maintainence/lubrication/cleaning. Last resort will be to live with it.
By the way. This is not just any old Athearn BB locomotive. It is a custom painted T&P GP-7 fully detailed and weathered and painted in a proto-typically accurate Swamp Holly Orange and Black. Try to find one of those in your LHS.
With that in mind, remotoring would seem a good idea. BUT, sometimes, you can buy an RTR Athearn GP-7(there's tons of them) that's beat up with good running gear cheaper than you can for the price of a remotor. That way you get updated complete running gear and those bodies should fit. At a train show, you can even try them out. The coupler boxes may need some work, but that's just plastic shims, etc. I just bought an RTR with hex brass flywheels GP38-2 for $35. Just had to work on the body where it had been dropped, no big deal.
Richard
On a lot of those older motors, they don't draw a huge amount of current unless the motor is stalled - then watch out.
The need for a high starting voltage isn't really because of the high current draw, but more because of the rather slapped together character of those motors. Irv Athearn figured out how to make a cheap motor that was also reliable, rather than say the Bachmann pancake motors who have a lifetime often measured in minutes. Natrually, some compromises had to be made to get cheap and good together. They were also mass produced a good bit by hand, so there is quite a wide range of quality.
The first thing to do is a complete tune up. There are several sites, including an article on the NMRA site, about tuning up the motors in BB locos. The other thing to watch out for is if the motor was disassembled previously - take them aaprt too much and the magnets get weak. You can;t readily repalce the Athearn motor magnets with the rare earth types like you cna with older Pittman-style motors, so if you have one with a weak magnet, it's probbaly best to just replace the motor. It's just too easy to completely take one aprt - just remove both the top and bottom brush clips and the whole motor comes apart, that's all that holds the ends to the center part of the housing, there are no bent tabs or screws. For that reason, when soldering decoder wires or replacing the brushes or adjusting the brush springs, you should only do one at a time, so that the motor stays together.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
mreagant I have several Athearn BB locos pre-1990, and some, not all, take a lot of voltage to get them moving. One, for example, won't budge until I'm past 16 on a 28 speed step scale. I've read several discussions here that suggest the sluggish performance is a consequence of old motors with high amp draw. Question, short of replacing the motor, is there any any way to tweek CVs to help with this problem? Any other tricks to get it moving? I don't recall which decoder it has, but may be either a LocSound (v.4?) or an older Lenz (Gold?)
I have several Athearn BB locos pre-1990, and some, not all, take a lot of voltage to get them moving. One, for example, won't budge until I'm past 16 on a 28 speed step scale. I've read several discussions here that suggest the sluggish performance is a consequence of old motors with high amp draw.
Question, short of replacing the motor, is there any any way to tweek CVs to help with this problem? Any other tricks to get it moving? I don't recall which decoder it has, but may be either a LocSound (v.4?) or an older Lenz (Gold?)
Your message does not indicate High Amps. Most HO decoders are good for one amp. You have not burned out any decoders.
Are you running the locos with DC as the decoders are dual mode and running with DC requires a lot more power pack voltage.
I have run old MDC open frame motors using a decoder and they ran fine, just noisy. Maybe about 700 ma current.
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.
I know a fella who has an HO brass F-unit(s) that pulls a whopping 3-amps. He told me that it was the hands-down winner of a grade climbing contest at an NMRA meet one time. I forget what the actual grade % was but it was pretty ridiculous.
Tom
https://tstage9.wixsite.com/nyc-modeling
Time...It marches on...without ever turning around to see if anyone is even keeping in step.
You should always test an older locomotive on DC to see what the current draw is before installing a DCC decoder. For that you will need a digital multimeter and know how to use it.
The speed step scale on a DCC system is NOT a measurement device. Is your DCC system set for 28 or 128 speed steps?
Elmer.
The above is my opinion, from an active and experienced Model Railroader in N scale and HO since 1961.
(Modeling Freelance, Eastern US, HO scale, in 1962, with NCE DCC for locomotive control and a stand alone LocoNet for block detection and signals.) http://waynes-trains.com/ at home, and N scale at the Club.
Newer Athearn motors are a drop in replacement. When you order them just specify that you want a non-hex drive version and whether you want long or short flywheels. Six axles have long flywheels, 4 axles have short flywheels. The motors are not expensive about $18.
Jay
C-415 Build: https://imageshack.com/a/tShC/1
Other builds: https://imageshack.com/my/albums
mreagantI have several Athearn BB locos pre-1990, and some, not all, take a lot of voltage to get them moving. One, for example, won't budge until I'm past 16 on a 28 speed step scale. I've read several discussions here that suggest the sluggish performance is a consequence of old motors with high amp draw.
The question is how does the motor/loco run once it gets going? Seems to me that if it runs smoothly once the higher voltage level is applied, then changing the value of the starting voltage CV (CV2) might be something you can try. If it runs crappy once it gets going, then other improvements will be necessary.
Pre-90's Athern stuff was only OK then and rather poor by any of today's standards. Assuming good lubrication and no worn or binding gears, your issue is your motor. You can't compare even a 90's atlas diesel with an older Athern unit.
The older Atherns ran noisey but smoothly once you got 'em goin'. Older Atlas diesels were a dream and could crawl a bit on modern pulsed DC. They set the standard at the peak of the DC era. Athern cost a lot less and this was a reflection of the motor and gearing quality. Athern stuff looked pretty good in spite of rather lack luster slow speed control and noisey running.
The above being said, If you are really in love with the old Athern, try a better motor and good luck adapting a better one. You might still have a noisy gear box in the end.
As noted prior, changing CV's will not solve the low speed issues. You have a nice old inexpensive model of its day and there is no modern electronic or DCC solution that will make it into a modern functioning unit that can compete with a modern, post 2000 DCC loco.
If I can't fix it, I can fix it so it can't be fixed
The obvious first thing, which you may have already done, is was the loco running great while DC. That is would it start moving when the DC throttle was barely open. If it didn't creep with very little DC voltage, than the problems are more likely in the drive train and/or motor.
1, Those old motors can need new brushes and brush springs which are cheaper than a new motor.
2. The driveline can sometimes be binding, anything from the joints to the worms, etc. Sometimes the worm gear can be shimmed too much for example. It's a process of elimination.
I would check the base unit before changing CVs since binding or bad brushes can cause too much draw.