Frustrated with a Athrean Loco

Discussion in 'HO Scale Model Trains' started by jflessne, Jul 20, 2006.

  1. jflessne

    jflessne Member

    I have this older Sd38-2 that a friend converted to DCC months ago. We ran it on the test track and it ran great. Needed a bit more power to make it move but it still ran smooth.

    Anyway pulled it out last night on the test track. It ran back and forth several times on the test track and then....nothing. So I push it a bit and then it goes again. It's fine until I shut things down and try to run it again later.

    So I thought I needed to clean everything. Cleaned the wheels and the track and it ran again.

    I hear you guys talking about wipers? Are those contacts that touch the wheels or something? Could those be bent???? My other engines run fine.
  2. LongIslandTom

    LongIslandTom Member

    I don't know if Athearn changed the basic mechanism for that particular SD38-2 you got, but the SD40-2s I have (which uses the same HTC 3-axle trucks as the SD38-2) don't have wipers. The electrical pickup is achieved via conductive axles and square brass washers.

    If your engine feels like you need to give it a shove to overcome some sort of resistance to get it to move, I would check the drivetrain and gears. I would toothpaste-polish the gears, clean them off, lube and reassemble. And also check the driveline and make sure it's deburred and does not have excessive slack.

    Good luck.
  3. jim currie

    jim currie Active Member

    agree with Tom sounds like it needs lubed.
  4. Russ Bellinis

    Russ Bellinis Active Member

    Athearn relies on making electrical contact between the frame and trucks without hard wire. Any dirt, corrosion, or anything that will create electrical problems at any of those connections will create the problems you mentioned. Check out about half way donw the page you will see Tuning up Athearn and other HO scale locomotives. Go to that page and read about Jim's 5 wire system for powering Athearn locomotives. With dcc, by pass the frame as a power source all together, just wire track power from the trucks directly to the input and ground side of the decoder. Since it has been converted to dcc, you probably don't have to change anything else.
  5. Ralph

    Ralph's for fun!

    That's a handy link Russ, thanks!
  6. Tommybza

    Tommybza Member

    I also have a issue with my sd 40-2 almost all of the above apply to me , sloppy motion runs better one direction needs a push here and there . great site . Waiting for the missing gear from Athearn and i will follow the info on that site .

  7. myltlpny

    myltlpny Member

    Also check that the motor is still isolated from the frame. Athearn motors have two tabs sticking out of the lower half of the motor that are used to ground the motor to the frame in DC mode. I cut those off and lay down a layer or two of electrical tape to keep the motor from touching the frame in that area. On a couple of occasions, I didn't completely cut the tab off and left a burr that worked its way through the tape and shorted the system. As they worked their way through the tape, they exhibited symptoms similar to what you're talking about.
  8. Russ Bellinis

    Russ Bellinis Active Member

    The trick that Jim Furhmann showed us (owner of the web site I linked above) for doing dcc in the Athearn locomotives is to take the motor out of the frame. Once the steel clip is removed so that you are down to the 2 brass clips that hold the motor together and the brushes in place, carefully remove both clips and swap them. Then put your insulation in the frame. That way the 2 tabs are now up and can't interfere with anything and you have a smooth clip on the bottom that won't wear through the insulation between the motor and frame.
  9. Gil Finn

    Gil Finn Active Member

    This is the second post here about problem Athearns.
  10. brakie

    brakie Active Member

    Well,I wonder if its the loco or the DCC.You see I have 2 SD40-2s that run smooth as silk..I seen them run at both clubs as well on DC with no problems..
    Can't help but wonder when DCC is involved.
  11. myltlpny

    myltlpny Member

    You know, that's an excellent idea. They are indeed interchangeable, so there's no reason they couldn't be swapped out. Thanks for the tip.:thumb:
  12. IAIS 604

    IAIS 604 Member

    If Athearn sold the loco as "DCC ready", then the Furhmann trick should not be necessary - but the problem seems to be that some makers don't seem to have a clue about what it takes for a loco to be really "DCC ready". If they did, the motor/frame should already be insulated. But we keep finding "DCC ready" ones that aren't.

    On the other hand, if the loco is old enough not to be DCC ready, then folks need to understand what it takes to make it so. This is where Furhmann's (and others) instructions come in handy!

    Either way, the problem is with the loco, not DCC, Larry!
  13. brakie

    brakie Active Member

    Hi George :wave:

    I have seen and help with locomotives that had serious CV setting mistakes..Thats what I was referring to.You will be surprise how some folk can mess up CV settings.After leaving the hobby shop 4 years ago where I was working part time I no longer do that type of work .
  14. IAIS 604

    IAIS 604 Member

    That's true, Larry ... and it's even worse when the maker hasn't given out the CV "map" along with the decodered loco - then one can REALLY get lost! :confused: wall1

    Even my favorate maker (Atlas) has been known to do this (or NOT to do it, if you get my drift). :curse:

    Luckily, there is a LOT more "smooth sailing" than "rough seas" in DCC operation !!!

  15. sumpter250

    sumpter250 multiscale modelbuilder

    Yes!, and no. With a DC operated loco, only motor current has to get from the track to the motor. As a general rule, DC operation is a little more "dirt forgiving". DCC, on the other hand, is not "dirt forgiving" at all!
    The reason for this is the fact that all the control is "in the loco"(decoder). Commands have to be transmitted through the rail-wheel-axle-wire-decoder plug connections. If the commands are blocked by dirt.........screeching halt! Commands have to be re-established for motion to continue.
    Clean track, clean wheels, if there are any wiper type connections, they also must be kept clean. One thing I have noticed is, just before dirt "shuts down DCC operation", you will begin to see flickering in the headlight, especially if you are using incandescent bulbs.
    To my knowledge, Athearn still uses "wheel-axle bearing-metal bearing plate" pickup in their trucks. Lubricant from the gears, can get into the axle bearings, and begin to insulate that point of contact. That would be the place to look, if wheel/track cleaning leaves a flickering headlight.
  16. jeffrey-wimberl

    jeffrey-wimberl Active Member

    I have an SD40-2 BB that I cut down the brush springs on to help lessen the motor noise. That took some of the noise away. A couple drops of CRC-2-26 on the commutator eliminated most of the rest of the noise. As for mysteriuos stopping and stalling, that can be due to dirt and/or too much lubricant in/on the brass bearings in the trucks. Disassemble the trucks completely, clean everything, lightly lube and reassemble.

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