I have had the MDT Plymouth switcher for a while. Going forward, the gears will lock up once every revolution. Reverse works fine. From time to time, this prevents the engine from starting. Once it is running, it works fine though it will sometimes stall at low speed. I was never able to find the problem as none of the gears have broken teeth or any problems that are obviously visible. According to Bachmann's website, I can send it out for repair or replacement with the check for $15. Add $5 for shipping and I am out $20 for a switcher that usually sells for $25 (or less on Ebay). Is it worth saving this little switcher by sending it out for repair? Obviously it is not my only engine so it is rarely being used anyway.
I guess it depends how emotionally attached you are to it. If it does not have to be the exact same switcher I would just buy a new one
Have you pulled the wheels and checked the gears up close? Not difficult to do. I have pulled mine part to isolate the motor contacts and convert it to DCC.
Rich
I am not attached to the engine at all. I just need to decide if I should fix it or toss it. Running this switcher in its current condition is very frustrating.
I have removed the body, cleaned wheels, inspected the gears but I can't find anything wrong with the loco. Most likely because I have no experience with model train engine troubleshooting.
Out of curiosity drabina, do you think the problem comes from running it in forward a lot more than running it in reverse? Which is why it runs ok in reverse but not forward at this point in time. The only reason I bring it up is perhaps that can help you chase down the problem, ie: a wear problem. Of course, I don't know if this makes it any more repairable, but maybe points you in the right direction (no pun intended ;))
Quote from: jbrock27 on June 11, 2013, 02:29:24 PM
Out of curiosity drabina, do you think the problem comes from running it in forward a lot more than running it in reverse? Which is why it runs ok in reverse but not forward at this point in time.
The problem occurs only in the forward motion of the gears. Reverse works fine. Basically, when I spin the motor manually, once every gear revolution, something catches and gears stop. Applying a bit stronger force gets the gears moving again so when the engine is running, the problem is not really visible. Only when the engine is parked and gears are close to the stuck point, I can't get the loco to start. Also when the engine is moving slowly it sometimes stalls because of that.
Yes, I understood from your original how it runs fine in reverse, but not in forward. What I am asking (or should have been clear in asking) is, have you primarily run this loco in forward for most of it's life?
Quote from: jbrock27 on June 11, 2013, 04:11:50 PM
Yes, I understood from your original how it runs fine in reverse, but not in forward. What I am asking (or should have been clear in asking) is, have you primarily run this loco in forward for most of it's life?
I am not an original owner of this engine but since I got it, I have run it in both directions. I would say about 60/40% (forward/reverse).
Did it always have this trouble from the day you got it or did it show up later?
I take it, this is HO gauge?
Do you know if this is an 1980's era model?
Drabina, Did you use magnification to look between the teeth of every gear? Sounds like a very small piece of debris stuck in there.
This has been the case when I have had an engine act up this way. You may have to remove all of the gears to see between the gear teeth, but it may be the only way to look at them.
Then when you are done doing this, the junk box will still be there if needed. ::)
I agree with KennyG, but where I was going with this was to try to establish if this is model that is prone to axle gear cracking, first.
I've seen this with a couple of other single end drive locos. It's usually one of two things. With the shell off, watch the motor shaft and worm gear closely when you apply power:
In forward, does the motor shaft and gear move out, away from the motor body as power is applied? If so, use a pencil to keep it from shifting and see if you still get a jam when power is applied. If not, you need to either press the worm farther on to the shaft an amount equal half of the shaft movement. Or install a shim to prevent the shaft from moving out from the motor.
If the motor shaft isn't moving relative to the motor body, is the entire motor loose? Being loose even a little can allow the drive shaft to get cocked at an angle relative to the worm wheel, creating a jam. This usually happens in only one direction, as the motion in the opposite directly tends to pull the worm tighter into the worm wheel.
Len
I just realized I have the Plymouth with the pancake motor. Yours must be the newer version with a can type motor.
I have seen your issue when the worm on the motor shaft moves too far when connected to the work gear or the worm is not properly positioned.
Rich
Another issue comes to mind. The worm will push the worm gear to one side in one direction. The opposite direction in reverse. In the bad direction, the worm gear might be hitting part of the frame depending on the installation. Worm gears are cut at an angle to match the worm.
Not so with the remaining gears which are spur gears. Those pretty much run straight with little side to side motion.
Rich
drabina-
You've answered your own question. Let me paraphrase: "I have a used locomotive with I don't know how much time in
service. It doesn't operate reliably and it will cost me about $20 to fix my somewhat mysterious problem. There is no
guaranty that there isn't another problem which hasn't shown itself due to the identified problem and there is no guaranty
that another problem won't soon develop in this older locomotive. Or ... I can throw another $5 at the situation and get a
new locomotive from eBay faster than I am likely to have my wounded unit returned from Bachmann. Plus, if I purchase a
new loco I can use my old one for parts, experimentation or as part of a diarama on my layout." Now make your decision.
-- D
Thanks again for all the replies. I will try to take the gears apart and see if I can locate the problem based on your suggestions. The MDT I have looks to be the very first iteration so it is probably very old. I have decided that if I can't fix it, I will just junk the switcher. Definitely not buying a replacement one.
The below is probably what you have. Mine is like it. The motor is white plastic. What is called a pancake motor. Bachmann used this motor a lot some years ago.
http://www.hoseeker.net/assemblyexplosionbachmann/bachmannplymouth060diagram1990.jpg
Again, to make this easier for you, go to the below link and get an account. Many here use it. A lot of mystery can be solved with a photo.
Bachmann products have gone though many changes and are still changing a lot.
Some here like long drawn out discussions though.
http://photobucket.com/
There are four possible links to use when you copy and paste to a forum. The one labeled, IMG is the one you want.
Rich
After looking at the posted schematic it looks like my MDT does not have the pancake motor. I have an open frame motor with worm gear in the front of the engine. Frame is solid (not split). I will post pictures today in the evening when I get back from work.
Richie G, care to elaborate what you mean by your snide remark "Some here like long drawn out discussions though."? Do long discussions somehow bother you? Seems like you contributed to this "long" discussion by not being able to make up your mind which loco you believed drabina to have. Got somewhere to go in a hurry, on your bike maybe? The weather has not been very cooperative lately for that, so what's your hurry?
A friendly reminder that everyone's opinion is respected here, as long as your comments do not include disparaging remarks about other Forum members. Please think before you post.
Thanks for the reminder InsideTrack.
But I don't see respect for others being conveyed when I read a comment that states: "Some here like long drawn out discussions though."
If it's the open frame motor with worm gear, I would definately be looking at either play in the motor shaft, or a loose motor mounting. Both are fairly easy to deal with.
Len
I have owned a Bachmann Plymouth MDT (which those of you 'Critter Junkies' will notice it isn't...an MDT only has 4 wheels...not 6) for some time, and although I no longer use this particular locomotive, I never had much trouble with it. I said MUCH, because the only trouble I experienced was one of electrical continuity (electrical power is transmitted from the axles to the motor via the axle/frame interface). [OK, OK Ray; get to the point.]
My point is that this particular locomotive isn't worth fixing. This leaves you with two choices: 1) replace it with Bachmann's excellent GE 45-Ton or 2) purchase another [new] example of this 'wanting' locomotive. Personally I chose option #1.
Good luck,
Ray
Hey, I LIKE long, drawn-out discussions!
Les
Me too Les; more chances to pickup helpful tidbits!
Ray, I hope you did not feel you had to keep it short-please say more if you wish. What you said so far certainly sounds like wise advice.
Here is mine torn down.
(http://i98.photobucket.com/albums/l267/richg1998/Misc/Plymouth%20Switcher/IMG_0641.jpg) (http://s98.photobucket.com/user/richg1998/media/Misc/Plymouth%20Switcher/IMG_0641.jpg.html)
The pickups are the weak link for DCC. I used a DZ125 decoder and the kept the light bulb.
(http://i98.photobucket.com/albums/l267/richg1998/Misc/Plymouth%20Switcher/Wipers.jpg) (http://s98.photobucket.com/user/richg1998/media/Misc/Plymouth%20Switcher/Wipers.jpg.html)
It was a fun project. Easy to separate the frame halves. Just keep track of all the parts.
Rich
Here are few pictures of the engine I have:
(http://i1215.photobucket.com/albums/cc506/drabina2010/For%20sale/mdt01_zps597f1325.jpg)
(http://i1215.photobucket.com/albums/cc506/drabina2010/For%20sale/mdt02_zps2d2c498f.jpg)
(http://i1215.photobucket.com/albums/cc506/drabina2010/For%20sale/mdt03_zps79797ad3.jpg)
(http://i1215.photobucket.com/albums/cc506/drabina2010/For%20sale/mdt04_zps8718c649.jpg)
To get to the gears, I guess I have to remove the two screws visible in the last photo. Is that correct?
Glad we got the photos! The couplers make this seem to be the N scale version; up to now we've been working on the assumption it's an HO scale model.
OK, any N-scalers care to chime in?
I had asked that question, for that very reason ;D
...of course, in asking that question, I was looking to avoid a long, drawn out discussion ;D
I found the decoder installation fascinating...thanks for including that Rich. I still maintain, that since the Bachmann MDT doesn't represent any Plymouth product (the closest would be the WDT...and it isn't all that close)...and has poor electrical pickup ('could be improved with Tomar pick ups), this locomotive isn't worth all the effort you guys apparently put into it. We have had several in stock over the years; and all were difficult to sell. I view this model as being strictly train set quality.
Again, a far better choice is Bachmann's excellent Spectrum GE 45-Ton. The model comes with dual-mode DCC and is easily upgraded to sound - if one desires. I would imagine that the cost of installation of a decoder (+ installation) will bring the price of the 'MDT' close to the cost of the Bachmann GE 44-Tonner (the GE 45-Tonner is considerably pricier than the 44-Ton).
Well, whatever 'cranks your tractor'. Great pictures (and explanation) Rich. Judging by the couplers, this looks like the N-scale version.
Regards,
Ray
Yea, terrific pictures. Too bad they're not of the same loco the original poster, drabina is having problems with ??? Not sure exactly who they are helping.
...and what included decoder installation? What else am I missing?
just an opinion from a person who's been in and out of n scale since the 1970s.....
most older n scale locomotives ran very poorly. the only ones I've seen from the 1970s and 1980s which are not a total waste of time by to-day's standards would be the trix locomotives, I especially liked the trix f9s. most of the rest had cheaply made 3 pole motors more suitable for slot cars than model railroad use. gear binds such as you have could quickly cause those motors to burn out. as a matter of fact, I stopped buying one brand, even though they made the alco diesels I love, because just about every one I bought developed a gear bind and burnt out motor.
your locomotive probably falls into this category. I would park it near the engine terminal, with the stack wrapped, as a stored locomotive. use the money you would have spent repairing it to get another, new locomotive. you'll be much happier.
You guys convinced me to leave the engine alone. I do not even think I have the skills to work on the small gears like that. Thanks again to all who contributed.
Sounds like a new purchase would be prudent ;). Converting the old loco to a dummy or a static display till "whenever ::)" sure beats the circular file 8).
You could put it on the end of a track by the engine house with all kinds of junk on and around it. This would make it look like it has been there for years.
I used to have a couple of these critters in N scale a long time ago. I used them on a tiny railroad built in a desk drawer. It had a desert mining theme. I called it the "Bonanza Borax Railroad". It only had a couple switches, operated by throw rods from the front panel.
These locos worked fine for me, but I didn't ask much of them. Pulled a few short cars around an "up and over" double loop. You just had to get some momentum up before crossing the switch frogs. I sprayed them primer gray and weathered them so they looked like they spent a lot of time outdoors in the desert.
This railroad met an unfortunate and untimely end. One of my friends liked it so well he asked to borrow it. While he had it at his house, he was killed in an industrial accident.
His girlfriend assumed it was his. In the confusion following his death, she sold it (and the Plymouths) at a garage sale. Never even offered to pay me for it. :'(
Les