OK, I am at a total lost now? I posted sometime ago about a older Athearn F-7 A that I use to make a power B unit. It ran great but sometimes it would lock up while running but mainly after sitting for a while.
It is a older Blue Box with no flywheels. I hard wired the top of the motor thinking it was a contact problem. (at this point you need to know what a older BB engine looks like) I cleaned the brushes and lubed all points that need lube.
Again, if it sat for a while sometimes it would not run till I spun the motor? It was better but still not right. After I went though all this I posted about the problem for the first time. One of the kind folks here thought the problem was one of the windings had brunt up. Sounded like it could be it so I bought a new motor.
Installed the new motor, same problem would run then stop, spin the motor and it would run. In fact it was worse than before. But, I found one on the mounts was weak and may not be holding down the lower contact strip of the motor tight to the chassis! That must be the problem! So I hard wired the lower section of the motor to the old head light holder that is grounded to the chassis and installed a new motor mount. Ran like a champ, probe gone! Pulled from the bench say 2 weeks ago because the wheels where dirty.
Tonight one of my SD-50’s was in need of repair so the F7 A and F7 B (B is the problem child) was pressed in to duty. Cleaned the wheels of the F7-A with no hitches, F7-B? Would not run on the cleaning track till I spun the motor? It and the A unit are running fine dragging 40 or so cars as I miss spell.
Recap.
New motor
Hard wired top and bottom.
Spin the motor and runs fine.
Only 2 thing I can think of is.
The wheel to truck contact points may need cleaning.
Or a drive shaft may be binding. Front shaft is at about a 30 percent but spins
You don’t mention how much power you apply to the track but I’m assuming full track voltage as some motors don’t turn over at low volts.
Have you tried running some wires direct to the motor terminals, this would help locate the problem. If the motor runs every time you touch the terminals, look for dirty wheels/track or other contacts, if not, check the brushes on the motor, It’s years since I played with a blue box loco but maybe something is reducing the tension on the brushes.
Check the motor armatures. It’s possible that the brush interference JW mentioned could be a layer of grunge under them. Open frame motors (of which I have a bunch) are notorious for collecting crud on the armatures.
I clean mine, when necessary, with a Q-tip soaked in rubbing alcohol.
Old Athearn B.B. engines had notorious electrical pickup.
It probably still is.
The ‘ground’ connection needs to be bypassed. A wired grommet into a drilled hole in the chassis works____. (then) 2. if you have replaced the brushes, clean off the spinning armature with the eraser end of a pencil. That cleans off old residue to make better brush contact. ____A-LINE PN#12055
A-Linehttp://cs.trains.com/forums/AddPost.aspx?PostID=1486158 should be your source for improving all old Athearn BLUE BOX ENGINES (yes - I practice what I preach).He’s made his living off of ‘improving’ Athearn products, for years.
First, remove the shell and arrange for easy access to supply power directly to the motor. When the event happens, touch nothing except for applying power to the motor. Motor runs means power not getting to motor–motor doesn’t run means problem with motor.
Anyway, that’s how I would approach it. You should then have a direction for further investigation.
I do wonder if the critter is mechanically jamming up or having an electrical problem. The latter might be caused by poor contact between the kingpin on the frame and the steel plate that it fits on. Any chance there’s some paint at the kingpin location that might be providing occasional insulation?
If the mechanism is mechanically jamming, the motor will be drawing power and your ampmeter should be reading “not zero”. If it’s electrical, should be zero. Unless there’s a short, then the your circuit breaker should be tripping–something you probably would have noticed, so that’s probably not it.
If you clean the commutator with an eraser, it’s possible some of the grit or rubber MAY stay behind and cause problems. After the abrasive cleaning, it’s ideal to remove these substances if still present. But, if your motor runs well after the eraser, you dodged the bullet and can skip the latter step.
Funnier solution, maybe you need to just install one of those old crank arms like the old cars had? something removable like the keys for the Breakdown Cranes Athearn and Bachmann put out?
Rotor, it is a brand new engine from Athearn. Has maybe 10 hours if that on it. Far as the arm and brushes still looks all most brand new, there is no notable build up. On the old motor, I thought that was the problem and cleaned ever time it stalled.
On applying power to the new motor, yes it starts right up. In fact it did with the old motor as well! That is one of the reason I thought I had the problem fixed when I installed the new motor. Weak motor mount was on the old motor, and bottom was not hard wired. Only reason I replaced the motor was a burnt winding could cause the same issues.
Locked up gear or drive shaft? If the engine was mechanically locked up, shouldn’t the motor still hum when I crank up the throttle? Last night it acted like it was not getting any power, just dead.
King pin? That is a new term to me, is that the mounting point that holds the head light stand? That is something I have not checked and I may have moved one bad ground to another bad ground! Don, as far as mounting a eyelet to the chassis that would be the prefer way. At this point I do not have a drill press or taps that small.
Tonight, it started up fine and is earing a living as I miss spell. If or should I say when it acts up again I will up date this posting.
Don, as far as my communication skills, I have been trying to improve them. Last thing I want to do is embarrass this great site and other MRR on the Internet! I rather do that in person so I can see the silly looks they give me! [;)]
Thanks to all the kind help answers that where posted as well.
A nickle says your wheel/axle pickups are faulty or dirty, on the frame side for starters.
Gear problem would manifest by dragging or clicking at least some of the time when the motor runs.
Has the headlight ever acted flaky? A filament shorting to ground might shunt enough current that the engine never reaches startup levels, but you’d think such a filament would melt pretty quick. In any event, bulbs are cheap. Look hard at the bulb socket and soldering there too.
Traditional Athearn locomotives wiring system can be improved. Buy some 1/4" “Fastons” at the hardware store. These will slip over the power strip “thingie” coming up from each truck. Crimp or solder a wire to each faston and solder the wires to the motor top strap. The Fastons slide on and off, permitting disassembly of the locomotive without unsoldering anything. That fixes the intermittant connections that sometimes occur where the motor top strap wipes upon the truck “thingies”.
Then, remove the motor and solder a wire to the bottom brush connector. Drill and tap a 2-56 hole in the locomotive frame to secure a small ring lug to connect the bottom motor brush securely to the frame. That fixes intermittant problems with the bottom brush connection.
Check that the motor is level in the frame. Sometimes the rubbery motor mount isn’t seated fully in the frame whch results in cocking the motor. This causes the universal joints to run at a stiff angle which they don’t like. While you are at it, file off all the flash on the u-joints and t he drive shafts.
Check for flash and dirt in the gear towers. Each truck has a gear train inside that carries the torque down to t he wheels. Take the gear towers apart. Inspect the gears for flash, broken or lunched teeth. Use a pipe cleaner to wipe each tooth of each gear. This will remove any invisible flash or dirt from the gears (black flash on a black plastic gear is invisible).
An ammeter in series between your DC power pack and the locomotive is most useful. If there is current flowing, and the motor doesn’t turn, you have a mechanical bind. If no current is flowing, you have an open circuit. I wouldn’t depend upon hearing a hum from a stalled motor. It’s a DC motor, which doesn’t hum as much as an AC motor, and I don
The kingpin is the nub that the truck swivels on. I recall that it is a part of the frame casting. The nub drops down into a hole in a sheet steel piece on the top of the truck. It is supposed to conduct electricity from one side of the truck up through the frame and then to the motor.
It’s certainly possible that a motor pole could be defective, but I believe you said it happened twice–there’s a co-incidence–I believe it’s a pretty rare event. You could be the lucky one, of course. If it is, you HAVE TO turn the motor to get it to run. If there’s a bad pole, the motor should fail to start 1/5 of the time. The distribution is a random event, so if you just try a stop and start test on the layout, the problem should easily show up by the time you’ve done the test 10 times.
It sounds like you/we are getting closer to an answer.
Again, thanks for all the answers. For now the problem is gone, for the last few days it starts up just fine. I am 90% sure at this point when it happens again, I will find the problem in the power pick up in the trucks.