F7-A

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chris woolley

New Member
i have a F7-A that won't run the motor is working when on the track. i have pulled the gearbox apart and cleaned all the gears and replaced them and it still move do i need to buy new trucks please give me some ideas.
 

MHinLA

Well-Known Member
When you say the motor is running while on the track, if you turn up the speed to full does the motor go to full speed ? If yes, this would eliminate the motor as the problem..What kind of throttle do you have ? Is it an analog, DC power, such as an MRC TECH 2-5 ? Or, is your throttle DCC like a Digitrax or NCE PowerCab, say ? Same with the Diesel. Is it DC, or DCC ? If everything matches up well in this department then we can go to the physical side, such as cracked gear/s, axles, whatever...
 

trailrider

Well-Known Member
yes then i put power to the train the worn gear turns then stops on both trucks.
Sounds like something is binding in the gear trains. If you take the shell off so you can see the motor and drive shafts, does the motor continue to turn, including the flywheels, even after the wheels stop? If so, you have some problem with the shafts from the motor to the trucks. If the motor and flywheels stall when the wheels do, then there is something wrong in the truck gears that is causing the problem. When you looked at the gears, could you see if they are slipping on their individual axles? There may be a hairline crack in one or more of the gears. This has been a problem with a lot of the wheel/axle assemblies made in China. The plastic gears shrink with age until they crack. In some cases you can replace those with Athearn or NWSL gears.
 

GeeTee

Active Member
the motor has two flywheels on it i am not sure if this is a slot car motor.
no, the slot car motor are those 3 pole pancake jobs .

Sometimes when a motor has been sitting without being run the commutator oxidizes and you have to turn it by hand and run it at full speed for several minutes to wear the oxide layer off. Lub the ends of the motor light oil and check the gears , if the grease in the gearbox has dried out , instead of being slick ,its the consistency of candle wax.

As trailrider said check for broken gears.

You can try running the motor directly to eliminate it as a possibility.
 

bnsf971

Gomez Addams
Staff member
no, the slot car motor are those 3 pole pancake jobs .

Sometimes when a motor has been sitting without being run the commutator oxidizes and you have to turn it by hand and run it at full speed for several minutes to wear the oxide layer off. Lub the ends of the motor light oil and check the gears , if the grease in the gearbox has dried out , instead of being slick ,its the consistency of candle wax.

As trailrider said check for broken gears.

You can try running the motor directly to eliminate it as a possibility.
The OP said in Post 3 the motor runs.
 

chris woolley

New Member
i have left the truck in the body and turned it upside down on the test track all the gears turn with out the wheels in the gearbox when i cleaned and looked at the gears i did not see any cracks. when i replaced the gears in one gearbox whey where hard to put in and and didn't move as free as the other one.
 

GeeTee

Active Member
Did you break the truck down all the way and take the gears out completely ? I think new gearboxes from Bachmann are not that expensive the problem is supply.
 

chris woolley

New Member
Did you break the truck down all the way and take the gears out completely ? I think new gearboxes from Bachmann are not that expensive the problem is supply.
yes this was a second hand loco it ran very slow it was full of grease so i pulled the gears out of truck. then bachmann open back up i will get a new one
 




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