Battery power?

That is just one of many.  Look at the electrical pick up from each truck.  Did you clean those?  They will tarnish and in some cases corrode too. 

Den

How about the invisible?

You stated in your writing that you"Found no dirt or visible corrosion."  The key word is "visible" . There could be problems inside the motors.

Could be the motor brushes and/or commutator are worn or the copper windings are corroded. Hard to say but easily tested with VOM. (as well the electrical pickup)

G. T.

Testing Locos With A Voltage Tester

I have a voltage tester.  How would I test locos without them being connected to power, such as on a test track?  I'll admit to being uninformed on electrical matters.

Try this.

Firstly, disconnect all power from your loco before doing the following. And, remove the cab from the base of the loco.

Testing is easy if you do a basic test for continuity on all visible wiring and connection points. If need be, unplug or desolder the wires so as not to get false readings. (be sure to draw a wiring diagram so you know where each wire was connected before moving on to the next wire)

Set your meter for testing resistance (Ohms) to the lowest value on the meter. Connect each probe to each end of the wire. If you get a zero reading , on the meter, your wire is fine. No reading means the wire is broken. Continue with all other wires in the loco to be certain none are broken.

Please, post a clear photo of your meter. I may be able to tell you what the actual continuity setting is.

If you trace all the wiring in a loco back to the motor, and if they all read as being good, the the motor is more than likely the problem.

If the motor is sealed unit, then replace it.

If the motor is an open faced type, inspect it for damage or worn parts such as brushes, commutator or windings that may be corroded or broken. Also, check the motor shaft for corrosion - it could be binding.

Needless to say, if the motor appears fine, "lightly" lubricate the motor shaft at each end. Do not get oil on the brushes, commutator or windings.

With the loco wiring reassembled, and no cab on the loco, place it on your test track, and slowly apply power to see if it operates, smoothly.

G. T.

Isolate Electrical Problems

Hi Keith,

You can determine where the problem is by the following process:

Remove the loco shell.  Place the loco upside down on the workbench.

Use wires attached to your powerpack, set at half throttle, as probes.

Touch both sides of the frame, does it run forwards/backwards smoothly?  If it's only an electrical issue, the loco should run freely forwards and backward when the wire supply the power.  If not, remove the trucks and repeat the test.

If that fixes it, try rolling the trucks with your fingers using light pressure.  If they bind at one or more spots, uou'll have to disassemble and clean the gears, wheels and axles.  NOTE-This requires careful work to prevent losing any parts.

If the truck are not the issue, try probing the metal sideframes of the front truck, then the rear truck, then one side of each truck.  The ones that don't work need to have the contacts cleaned or adjusted.  NOTE-the contacts are thin and fragile, so be gentle when making the adjustment.

If you still haven't found the problem, try cleaning the wheels.  Some of the early ones were not the best casting and tend to oxidize.  You can use contact cleaner, wahl clipper oil, goo-gone, etc., just use SMALL amounts and clean the excess off with alcohol and paper towels.