kw acting up

[northernpike]

Need some advice-

My kw does not work, no power to track.  When I put load on (engine), the red light glows constant, does not blink light my other kw.  I know track is good, engine good because I hooked up my other kw and everything worked great.  Took cover off, traced all wires with my Greenberg repair guide.  All solder good, wires in right spots.  I am baffled.  Is this a bad breaker?

thanks

Tom

[lionelsoni]

Could be.  I don't understand "the red light glows constant, does not blink light my other kw".  Does the other kw's overload light flash when there is no short circuit?  Or do you mean that it cycles when you put a short circuit on the transformer?

If the latter, try briefly bypassing the circuit breaker of the bad transformer to see whether the train runs.  But do not deliberately put a short circuit on it when the circuit breaker is bypassed.  If that seems to fix it, you can get a replacement for less than $10; or you can use an automotive circuit breaker rated at 10 amperes.

[northernpike]

The kw light cycles with a short only.  I will try that and let you know.

Thanks for the help!

[steinmike]

Tom:

A couple of quick thoughts that may also help:

(1) Is this happening on both the A and B throttles on the KW?

(2) Does this happen when the KW is completely disconnected from the track and accessories?  If this happens with no load on the KW, then you might have a short baetween the binding posts inside the KW.  If it doesn't happen, then I'd try adding load back on to the KW one track block and one accessory at a time until you get a steady red light and that track block or accessory is the source of the short.

(3) Is the KW still producing fixed voltage from the U-C, C-D, and D-U posts?

The KW's are pretty robust (I have a KW that was last overhauled in 1983 and is still working great), if you can isolate the problem a bit more, I'm sure the folks on the forum can find an answer for you. 

Good luck!

Mike

[lionelsoni]

Mike, he says that the red light is on all the time, not cycling.  So, unless an internal short circuit was the cause of a failure that left the circuit breaker or its wiring open, I don't think that could be the problem.

If the circuit breaker has failed open, practically any load will cause the red light to light; but that doesn't mean that the load is the cause of the problem.

Because of the conductance of the lamp and its series resistor shunting the circuit breaker, all the voltages will appear normal until the transformer is loaded, if an open circuit breaker is the problem.  Even with a load, several of the fixed voltages will appear normal since they are not all protected by the circuit breaker.

[ADCX Rob]

The original symptoms described are classic of a stuck open breaker.  With nothing on the track, & no power, the red lamp will stay out.  The first load will light up the overload indicator.

If you want to test the transformer w/o diassembling again, briefly short the overload lamp socket(remove the bulb, of course) to send current around the open breaker. 

Rob 

[lionelsoni]

There's a resistor in series with the lamp; so shorting the lamp is not the same as jumpering around the circuit breaker.  It will allow the transformer to operate only the lightest of loads.

[northernpike]

Thanks for all of the insight on the kw.  The light is constantly on with an engine on the track. Engine dead. I tried a separate 3' section away from the layout on the kitchen table and it did the same.  A and B both.  Engine dead.  I will have to try the lamp next.  I have read once that the kw has a troublesome breaker.  Have any of you had any problems with breakers?

Thanks

Tom

[lionelsoni]

If it is the circuit breaker, here's what you can replace it with:

http://www.delcity.net/delcity/servlet/catalog?parentid=167865&page=1

 

[Back2Trains]

I would remove the case and clip a temporary jumper around the breaker terminals. If everything works normally, replace the breaker. Except for testing don't run the transformer with the breaker jumpered out and don't try jumping the breaker at the light socket because the resistor in series with the light bulb will cause erratic or false results. I have had four KWs and they have all given excellent service. It will be well worth the effort to troubleshoot and repair your transformer. While you're inside the unit, check the rollers and replace them if they are too badly worn.