# Lionel KW transformer troubleshooting



## mdh157 (Mar 27, 2008)

This afternoon I attempted to run my vintage lionel set. i'm having a problem with the transformer - first, when i turned the knob it started to smoke from the back - appeared to be the wires I was using so I replaced them with a slightly larger gauge wire, now the overload light comes on. I did nothing further, just shut it off immediately, but now i'm at a loss on what to do next. Anyone have a suggestion? BTW, I had the wires hooked to the U and A terminals on the right side.


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## gunrunnerjohn (Nov 10, 2010)

Well, it sounds like there's a short inside. My guess is the bus-bar that connects the U terminals is loose and is shorting the outputs. You'll have to pull the shell off the transformer to take a look. The four large screws on the top releases the shell, the knobs just pull off.


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## mdh157 (Mar 27, 2008)

*looks ok*

Hey John,
The bus bar is tight...checked the other connections I could see and they seem ok as well. Wondering if I should try the left side or not...the last thing i want is do damage it.


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## gunrunnerjohn (Nov 10, 2010)

Does it run without incident with nothing connected to it? I'd make sure you don't have an external short as a first step.


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## mdh157 (Mar 27, 2008)

*got some power*

put it back together and reset the track power bar - now it works - sort of - i get pwr to the locomotive, light goes on, but train won't move.

gunner john: how do i test it with nothing connected to it..ie, if nothing is connected, how will i know it's working? And by nothing you mean disconnected from the track as well?


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## gunrunnerjohn (Nov 10, 2010)

Well, I test them with a voltmeter and a handful of 75W resistors. A good investment would be this Clamp-On Ammeter from Harbor Freight, it's nice to be able to measure current draw without breaking the wires. Valuable for debugging and only $10.


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## mdh157 (Mar 27, 2008)

sounds good...i have a voltmeter and can test it tomorrow.....and i place the voltmeter leads on the a/u and b/u posts while the transformer is powered up? 

If it tests good then we are looking @ track problems, i assume?


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## gunrunnerjohn (Nov 10, 2010)

Yep, just measure the voltage and run the control up and down. It should go from a low of around 6V just above the 0 setting to close to 20 volts at the top setting.

Next, I'd take all the trains off the track and see if you get the same results connected to the track.

As far as a load test, if you have an automotive headlight bulb, you can set the transformer to 12-13 volts and connect the bulb to it, it should be able to handle that easily. Obviously 20 volts will probably take the bulb out, don't do that.


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## BigAl56 (Dec 14, 2011)

It sure sounds like you had a short. Those old AC transformers put out a lot of current. If you have a hard short the transformer would make a bad hemorrhaging sound and start to smoke. I'm wondering why the internal breaker did not pop?

OK, so you now have power to the engine? What kind of engine is it? A postwar or a newer electronic model? I hope its an older postwar model as if it was a newer engine and it was off track and shorted it's internal wiring could be melted.

If this is an older model with a traditional e-unit check the switch and make sure the engine is not locked into neutral.


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## mdh157 (Mar 27, 2008)

*voltage good*

Just got done checking the voltage......using the u-a and u-b it matches the control setting on the transformer on both sides.

the u-c has abt 6.9 v constant and the u-d has abt 19.75 constant.

going to connect to the track with nothing on it and see if it changes

engine is an MTH, abt 15 yrs old and def not locked in neutral.


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## BigAl56 (Dec 14, 2011)

Voltages sound normal. A 15 year old MTH engine may have a bad or discharged nicad battery under the hood. With older MTH engines if the battery is dead the engine will not cycle out of neutral. Try charging the engine up by leaving it on for an hour or so. Then set the throttle about half way and press the direction button for no more than a second.


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## mdh157 (Mar 27, 2008)

funny you should mention that areizman.....the older MTH seems to need time idling whenever i put it on the track, even if it ran for an hour the night before. the longer it sits, the better it runs. I replaced the batt last year though, so it shouldn't be bad already (you would think).

anyway, back to the transformer - checked it with the track connected, voltages good, checked it with the train again, just the engine, no movement but lights on the engine. dir change did nothing, so i put my new MTH (bought from 2011 catalog) on and it ran perfectly, really fast, dir change worked (unfortunately the whistle lever is broken off so I'll have to try and find a replacement). so i decided to take both the older mth and my postwar engine down to my local shop. Owner says the e-unit is sticking on the postwar but the armature appears to be fine. He initially mentioned the battery on the older MTH but wen i told him what i was sometimes doing he scratched his head (sometimes changes direction when pressing the speed lever on the remote - downright eerie).

so i left both engines at the shop for repairs......will have to call him tomorrow and make sure i have the inside of the postwar one cleaned good as it has a lot of grime on it.


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## gunrunnerjohn (Nov 10, 2010)

Sounds good, let us know how everything works out when you get them back.


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## servoguy (Jul 10, 2010)

I have 4 KWs, and I have disassembled all of them to lube the whistle control mechanism. This really makes the whistle controller work easier and smoother. One of them had a broken piece in the whistle control mechanism which I repaired, and it now works just fine.

I use 5W-20 motor oil for lubing everything. No grease or "light machine oil" or WD-40. I have had one engine in the box for 45 years. It was lubed with 20W-40 Valvoline before I put it away. When I took it out of the box, it ran just fine. I have had bad experiences with grease and light machine oil. They dry out over time.


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## mdh157 (Mar 27, 2008)

thank you servoguy.....i'm a car mechanic so i got soem 5w-20 out in the garage...will be sure to use it before i store the transformer.

And i plan to make some space and set up a layout that stays up, which i think will be good for the engines in the long run


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## mdh157 (Mar 27, 2008)

Well, i got the MTH back yesterday.....he had one of his local experts take a look at it, just messed with it a bit and after a short time he got it working just fine (appears to anyway). He said the sound board is going but with the repl cost i'm better off leaving it alone. His main point to me was that the MTHs need to be run fairly often, they cannot be put away for years like the older Lionels.

The postwar engine is still out for repair.


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## BigAl56 (Dec 14, 2011)

That's a common problem with Protosound MTH locomotives. The internal 9v Ni Cad battery loses charge and you cannot get the engine running until they fully recharge. A couple of things you can do. Replace the NiCad batteries with newer style NMH batteries or purchase a capacitor battery eliminator. The Capacitor replacement is more pricey at about 20+ bucks but is more reliable. I just recently bought a couple of NMH batteries on Ebay for about $10 each. MTH also makes a Plug-in recharger you can plug into the bottom of the engine so you can recharge it priro to an operating session.


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## servoguy (Jul 10, 2010)

I don't think a NiCad battery or a NmH battery will give good service in this application. Both have memory problems and do not like to partially discharged before recharging. A capacitor is a much better choice. A lithium battery would be a good choice.


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## gunrunnerjohn (Nov 10, 2010)

You can't use a Lithium battery in the PS/1 or PS/2 locomotives, the charger is designed for NiCad or NiMh.

BTW, if the sound works, I can't see how the sound board would be "going", exactly what does that mean?


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## servoguy (Jul 10, 2010)

I was just commenting that both NiCad and mNH batteries are not well suited for this application, that a lithium batter would work much better. I didn't suggest that anyone use a lithium batter. You are right, John, the charger must be compatible with a lithium battery.


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## gunrunnerjohn (Nov 10, 2010)

OK, I just didn't want to mislead anyone here, I would agree that Lithium would be a good choice, just not an option.


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## mdh157 (Mar 27, 2008)

*still not working right*

Hey Guys, my lionel is still not working as it should....you can hear the elec sound but it seems to want to move but won't or moves @ a trickle. I did move the lever on top of it a bit and then it seemed to work a lot better, buut i have to play with it awhile to get the train to work, so my guess is that it is related to the lever position.

Any input would be appreciated.


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