I bought a used LW transformer a while ago and soon realized that its polarity is the reverse of all my others I.emphasized texte. the U is the positive and A negative. I have a two loop layout with the LW powering one loop and a 1033 powering the other. I can easily reverse the wires which connect to the track on one transformer so the an engine can successfully move from one loop to the other
Blockquote
but if I am running a more modern engine, the whistle controller of one of the transformers will not activate the whistle. Is there a way to reverse the polarity of the LW to match my other transformers?
Here’s an article on the subject: Lionel KW diode installation - The Silicon Underground
If I recall correctly, A on the 1033 is also ground, but the whistle diode in it is wired normally. The whistle diode inside the LW is wired backwards, so it will not work normally. The easiest way to fix the issue is to buy/make an external whistle controller and use that instead of the LW’s (though the LW should, if I recall correctly, actuate the bell if there is one). A more sophisticated solution is to replace the original whistle diode. All of Lionel’s transformers of the era used a selenium diode to create the DC offset. Selenium diodes are rather fiddly, and so many people replace them with new diodes. You can replace the diode “backwards” which should rectify the issue. Follow the tutorial in this article (it’s for a KW, but the basic elements should be the same), except you should put the diode in opposite of the instructions. That should cause it to work properly.
Here’s some suitable diodes: 50PCS/LOT 10A10 10 Amp 1000V 10A 1KV Axial Rectifier Diode 22A: Amazon.com: Industrial & Scientific
Of course, reading the manual for the LW, you will find that the “U” is supposed to have the positive offset as this is the post that goes to Lockon clip 1 for the center rails, the “A” post(there are two, A is common) goes to Lockon clip2 for the outside rails. Problem solved.
The 1033 has the A post designated common as well - same applies to it - "U is the post that goes to Lockon clip 1 for the center rails, the “A” post goes to Lockon clip2 for the outside rails.
These both follow the convention with single throttle transformers in that “U” goes to the center rail.
Well, be careful there and actually test it - the Lionel schematic for the LW shows the rectifier in reverse polarity than it’s actually installed.
It sounds like when the LW is connected correctly, the whistle sounds just fine based on your finding/reporting that “A” is the DC positive - that is correct.
Your issue may actually be that your 1033 is wired wrong.
In that case, the three articles I read on the subject are wrong–so it’s either the repair diagram or the articles. Perhaps that is the case, so I’ll shut up for now.
Not trying to hijack this thread, but, when I tried to use my LW earlier this month at a display at church, it would run the train just fine for a few seconds and then die. A brief foray into the guts suggests to me that the circuit breaker is bad.
I am comfortable replacing it, but I would like to investigate alternatives to the stock unit. Does anyone have a suggestion? And, if I go stock, how likely am I to find a new part?
I use similar (though manual reset) ones. Make sure you get the 5 amp model; I think that that’s what I’ve got. Just bypass the old breaker with these.
Back to the topic:
I’m pretty sure Rob is correct. I had someone quite a while ago put a new rectifier into one of my 1033’s and he also put a new electric cord on it. I don’t know if he did anything else, but ths is the 1033 which has U common and A hot. My other 1033 has A common and U hot. By the way, the LW has imprinted on the plastic case “common” under the A,B etc.
Ah, that clears this up. He did, indeed, do something else: he swapped some wires around inside! That, evidently, is why there was some whistle confusion. Say, do you by any chance have a dedicated test bench to which you could demote the “backwards” 1033?
I’m afraid not. I am also very poor at soldering. My latest project was to solder two wires together and that took me over ten minutes. The way I tested the 1033 was to attach
a transformer for which I definitely knew the polarity to a test track and then tap the U and A wires of the 1033 I was testing to the center and outside rails to see which way sparked and which didn’t.
All single throttle transformers have “U” to the center rail, as the direction and whistle controls are on the “U” post circuit(with “A” being common), 1033 & LW included, and your “backward” 1033. The only difference would be that somebody installed the rectifier/diode reversed to activate the bell function erroneously instead of for “whistle/horn” function by following the bad schematic drawing rather than actually test it with a meter, scope, or a known good piece of equipment.
I see. In that case, unless you do eventually want to try modifying the 1033, there’s not much else that you can do except to oust said backwards 1033 from your railroad’s power center.