# Rewiring a 252



## Konga Man (Dec 12, 2010)

I need to rewire a 252 that has been previously modified. I'd appreciate any help that you might be able to provide.

First, there's no headlight, and no remnants of a wire for one inside the shell. Where was the wire to the headlight originally attached?

The more interesting task is rewiring the motor and the reversing switch. As you can see in the attached pics, the switch has been completely bypassed, and the coils and brushes are connected directly. It runs fine in one direction, but I'd like to restore it to full functionality. To do that, I need to confirm the correct wiring for the switch.

I'm guessing that the solder joint indicated by the blue arrow in the picture below is part of the earlier modification. I'm thinking that I need to break that joint, then run wires from each coil to the switch, and from each brush to the switch. Specifically, I'm thinking that the two brush wires should be opposite (e.g. terminals 1 and 3) and the two coil wires should be opposite (e.g. terminals 2 and 4).

Can anyone confirm that this is conceptually correct (or straighten me out if I'm wrong)? Even more to the point, would you happen to know which wire connects to which terminal?

Finally, the switch itself is a bit of a muddle. It's got the 4 spring-loaded contacts, but only two them currently have springs in them. The result is that the other two contacts aren't pushed against opposite plate, so the switch doesn't work as intended (maybe this is why the switch was bypassed?). As a sanity check, there should be springs in each of them, correct?

Thanks again for any help.


----------



## Boston&Maine (Dec 19, 2007)

Here is a wiring diagram for a 252: http://pictures.olsenstoy.com/cd/b123/000361.pdf

As you can see, the headlight and pickup wires are mounted to the same screw on the switch... The most important thing which matters when wiring the switch is that the wires coming from the motor brushes are diagonal from each other... Also, you are correct in assuming that each switch should have a spring in it...


----------



## tjcruiser (Jan 10, 2010)

Konga,

Good link from B&M above. Additionally ...

I rewired a prewar 1681 with a manual switch like yours, recently. In the process, I wanted to make sure I understood how the switch worked in its different positions, and ended up drawing a wiring diagram for the loco that shows how the switch works. You might find the pics and info in Post #72 (scroll down a couple of pages) in this link helpful:

http://www.modeltrainforum.com/showthread.php?t=3847

One other note ...

On these old Lionel locos, loco direction is reversed either by: (a) flipping the "direction" of current flowing through the armature, with the field direction left untouched, or (b) flipping the "direction" of current flowing through the field, with the armature direction left untouched. Either option will work just fine, as long as things are wired correctly. There's no real difference in the parts required, other than how the wires are run.

In looking at the wiring diagram link of the 252 from B&M, I think (???) it's likely option (a). I say that, because it looks like the "end" of the field winding is grounded to the motor frame. If that's true, than current through the field always goes one way (ending up at the frame ground), and it's the current through the armature that gets flipped.

Having said that, my 1681 loco (and its wiring diagram) uses option (b), instead. So if you look at that diagram, you need to make the mental flip-flop of wires to the armature / field.

I hope I haven't confused you there ... ping back with questions, if it doesn't make sense.

Oh ... in answer to your last question, "yes", there should be springs in each of the 4 contacts on the switch. They should all ride firmly against the contact plate on the mating side of the switch. (These springs are essentially the same as brush springs within an armature assembly.) Along the line, someone probably lost 2 springs, and simply opted to rewire the loco to bypass the switch and run in one directly, only!

Good luck,

TJ


----------



## Boston&Maine (Dec 19, 2007)

Well TJ, your diagram blows the one from Olsens right out of the water! :smilie_daumenpos:

One question though, your diagram shows one of the brushes being grouned to the frame, but the Olsens diagram shows both brushes going to the switch, which I remember from when I had my prewar electrics


----------



## tjcruiser (Jan 10, 2010)

B&M,

We're cross-posting, I think!

Read my (updated/editted) comments above about how some motors are wired with "option (a)", whereas some are wired with "option (b)" ... that should explain.

To visualize the 252 setup, simply imagine the diagram above (mine), but with the pair of wires going to the field and the pair of wires going to the armature flip-flopped.

TJ


----------



## Boston&Maine (Dec 19, 2007)

Very interesting... I guess you learn something new everyday


----------



## T-Man (May 16, 2008)

My mystery motor grounds the coil to the frame, so on the switch that is opposite the center pickup. Then the brushes connect perpendicular to that.


----------



## Konga Man (Dec 12, 2010)

Thanks to all who responded -- and a very helpful drawing. It's nice to know I probably won't be burning anything up. 

A couple of notes that might help the next guy:
- On this switch, forward connects the two top contacts to each other and the two bottom contacts to each other. Reverse connects the two front contacts to each other and the two back contacts to each other. This is opposite from the drawing above.
- Don't use springs that are too strong in the switch contacts. I had some handy-dandy springs that fit perfectly, but they were hard to compress when the contacts had to ride up onto the plates. As a result, the backing plate rotated slightly when the switch was moved. I downgraded to a softer spring (from a ballpoint pen, cut into 4 pieces), and it works perfectly.

Does anyone know where I can find the small (preferably brass) spade lugs presumably used on these wires? I could wrap the wire around the screws, but the lugs would be cleaner, easier, and likely more correct.

Finally, what kind of screws held this assembly together? There was a hodge-podge when I took this apart: the motor was held to the frame by a 1/4" fillister head, a 1/8" fillister head, a 1/4" low-profile, wide head, and a 3/16" roundhead. The switch was held together by a 1/4" fillister, and attached to the frame by a 1/4" fillister with a brass nut run up against the head so the screw wouldn't bottom out in the hole. I can easily believe that some of the screws were mixed up during a previous disassembly. If I had to guess, I'd say low-profile head should hold the switch together, the 1/8" fillister should hold the switch to the frame, the 3 1/4" fillisters should hold motor to the frame, and the roundhead is a replacement for a lost 1/4" fillister.

Any insight on this?

Thanks.


----------



## tjcruiser (Jan 10, 2010)

Konga,

Glad the wiring diagram helps.

On my 1681 (with as-found original wiring), the wires connected directly to the screws on the manual switch without lugs. I agree that lugs would be a "cleaner" connection, but I suspect they were not original Lionel setup.

I can't offer much help on screws, except this ... a lot of my prewar locos use #4-36 screws, which was a common thread type back then. However, it's essentially non-standard and not available at your typical hardware store today. However, a good Lionel parts guy will have them in stock. Jeff Kane at the Train Tender, for example, if you ever need some.

As for other screw lists on that loco, you might try the Olsens library, though when I click on it a few moments ago, the link wasn't working. (That happens with them frequently ... try back later ...)

http://pictures.olsenstoy.com/searchcd2m.htm

Regards,

TJ


----------



## Konga Man (Dec 12, 2010)

Hmm... On this setup, both wires which connect to the brushes use spade lugs. One wire comes from the pickup; I assumed that it had been relocated from the switch. The other wire is spliced to the field coil. I kinda figured that it used to go to the switch as well. I guess it's always possible that the lug was removed from one wire and soldered on to another. Never say "never" when trying to figure out what someone else did 50 years ago. 

Believe it or not, I just went through an escapade of trying find 4-36 screws for another application. Freakin' hen's teeth, they are.


----------

