Hi Everyone,

I own a 1999 Lionel ZW transformer with 2-135 Watt power bricks.

The problem that just developed this month is the A-U terminals do not go to zero when I close the throttle. I measure 5.3VAC at the track when it should be zero. Any locomotive or lighted rolling stock still has their lights on when they should be OFF. The B-U, C-U and D-U terminals go to zero like they should.

Is there a repair procedure available to open up the control unit to adjust for proper voltage? Or has anyone done this who can tell me the procedure before I start cracking the case out of desperation?

Thanks in advance!


Original Post

There is a recalibration process that should fix that. The instruction manual outlines it but I can't seem to locate it online right now.


Take a look near the bottom of page 14. That covers it. Just be sure to use a plastic tool to depress the programming button and not a metallic one as you can short out the board.



Glad that worked for you.  You may want to check the white plastic gears inside.  There was a part (white plastic also) connected to the handles that would crack and cause the handles to not bring the voltage all the way down.  Lionel offers a replacement metal piece for this.  This is for the PostWar Celebration ZW which I am pretty sure is the one you are talking about.

Hi Bigrail,

Yes that's exactly the one I have...PW Celebration ZW...I did wonder why I couldn't find a model# for it (my box is stored away).

Thanks for the heads-up on the plastic gear & handle part vulnerability. I assume I can order the metal replacements through Lionel Service? Do you have a part# or an exploded diagram for that control unit?


Actually 3 problems with this tranformer

1) The potentiometer nut would loosen allow gear tooth slippage

2) The horizontal bracket that the vertical potentiometer bracket mounts to was upgraded to a metal. I believe

    improper dimensions and breakage.

3) The potentiometer bracket breaks where it screws into the horizontal plate. This part is not available...from lionel...Start saving pennies for another transformer!






Well that's a pain!

I think I'll overhaul my 1950's ZW as a backup. The only thing I really like about the new one I have is the circuit breaker is really fast-acting when a car derails. With my old ZW, I ended up with burnt rivet connections on my 1122 027 switches when my son (then a 5 year old) didn't know to throttle OFF when a derailment and short occurred. That was 30 years ago.


Hold on there....the part is available from Lionel.  I ordered it last summer.  I'll look it up for you and posy it here.  It's a great transformer.  Just needs a slight upgrade.

Not sure if this was covered but there is also a potential issue with the main board in this unit not playing well with the Legacy system. 

Some command gets interpreted as a full system shutdown as if the red halt button was engaged on the remote. It doesn't show up in all units nor is it easily repeatable. Lionel does make a replacement board that remedies this issue and it was an easy swap. MartyE has a really good photo outline of the process on his website.

It started with mine about a week or so after we added Legacy.

graz posted:

Not sure if this was covered but there is also a potential issue with the main board in this unit not playing well with the Legacy system. 

Some command gets interpreted as a full system shutdown as if the red halt button was engaged on the remote. It doesn't show up in all units nor is it easily repeatable. Lionel does make a replacement board that remedies this issue and it was an easy swap. MartyE has a really good photo outline of the process on his website.

It started with mine about a week or so after we added Legacy.

Does anyone have a part number for the replacement main board (or could post a link to MartyE's web site.)?  My unit's main board has an issue that I would like to remedy and I have been told the main board was no longer available.


Bimmer, the ancient ZW is a great warhorse.  The breaker problem is easy to solve.  Use external breakers that use a push-button to reset.  They open quickly and don't reset until you press the button, after clearing the derailment.  I get mine from boating supply houses for about $6 each.  Maximum aggregate amperage of all outputs should be 10 amps.

Got the part number for the metal brackets for the handle inside the PWC ZW.  Here ya go: 

26102859065BRKT-ZW POT.ASSY MTNG L&RH$14.00



While the old is a great xformer and is solid. The new provides remote / command compatibility with built in powerhouses. 

Yes, the unit has it's issues mentioned above, but once addressed, the ZW-C is a solid performer. I've had mine since 99 and it handles everything we throw at it.


Hi Everybody,

First, let me thank each of you for sharing your collective knowledge on the "new generation" ZW. This is what makes this forum great!

First a hearty thanks to Bigrail for the part number for the metal brackets!

Next to RJR, what value external breakers do you use for the old ZW? I saw a Youtube video where the presenter tested 1A, 3A, and 5A breakers and concluded the 3A worked for him. His load was a steam engine with a diesel, and two heavyweight lighted passenger cars. In my experience my twin-motored F3 draws quite a load on the "new" ZW. I guess I should test what it is drawing with an ammeter. Also do you know the brand of the breaker you use? The one in the video is made in Germany and requires a mounting rail to hold the breakers. That's fine for a permanent layout, but my "layout" is Christmas tree dependent, hardly permanent.

I'm also reading other threads on using the old ZW's with TVSs (transient voltage suppressors). Anybody have a recommendation of the voltage and amperage spec one would use with the ZW? One source I read about was using ~30 volt but did not mention an amperage spec.

I haven't graduated to remote/command control of my trains as none of my locomotives are so equipped. I've got a 19 month-old grandson who is crazy about a loop of track around the Xmas tree running 60-year old trains so I've got to keep things simple.



I don't know about the problems people have with the expensive new ZW's but the 60 year old version still seems to work.  They charge you a lot of money and then they don't last. We didn't have all these problems years ago when the ZW was just a simple coil wound variable transformer. Call me a cave man if you will, but keeping with the simple approach, has saved me money and many a headache  .

I agree with Dennis that the old war horse ZWs are great, even for modern layouts.

Their internal thermal breakers are unreliable, and if they reset automatically, the current will keep coming on and overloading it, as well has hazarding the trains' wiring and parts.

Roger, you question does not have an easy answer.  The internal breaker in a ZW is on the wire to the U post.  If you were to set the left handle at 6 volts and the right at 20, and connect the A&D posts, you'd have a dead short fed by 14 volts.  It wouldn't be too long before your transformer, and possibly your house, went in a puff of smoke.  This is the situation that can exist in a loco passes from a section controlled by one lever to a section controlled by another, while its rollers span the fiber pin.

So most users add a 10-amp or less breaker or fuse in each feed coming from A,B,C, & D.  However, this can permit up to 40 amps to be drawn from the ZW, which yields the result noted above.

For maximum and proper protection, I'd put a 10-amp breaker in the line from U, and a 5, 7, or 10 in each of A,B,C, or D--the minimum that will run the trains.  Do be aware that fuses and breakers do not open immediately upon the current exceeding their rating:  time delay depends on the percentage and duration of overload.

On my layout, where I never turn smoke on, I use 7 and 5 amp breakers.  But most all my lighted acrs are now LEDs, and I want the breakers to open ASAP on a short.  The 7 amp runs 3 trains at a time; the 5 easily runs 2.


I had the PWC ZW once upon a time. After buying it NOS, it had to go in for the metal bracket/gears repair. Then I bought a Legacy remote and mine needed literally a new chip installed to regognize the Legacy remote. I got rid of the PWC for the trusted PW original and haven't looked back since. 

Hi Everyone,

Not sure how to do this; is this a closed thread? Or can I add a new/old question to it?

Up above, BIGRAIL gave me the P/N for a metal bracket that supports the potentiometer backplate inside the PWC-ZW controller. I now need to replace the actual (vertically mounted) potentiometer backplate that screws into the metal bracket that BIGRAIL supplied the P/N for. 

I can't seem to find any parts diagram for that controller to find a part number to order from Lionel Service. Can anyone on this board help?IMG_3840

Here's a photo of the broken part; note the broken plastic under the philips screw to the left of the potentiometer shaft.

Thanks in advance!



Images (1)


Shows as being part of the pot assembly. Looks to be your broken part with the pots and wiring harness. Was $24 when it was available.

Thanks Bill!

Don't know how I failed to pull up that list...picture's worth 1000 words as the saying goes...

I did have thoughts about using super glue to secure the piece in place; epoxy sounds better. At least I don't have to add to my doorstop collection.


OK next question: are there any disassembly instructions, diagrams, or videos anywhere? 

I suppose I could just hack into it but if someone has done it before and shared the procedure, I might save myself from breaking something else along the way...


No instructions that I found. I did put the metal replacement brackets in both of mine. Go slow. Large clean well lit work surface and keep your parts organized. Mine are not PWC, I have an early production 180 watt (had gear problems) a lot of tinkering to stabilize that, and one from a couple years later. What I did find on mine, the screw holes for the screw in your broken part, those are machined in the metal replacement Lionel part. The screws in your ZW are a self tapping type. I don't know what size you need, I was able to match it from a screw cabinet at work. A well stocked hardware store should have them, however at the time (3 or 4 years ago) I was not able to find them at Menards. Also, if you have not viewed the Mike Regan tutorial on the ZW-C it is worth the 35 or so minutes it takes. https://www.youtube.com/watch?v=g5A-KFr5SS4

Interesting that Mike Regan mentions the plastic gears & brackets; guess Lionel knows they have a materials durability problem. 

I decided to tear into the transformer. After all, what could go wrong?? 

After removing the pilot light assembly (glued in place with hot melt glue) I unscrewed the two self-tapping screws you mentioned and the Pot assembly was easily lifted out for inspection. The tricky part to master was to align the teeth of each pot with the voltage markings corresponding to the A-U and B-U handles.

It's getting late here so I'll tackle the epoxy tomorrow. That's a one-way dead end. If that fails, removal requires breaking irreplaceable plastic parts....Hmmm...I think I'll sleep on this one.


Parts not available is a real sore spot for me.  I have this exact ZW.  One of my handles does not go to zero volts.  But in my case the reset button is broken.  I found the button piece of the reset button in the bottom of the styrofoam packing for the ZW and thought no big deal because I thought the only reason to use it was for a reprogram.  Then when the handle wouldn't go to zero volts, my dealer gave me the bad news about the replacement board not being available.  I was micro/miniature board repair certified years ago when I was in the Navy so I am sure I could replace the button or put something in its place but it's the point of it.  Both handles broke on mine and I don't manhandle my stuff at all.  Parts were still available at the time for that.  IMHO when you pay the kind of money we shell out for this stuff, there should parts support for more than a couple of years.

For the handle parts that are not available it might be possible to get replacements 3D printed.  I don't have a clue how to get a design done that could be printed but I've seen where this has been done for other stuff.  If you can't find the handle parts, it might be something worth looking into.


Thanks, Carl! Guess I don't know how to navigate the Lionel Support website very well. I didn't think to search 6-32930 which shows the parts explosion.

Now that I have the part # I'll email/call a number of parts places in the hopes of finding the part(s) I need.


Dug my 1999 lionel zw out that I had previously determine had a bad motherboard. Though I would test it again since that was many years ago. Plugged it in and motherboard began to smoke😀. Remembered why I purchased a mth z4000. My postwar celebration zw was nothing but trouble. Also had the handle gear problems early on. Funny thing is on my current layout I am using 2 kws ,1 r and 1rw. The olds ones just keep on working

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