A Complete Tear-Down of Lionel ZW Transformer

Dennis,

Perfect timing!  I just got a box of postwar trains from friends of ours, who were downsizing.  In the box was set 2171W and a ZW. The ZW is the early 275 watt version with small name plate on top.  I quickly popped the top off and one of the rollers is practically gone.  I plan to do a complete service of the unit same as you.  I just ordered a ZW repair kit which includes rollers, new 15 amp breaker, stud diodes, and power cord.  Good luck on the rebuild.

Joe

Very interesting.  You chose the 16 amp diode.  I bought a reconditioned ZW and the guy pointed out he used the 40 amp diode. Was that overkill?  BTW, the whistle on it works very, very well.

I think a 16A diode is more than sufficient, if you're locomotive is drawing even close to that kind of current, something is drastically wrong.  Remember, you wouldn't be using the whistle unless you were running a train in conventional mode.

@Joe Fermani posted:

Dennis,

Perfect timing!  I just got a box of postwar trains from friends of ours, who were downsizing.  In the box was set 2171W and a ZW. The ZW is the early 275 watt version with small name plate on top.  I quickly popped the top off and one of the rollers is practically gone.  I plan to do a complete service of the unit same as you.  I just ordered a ZW repair kit which includes rollers, new 15 amp breaker, stud diodes, and power cord.  Good luck on the rebuild.

Joe

Joe: What is this ZW Repair kit you referred to and where did you purchase it? I have two ZW’s one a 275 and a 250 both showing and acting their age.

Several Forum sponsors have the parts, as well - The Train Tender, Brasseurs, etc.  Perhaps not a kit, but parts can be ordered piecemeal.

A couple of steps today.

I decided to have another go at the cover and that residue.  I used a heavier grit polish and was able to remove most of it and I think it looks better. 

I also cleaned a few of the parts for the left handle with a vinegar and water solution.  Here's a before and after shot.

Gosh, that worked really well... 👍

Mark in Oregon

Dennis, you’ve gone above and beyond the call of duty. That ZW will be brand new when finished. Can’t wait to see it finished.

A little progress with the handle components:

But first, to give credit where credit is due, I am following to rebuild job that I found on YouTube by a fellow who goes by TheCreativeMind.  He shows the process that I am completing and my steps mimic much of what he did.

First, I have to label wires lest I forget what goes where !

I got a little ahead of myself with the stud diode.  That will come out and go back in during the rebuild.

A 'before cleaning' and 'after cleaning' picture of the components:

Thanks for the comments and for checking in!

I did a complete rebuild of my two zw’s last winter. Noticed you drilled out the center rivet of the whistle/direction assembly. I did the same but used a machined part from PE Design and Manufacturing instead of retaping the old rivet. It is called a "ZW-74 Switch Rivet" sold as a pair. I picked them up at York, but they can be bought on line. I think it was around $20.00, but since I didn’t have the tools to re-tap the original, it made sense for me.

Also picked up a “Universal Mini Press” to crimp the roller pins. This is not a cheap solution, but it made the rebuild easier with very good results.

Robert,

I have a pair of rivets for the whistle/direction assembly.  Not sure if I am going to use them or drill-and-tap.  I do not want that screw to loosen over time.  I cam press the rivet on with the arbor press.  I have a pair of parallel jaw pliers that work well for pressing roller pins.

I had to "repress" a couple of the soldering lugs on the whistle/direction assembly.  One had completely broken loose (I believe it was channel A, one of the offending channels in the first place).  A couple others simply spun around but had not become disconnected.  The Hobby Horse press sure made that job doable!

Did you replace the resistor wire and 6-volt lamp with an 18-volt bulb?  If so, what wire gauge did you replace the resistor wire with?

Dennis

Dennis

Where did you need the ZW-81 tube insulation gasket?

just curious!

Alan,

It goes between the rectifier frame and the contact spring insulation.  This ZW was missing BOTH of the tube insulation pieces.  I find the name "tube insulation" misleading !  It looks nothing like a tube.

Thanks a bunch for cutting them for me,

Dennis

Dennis,

I did not change to an 18 volt bulb.

Some parts arrived today and I made some progress on reassembly.  There were 3 parts in the rebuild that were completely missing from this transformer: the tube insulation (ZW-81) on each side, a bushing (ZW-157) on each handle spindle and a spacer (ZW-166) between the contact plate and contact springs on each side.  Maybe they made them without those parts back in the late 40's and they are part of the reissue of the 275 watt ZW.

\

We're getting closer!!!

Dennis

Fantastic work!

Hi Dennis,

When you serviced the whistle/direction control, did you put any conductive grease where the contacts slide?  I am rebuilding my ZW and I am up to taking that apart to clean and service the contacts.  I saw one video where a guy put a dab of grease on all the contacts.

Also learned that a simple solution of lemon juice and table salt are a great cleaner for the metals parts.  It has completely restore the arms for the rollers to shiny condition.  Looks brand new!

Joe

I am happy to report that the 250 watt ZW is back together and functioning well!  Whistles like a champ!  The only thing I am not happy with is the 15 amp resettable circuit protection.  It does not trip and reset as quickly as I hoped.  In fact, it is very difficult to trip period!  I am thinking of using a 5 amp resettable circuit breaker similar to the ones we use between the exterior of the transformer and the track.

It has been a journey that I look forward to repeating again.  Our club has twelve ZW's that need cleaning, refurbishing, etc.

Joe, I am sorry I did not see your post.  I did not put any conductive grease on the contacts.  I just scrub them with vinegar and salt and polished them with some ultra fine sandpaper.