RECONDITIONING AND UPGRADING A ZW TRANSFORMER

Jim, a very professional refurb

Jim,

Nice post. I'm curious what steps you take to refurbish coils.

Thanks,

Jim

I love "poof" tests! (It makes that "pooof" and then smokes better than an MTH)

How did it fare?

Also, I agree! Despite the lack of electronics, some things were designed to withstand a nuclear blast back then.

Honestly Jim, I have yet to run into a bad coil, either primary or secondary.  If I suspected the coil I wouldn't buy the unit to refurbish.  If I got stuck with one I would look at the easy fix items, but as far as a rewind, no way.  If I was getting voltage at the power cord connection with good solder connections but no voltage output, I would be sure the CB wasn't stuck open and all the wiring to and from the CB was intact.  If the CB and wiring looked good, I would check all the leads out of the secondary winding and if they all looked good and still no voltage output, I would junk the core and either use the remainder for parts parts or maybe run into a new core down the road.

You are correct that with a hard wired short, even if the CB trips very quickly you get a puff of smoke and a "poof" sound.  It is even more evident with the cover removed.  The one in the picture tripped in about two seconds and after resetting with the short still there tripped almost immediately with very little smoke and no poof.

Incidentally, in all my rebuilds, I normally find the ZW CB's in good working order including the ones mounted on the transformer support plate and the original black box shaped one mounted in the corner of the base.  The latter one was originally used as a CB in WWII aircraft, used somewhere in the dash panel.  I have yet to find one of those that didn't work well, and thank goodness as they would be a bummer to change out.

I find about half of the KW CB's defective.

Jim

How do you remove the binding posts for repair when they separate from the bus bar.

Greg

What diodes do you use and where do you get them?     Lenny J

Nice thorough job of reconditioning for top to bottom.  For a complete job, you are the man and I'm sure that you have many happy customers.

For those hobbyists that just want to upgrade by just replacing the diodes with the solid state type, you can do this without removing the lamp bracket. I won't hijack the thread by explaining the process but its not hard to do.

Lenny: The diodes used are 16-20 amp stud diodes with anode to screw-case /cathode to solder terminal orientation. Any rated voltage over 100V will work. Do a search for ZW replacement diodes on eBay and you will find them. About $10/pr shipped.

Some talented folks, like Jim, on this forum when it comes to bringing these classic Lionel gems "back to life." I've purchased a few ZWs from folks here on the forum and have found the work to be top notch.

What is the best way to polish the bakelite case?

Hi Greg,

With a pair of pliers.  I turn the post nut down tight to give me a larger holding surface and wiggle and pull and they come right out.

Jim

I use 40 amp, 600 volt and buy them in bulk from All Electronics

If someone wanted a diode upgrade only, I would not remove the lamp bracket either.  I only do it on a total recondition to check the inner contact assemblies on the B and C circuits and clean and lub them.  While the bracket is off it does make installing the diodes easier.  Installing diodes only without removing the bracket is about a 10 minute operation with the smaller diodes but a bit more with the larger 40 amp units I use.  

Please share your method with all of us as it certainly would not be hijacking this thread.  It would be a service to the members.

Jim

Hi Dale,

The ZW cases were molded out of Union Carbide Bakelite.  The black compound had a high carbon black content that gave it its color and made it very resistant to the big enemy of plastic, ultra violet exposure and it is a very strong material.  Keep in mind the ZW's can range in age from about 50 years to 70 years.  Over time the surface of the Bakelite can oxidize.  The amount of oxidation depends on many factors but mainly to daylight exposure and heat.  If a ZW sits on a layout for years (daylight exposure) and when in use is running three trains and powering many accessories (heat) it will show more oxidation than one that spends the majority of its life stored away.  That is why many ZW's have that dull, marbled look.  I have tried auto rubbing compound, fiberglass jel-coat polish, Armor Al and granted these things do clean the surface but don't bring back that original shine.  Be assured it is only cosmetic and the case will last for sure another 70 years.  

The A and D handles were molded of low density polyethylene until the mid 50's then switched to high density polyethylene.  These products maintain their shine better but are not a strong as Bakelite.

Jim 

 I run my layout with two old "refurbished" ZWs.  I hope the dudes that refurbished mine did half as good a job as you do.  Now I know who to send mine to if I want them gone over again.

.....

Dennis

Jim, have you tried using Simichrome Polish? I have not used it on a ZW, but have had good results on similar surfaces.

No, but I have a case I can try it on so I will buy some the weekend, try it out and report back.  Thanks for the recommendation.

Jim

Jim:

You do great and careful work.  Thank you for posting this and sharing.

Hope all is well with you and the Mrs.

John

I want to upgrade my ZW to diodes. I don't follow ebay at all, is there another source for diodes? Say like mouser electronics? I would rather buy the diodes brand new then from ebay.

Lee Fritz

You can buy diodes from Digikey or Mouser.  They're common silicon diodes.

Here's a search on Digikey, the top two are a standard and a reverse polarity.  One may be a better fit as far as polarity.

http://www.digikey.com/product...id=0&pageSize=25

John,

Which one would work best with the 275 watt post war ZW?

I am not that good with electronics but know about AC & DC voltages pretty well.

Lee Fritz

Here's a diode that Boxcar Bill recommended in the past, cheaper than the Digikey diodes.  I'm assuming since he recommended it, it was the correct polarity for the job.

http://www.allelectronics.com/...olt-rectifier/1.html

Lee and John, this is the one I use and it was also based on Boxcar Bill's recommendation.

Jim

Thanks Jim, I haven't actually done the ZW diode upgrade yet, so I didn't want to mislead anyone.

Thats funny, considering thats the Diode I turned Boxcar Bill onto.....

Been using them for years, no issues....

Why is it funny?  I didn't say it was an original idea, only that it's where I heard it was compatible.

Hi

I done the upgrade on KW and ZW. I have used the allelectronics ones and they did work but I really did not get sound very loud.  I did not use the Digikey so I can not comment that part Zenor diode. However the one I used was the Newark and works great but it is expensive.  http://www.newark.com/solid-st...Id=&categoryName=

Boy, I have two VW transformers sitting on my workbench, waiting for me to turn my attention to them. They both need a good cleaning, and one needs to have all of its common terminals replaced. Plus I've recently acquired a couple additional ZW transformers.
I am tempted to send out the VW's, I am just not up for doing them right now.

Thanks Jim.

Greg

I've used lemon pledge with pretty good results.

 Could you buff lightly with schotch brite pad then clear coat?

quote:

Could you buff lightly with schotch brite pad then clear coat?

IMHO, you'd wind up with a very scratched up case.

There are specific products on the market for polishing up plastics. I've heard that radio collectors use them. I purchased a set from a pinball machine supply house . It is called Novus. The product does remove scratches, and will polish plastic, but unless you do the whole thing, it looks funny. Then there is always the problem of polishing around molded in details, and in corners and cervasses.

I have tried Novus on some Lionel plastic freight car bodies. I have not tried it on a transformer. (Novus comes in 3 grades, and can be a multi-step process, be certain to follow their directions).

I have cleaned various Lionel and American Flyer transformer cases by washing them with very hot water and dish washing soap. Once the case is completely dry, if necessary, it is polished with Johnsons Paste Wax. I also use Johnsons to polish my pinball machine's playfield. I have been using the same can I purchased around thirty years ago, and there is still plenty left.

quote:

I done the upgrade on KW and ZW. I have used the allelectronics ones and they did work but I really did not get sound very loud.  I did not use the Digikey so I can not comment that part Zenor diode. However the one I used was the Newark and works great but it is expensive.  http://www.newark.com/solid-st...Id=&categoryName=

Using heavy duty Zener diodes has been discussed from time to time here. Did you leave the resistor in the whistle control circuit connected? There was some past comments about that.

 John,

Would that diode also work in a KW? I have one that needs the whistle electronics replaced also. If so I will buy 4 of them.

Lee Fritz

Should be exactly the same for the KW, it'll work fine.

As far as polishing Bakelite, I think any abrasive will ruin it for a shiny surface.  Bakelite is not standard plastic, once it's molded the surface has a smooth finish, but if you remove the surface you get a grainy finish.  I know of no way to fix that.

Try polishing an old O22 switch control case or switch motor housing first, you'll see what I mean.  Once you rough up the finish, it stays rough.

The late Al Rucchio wrote an article for I believe LCCA.  In it he described how he cleaned and shined ZW cases.  He used two chemicals, one was Linseed Oil, but for the life of me I can't remember what the second item was.  This was many years ago.  The other might have been some sort of mild paint thinner.

That sounds like the only route that will yield a decent result.

There are tons of pages on cleaning Bakelite, none of them suggest abrasives, which would destroy the finish.  Take your pick of cleaning methods...

How To Clean Bakelite

I have done this method on plastic fenders on a ATVs, bug shields, lexan and such with perfect results no scratches at all  eh

Gentlemen,

    Jim does great upgrade and refurbish work, no doubt about it.  I own a couple of them myself.  I then upgraded them some more with Banana Plugs, his upgraded transformers work better than brand spanking new.

PCRR/Dave