ZW 275 W with Legacy

@Piedmont Central RR posted:

I have a classic ZW 275 W running two independent tracks (AU and DU). Both tracks have a common wire to the Legacy system and Legacy locos work fine. The main line (AU) has a separate connection from the track for the Legacy, while the other track (DU) I spliced another wire to the common wire to connect to the Legacy base.

The issue is when I try to run my post war Lionel locomotives. I didn't really notice before, but if I power up AU track, DU track is also getting power as well so I can't control conventional locos independently (same viseversa). If I remove the Legacy connection, everything works fine, so the issue has to be with both tracks connected to the common Legacy base.

Barring having to remove Legacy base connection every time I want to run conventional independently on both tracks, is there another fix?

No, simple answer- correct your wiring. Clearly you have something messed up.

I'm being dead serious about this- common U goes to outside rail of both tracks right?

U is supposed to be 100%common inside the ZW- that said, it's not unheard of for the old original posts sort of riveted or staked into the common U bus bar to come loose inside the ZW. Again, a known fault and or rebuild/repair thing is replacing failing U posts on a ZW https://ogrforum.com/...ad-posts-bad-rollers

A and D should go to center rail of respective center rail of your loop tracks.

The base is simply connected to U common- and being common well, it's all common. So the base should have nothing to do with it.

Although I'm not certain how anything with the Legacy would work if I had wired it wrong so that the middle rail was connected to it, but I doubled checked everything and yes, all wires are connected to the correct rails. I'm also curious how the issue with power crossover between the independent tracks is corrected if I disconnect the common wires from the Legacy if, in fact, the Legacy base has nothing to do with it.

Perhaps the issue is with the ZW transformer. I recently had it serviced but I may have him look at it again.

Also, your diagram does not illustrate what my question is asking. I have a second connection from the AU to the Legacy for that block. Again, two separate blocks are connected to one Legacy base. Maybe that is the issue? I have not tried to take one common away and see if it will still control both blocks.

@Piedmont Central RR posted:

Also, your diagram does not illustrate what my question is asking. I have a second connection from the AU to the Legacy for that block. Again, two separate blocks are connected to one Legacy base. Maybe that is the issue? I have not tried to take one common away and see if it will still control both blocks.

OK but......... The reason I'm saying we have a bigger problem- a second connection from the base to the other track SHOULD BE on the COMMON that is already COMMON. That wire should just be in parallel and completely unneeded, but even more so redundant- so removing or adding it should not change the end result.

In other words, if the wire is shorting out and connecting the 2 outputs- either

you are not connecting it to common "U" post,

or the common bus bar in the transformer is open,

or your track is not properly connected and isolated.

Again, let's go over the diagram- You should ONLY need one connection from the base to COMMON- aka "U" of the ZW.

By doing that, then ALL "U" are in common, and thus all track (both independent tracks) are common on U and thus connected to the base.

Again, the facts:

Your transformer should be common between all U posts.

Thus all outer rail would show continuity or connection and by connecting the base to any U post, thus everything is all common.

You can add a wire and double up on different U posts- this should not and does not change the circuit. If it does change the circuit, this indicates that U post was isolated and broken internally or other problems.

A and D are the independent variable "hot" terminals compared to common U. They get connected to center rail of each loop or track and then the tracks at any switch connecting the two tracks or loops should have isolation (a fiber pin, plastic pin, or isolation gap or cut).

Ok. That is very helpful information about the U posts and explains the term common. My repair guy freely admits he does not do modern electronics but he does great work on the post war stuff. Either way, he thought the Legacy was the issue but I don't think he understands Legacy well. I will play more when I get home. Is it possible for the A and D posts to he somehow connected within the transformer?

Does the problem exist only when the Legacy base is powered up?

..or does the problem exist only when the Legacy common wire is connected regardless of whether the base is powered or not?

Also, try powering up only one handle - either A or D and see if Legacy works on both loops. If it does then A and D terminals are connected internally. If Legacy only works on the handle that is powered up, the answer is elsewhere.

If the problem occurs only when the Legacy base is powered up, it would indicate that the problem is in the Legacy unit. How any problem in the base could result in connecting hots would be a real mystery!!

If the problem occurs when the Legacy ground wire is connected regardless of the base being powered or not, then it would seem the ZW might be suspect.

A couple more basic questions just to be sure. Are the loops totally unconnected to each other or are they connected by switches and insulated from each other by plastic rail joiners?

Do the A and D terminals power anything else on the layout such as lights, accessories etc.?

Ruling out any of the above possibilities and if the problem occurs when the base is unpowered, I think the thing to do is to open up the ZW and check the wiring.

Check to see if all terminals are staked to the binding posts as they would be if all original. If any of the terminals have been serviced and replaced in the past, they will have nuts on the inside holding the wires and binding posts in place. Check that the ground bus bar connecting all the U's is in place and securely connected.

Check also for soldered posts and wires, a quick but less reliable repair job perhaps indicating sloppy servicing in the past and a clue that something may have been miswired during a past service job.

Jim

Fixed.

I'm a little floored, but Vernon guided me to the answer.

I disconnected my Legacy base from both blocks (which are not connected, one on table and other is elevated). Tested both blocks and both worked perfectly with conventional locos. No shared power at all just as I had indicated.

So now I reconnect just one block (the table) to the Legacy as Vernon's diagram showed. I power up that portion of ZW and that block powers up and the elevated track does not light up (passenger cars). I test the conventional loco on the elevated track to be sure and it worked fine. Legacy loco on the table works fine, too.

Now I put a Legacy loco on the elevated track to test it thinking "how is this going to work??? According to Vernon it should, though" I grab the remote, hit the ID number, hit power-up and...bam, it turned on! Everything now works exactly right with no power sharing.

Problem solved. Thank you.

@Piedmont Central RR posted:

Fixed.

I'm a little floored, but Vernon guided me to the answer.

I disconnected my Legacy base from both blocks (which are not connected, one on table and other is elevated). Tested both blocks and both worked perfectly with conventional locos. No shared power at all just as I had indicated.

So now I reconnect just one block (the table) to the Legacy as Vernon's diagram showed. I power up that portion of ZW and that block powers up and the elevated track does not light up (passenger cars). I test the conventional loco on the elevated track to be sure and it worked fine. Legacy loco on the table works fine, too.

Now I put a Legacy loco on the elevated track to test it thinking "how is this going to work??? According to Vernon it should, though" I grab the remote, hit the ID number, hit power-up and...bam, it turned on! Everything now works exactly right with no power sharing.

Problem solved. Thank you.

The TMCC/Legacy radio signal makes its way through the transformer to both loops even though there's only one wire connected anywhere from the Legacy base.

If it helps you to understand it a little better, connect that wire to the 'U' post on the ZW instead of anywhere else on the layout (like perhaps presently the outside rail of one of the loops?).

Many thanks to Vernon for the clear and precise guidance, as usual.

Mike

Glad to hear that you solved the problem.

Still not sure why the extra ground wire to the Legacy base in your original setup caused the problem, but I've stopped being amazed by the marvels of modern electronics!!

Jim

I'm with you, Jim. If I understood Vernon correctly it was redundant and shouldn't matter, but it clearly did. There may be an issue in the fastrak that only shows up in that situation, but I'm happy it's fixed.