ZW Rescue Needed

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ZW Rescue Needed
Posted by Anonymous on Monday, June 5, 2006 12:10 AM
I 've just installed a second ZW on my layout to power 2 of the six "districts"(each with its own Powerhouse). The ZW operates fine in conventional mode, but when it's connected to the layout in TMCC mode, there is zero voltage on the A and D terminals, 7.5 on B and 14 on D. When connected this way, each ZW common ground is connected to the TMCC command base, as per the manual.

I had a similar problem when first installing with the first ZW, but foolishly did not document it, and now I can't recall the solution. I think it was to reprogram the ZW via CAB-1 by entering SET, TR, and 0, but I'm not at all sure if this is right. Ordinarly, I'd fiddle with it myself if I didn't fear completely unprogramming it beyond salvation.

Has anyone had this problem, and if so, could you please remind me what it takes to get the ZW powering the A and D channels in TMCC mode?

Thanks in advance for your help.

Bob W.
Houston, TX
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  • From: Fremont, CA, USA
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Posted by macdannyk1 on Monday, June 5, 2006 1:06 AM
From the ZW Instruction manual: (Found online at

To control your ZW Controller transformer by remote control, each pair of output terminals must have a unique track (TR) ID#. The four terminal pairs have been assigned track (TR) ID#s 1-4 respectively. The ID#s are automatically assigned in sequential order when you assign the “A-U” pair. For example, if you program “A-U” as ID# 2, “B-U” will become ID# 3; “C-U” will become ID# 4; and “D-U” will become ID# 5.
To assign the output ID#’s, use the special T-shaped tool (included) or any other non-
metallic tool to press the PROGRAM button on the back of the ZW Controller. Refer to Figure 7 for the location of this button. The red light will begin to flash. On the CAB-1 Remote Controller, press TR, enter the first ID# (1-6), and press SET. At this point, all four ID#’s have been assigned.

So, since from what you've stated in your message, your first ZW is set for ID's 1 - 4, so you would then power up your command base, then power up your 2nd ZW, hit the button in the back, and TR, 5, and SET. Then your 2nd ZW would have ID's of 5,6,7 and 8

Dan Member and Webmaster, Golden State TTOS
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Posted by Anonymous on Monday, June 5, 2006 11:21 AM
Dan --

Many, many thanks for the guidance. I really appreciate your time to educate me.

In my search for an answer, I read and re-read the ZW and Powerhouse manuals, and remember well the passage you noted. However, I had no idea of its significance.

Lionel might consider revising the manual to make it more friendly for people like me, who apparently have just enough knowledge to be dangerous!

A quick follow up question now that you've educated me: I can understand why the A and D terminals were not getting voltage (no assignment of track numbers), but why didn't the B and C terminals also show zero voltage? They were getting 7 and 14 volts respectively.

Would it have something to do with the fact that on the 2nd ZW there were only 2 PowerHouses?

My sincere thanks again, Dan.

Bob Westbrook

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