PWC or Modern ZW Controller chip replacement for

 Legacy Operations

from the Legacy Users Gathering Fall 2008

This procedure is only needed in cases were the ZW exhibits a shutdown similar to a “HALT” command being issued.  This is a ZW issue which Legacy exposed.  TMCC1 operations did not expose this issue.  If you are using the ZW controller and are not experiencing this issue then no change is needed.  I found this issue and thanks to the great folks at Lionel they came up with a solution.


It must be stressed that if you do not feel comfortable with opening up and working on your ZW, then please take it to a local service center.  This procedure is done at your own risk.


The procedure involves opening up the controller, removing and replacing the chip in location U2.  These directions should give you an idea how this is done.  The chip I received from Lionel was marked ZWPC S01.HEX.  Contact Lionel service for the chip or in some cases they have sent out a whole new circuit board.



Starting with the ZW controller, make sure it is disconnected from all power before beginning. The knurled nuts have already been removed and put in a safe place.  The tools I used for this repair included an 11/32 nut driver, a medium sized Phillips screwdriver, a small Flathead screwdriver and a small pair of needle nose pliers.  An ESD wrist strap is also recommended any time you work on electronics. It is very important to have a clean, well-lit area to work in.  I would also recommend a small container to hold the hardware that is removed for safekeeping.


Using the Phillips screwdriver, remove the 4 screws on the top cover and set them aside.  Carefully remove the cover and place it out of harms way.  The circuit board is held in place by the terminals and supported by plastic retainers that hold the heat sink panels in place.

 This view is from the front of the controller and shows the heat sink supports and antenna.  The circuit board is in the background and the chip is visible just below the connectors.

Click on image for larger version.

It will be tight but you should be able to carefully remove the old chip.  The picture to the left shows the proper orientation of the chip.  Make sure when re-installing the replacement, the pins are properly lined up and the key (marked by the red arrow) matches the outline on the circuit board.  Once lined up carefully push the chip in the socket paying attention that no pins bend or miss. 


Click on image for larger version.


Once the chip is in and you have confirmed it is properly seated you can re-install the top.  Carefully put the cover back on making sure the direction/whistle and bell buttons line up with their respective holes.  It should seat completely onto the bottom case.  You may have to align the uprights a little to get the screws in. 

This pretty much covers the chip replacement.  Be sure to take your time and check your work.  Make sure your new chip is oriented correctly.  Reconnect the ZW to your layout and you should be good to go.


It’s not a hard project and should take at most 15 minutes if you really take your time.  No soldering is needed and just some basic mechanical skills are required.  In reality you could take this to your local service center or Lionel but I think it’s something that most folks can handle especially with some direction. 


That being said, I cannot stress this enough…


If you are NOT comfortable with this procedure let a service center or Lionel do the work.  

Lionel is not responsible for anything contained in this hand out.  

Lionel or I assume no responsibility for any damage that results.  All work is done at your own risk.