Thomas gets a decoder!

[jward]

as promised a while back, here is my pictorial on installing a decoder in thomas.

the decoder i chose was a digitrax dz125, a z scale decoder with enough current capacity for HO locomotives. there isn't alot of room inside thomas for a decoder, and this one is one of the smallest on the market.



first, turn thomas over on his side. remove the 4 screws the red lines point to. two are in thomas's chassis under the cab. the other two sit on the gearbox cover between the drive wheels.



remove the drive wheels from the chassis to uncover another screw which holds thomas's boiler to the chassis. remove it as well.




remove the chassis from the boiler. inside the boiler are two screws, marked in red in the photo, that hold the motor inside the boiler. remove these and the motor too.





fully disassembled, thomas is dcc ready. the two motor leads, orange and brown, are isolated from the wheels, red and black leads. by the circuit board. unsolder the board and discard it.





thomas, with the circuit board removed. the dz125 decoder sits in the foreground. its size is perfect for thomas.




connect the decoder wires to thomas's wires. red to red, black to black, orange to orange, the only mismatched colours should be the grey decoder wire connected to the brown motor lead. i used short pieces of heat shrink inserted each of thomas's leads before the wire connections were made.

solder the wire connections together and fold back the bare wires along the insulated wires.




slip the heat shrink tubing over the wire connections and heat them with the soldering iron until they shrink around the connections. trim the bare wire ends off the decoder's white, yellow and blue leads. these will be unused.  tuck the decoder into thomas's coal bunker, and the excess wires into thomas's cab. reassemble thomas, taking care  when installing the motor. inside the boiler there is a little pin which moves thomas's eyes, this must be aligned into a slot in the motor housing or the motor won't seat properly.

everything will go back together the same way you took it apart, except that the original circuit board and the two screws which held it in place will be discarded. take extra care to make sure the two screws between the drive wheels are tightened until snug, or else thomas will slip his gears.  test run thomas, then reprogram the address and anything else you want. the dz125 has back emf, a sort of cruise control for model trains. by programming this and cv2 (start voltage) you can make thomas run much smoother than he ever did on dc.....

[DinoNTrains]

Very cool, and nicely done!

[Anthony P2]

My Thomas and Percy will be DCC-ed a year this month! only i used the digitrax DH123 decoder and had enough room. i thought it was pretty easy.

[jward]

it was a pretty easy install. i had thought of using a dh123, but the z scale decoder was smaller and had back emf. the dh123 lists for $19.99, the dz125 for $24.99.

if you want to see how difficult a dcc install can be, try a bachmann b23-7......i am still working on that one.

[andrewd]

what about for an older Thomas like a Thomas that was got in 2010 what then

[jward]

this one was purchased in 2009, and is identical to one purchased in 2005.

[Fergusfan17]

Where can I get one of the controllers that control the kind of decoders that fit in the engines?

[jward]

any dcc controller will work.   the standards are such that decoders and controllers are universal. any decent hobby shop should have them. if not, try ebay.

[andrewd]

what a bout a Thomas that needed its moater fixed what then do I do oh and my Thomas is really banged up and I'm actually afraid to open him up as he might just fall completely apart what then