Tomix DE10 DCC Pt 1: Disassembly

It’s a shame that Kato only manufactures a DE10 in H0 scale. The Tomix model that I have (part number 2208) is not a brilliant runner; moreover, it is a notoriously difficult DCC conversion. This article series is all about how to convert a Tomix DE10 to DCC. And I’ll say this now: It’s not so hard as it might seem. Tedious, yes; difficult, no.

Prior to even purchasing the model, I did an extensive Google search to find out what people’s experience converting this model to DCC have been. I was only able to find one person who’d documented their conversion online, here (Japanese language). The pictures say quite a lot. He located the decoder in the place of one of the light boards (see below), thus losing one set of headlights. While this made the installation easier, no doubt, losing a set of headlights is not an acceptable outcome for me.

Anyway, it turns out that simply disassembling the DE10 is difficult enough; I’ll just start with that, and turn to planning the decoder install in the next post.

For this project, I chose the Digitrax DZ125 decoder, as it is both incredibly tiny, and incorporates a number of features that I wanted. Lenz also makes some of the smallest decoders on the market, and so would be a suitable choice for this project.

Here we see the model itself, awaiting mutilation. Although it has a reputation for being a poor runner and hard to convert to DCC, it sure is a pretty and well-detailed model. The model has working headlights (but no tail-lights or running lights), and unusual couplers: Rapido couplers that lift up when over a magnetic uncoupling device! While really cool, this means that a future Micro-Trains coupler conversion may be very difficult indeed.

The fuel tank (at least, that’s what I presume this part is!) is removed by squeezing the sides gently, and pulling it off.

Next, remove the trucks by again lightly squeezing while gently pulling first the left side then the right. (Or the right then the left, doesn’t matter. Lateral rotation is what’s important.)

This is the most difficult part of disassembly. Moving from upper left to lower left, to upper and lower right, use a tool like a spudger or a toothpick to gently press these six tabs in. The tabs are very tightly fitted, and require just a little force. Moreover, they must come straight out: The last two will be a problem because they won’t come out with the bottom shell at a severe angle to the frame. Also, be very careful not to break any hand-rails, like I did. Oops. Thankfully it wasn’t anything that a tiny touch of superglue couldn’t fix, but an incident like that is enough to make your heart skip a beat!

Here is the top and bottom shell (finally!) apart. You can see the metal frame nestled inside the top shell.

The frame just slides right out of the top shell. We can now see why DCC conversion is so difficult: There isn’t a milliliter of spare room anywhere!

Remove the two light boards, remembering that the one with the capacitor goes on the short-nose end, and that the bulbs face down. If there’s any easy-to-access room in this shell, it’s where these fit. Indeed, with only minimal cutting, the DZ125 could easily fit in place of one of the lightboards. But we’re not giving up one of the headlights just for an easier install!

Split the frame. The drive shaft guides will want to stick to one or the other half, but just use the spudger or toothpick to keep the guides and motor in one half of the frame. The locomotive is of a standard split-frame design. There are small brass pickups in the bottom of the frame that make contact with the trucks; power is transmitted through the frame to the motor and the lightboards. This means that, however we settle on doing things, we must isolate the motor and the lightboards from the frame. However, the brass contacts at the bottom mean we don’t have to solder the decoder’s power pickups directly to the frame, which is good news at least!

Simply pry the drive shaft guides from the half of the frame they’re stuck in; a toothpick of spudger will again be of help. The drive shaft is actually a spring, which has been pulled apart at the ends to form a sort of worm gear. This obviates the need for universal joints along the shaft, and makes for a very simple and reliable, if incredibly noisy, power transmission system. At this stage, you might gather up any loose globs of lubricant off the frame halves and stuff them back in the drive shaft guides.

Finally, use a pair of tweezers to remove the brass pickups in the bottom of each frame half.

When reassembling, if there’s any doubt about which way a part faces, most have arrows on them. Just make sure all the arrows are facing the same direction (towards, as it happens, the long nose of the locomotive).

In the next post, we’ll form a plan for locating the decoder and routing the wires. There really isn’t much room at all! But there is room, and we’ll get to it.

Continue to Part 2 of 3 of this article.