A decoder for KAto DD51 7002-2

[herve37]

Hi

Has anyone tried to install a decoder in a DD51 kato 7002-2?

There is absolutely nothing inside, except the lights which are bulbs.

I have bought this diesel loco believing that there was just to drop in a digitrax decoder . But after having opened the shell, surprise! :hmh:

How to install a decoder like Dn 136 without burning it because there is no isolation.

I think that the power is captured through the weels and transmitted to the motor through the two halph frame ( see picture)

Some help will be very nice

Herve

 

 

[Marcin]

No problem ;) Lenz mini.

[kvp]

First, you have to isolate the motor by insulating the brushes (possibly milling out the half frames around them) and adding two wires to the brushes. Then you have to take track power from one of the light panels with another two wires. Finally you have to remove the bulbs and their diodes and add two leds with each ground pin of the leds connected to the decoder's light output and the power pin connected to the decoder's common power out through a current limiting resistor.

 

If you use a small 7 wire decoder (track x2, motor x2, light x2, +light power) from digitrax, then you can hide the decoder in the cab and just solder each wire to its place. You have to split the light power to both ends with an Y cable or route an extra wire from one end to the other. I would try to modify the light boards to securely hold one led and its resistor by cutting traces, desoldering the old parts and rigging the setup above onto the board. The 7 wire decoder is your best bet if there is no 6 pin socket or there is no main board. Reusing the light boards allows you to avoid soldering to the two frames, so you only have to get two wire connections onto the motor brushes and everything else can be done on the two small light boards.

[kvp]

One more bit of info on the 7 wire DCC decoders:

Orange: Motor right

Grey: Motor left

Red: Right rail (or frame right)

Black: Left rail (or frame left)

White: Front headlight

Yellow: Rear headlight

Blue: Headlight common

 

[herve37]

Thank you so much you two for your answers and advices.

KVP, your explanations are accurate and very helpful. Thanks a lot

[kvp]

You're welcome!

 

ps: for milling out the frame around the motor brushes, a small file might work too and afterwards some duct tape to securely insulate the brush+wire assemblies from the metal half frames