MTL F7A questions

Hi!

I am trying to put a decoder in a MTL F7A unit but I am struggling with how to isolate the engine.
Does anyone have any hints and tips for me how to do this and if anyone knows where I might find
the schematics for the loco I'd be most obliged.

Petter

You might contact Glen Chenier. He is an expert on the MTL F7 and installs decoders in them. His email is This email address is being protected from spambots. You need JavaScript enabled to view it..

John

hokenstrom wrote:

Hi!

I am trying to put a decoder in a MTL F7A unit but I am struggling with how to isolate the engine.
Does anyone have any hints and tips for me how to do this and if anyone knows where I might find
the schematics for the loco I'd be most obliged.

Petter

I've recently had cause to disassemble 2 F7. Although the locos in question had been seriously mucked about it appears that the motor mounts are designed to keep the motor isolated from the chassis halfs. Power pickup is achieved by 2 copper tabs which are held in place by the brass brush bushes (Try saying that after a couple of drinks).
These press against the chassis halfs when the chassis is assembled and transmit the power to the motor which is held off the chassis by the plastic motor mounts.
as far as I can tell to isolate the motor is simple a matter of clipping or moving the copper tabs so they dont touch the chassis. To be on the safe side you could insulate the area around the motor using nail varnish or rubber solution glue or an old trick of gluing tissue paper to the chassis surfaces.
What may prove a bigger issue is the amount of space available for the decoder. There is very little of the chassis structure that can be removed with severely compromising the strength and weight of the chassis. If you remove any of the fuel tank be sure to leave a piece connecting the chassis ends or you'll break the back of the loco. HTH

hehe...
I feel like a complete newbie (btw...I am a newbie...)

When I opened the loco I saw exactly what you wrote - that it will be rather an easy task to isolate the engine.
The problem will be carving out space for the decoder and the wires. I am thinking of removing some weight around the rear condensatorthingy instead of the fueltank - looks easier.

What is that condensator/resistancethingy thing by the way?

Petter, I dont have a F7, but from the conversions I seen, they milled the front of the chassis. Maybe theres more room in the front. Also, if you choose a smaller decoder like the TCS z2 will require less milling.

hokenstrom wrote:

Hi!

I am trying to put a decoder in a MTL F7A unit but I am struggling with how to isolate the engine.
Does anyone have any hints and tips for me how to do this and if anyone knows where I might find
the schematics for the loco I'd be most obliged.

Petter

I find the Kapton tape very good for using on the frame to isloated the brass pickup tabs from the motor to the shell. It is available from TCS I used the TCS Z2 decoder and used the plastic capacitor holder at the rear of the locomotive as my track power source and used the space the capacitor used to occupy as the location for the decoder and place Kapton tape over rear of the two chassis halves to isolate the decoder from the chassis. I used the gap between the chassis halves to route the motor wires to the motor cavity to connect to the pickup tabs. I used one of Glen's light modules to provide mars lite and headlight for the engine. The TCS Z2 has only 2 functions for lights but it does do the job.

cheerz Garth

hokenstrom wrote:

hehe...
I feel like a complete newbie (btw...I am a newbie...)

When I opened the loco I saw exactly what you wrote - that it will be rather an easy task to isolate the engine.
The problem will be carving out space for the decoder and the wires. I am thinking of removing some weight around the rear condensatorthingy instead of the fueltank - looks easier.

What is that condensator/resistancethingy thing by the way?

The capacitor has to do with interference supression, I think.
The amount of metal avalable to be removed is pretty limited. You'll have to be careful that you don't break into the cavities inside the chassis as these are used to hold the various bearings and mounting points for the trucks. Have you considered mounting the chip in a dummy B unit?

What decoder are you trying to install? There is allot of room at the rear of the F7 shell that is not occupied by the chassis. I did a little filing with a hand file. The piece that the capacitor is held in is part of the spacer that holds the back of the chassis together and provides insulation for the two chassis halves so you do not want to destroy that part.

cheerz Garth

Hi

I put last week a decoder in the MTL-F7.

It is easy, but you needs a some time.

Here is a pic from the F7

(sorry it is made with my mobile cam:( )

I opened the chassy, file at the backside 2 mm down to find a space for the decoder (DCX75.
The motor I isolated it with tape to the chassie, also unter the decoder I isolated
zhe chassie (between, because the original plastic I remove).
The red/black cable I fixed unter the chassie srews, the orange/grey you can fixed at the copperstripes from the motor.
Isolate the frontlight at one side and fixed the wihte cable on it.

caution, dont change the axles!