Motor Replacement for T Gauge Inter City 125 Power Car

[grahame]

I love my 9 car Inter City 125 T gauge set. I have owned it since they were first available:

http://youtu.be/oeHYIgx9hBc

http://www.tgauge.com/product/260/2/br-inter-city-125

5 days ago I found, to my great dismay, that one of the power cars was not running correctly. Forwards is sporadic, will not run in reverse. I cleaned the wheels and axles but this did not fix the problem. I have to admit it really scared me to death but It's time to take this thing apart. I spent a long time trying to get the body off but eventually was able to lever it up from the back with a needle and then pull the chassis down, pivoting on the front. (Thanks to Alan Ramsay for several phone calls across the Atlantic).

Then followed a total strip it down.









Unfortunately it turns out the motor is defective. I am waiting for a new one to arrive. then comes the scariest part, putting it all back together. hopefully this will turn out well.

[mattd10]

Sorry to hear of the problems but I think this is the first time I've seen inside one of the power cars! Looks very sleek compared to the old 103 units! Hopefully your new motor will sort out the problem!

[grahame]

Sorry to hear of the problems but I think this is the first time I've seen inside one of the power cars! Looks very sleek compared to the old 103 units! Hopefully your new motor will sort out the problem!

Thanks "mattd"..me too. I have never seen inside this little fellow so I was not sure what to expect. I was pretty scared to be honest but it had to be done. I got lots of help from that excellent fellow Alan Ramsay of Ramsay Models in Edinburgh. The drive train is very nicely designed. All gear wheels were removed and cleaned in ultrasonic bath with special hydrocarbon solvent. The part that scares me most is putting those tiny gold bogie springs (safely stored in that glass sample vial) back on but I have a few ideas how to do this and have magnifying equipment where I work.



Here are the gear wheels after cleaning:




and the motor which needs to be replaced:

[dkightley]

The re-attachment of those little springs is indeed the trickiest part of the process. And if approached correctly is actually a lot less frightening than you may think.

Firstly, make sure you are doing any job on small things in a clutter-free environment on a smooth clean work surface. Also, I would recommend wearing short sleeves to prevent cuff or hanging sleeves from sweeping your work area if when you move around. And just have the tools you need at hand and easy to pick up. Ideally, use either a desk or head mounted magnifier and plenty of light!

Finally...make sure you're not going to be disturbed...the last thing you want is a disruption just at the critical moment! No pets, kids or loved ones within hitting, kicking, or earshot, as appropriate....just in case.

The way I approach fitting the springs is to hold the unit between thumb and fingers..like this:

IMG_0954_red.JPG (31.16 KiB) Viewed 25317 times

You will find you can roll the unit round so your thumb presses on the lower half of the spring..try it with an assembled unit!

To put the spring in, first put the bogie in place and hold the unit as shown above.

Using a pair of needlepoint tweezers, pick up the spring by the top loop, and locate the bottom loop in the hook on the bogie.

Roll the unit so your thumb is holding the spring in place.

Once you're happy you're holding the spring with the side of your thumb, stretch the spring so you can then carefully drop the top loop into the hook on the busbar.

Sounds easy! Well, the first time you put tension on the spring, I can guarantee it will slip out the tweezers......and because you're restraining it with the side of your thumb, it won't go anywhere. So you'll be able to grab it again....and try again. It might take half a dozen tries to hook the spring up....but providing your thumb stops the spring from escaping, a little perseverance will win the day!

With the first spring on, carefully turn the unit round...ensuring you keep the bogie in place...and repeat for the second side.

Stop for a breather.....and then its on with the other bogie!!


And just in case you're wondering......yes, I have lost a spring. Only one! But that was before I started using the above method. Once they go.....boy do they fly! And in my case, probably only to be seen by the inside of the vacuum cleaner!! Its a good job you can get spares!

[grahame]

Hi Doug, Thank you so much for writing such a detailed procedure. I will certainly follow it to the letter when the new motor arrives. I think you're the very person I hoped to find. The only other person in the world who has the "bottle" to take one of these tiny things apart,

Cheers,

Grahame

[ConnorL]

I was wondering...but what kind of motor is this? This looks extremely similar to one of my phone's motor when I changed the battery of it. I can't remember the phone since I got rid of it.

[dkightley]

You're right, Connor.

The motors used in T gauge power units are the same sort of motor that is used as the vibrator in phones. And its probably the demand for motors small enough for phones that resulted in the availability of the motors that just happened to be perfect for T.

So T gauge has the world of mobile phones to thank!

[ivanf]

When replacing the springs, the first spring can be attached to the chassis connector and then hook the bogie on it, then wrap that round the bottom of the chassis block. The proceed as detailed above.

That way you only have to play the twangy spring game once.

Don't know if this works for the driving bogie but it's fine for the none driving bogie.

[dkightley]

.....the twangy spring game....

I like this description of the challenge.

[grahame]

New motor and spares springs just arrived in Houston from Tgauge.com......will report back when the job is done. thanks for all the advice.

[grahame]

After a few misfires I managed to get all four springs in place. Many thanks to Alan Ramsay at Tgauge.com for sending me a pack of spare springs. I needed at least one. After several attempts they can get stretched and deformed. All 3 motorised units (front, rear and buffet) running well now in both directions. I found a combination of Doug's method and sliding the second spring eyelet off the tip of a needle on to the hook worked the best.It IS tricky but the last one was a lot easier than the first one .One at a time...I did the drive bogie first...

My advice to any one doing this for the first time. Be sure to buy a pack of spare springs along with the motor. That will be the best 2.50 GBP you ever spent and you will sleep a lot easier the night before .

[dkightley]

Glad you got it sorted.

Tricky blighters, those springs!!

And I'm glad you've now got all three units running okay now. Don't spend too long playing, though! You might get into trouble with "'er indoors"!

[grahame]

I wonder if some type of design change might be possible, where the spring is actually attached/welded to the bogie hook..that way you would only need to attach one end...to the bus bar.

[grahame]

For those people who have not seen these tiny gold springs here is a photo. On the right is a normal sized paper clip, not one of the big ones..to give an idea of the scale



They have two functions:

a) Hold the bogies into the chassis.
b) Provide electrical conductivity from the wheels to the bus bars and hence the motor.

There are 4 of this little blighters to install too

I would love to watch the assembly line for these, they must have a special tool to do this.