brass AT&SF M190 dcc and improvement

[u18b]

During these cold evenings, did a little work with a pair of AT&SF motor cars.

First up was the phase 2 in the Pullman scheme.




Pull the shell and the internals are almost all motor.



Space is tight.  And a previous owner had pinched a wire.  You have to make sure they are out of the way.


The rear motor shaft has been cut off flush.



As for adding DCC, there is very little space.   The space above the motor is too tight, but there is a gap between the cab weight in the roof and the drive shaft.  Not how the docoder dips down a bit.



I made a little circuit board up top for connecting wires.
https://www.therailwire.net/forum/gallery/31/medium_1277-291222142646-316981877.jpeg

I also made a little board for the motor tabs.  This sits over the gap for the commutator.



Once running properly, I installed window glass throughout.





This version uses a steam engine headlight and it would be VERY difficult to drill through all that to get an LED up there.  So I left it off.

[u18b]

A second M190 was the later phase 3.



When Santa Fe rebuilt these, they moved the headlight down to a more traditional place above the wiondows.



I made a couple of small circuit boards.  One was for the micro LEDs at the headlights.
The other was for the resistors.  Each LED has it’s own resistor.



A socket allows the shell to be removed with unsoldering wires.



A Digitrax DZ126T was installed.







Window glass installed.



The lit headlight makes a huge difference.



These old brass locomotives run great.  That massive motor with extra makes all the difference.  Hard to believe these are about 35 years old.

[Mike Madonna]

Ron,
VERY Well done! Wondering what SMD resistors and LEDS that you used? I like the "homemade" circuit boards. It appears as though you glued the wires to the roof, is that correct? You gave me a few ideas.... thanks!

[u18b]

Hi Mike.  Thanks.

Not sure of the wattage of the resistors.

The LEDs are 0603 I believe.  Pretty sure they are larger then 0402.
You will also note that a 4k resistor is overkill protection.   But these LEDs are plenty bright even with that resistance.

And yes, I used epoxy.   I did not mention that I used magnet wire for the LED wires.

[nkalanaga]

"As for adding DCC, there is very little space. "

Could you have put the electronics in the baggage section?

[Rivet Miscounter]

Those are purty.   

[peteski]

Hi Mike.  Thanks.

Not sure of the wattage of the resistors.

The LEDs are 0603 I believe.  Pretty sure they are larger then 0402.
You will also note that a 4k resistor is overkill protection.   But these LEDs are plenty bright even with that resistance.

Nice work Ron!  I never seen those models, or even knew such strange looking prototype existed.

The resistors (labeled 472) are 4.7 k Ohms (4700 ohms).  They look to me like SMD 1206 size. Those are rated 1/4W, but the power they dissipate in that application is much less than that, so those are plenty safe.

If the power used is 12V (like it is often the case with DCC decoders), and white LEDs have forward voltage of 3V, then the LED current would be (12-3)/4700=0.0019A or 1.9mA.    Power dissipation across that resistor is voltage across the resistor multiplied by the current through it.  So  9*0.0019=0.017W.

I don't  think I ever heard the resistor in series with the LED called a "protection resistor".  It is a current limiting resistor calculated for some desired current (thus LED's brightness) at whatever supply voltage is to be used.  I suppose it does protect the LED because it would burn up if 12V was applied to it directly.  It just sounded unusual to me because I always think of that resistor as brightness control, rather than protecting the LED.

[Dirk Jan Blikkendaal]

Those are purty.   

Hi, these are nice!

As for the quote/question: I put the decoder/capacitor/sugar cube speaker in the baggage section (plenty of room), enlarged the slot in the rear bulkhead and drilled a small hole in the front of baggage section to pass all wires through.
Also added some lead weight over the front truck to improve traction and added all wheel electrical pickup to the rear truck......... only disadvantage is I cannot store the M-190 in its original box..... plus the fact its not in "original" shape anymore but the improvements outweigh that for sure for me......... Its a good running engine with nice sound.   

[u18b]

Hi Dirk.

Post pictures of what you did!  Would love to see it.

I considered much of what you said.  My concern was all of the wires which would be running between the car and the cab.  The cab is a little tipsy and I felt those wires would not be good.

Sounds like you solved that by permanently putting them together.

[FlyGuyB]

As usual Ron and excellent job upgrading N Scale models.

[Ed Kapuscinski]

You're such a mensch!

[Nick Lorusso]

Got to love the M190s. Great work as usual.

[Dirk Jan Blikkendaal]

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A very old conversion....... done in 2014 after John McMasters kindly made a soundfile for the M-190 to go with the (cheaper) programmable Digitrax decoder.
Lead weight glued over the powered front truck to improve pulling power, Evergreen clear styrene sheet inside alle windows/doors, large speaker/decoder/keepalive inside trailing baggage section, diaphragm added between the sections to conceal connecting wires, under side of truckframes and front truck filed down a bit to prevent shorts on turnouts (doodlebug is riding quite/too low), current pickup added to insulated wheels on 2nd and 3rd truck (all wheel current pickup now).
Result: I very good running/pulling unit with reasonable sound.......

 

[Cajonpassfan]

Nice job, Dirk! I hate how prolific you are!
Otto

[u18b]

Dirk.
Thank you for sharing.
What a wonderful job.