Thanks Guys,
Randy I did go to the TCS website and sure enough there were pictures of an installation on an old Atlas model very similar to what I have. I got my answer.
Thanks Again
Jim
Best advice - check out the TCS web site. They have installation pictures of most anything. You can use any physically similar decoder, but I use only TCS for motor decoders since they have excellent performance and are reasonably priced.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Jim,
I put a decoder into one of those old Atlas GP's. It was an easy conversion. There's a lot of room in the top of the shell so just about any HO or smaller decoder should easily fit.
I used a board-replacement decoder since I could solder LED/resistor combinations directly to it, and after removing the stock Atlas bulb, etc, stuck the decoder in place with double-sided tape.
You could also use a wired decoder, but you'd have to come up with a different arrangement for the lighting. I wouldn't try re-using the Atlas bulb as I'm sure it draws too much current for most decoder function outputs.
I didn't check the current draw of the motor itself, but the decoder doesn't seem to get excessively warm. You should be okay there as long as yours is in good running condition, with no binding or 30-year-old solidified grease in the trucks!
I did have to modify the frame on my Walthers SW1 switcher (with a Roco motor - ca. '91) to make it "DCC-friendly". (See link for details) I installed a Lenz Silver MP into it and it's my best crawler. It will do 0.33 sMPH on speed step 001.
I'm not sure how involved your Atlas GP40 will be but those Roco motors are top-notch. I would also recommend removing and cleaning all the old dried grease from the gears and replacing it with Labelle 106, as well as relubing the axle and motor bearings with Labelle 108.
Tom
https://tstage9.wixsite.com/nyc-modeling
Time...It marches on...without ever turning around to see if anyone is even keeping in step.
And, once you've got the meter, you can use it to check and make sure the motor is isolated from the frame. Most meters have a "continuity" setting, where touching the probes will give you a beep, buzz or perhaps a light to tell you there is effectively zero resistance between them. Hold one probe in contact with the frame, and then touch the other to various points on the motor itself, particularly the contacts where the power wires are connected to the motor brushes. You should have NO beeps or lights, if the motor is truly isolated.
For the decoder, I'd recommend a TCS from Train Control Systems. These are good decoders, and they are sold with a "goof-proof" guarantee. If it burns out, even due to your own inexperience, they will replace it.
It takes an iron man to play with a toy iron horse.
Hi Jim:
Please bear with me. I am going to assume that you are totally new to decoder installations.
First thing to do is to test the amperage draw on the motor. For that you will need a DC power pack and a multi meter tester to measure the number of amps the motor uses when stalled at full power. Multi meters are not expensive if you don't already have one. You should be able to find one for $20.00 or less.
Here is just one retailer with tons of low priced options:
http://www.multimeterwarehouse.com/digitalmultimeter.htm
To test the draw put your locomotive on the track with the ammeter connected between one lead from the transformer and the track. Hold the locomotive down so the wheels can't turn and turn the throttle up to full power. Then read the meter. Since this procedure is rather hard on all the components involved including the locomotive it is not recommended that you keep the power on any longer than is necessary to get a reading. A modern locomotive should draw less than 1/2 amp.
If your locomotive passes that test then there really aren't any restrictions on which decoders you can use. If your locomotive draws close to 1 amp or more then you should try to figure out why the draw is so high before attempting to install a decoder.
One possible problem with older locomotives is hardened grease in the gear boxes. Normal maintenance recommendations would suggest that the gear towers should be cleaned and re-lubricated every few years. Yours might be long overdue despite its apparent good performance.
The simple rule is that there is no use installing a decoder in a DC locomotive that is not running extremely well on DC. DCC will not cure old grease or binding gears, or anything else for that matter.
Your Atlas loco will have a ROCO drive. That is a good thing. Starting with a decent quality unit is very important. Don't ask me how I know!
Dave
I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!
Another issue to determine is how much room do you have under the hood for a decoder?
I recently acquired an older Atlas GP 40 (made in Austria). I'd like to add a decoder, but I'm not that familiar with the drive/motor on this model. When I removed the shell it appears that the motor is isolated from the frame. There are wires running from each truck directly to the motor and an ancient large light bulb. No electronics whatsoever. Because this motor is probably 20 to 30 years old (it still runs very good) would it be less efficient and draw more current than todays motors? Is there any particular decoder that may be specifically designed for these older motors? Any advise would be greatly appreciated.
Thanks