DCC and athean F7A and SD 40-2

Hi,
I'm investing in a DCC controller in the new year when Hornby release their Elite system and most of my european engines shouldn't pose to much of a
problem to convert over to DCC . But I popped the cover on one of my F7s and all of the wiring and pickups seem to be in the truck with a few cogs which then are connected to a drive shaft.
Anybody here ever do a DCC conversion on the F7A unit or a SD40-2 which has a similar layout?
hope somebody has as I don't want to mess up either the chip or the unit.
thanks
Bill
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Bill, there are many companies that make the F7 and the SD 40-2. It would help if you told us who makes them.
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Bill wrote:

Athearns are converted to DCC all the time using various methods. Search for "Athearn DCC decoder" (without the quotes) or something similar and you'll get lots of hits.
That said, what I usually do is first isolate the motor by removing the tabs from the bottom brush clip and adding a strip of electrical tape to the contact area of the frame. Be careful when you remove either brush clip as the springs tend to fly out.
Then, solder lead wires to the brush clips. Removing them first allows you to accomplish that without melting the motor.
Finally, I re-assemble the motor and add a strip of electrical tape to cover the top brush spring as well. Then I tape an NCE DA-SR decoder to the top of the motor and wire everything up, usually using a couple of "day-glow" or "yellow-glow" LED's with appropriate resistors.
HTH, Stevert
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in article VZFch.16574$ snipped-for-privacy@news.indigo.ie, Bill at snipped-for-privacy@eircom.net wrote on 12/3/06 11:56 AM:

Here is a web site (Digitrax) with instructions for installing a Digitrax decoder in an Athearn "not ready for DCC" (that is, old style) locomotive. The key is that in these older Athearn locomotives, the motor is electrically connected to the frame (at the bottom); you have to remove the motor, insulate it from the frame, and then insure that all electricity flows to the motor via the decoder.
Once you've done it, the hardest part is removing the motor since it is a pressure fit with some plastic plugs on the bottom.
While you are in there, tune up the motor; there are a bunch of web site about that, too.
--
Ed Oates
http://homepage.mac.com/edoates
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in article C198A4CC.25421% snipped-for-privacy@unearthlylink.net, Edward A. Oates at snipped-for-privacy@unearthlylink.net wrote on 12/3/06 3:59 PM:

And of course I forgot to include the link. Here it is:
http://www.digitrax.com/appnote_dash9app.php
--
Ed Oates
http://homepage.mac.com/edoates
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On Sun, 03 Dec 2006 23:59:09 GMT, "Edward A. Oates"

I believe Athearn now makes a set of hard plastic replacement plugs that let you use screws to fasten the motor. Since you are removing it any way this would be a good time to convert.

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Bill wrote:

The older "bluebox" Athern diesels were "hot chassis". One motor brush was connected to the frame of the locomotive and the other brush was coonecter to the other rail thru a springy metal strip running from the front truck to the rear truck. To run under DCC, both motor brushes need to connect to the DCC decoder rather than the chassis to give the dcc decoder full control of motor current. The motor and its brushes need to be electrically isolated from the chassis. The juice from the metal strip needs to feed into the DCC decoder rather than a motor brush. The DCC decoder needs to connect to, and control the juice thru, both motor brushes. A 1/4" "Faston" connector, available at ordinary hardware stores for a few cents, will slip over the metal current carrying strips coming up from the trucks. Use of the "faston" allows one to disassemble the locomotive for service with use of a soldering iron. The DCC decoder ought to have a pair of wires to accept power from the track. Of these two wires, one ought to go to the chassis (one rail) and the other ought to go to the strips coming up from the trucks. The DCC decoder ought to have a second pair of leads intended to run the motor. These two lead ought to go to motor brushes. If you get the polarity reversed, the worst that can happen is the locomotive runs backward, which can be corrected by swapping the motor leads. Good luck
David Starr
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Do a bit of research on the Hornby system before you buy it.
I received an email from my "pusher" with details. My comment was YUK,.
Unfortunately I deleted the email so cannot post details
Did a quick Google, found this
http://www.sherwoodmodels.co.uk/catalog/product_info.php/products_id/3091?ecSid 2916e83a1976eedf1de7b1c6d0ce47
I believe it has limited capacity will run 10 trains max
- at the club we sometimes run out of slots ie more than 22 locos on the DB150 until we make more power blocks with circuit breakers and use a DCS200
and limited compatibility with DCC standards. 9 functions, 254 loco addresses no 4 digit numbers ??
gotta study it more to check, but will not be changing from Digitrax. The only advantage seems to be a USB port instead of RS232
The only one I would consider changing to, is the new ESU - very nice - great hand controller
NCE & Lenz are also good but no advantage for me to change as there are only minor feature differences other than Loconet & IR
Alan, in Gosnells, Western Oz. VK6 YAB VKS 737 - W 6174
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snipped-for-privacy@iinet.net.oz wrote: [...]>

It appears that Hornby's DCC unit is designed for the small to medium sized home layout, which rarely has more than three or four engines "in steam" at any one time. The only limitation would be if you have more than 10 engines, -- you'd have to be careful to avoid putting two engines with same address on the layout at the same time. Not an onerous limitation if you're looking for a (somewhat) cheaper DCC system.
HTH
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Chaps,
thanks for all that info on the Athearn units, I'll probably get a different DDC controller than Hornby, the Elite model looked good but did a bit more reading in the mean time so trying to get the best out there for the money I have with good future-proofing.
Any suggestions on a good mid to high level DCC controller based on experience?
Bill

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