There's two versions of the Atlas GP35. The Roco one has no board worth metnioning, not like the Kato boards in the RS-3. But the motor is already isolated, so it's super easy to wire in a decoder. There is a newer version of the GP35 that was made by Kato, shortly before Kato started putting 8 pin sockets on their boards. This doesn;t have the grey plastic 'board' either, it has a real PC board, with seperate front and rear lights. However the design is identical to the older grey board ones, complete witht he exact same two mounting tabs, so the same decoders work. Include a TCS A4X in there, their motor drive blows Digitrax's away. And the difference between the two Digitrax ones is that the K0 version includes 4 pieces of brass soldered on to repalce the pieces that are snapped into the greay Kato boards - definitely not needed and at least at one time they charged an extra couple of bucks for the Kato version vs the otherwise identical Atlas version. One nice thing about Atlas that as they transitioned over to making their own drives, they kept the same physical layout as far as where the wires go and how to attach the board to the chassis, so even for newer Atlas locos that have an 8 pin socket you can ALSO just do the board swap, with the exact same decoder. And since the Gold series locos have been including QSI sound, the Silver DC versions still use the same chassis so it has the speaker mounts, making these ideal candidates for easy sound installs.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Sleep like a kitten (SLK) I've already converted three of my Blue Box engines without any real problems. It was a lot easier then I thought it would be.
However, I'm a little confused on converting my old yellow box Atlas engines. ...Does Digatrax or any other company make a conversion harness like the one for the Blue Boxes?
There are three decoders to consider. The Digitrax DH165A0, the Digitrax DH165K0, and the NCE DA-SR. These three decoders can either replace that stock grey plastic piece over the motor using double sided foam sticky tape. OR the grey plastic piece can be filed down flat and the decoder just on top of it. One difference between the A0 and K0 is that the K0 already has power leads soldered onto it. This works great on the Atlas RS-3 type locos that just slide right on. I do not remember if the GP35 have that or not.
The hardest part is deciding how to do the headlights/tailights. These decoders have built in resistors on the head and tail lights to choose full power bulbs (18V) or 1.5V bulbs or LEDs.
Indeed, since you'll have the loco all apart - might as well take care of cleaning and lubing it too. If it's an old loco that hasn't been run much - likely the old lube will be all gummy, amking for a poor runner. If it's old and HAS been run a lot, it might be all dried out.
Even some brand new locos - there is often a tendency (thankfully less than it used to be) to put WAY too much grease int he gearboxes, on the idea that the owner will never bother to clea and lube the loco, so better too much now than none later. But having too much is just as bad as not enough, it can bind up the gears, and even worse, run out on the track and wheel pickups.
Good example are my 4 Proto 2000 GP7s. They are known for having the axle gears crack, so rather than wait and repalce, when I had them apart for decoder installs I also swapped out the factory gears for Athearn ones, head the problem off before it happens. Especially with new locos with lots of scale-size details - the less you handle the loco, the less chance of damaging anything.
The link Randy posted should show you what you need. The TCS website has great info and pictures to help with almost any type of install.
The worst case scenario on any loco is you have to hardwire a decoder and maybe isolate the motor from the frame. Some basic soldering skills will be necessary, but easily learned.
I you are up for it I will suggest that before installing decoders on older locomotives give the locomotive a thorough degreasing and relube. If the locomotive has a build up of nasty earwax looking lube then I disassemble the trucks, clean and lightly relube them. Well worth the extra effort. Its intimidating at first disassembling trucks, just take your time the smooth running results are worth it.
Good luck. Martin.
Take a look at the TCS install photos here: http://www.tcsdcc.com/public_html/Customer_Content/Installation_Pictures/HO_Scale/HO_Search/search.html
scroll down to Atlas. They have both versions, the Kato one and the Roco one. You cna use anyone's decoders that are similar in size and type of connection, I happen to prefer TCS to the others I've tried and use them in all my locos that don't have sound. Even if you don't go with their decoders, the install pics are a valuable resource on getting decoders in lots of different locos. I haven't found a more comprehensive list of examples, at least for motor-only decoders.
If it's the wired in type, you'll probbaly want to pick up some small diamete heat shrink tube to cover the joints, outside of a small soldering iron and solder that's about all you'll need tool-wise.
(If it's the really old GP38, the one by Roco, it's strictly a wire job)
Ok Randy you've talked me into it. Worst case is I totally mess this up and can't use it. So, I either try to convert it so I can continue to enjoy it or just shelve it and forget about it!
Which decoder would be easiest to work with?
Converting older Atlas locos, even all the way back to the kato made ones, is crazy simple. The 'Atlas' form factor replacement boards simply snap on tot he tabs that hold the factory boards, the power pickups connect at the corners (in the same physical location as the factory board) and the motor wires connect near the middle, also in the same physical location as the factory board.
The Kato made ones don;t have a circuit board, it's a piece of plastic. But the same decoder drops right in. The decoder even has pads int he middle so you can solder ont he stock light bulb in the middle to avoid having to modify the light bars. It's pretty easy to cut back the light bars and connect individual lights though. The light bars typically attach tot he shell in to palces, just leave the end nearest the end of the shell so there's something to hold the bar in place - a little white glue works as a good non-permanent adhesive. There are many ways to attach an LED to the now shortened light bar, I've used shrink tube, but clear cements like Faller's Xpert can glue the LED to the plastic without harm. The Kato-made GP38 already has 2 LEDs for individual lights, so it's not like the Alcos.
If it's the really old GP38, the one by Roco, it's strictly a wire job, but this is MUCH more obvious than a Blue Box, since there are wires for both sides of the track pickups. A total of 6 wires - 2 from the left side pickup, 2 from the right side pickups, and 2 from the motor. Ig you can do the BB you cna do this, it's pretty darn obvious where all the wires go.
This may be more then I want to tackle. But, I'd just hate to shelve it.
I am not sure if anyone has a 'replacement' light board decoder for those old 'yellow box' engines from the 70's. You are going to have to 'cruise' the manufacturer web sites to check them out. The later GP's had a 'dual mode' decoder installed, and the current Silver Series 'Master' line have DCC socket, as do the Trainman line of GP's.
The Digitrax decoder selector lists the 'Non-DCC' GP38, and suggests wired decoders like the DH123.
TCS has a series called 'A Line' that is a drop in decoder for Atlas. Check out the web page and see if this will fit in your engine:
http://www.tcsdcc.com/public_html/Customer_Content/Products/Decoders/HO-Scale/HO%20Series.htm
With light board replacement decoders you have to be very careful about what vintage the old DC light board is. They seemed to change the specs through the years, and sometimes the new replacement decoder is not the same 'form factor' as the old light board.
Jim
Modeling BNSF and Milwaukee Road in SW Wisconsin
You would need to either do a hardwire installation using a regular wiring harness, or do a 'drop in' installation using a lightboard replacement decoder. (The decoder is shaped like the green lightboard, and takes the lightboard's place. Several companies - in fact most all decoder makers - make lightboard replacement decoders designed to fit Atlas diesels.)
Ok, so I have taken the plug w/DCC. I've already converted three of my Blue Box engines without any real problems. It was a lot easier then I thought it would be.
However, I'm a little confused on converting my old yellow box Atlas engines. I have a GP38 that has always ran like silk and I'd love to convert it. Does Digatrax or any other company make a conversion harness like the one for the Blue Boxes?
P.S. Putting sound in a Blue Box GP35 not easy to do......