[Ozzie21]

QUOTE (Branchliner @ 5 May 2006, 06:45) <{POST_SNAPBACK}>I intend to fit a decoder to my HO gauge DD40AX, this loco was claimed to be the largest diesel ever built and was run by Union Pacific, it pushed out 6000 HP using two separate engines.

In common with the prototype the model also has two motors each driving its own 8 wheel truck. Has anyone ever fitted a single decoder to run two motors and if so are there any special considerations regarding the amperage required?

I would like to fit a sound decoder but there is not enough room unless I cut away the part of the die cast split chassis which occupies the fuel tank space.
Brian

Is it the Bachmann or Athearn model

Both models had fairly high current draw motors in their time, the Athearn was especially hungry and noisy. The Bachamnn model was prone to motor failure as was most of the early Bachmann diesels. It might pay to look for a minium 1amp capacity decoder to power this brute.

Ozzie21

 

[Ozzie21]

QUOTE (Branchliner @ 6 May 2006, 19:39) <{POST_SNAPBACK}>Ozzie,
As I said earlier, the loco is a Bachmann product now out of production, it is one of their Spectrum series models but in my opinion is not up to the standard of their current Spectrum range. This one runs very smoothly on DC so should be OK for conversion. As far as I can see from the armatures without removing the motors they do not appear to be skew wound, pity, all the new ones are. I have a good local supplier who specializes in DCC conversions, he will probably have a suitable decoder, I can take the loco in and check for size.

Brian

Yes, I know the model. It must be 10yrs since they last made one. Those early kradar motors weren't up to much and failed pretty regular. Also the hotor shaft is pretty fragile so I wouldn't recommend pulling off the flywheels to check the motor. I can't remember how many we stuffed trying to get the flywheels off when the motor failed as the Bachmann replacement came without the flywheels. I would recommend that you replace the motors with Mashima 1836's or a large can Sagami if you can find one. NWSL used to do a flywheel and shaft kit for the Bachmann model but that was along time ago.

Ozzie21

 

[Ozzie21]

QUOTE (Branchliner @ 7 May 2006, 21:58) <{POST_SNAPBACK}>Thanks Ozzie/Peter for that useful information, I have noted it down on the spares sheet for future reference. Setting up two decoders simultaneously? Thats an interesting problem, if there was a conflict of values for the same CV what would the feedback read if anything at all. One solution would be to isolate one decoder whilst setting up the other then reverse the process, every single CV would need to be identical on each decoder, you would have to pay attention to the polarity of the pick up and motor connections to avoid the trucks running in opposite directions, normally I don't bother which way round I connect the wires, if it runs the wrong way I just change the value of CV29 to correct it. I intend to start the installation next week, I shall keep you all posted, if nothing else it may help someone in the future.

I should not have bought this loco really,

it has just diverted me from the task of completing the loft layout and all that scrabbling about under the boards, another problem here, see my post on tracks etc.

Brian

Brian, I tried the twin decoder setup in a twin motor DJH NSWGR AD60 Garrett. It didn't work terribly well as one motor would stall and the other kept going which meant the stalled one had to catch up. So I went back to a single decoder driving both motors, 1612Mashima's mated to NWSL 1/8th 36:1 gearboxes. It works well but as with all kit built, all wheel pickup engines I get the odd brake shoe out of line and the damn thing shorts out. One day I'll sit down and sort it out. The NWSL motor kit for the Bachmann DD40X was really good as you ony used one motor, a Sagami with flywheels, but it was about 10hrs work to get it to fit and those NWSL cups and balls universals were a little finicky to fit.

Ozzie21

 

[Ozzie21]

QUOTE (Branchliner @ 9 May 2006, 06:06) <{POST_SNAPBACK}>Getting there slowly, I bought a Zimo MX64H decoder today from Digitrains, it has a 1.8 amp continuous rating which should do the biz for the DD40X. There is sufficient space to place the chip upright at the rear end of the chassis, a spin off is that it also gets some air from below.

I have done a quick installation to check it all out and the loco runs smoothly and quietly. Nevertheless I have decided to strip the chassis completely and carry out a better quality installation, this will require a bit of surgery to get full access to the brass connectors, there are no natural connections for the left and right pick ups, it might be an idea to drill and tap two connector screws directly into the chassis halves.

The Zimo decoder has 3rd and 4th function wires but I'm not sure whether I can use these to operate the flashing beacon.

Brian

Watch those little plastic spacers when you split the chassis as they have a habit of hanging up and falling off when you least expect it. A mate did exactly what you are doing in that he drilled and tapped the chassis to mount the pickup wires. The Zimo should have a selection of lighting CV's to cover the flashing beacon. The preserved example is now fitted with type 2 ditch lights.

Ozzie21

 

[Ozzie21]

QUOTE (pedromorgan @ 11 May 2006, 15:16) <{POST_SNAPBACK}>yep microscale are good. they also sell microsol decal fluid which is very hard to come buy over this side of the pond. if you get the decals imported it mnight be a good idea to get a bottle of microsol and decalset(is that the name of the second one? mine ran out ages ago) at the same time.

Peter

Yep, Microscale make a blistering array of UP decals but hetting the right ones

Well you'll just have to wade through them till you find them. Microscale make two types of decal setting solution "Micro Set" which is in a plastic bottle with blue writting is your basic solution. It'll prepare the surface for the decal, soften the decal and make it sit. You can use this one numerous times to get the decal down and bubble free. "Micro Sol" is the vicious one. Easily identified by it's red printing. You use it on irregular surfaces after you have used the other. This one really softens the deca, so much that if you brush it after applying it the decal will just wrinkle up and be ruined. So you brush it on after the decal is applied with the Micro Set and has dried, brush the Micro Sol on once then let it dry. So long as you let it dry before applying it again you'll have no problems. Oh and you'll need Armour Yellow, Harbour Mist Gray and Antique Silver to paint it with.

Ozzie21

 

[Ozzie21]

Peter, It's funny you should say that as the price of the kit down here is a lot less that it is up there. The big plus is that everything is supplied with it, motors, gearboxes and wheels. Motors are 1620 Mashimas, gearboxes are NWSL 36:1 single idlers and wheels are RP25 profile Romfords. Have a look on www.arkits.com.au
under Footplate Models. I think it's listed as A$595 which is about 245 UKpounds. It's not a hard kit to build just time consuming but well worth the effort. Send me your email and I'll send you some pictures of mine.

Ozzie21

QUOTE (pedromorgan @ 10 May 2006, 15:06) <{POST_SNAPBACK}>You luckey

Peter