Atlas GP39-2 ---- my new favorite locos

[peteski]

How do you install a TCS AMD4/ASD4 decoder into a new non-DCC GP39-2 or SD35?

I assume that the 4 contacts from the motor (speaker?) have to soldered to the decoder? 

   Javier

Most likely.  That chassis is specifically designed to accept both, the sound, and non-sound versions of the ESU decoders.

[spookshow]

Things got better - 5 (or so) hours of additional running time and now it's pulling 23 cars.

[peteski]

Things got better - 5 (or so) hours of additional running time and now it's pulling 23 cars.

So whatever on the wheel treads was causing the problem has worn off.   Consider the loco broken-in!   

[Ngineer]

The grooved flywheels, bits of blue (epoxy?) weights and numbered poles have been seen for quite some time already (on Atlas and other brand models).  (...) The blue weights are used on both the motor armature and the flywheels.

Thanks for mentioning that! 

I always thought that the blue stuff is dirt/residue from the production process.   

   Javier

[jdcolombo]

How do you install a TCS AMD4/ASD4 decoder into a new non-DCC GP39-2 or SD35?

I assume that the 4 contacts from the motor (speaker?) have to soldered to the decoder? 

   Javier

You don't, at least not easily.

Instead, you use an ESU LokPilot Micro Direct:

http://www.esu.eu/en/products/lokpilot/lokpilot-micro-direct/

Available from various dealers.  Here's one:

https://store.sbs4dcc.com/ESU54650LokPilotV4.0DirectMicroOEMNMRADCCDecoderDrop-InforPost-.aspx

John C.

[peteski]

Thanks for mentioning that! 

I always thought that the blue stuff is dirt/residue from the production process.   

   Javier

Nope, those are carefully placed, just like the weights used to balance vehicle wheels. 

[Ngineer]

You don't, at least not easily.

Instead, you use an ESU LokPilot Micro Direct:

Thank you, but that is bad news.   

I bought the DC models hoping to replace the DC circuit board with TCS DCC boards, which are my favourite DCC boards.

   Javier

[u18b]

When I get some time..... I may see how a TCS AMD-4 fits in this chassis.
Hopefully, the motor pads are in the same spot. 

If so, then a little Kapton tape would protect the decoder from the sound tabs.

[spookshow]

Things got better - 5 (or so) hours of additional running time and now it's pulling 23 cars.

Got it up to 24 cars after another 10 hours of running. I think that's about as good as it's going to get. Not jump up and down impressive, but not anemic either.

-Mark

[jdcolombo]

Thank you, but that is bad news.   

I bought the DC models hoping to replace the DC circuit board with TCS DCC boards, which are my favourite DCC boards.

   Javier

Well, you could try one and see - but as Peteski noted, the chassis was designed for the ESU boards.  I suspect the frame "fingers" for holding (and powering) the boards are not the same, but you'd have to try one to see for sure.  The motor tab issue could be solved with soldering wires, as you suggested, if necessary.

Mark's article on the new frame might be helpful: it shows the differences in frame design between the old DCC-ready frame and the newer one designed for ESU boards:

http://www.spookshow.net/loco/atlasgp3840.html

John C.

[u18b]

I notice that there is another more minor change in what Atlas is doing.

The old chassis....  for about 30 years... has a separate cast plastic piece that sat on the mechanism inside the cab.  It's purpose was to block light from the headlight and make the cab appear dark.

I hated that piece.
I would lose them.
Also, they would wiggle out of position when I was trying to put the shell back on.

Well, Atlas has done away with that piece.   The light restricting function is now performed by the shell itself.

This is a plus for me.

[rrjim1]

  This tiny U-joint (which I assume first appeared on the SD35 with the chassis redesign) is a great piece to have in the parts box for kitbashing and tinkering.   I'll probably buy a dozen or so in my next parts order from Atlas.

If Atlas adds this joint to all their 4-axle locos.... then Beardenizing a GP7/9/38/40 will be a thing of the past!

These new joints have been used for quite awhile I first seen them in Atlas U23B locos. I purchased a few of them from Ebay.

[daniel_leavitt2000]

I notice that there is another more minor change in what Atlas is doing.

The old chassis....  for about 30 years... has a separate cast plastic piece that sat on the mechanism inside the cab.  It's purpose was to block light from the headlight and make the cab appear dark.

I hated that piece.
I would lose them.
Also, they would wiggle out of position when I was trying to put the shell back on.

Well, Atlas has done away with that piece.   The light restricting function is now performed by the shell itself.

This is a plus for me.

If you look at the chassis, it still has the tabs for the light shield. My guess is that they tooled the new shell for faster assembly. I'd bet dollars to donuts that any new GP38/40/-2 will still have the light shield.

Did you get a chance to compare how the wired model runs verses the leaf spring mod?

As for TCS decoders, my guess is that they will have their own board come out to fit this chassis design. This will be the de facto board design for IM, Atlas and others. That is a lot of market share to give up. Besides, these engines are being sold without dcc too. There needs to be decoder options.

I know Kato has used ESU in their kobo jobs before. I wonder if they will start to offer engines that work with this board for easier sound installs.

[jdcolombo]

Thank you, but that is bad news.   

I bought the DC models hoping to replace the DC circuit board with TCS DCC boards, which are my favourite DCC boards.

   Javier

BTW - I don't want to start an argument over what decoder is better, but if you haven't tried ESU's motor-only decoders (the LokPilot series), you might be pleasantly surprised at their performance.  And even if you aren't, there is a second good reason to think about using the LokPilot board: there are certain features of ESU's sound decoders, principally the Drive Hold feature of the "Full Throttle" sound files, than can only be used in consists with other LokSound or LokPilot V.4 decoders.  You may not ever be interested in sound, and the Drive Hold feature may be unimportant to you, in which case it doesn't matter.  But if you have thoughts about having sound units in the future and maybe using the Drive Hold part of the Full Throttle design in operations, then any unit in a consist that doesn't have a LokSound decoder will need a LokPilot to be compatible with Drive Hold.

John C.

[u18b]

Daniel, yes--- though not extensively.

They appear to run the same to me.