G Scale Model Train Forum banner
1 - 15 of 15 Posts

·
Premium Member
Joined
·
251 Posts
Discussion Starter · #1 ·
I like DCC but I don't like gutting my engines. Here a simple way of adding dcc to a USAT f3a It should work with gp 9 as well.

I open the F3


Notice the plugs are the same as aristocraft part 29511 plug for power to tender



You will need 2 sets of these


Unplug the track power pick up line for the front and rear blocks, labled pick 1 and pick 2 plug in the new cables from aristo

I am using an MRC 1817 sound decoder. It is a new design and is considered "silent" the sound quality is equal to the Dalley unit and is much worse than a QSI chip.
It's also half the cost at $65. The 1817 is rated at 5amps.


All that's left to do is attach the leads from the track to the track terminals on the chip and attach the leads from the main board to the motor terminals of the MRC 1817.Be aware that the wiring is simulat to aristocraft in that the red track power wire from the front truck lead and the black track power wire from the rear truck are the same side. hook up your speaker ( I recommend using anything other than the supplied speaker from mrc as it is cr*p). I had a small pc speaker from a old PC that worked nicely. Close it up test it and you're done.


Now for the sd70 I still need QSI to come out with there USAT version.
Downside of this installation
1 When the train stops the lights go out
2 you cant use dcc to turn your head light on or off
Upside
1 the red to green directional led still works.I like this feature
2 I did not have to gut my engine
3 the dual smoke unit works fine, the chip seems to be able to handle the load fine.
 

·
Premium Member
Joined
·
5,629 Posts
Yep I got 6 USAT units just waiting on the QSI system. Do not even want to do what was done here. I want it all working when I'm done. Later RJD
 

·
Premium Member
Joined
·
251 Posts
Discussion Starter · #4 ·
Greg
The problem for me with the mrc 322 is that it makes so much noise in the motors that I'm concerned that it might be damaging the loco or it's electronics. Also it cann't do straight DC. I paid about a $170 for the F3 its hard to justify a QSI chip that cost near that much.
 

·
Super Modulator
Joined
·
21,424 Posts
I hear you Bill. Yep they make noise, and they are not perfect. But at $12 each, it's a good stopgap for me until the QSI comes out.

They do run on DC, the trick is to set the decoder for 14 speed steps. Jerry McCoolgan figured that out.

It will let me run trains for now, I have them in 6 F3s and 4 PAs so better than nothing on a DCC layout.

Regards, Greg
 

·
Registered
Joined
·
811 Posts
the MRC 322 runs on DC in 128 speed steps, just not very well

Anyway, the way that that decoder is configured, it is better just to turn analog conversion off
 

·
Premium Member
Joined
·
251 Posts
Discussion Starter · #8 ·
But how safe is that decoder on the electronics? It was designed to replace the electronics not interface between the tracks and electronics. I assume the noise is some ac component that is outputted from the decoder and originates in the dcc signal. I believe it goes away when you switch to DC.
 

·
Super Modulator
Joined
·
21,424 Posts
Jeeze Bill... I'm not on a one man crusade to bolster MRC AD322 sales!!!

It's a cheap decoder, it will blow up before the motors do. It makes noise... it's CHEAP... who cares if I have 20 and one blows up? The noise is the PWM drive, it's low frequency, and it's not in the DCC signal...

The "electronics" in a USAT board is a simple voltage regulator, nothing fancy.... anyway, I can run trains until the QSIs come out and throw them away....

I think you are taking these posts as an affront to your install, and it's just axillary information, not combat!

Regards, Greg
 

·
Premium Member
Joined
·
467 Posts
Clean and simple install Bill!

If you intend to use more of those two pin plugs, All Electronics sell them under catalog # CON-240 for $1.35 each, or $1.20 each if you buy more than ten. Our club members use them all the time.
The colour coding on the wires is usually the opposite of USA Trains and Aristo-Craft’s lithium-ion battery and charger. The wires can be changed over, but it’s easier to spray the red wire with Krylon Semi-Flat Black and use a multimeter to ensure proper polarity.
 

·
Premium Member
Joined
·
251 Posts
Discussion Starter · #11 ·
Greg
I agree with you about the decoder. Who cares if it blows up? The engine on the other hand might be upsetting. Anyway, I'm not try to make a big deal out of this just thought it might provoke an interesting conversation about these older and noisy decoders and there effects, if any on engines.
Greg please don't think that I take anything said as an affront to my post I put this stuff online for feedback and pointers as much as to show people how I approached problem.

Paul
thanks for the info, much cheaper than aristo!
 
1 - 15 of 15 Posts
Top