Need DCC Advice for AHM/Rivarossi 4-6-2 Pacific Install

[napa15]

Hello,

Haven't made many posts here in the forums, though I browse through all the time. I'm somewhat of a rookie in need of some advice and help from you more experienced folks.

I have just purchased an old AHM/Rivarossi 4-6-2 Pacific (Southern #1401) engine from a friend. I would like to install a DCC decoder and add sound. I have done some research on the subject and believe that I will need to install the DCC decoder in the boiler area and the sound decoder in the tender for this particular make of this model. Maybe.? I need advice on what brand/model decoder to get and which sound decoder is to get. It would also be hugely helpful for some direction to a site where I can get some guidance to installing a DCC decoder in one of these engines. This will be my first install.

Thank you in advance for your advice and feedback.

Thanks,

Chuck

[simon1966]

You are certainly brave, a hard wired decoder installation for a loco that was not designed with DCC in mind is far from impossible, but not what I would recommend for a first timer. 

First of all, does this thing run well on DC?  Being that it is quite old, it is worth seeing if it is actually worthwhile to convert.  If it does not run well on DC, then see what you can do with maintenance to improve its performance. A poor runner in DC will be a headache under DCC.

There are some basic issues that need to be understood.  How much current does the motor draw?  Older motors often draw current that would overload a modern decoder.   Is the motor isolated from the frame, and if not what has to be done to isolate it?  How good is the electrical pickup from the wheels, where is it from?  Does the tender have power pick up.

Prior to starting a hard wire install on an older loco, these are all things I would want to assess and help determine what has to be done to perform the install.

[cacole]

I've done a couple of these over the years -- an IHC Mogul and a Pacific.  The first thing you need to check is that the tender has electrical pickup wipers on the trucks.  If it does, a sound decoder can be installed into it rather easily.  If it does not, forget about sound.

For the engine, I used a TCS M1 decoder that was placed on top of the motor.  The headlights in these models are a big problem, though, because of the way they are wired.  Mine both used 16 Volt incandescent bulbs with their leads soldered to the front of electrical pickup wipers that run the length of the chassis.  The motor wires are soldered to the back of these wipers.  I left the original bulbs in place, which means that they are always on and cannot be controlled by the decoder.

The alternative if you want to replace the bulb with an LED is to run wires all the way back to the decoder across the top of the lead weight inside the boiler.  Spare decoder wire is small enough to do this without getting pinched by the weight.

The sound decoder and speaker in the tender is fairly straightforward, but synchronizing the decoder chuff rate to the motor decoder is practically impossible since there is no connection between the two.

[simon1966]

Cacole, I have done a number of the IHC Mehano made models.   These Slovenian locos are fairly easy because the motors are isolated.   I don't know about the AHM era Rivarossi locos?  Not sure if they share anything in common with the Mehano era models.  So my advice to the OP is to check and make sure things are isolated before installing a decoder.

[jeffrey-wimberly]

simon1966

These Slovenian locos are fairly easy because the motors are isolated.   I don't know about the AHM era Rivarossi locos?

I don't know much about the steamers. A couple I've worked on ahg isolated motors, one didn't. But most AHM/Rivarossi diesels I've worked on didn't have isolated motors. The ground side was almost always directly attached to the frame. Once in a while I saw one that had wires to both sides of the motor. Sometimes isolating these motors is as easy as applying a couple of layers of electrical tape and gluing the motor in place. A couple of times I used small cable ties.

[basementdweller]

As Simon has said, evaluate you locomotive to see if it is worthwhile adding DCC to it. A poor performing DC loco will only be very agravating once converted to DCC.

If you loco runs well and had adequate power pick ups, then it may well be a difficult but worthy install. Google wiringfordcc.com it does not have your loco listed but does have several othe Rivarossi locos listed. Look for "decoder instalation".

Good luck.

[napa15]

I really appreciate the prompt and informative replies. I am not intimidated by the DCC install, but obviously want to go into feeling as prepared as possible. Which also means making 100% sure I have identified exactly which loco I have (year and motor type - as you guys have suggested). I see the DCC decoder suggestion of TCS M1, but did I miss the Sound Decoder suggestion? After some research I believe the Tsunami TSU-1000 Southern Steam is the one that I need to go with.

Let me answer some questions first:

1. Yes, the tender has the wire pickups on the wheels. So that should not cause an issue with installing sound.

2. The engine runs surprisingly well, and smooth, for it being so old. It DID NOT when I first got it. I took it apart and greased the single gear and oiled all the moving parts and slowly got her back to moving freely after such a long still cold storage. But now, she is running smooth and free. The only thing not working is the headlight, but that is a minor, fixable issue.

Here are the diagrams I have found for this exact engine, maybe it will help to identify exactly what I have to help in your guidance with what you guys are suggesting. But I think that Cacole has hit the answer on the head.

[cjcrescent]

Run a stall test on the motor. Hook up one lead of a multi meter, with the dial set to amps, coming off one side of a power pack, then connect the other lead to the track. Place the loco on the track with power at full. Hold down on the loco just long enough to stop the motor, noting the amperage the motor draws. Stop the motor just for a few seconds. Keeping the motor stalled can damage it. If the max amp draw noted was over 1amp, the motor should be replaced.

Another thing you may want to do to make this engine more "Southern", is to replace the trailing truck with a USRA/Hodges trailing truck from Cal-Scale. IIRC this model came with a Delta trailing truck, which is incorrect for the PS4. At different times in its life it also had a headlight with a visor, but changing the headlight is up to you.

When you get the install done with the TSU, the correct whistle is the 3 chime.

[jeffrey-wimberly]

Looking at those diagrams it looks like the motor is grounded directly to the frame. Is that a metal frame? If so that can be resolved by removing the motor and putting a couple of strips of electrical tape across the bottom of the motor where it would normally contact the frame. Then run a wire to the ground contact on the motor. That wire would connect to the gray wire on the decoder (motor negative brush). The problem now is that the motor can't be secured in place with the screws anymore as that would ground it. For this I would glue the motor in place.

[CNCharlie]

As far as decoders go, I put DCC and sound into a Mehano Hudson.

I used a TCS M1 that was installed in the boiler. For sound I used a MRC Sounder in the tender connected to the tender pickup. The result was great motor control and reasonable sound. It was a fairly easy install.

CN Charlie

[Texas Zepher]

napa15

I have just purchased an old AHM/Rivarossi 4-6-2 Pacific ... I would like to install a DCC decoder and add sound. I have done some research on the subject and believe that I will need to install the DCC decoder in the boiler area and the sound decoder in the tender for this particular make of this model. Maybe.?

This is a pretty ambitious project for a 1st time install.   But, No, I would not install a decoder in the boiler and another in the tender.   I have done serveral locomotives like this and here is what I would do.

1.  Re-motor with a can motor.  If you choose not to do this isolating the existing motor is easy, just cut the one wire (or brass strip) going to the locomotive frame.
2.  Maybe regear with NSWL gears (I believe they make a kit specifically for this).
3.  Make the place for the speaker.  It is probably easiest to make it sound down through the bottom.
4.  Put the decoder in the tender.
5.  Run two wires from the decoder motor output directly up to the motor in the locomotive.   I would put a plug in the wire so the loco can be separated from the tender.

OPTION 1
6.  Change the tender trucks/axles so that all wheels pick up power from both rails.  Use that power to the inputs on the decoder.

Option 2
6.  Use the existing power feed between the tender and loco to feed the power from the frame of the Locomotive back to the tender.   This is reverse of its  normally function of passing power from the tender wheels up to the motor.  Use that power and the one from the tender wheels (opposite rail) to feed to the inputs on the decoder.   This configuration can cause problems when the locomotive passed from one power district to another one.  The locomotive ends up in one, the tender in another and it stalls that way.

For the headlamp run two additional wires from the decoder lamp circuits.

I suppose the decoder could be put in the boiler, but then as you say, unless two decoders are used one would have to run two wires back to the tender for the speaker.    With the decoder in the locomotive there is less room for weight, and the chance that the wires get caught or bind a moving drive shaft.

[richg1998]

If you need to isolate the motor frame, use Kapton tape. DCC suppliers sell it. It is thin and tough and does not ooze like electrical tape.

I have an install using Kapton tape with Nylon screws to fasten the motor instead of the metal screws. Make sure the threaded hole for the motor is smooth.

Rich

[Darth Santa Fe]

Actually, isolating a Rivarossi motor for DCC is one of the easiest things you can do. Here's step-by-step instructions on how to do it:

Step 1: Cut the grounding clip going to the grounded brush.

All done! Then just solder in a decoder like you would for anything else!

[napa15]

I think it is a metal chassis, but I'm not 100% sure. I need to check again.

I also think i would like to upgrade the motor to a can motor, and upgrade the gear. Exactly which can motor would I need to go with and which gear(s)? I did some looking around yesterday, but there are a lot of different can motors and I don't know how to tell which one I need for this loco. And then, how would I install it and still isolate it from the chassis if needed?

I think I'm going to go with the N scale decoder suggested, and the TSU-1000 decoder. Sound right? Also, I'd like to add an LED headlight and even an LED backup light. Should be easy enough, right?

[richg1998]

NWSL gears

http://shop.osorail.com/category.sc?categoryId=44

Email Dave at NWSL. He has helped me a lot.

You will see how "easy" this is when you do it. lol

You will need a Puller and Quarterer if you do any gear change on the driver. A can motor and flywheel may be all you need if the present gears system is ok.

Again, if you go with two decoders, put a 100 ohm, 1/2 watt resistor on the TSU1000 motor leads so your DCC system "sees" the decoder. This is dscribed in the below link.

http://www.mrdccu.com/curriculum/soundtraxx/tsunami.htm

Rich

[Scale Hogger]

Napa15 — are you still on here? Would like to ask how your AHM/Rivarossi Pacific DCC instal turned out.