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LGB Forney DCC ready decoder install?

18060 Views 32 Replies 16 Participants Last post by  Dan Pierce
I am about to install a Loksound XL decoder in my LGB DRGW Forney. I know that someone (Bob Grosh?) figured out the wiring some time in the past but when I search the archive, the link in the thread no longer works. Can someone point me to where the information is now located?

Thanks, Peter.
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This post was removed by Bob Grosh.
I removed it because of the broken links.

The corrected version can be found further down in the thread.

Bob, fantastic information. So I'm thinking that I could use the DC jumper to make a plug for the Loksound. If I cut the jumpers on the board and soldered leads onto the ten pins on the of the board, and followed connected the pins to the decoder following the standard DCC convention, it should work. I'm assuming that when running DCC, there is no need to connect the three pins on the right in you diagram to the decoder. Does that make sense?

The two wires going to the back that connect to the rear truck are wires intended for the sound card. They are disconnected when the switch in the cab is set to the "silent" position, which makes no sense at all,

This rest of this post was removed by Bob Grosh.
I removed it because of the broken links.

The corrected version can be found further down in the thread.

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Bob. Thanks for the detailed explaination. I think I can take what you did for the Digitrax and Phoenix and adapt it for the Loksound decoder. It's pretty amazing that LGB's definition of DCC ready requires this much disassembly but at least they have everything isolated. I wonder if I'll be able to fit the decoder in the boiler and just run the speaker cable to the coal bunker? Looks like a tight fit but the Loksound is pretty small.

Thaks again. Peter.
If you use a LGB type III DCC decoder or some of the other brands sold in Europe. Then all you do is open the boiler and plug in the card. The DG583S was too large to fit in that space, Therefor, there is a lot of extra work involved. In your case, the LokSound might fit (I doubt it) in the boiler, but you will still need to run wires to the tender tank for a speaker so I figured this was the closest match to what you need.

I've done and documented, (partially) several other installs in the Forney, so if you need any further help. just ask.

By the wa..., Which LokSound decoder are you using? And, Could you email me any high resolution pictures prior to buttoning it up? I'm tempted to try out the LokSound. Do you have a sound programmer?
I'm using the Loksound XL which is fairly compact. i originally purchased the correct LGB III decoder but the added cost and hastle of adding sound made me decide to go with Loksound. I've used Loksound in a DCC ready 2 truck Shay and a Bachmann 10-wheeler. I did get the programmer as the projects as downloaded from Loksound have some peculiarities. Some don't even follow the standard to F1, F2 convention. However the flexibility is amazing and I've swapped bells from one project into another and made numerous other small changes. Unlike the regular Loksound the XL works with 8 or 16 ohm speakers so thats not a problem. The documentation is very poor but the group on Yahoo has some useful info to supplement it. Overall I've been happy with the value for money and the sound quality which while 8-bit, is four channel. I find the volume plenty loud enough.

The only other sound decoder alternative which I'm looking at is the QSI Magnum which looks like a good deal. I have one on the way from Litchfield station to go in my Connie once I downsize it to 1:22. The Phoenix P5 plus a Digitrax/Lenz decoder is just too pricey although I'm sure it works great. I'm using the MRC wireless with their 8 amp booster and that works really nice. I have a booster for the proramming track which was necesssary for the 3 truck Tsuanmi Shay.

I have about half my rooster converted to DCC and hope to have another 2-3 done before I get back to running trains.

I'll post a picture of the install once I get to it. Peter.
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Bob, a year after you posted these instructions, I'm finally in the bowels of the Forney, installing a MRC 1819. It's going very well, except I have one more connection on the 9 wires from the LGB socket than I know what to do with?

I'm left with red wire on the cable "clump" number 3, which you connected to PIN 5 GROUND on the DG583S.

This is the manual for the 1819,


and it only shows two "common" connections for the various light functions.

Any ideas?

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Pardon gentlemen, but can both of you actually see the image files, because I can not. Not even if I take the link and place it in a separate browser window. Additionally, when I back it down to just the ALLY sub-directory I still get a HTTP 404 error. Just wondering?
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I can't see any pictures either.

I added a Massoth LS decoder to my Forney with great success. I removed the original control board. Was a pretty straight forward install with the speaker in the rear coal bunker. Although I forgot to change the lights so blew them on first run. Added 18V bulbs and they work great.
None here that I can see.
No, the images are no longer working. Fortunately I had printed all 23 pages of Bob's directions when he first loaded them so I was not working blind.

When you pulled out the LGB board for the Massoth install, how did you handle the smoke generator?

I ended up connecting the F2 to the red common postive, which basically simulated the bridge connection on the dummy plug. I got great smoke for a while,and now nothing. I have a horrible suspicion that somehow I ended up sending 18v to the 5v smoke generator. May need to pull off the smoke box and see what is being passed thru. I had planed to use a realy off the accesory lighting (mars) circuit to switch the connection I had made, but may need to invest in a new smoke generator now.

Without a handy switchable output function on this decoder to control smoke, I may look into a simple 2 function HO decoder to piggy back and give that functionality.

The fun of DCC conversions.

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What happened to all the images. I would like to install a deccoder in my Forney.

Lost Soul, MikeL.
Installing a digitrax 583s or a QSI magnum is very simple in these engines using the existing electronics.
Here is a Digitrax wired up to fit the existing LGB 10 pin connector.

Here is the same dicoder on the LGB pin out information in the provided instruction sheet

All you have to do is unplug the dummy plug from the LGB board plug this in ..correctly test it close it and you're done.
The forney install I did required that I put the decoder in the coal bunker so just use longer wires. The connectors are eflite blancer connectors for remote control planes with the male ends ut off.. Any of these type connectors will work.

Here is a QSI pluged into a Genesis same LGB main board as the forney.
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I converted my loco last year using Bob's instructions, the only difference real difference as that instead of servo cables, I built a colour coded harness to match the DCC conventions using hook up wire and a socket from the local electronics store & an NCE decoder.

I was planning to operate the smoke generator on F3 havent had success in getting the smoke Generator to work I have not been able to get continuity from the function + ground to the generator and I am reluctant to install a jumper.

Having worked in N,HO & G I am still not convinced on the benefits of "Decoder Ready" installations, the connections have proved problematical in the samller scales, apart from the Forney and a Bachmann Connie I found it much easier to rip out the wiring and start gain in G Scale.

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Has anyone yet figured out how to retrieve the missing images in the original bobgrosh post of 01/08/2008?
OK, I fanlly found a backup drive with these drawings. Sorry, but I was in the process of migrating my web to MLS when the MLS upgrade sort of scrambled my site.

It is often best to scrap all existing wiring and electronics when installing DCC. However, the Forney electronics works quite well and provides a number of benefits:
[*]It converts the function signal levels to operate the 5 volt bulbs and smoke generator. You do not need a decoder that outputs 5 volts or add dropping resistors. [*]It provides the current to drive the lights and smoke generator so you don't have to worry about overloading the function outputs on the decoder. [*]It provides a current limited output for the accessory socket on the rear of the loco. [*]If you run your DCC converted loco on analog DC, the board provides regulated voltage to the lights and smoke generator even if your decoder does not. [/list]

Important warnings:
[*]The board in the Forney does not have some of the sockets shown in the LGB manual. [*]The pins labeled "SND" do not go to the sound board connector, they instead go to the rear truck pickup. Do not get them reversed or the loco will cause a direct short when placed on the track. [*]There are two wires soldered to the underside of the board that go to the electrical accessory outlet on the back of the bunker. This loco provides a current limited, protected outlet to power the lights in trailing cars. do not use this outlet to improve electrical pickup by connecting it to cars with their own track pickups. [*]Before you disconnect the cab, note that the cables for the rear headlight and cab interior light are identical and disappear into the same hole. They are not keyed. Mark both the plug and socket for the headlight with a permanent marker to make it easy to reconnect them to the correct sockets.. [/list]
Here is what the main circuit board looks like. The underside has a pair of wires solder tacked to some lands. This pair leads to the lighting socket on the rear of the loco.

The instructions that came with the loco include a drawing that is not a lot of help. They only show a partial diagram of a similar board.

Here is a more accurate drawing: Notice that the two pins labeled "SND" on the LGB drawing are used to connect the rear truck electrical pickups. There is no connector for the sound unit.

Here is a drawing of the new universal DCC socket. It consists of 10 pins. Next to it are three pins that supply power to the decoder header. The DC jumper board has 8 sockets for the decoder pins plus three more for the DC signals. I outlined the jumper board in red and show the connections it provides.
I also indicated the standard NMRA colors for each pin.


By examining the DC jumper, we can determine a little about the voltages needed from the decoder. First; keep in mind that the blue wire on a DCC decoder supplies a positive voltage for all lights and accessories, and that when you turn a function ON, the function output acts as a switch completing the circuit to ground (or the - supply). This means that the GND pin on this header is the equivalent to a function output that is always ON. So, the circuit path on the DC jumper from F2 to GND is setting F2 to ON all the time. The F2 pin on the DCC header is wired on the main board to the smoke generator. Since applying ground to the F2 function pin turns on the smoke generator, and the generator is a 5 volt version, then there is a voltage regulator involved. The question is: How much current is required to drive the F2 Function pin? To find out, I removed the header and connected an Amp meter between the GND pin and the F2 pin. The smoke generator came on and smoked quite well. The meter read 40 MA. That's great. The smoke generator regulator is turned on or off by a transistor. That means practically any decoder can control the smoke. We don't have to worry about setting the voltage on the function output, and the generator does not count as part of the load when determining the function output total current rating of the decoder. Also. We don't have to worry about surge current or maximum current rating for the function output. Any decoder that can sink 40 MA on a function lead will work. One big Plus for using the board: The stock 6 volt smoke generator can be used. We do not need to swap it out for an 18 volt version.
The F1 input could be used to drive another 6 volt light. However, the connector shown on the LGB provided diagram is missing on the board.


The F0 inputs (F0F forward and F0R reverse) both work without any dropping resistor. Even though the decoder uses 18 volts for the functions, the LGB main board simply checks the input pins and outputs the correct 5 volts to the bulbs. We don't even need to swap to 18 volt bulbs.

The main board does a little logic internal to the board. If either F0F or F0R (either headlight) is on, then the cab light is also on. You can use F0 to turn on or off the cab light, but it is impossible with this arrangement to turn on just the cab light without a headlight also being on.

The connector shown on the LGB provided diagram is two pins with push on connectors. The pins are used to connect the track pickups from the rear truck. There are no connectors for the LGB sound system.


As with most newer LGB locos there is a square two-pin socket on the back of the loco above the coupler. This socket can be used to provide power to passenger car lights or sound cars. On some of my LGB locos, this socket had a current limiting automatic circuit breaker. While there appears to be an automatic circuit breaker on the main board, it does not seems to be to large a value. When I shorted the socket pins together, the loco tripped my over current protection on my 8 amp booster.


If you disconnect the motor block and remove all the electronics, you get this:
Notice that there are no dropping resistors, diodes or capacitors floating around on the ends of the wires, This is truely a clean design. The bulbs and smoke generator are all 5 volts.
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Thanks for providing the images in the 01/08/2008 post - but, even more critical are the images for the 01/09/2008 post for disassembly of the Forney. Any chance you can retrieve those as well?

Many thanks,
Roger Bush
Fredericksburg TX
Posted By pagosarr on 04/27/2009 5:50 PM
Thanks for providing the images in the 01/08/2008 post - but, even more critical are the images for the 01/09/2008 post for disassembly of the Forney. Any chance you can retrieve those as well?

Many thanks,
Roger Bush
Fredericksburg TX

Roger, I'll try ARGGGGGG! The problem is, some of the broken images are not images at all! They are instead "INCLUDED" html files. Those were common modules that explained procedures that were common to all my Forney installs. The thing is, I have seven Forneys, I installed different decoders and sound cards in each of them, including one that used and RCS RC/Battery. I made a page for each one, but I "included" whole sections of code that referenced parts of the installs that were the same across several Forneys. Those included files had internal references to images that no longer reside on either my original site or the one of the two MLS sites. (I had two first class sites cause one would not hold the entire site.)

Bottom line is, I have to edit the rather complex HTML code in this post because it was cut and pasted from the original site while it was still up. Would have been easier if the MLS site had sufvived the upgrade.

So, here goes.... This may take several attempts, so refresh the page if you still see broken links.

UPDATE OK, I think I got all of them fixed.... WARNING! Many of the images were click-able and took you to larger views of the same images, I did not check to see if all of those links worked, but at least some of them do.

The two wires going to the back that connect to the rear truck are wires intended for the sound card. They are disconnected when the switch in the cab is set to the "silent" position, which makes no sense at all,


The loco will operate as follows:
DG583 2K2 F0 Headlights F1 smoke Bell F2 Manual Whistle F3 Coupler F4 Crossing Whistle F5 Doppler F6 Drifting Chuff F7 Canyon Chuff F8 cab light F9 Flickering smokebox F10 F11 F12

In addition the motor control switch will work as follows:
[*]0, 1 and 2 = sound off, everything else on. [*]3 = everything on including sound. [/list]

The smoke generator will turn off when the loco is stopped to conserve fluid.

OVERVIEW The instructions that came with the loco include a drawing that is not a lot of help. They only show a partial diagram of a similar board. It is often best to scrap all existing wiring and electronics when installing DCC. However, the Forney analog electronics works quite well and provides a number of benefits: [*]It provides a current limited output for the accessory socket o the rear of the loco. [*]It provides a handy switch in the cab to turn off the sound. [*]It provides connectors for the lights and smoke. [/list]

For a complete rundown of the LGB Type III analog board, click here for a new window. Close the window to return to this installation guide

STEP 1 - Disassembly

Cab Removal [*]Pull the handrail supports out of the boiler shell. Do not pull on the hand rails or the upright of the supports. You can leave the handrails inserted into the front of the cab. [/list]

There are also three plastic pipes inserted into the front of the cab. Gently free them from the holes but it is not necessary to remove them from the boiler.
[*]Remove four screws from the underside of the floor that hold the cab and tender. The two screws that hold the steps no NOT need to be removed. [*]Gently work the cab straight up and away from the boiler. There are two cables (each is to conductor) at the front of the cab that will restrict how far the cab can be removed. These wires will be disconnected in step 1C. For now, just let the cab dangle. [/list]
Figure 1A Cab removal.

Firebox Removal [*]Remove one screw in the center of the ash pan, Remove the ash pan to expose the two screws that hold the firebox to the floor. [*]Remove the firebox by lifting straight up. Use a felt tip permanent marker to mark both the socket and the plug for the cable on the engineers side Now you can unplug the two cables. Set the cab and tender aside for now. [/list]

Figure 1B Firebox Removal

Slide the Boiler Forward to Expose Connector [*]Remove the screws in the center of the air tanks just below the running. [*]Remove the running boards. [*]Remove the two screws near the front of the boiler, then work the smoke box free. [/list]

You will have to tilt the front of the gearbox down to work the smoke box forward. Wires from the headlight and smoke generator will determine how far it will go.
[*].Now side the boiler forward just far enough to expose the ten pin DCC connector near the front edge of the circuit board. [/list]
Figure 1C DCC Access


STEP 2 - Cable Routing.

The motor decoder and sound decoder must be installed in the fuel and water bunker behind the cab.

Three servo cables will be used to extend the 9 of the ten pins on the DCC connector in the rear of the boiler. The tenth pin is not needed. The cables will run to the tank behind the cab.

For this installation I'll be using widely available cables that can be found at most any hobby store that sells Radio/Control airplanes. Servo extension cables come with a male connector on one end and a female connector on the other. I used three 6" extension cables and cut the male ends off.. I also uses a 12" extension cut in half as a programming cable for the Phoenix 2K2 sound card.

There is a wire tunnel that extends from the firebox to the bunker. You will need to route the following through the wire tunnel:
[*]Three servo cables, (three conductors each). [*]A red/black pair going to the rear truck. [*]A red/black pair going to the accessory lighting socket. [/list]

Decoder Wiring [*]Familiarize yourself with the LGB analog board. Note that the rear light cable and the cab light cable both contain two black wires and are not keyed or distinguishable from each other. [*]To avoid getting them mixed up, use a felt tip marker to mark both the plug and socket for the rear light. It is identified as L1-R on the right edge of the drawing below. It is located at the very rear edge of the board in the loco. [*]Disconnect the two black cables from LI-R and LI-C. [*]Unscrew the accessory socket from the back of the fuel and water bunker and set the cab and bunker aside. [/list]

[*]Remove the shorting jumper from the ten pin DCC header on the LGB main board. [/list]

[*]Install three 6" RC servo extension cables on the ten pin DCC connector of the LGB main board. Start at the left side of the loco (fireman side) and leave the last pin on the right (engineer side) empty. [/list]

[*]Mark both ends of each cable to identify them. You will not be able to trace the wires once you get the loco partially assembled. [/list]

I numbered them with 1 for the one closest the fireman side and three on the engineers side..

[*]Remove 3 screws from circuit board. Slide the board to the front of the loco to expose the screw wells in the small rear weight. [*]Remove the two screws in the small weight. lift the weight out of the way, and add the three servo cables to the two existing red/black pairs that run under the weight. [/list]

All wires go under the weight between the two plastic weight mounting studs. Make sure to leave some slack so the board can be slid back into place.
[*]Reinstall the weight and tighten the screws. [/list] FIG NN - main board seated
[*]Spread the wires around rear plastic standoff on underside of the circuit board. [*]Make sure the wires are not caught under plastic standoff or screw. [*]Start the rear screw into the weight. [*]Start the other two circuit board screws into the weight and be sure all three standoffs are seated on the weight, then tighten all three screws. [/list] [*]Line up all the cables so they are even and only two wires high. [*]Slide the wire tunnel over the wires from the rear in the bunker area until it is seated under the weight [/list]

[*]Make sure all the wires are captured in the tunnel and that the tunnel is resting completely on the cab floor or you will not be able to install the cab and bunker properly. [/list] [*]Cut the female ends off the servo cables so the wires extend one inch past the rear of the bunker floor. [/list] At this point it is a good idea to reassemble the boiler, smoke box, firebox and cab. This will make it easier to handle the loco.

STEP 3 - Assemble the Boiler and Cab
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Bob - Can't begin to think of a way to adequately thank you for all your efforts. I have had 3 Forneys sitting in boxes (paying no rent) because I was too intimidated to risk making junk of such expensive locos. Now I can get started while I wait for the rain storms to subside in TX.

Maaaannny thanks,
Rog Bush
Fredericksburg TX
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