F3Upgrades

11. Locate the connector that has five wires coming from the long hood. The two orange wires go to the speaker the blue wire provides power to the front headlight, the red wire provides power to the rear headlight and the black wire is common to both front and rear headlights. The blue and the red wires need to be swapped. The easiest way to do this is to remove them from the connector and reinserting them in the opposite hole. Use a small flat screwdriver blade to press the tiny tab which keeps the contact in place inside the connector housing. Be gentle, it does not take much pressure to free the wire. Once you remove the red and the blue wires, use an x-acto blade to just lift the tab on the contact. The tab is very small and very delicate, the x-acto blade just needs to slide under the tab to let it work properly, DO NOT BEND THE TAB. Insert the blue wire next to the black wire and insert the red wire into the center location. The tab on the contact must be aligned with the opening in the connector housing and the contact must be pushed all the way into the connector housing. Gently tug on the wires to be sure they are secure. The alternate method is to swap the red and blue wires on the main circuit board using a soldering iron, or you can cut the red and blue wires on the wire harness between the connector and the main circuit board and reconnect them red to blue and blue to red.

Description of the problem:

Aristo-Craft's model of the RS3 is one of my favorites. I have 6 of them that span the production life of this model. Aristo-Craft continually upgrades it's line of products to include new technology and improved performance. Among the upgrades that the RS3 has seen is the integration of a 'Plug-And-Play' circuit board that comes standard on almost all new production engines from Aristo-Craft. This upgrade is supposed to allow the consumer to buy either the Aristo-Craft 75MHz Onboard RC remote control board or a third party DCC decoder, and just plug it into their engine.

The problem that I am addressing in this article has to do with a conflict in how this engine is assembled at the factory which won't permit the installation of their onboard receiver unless you remove the factory installed speaker. This seemed odd to me and I wanted both Radio Control and sound in the same engine. I had heard of this problem about a year before I got one of the new production RS3s that have the 'Plug-and-Play' circuit board so when I got one I had to figure out what happened to create this conflict. I mean I figured that Aristo paid someone to incorporate this feature and being a product designer myself, I couldn't fathom the product designer making this big of an error.

I opened up my first new RS3 and tried to install the onboard receiver, sure enough what I heard was true, you can't close the engine back up with the receiver in place, it hits the speaker! So I sat and studied the problem for about 15 minutes and realized that the engine was assembled backwards! Holy cow, the factory is misreading the drawings or the drawings are wrong. I did a 20 minute disassembly and reassembly of the engine's frame and viola it all fits perfectly, meaning the designer did not blow the design, he (or she) just didn't relate the assembly procedures to the factory clearly enough.

The following article details how you can fix the mistakes the factory made when assembling your new RS3.

The Modification:

1. Remove the entire superstructure: Handrails, stanchions, fuel tank – 4 screws, long hood, short hood, battery boxes and cab – 17 screws.

2. Unplug two connectors that attach the main circuit board in the long hood to the power distribution board on the frame assembly.

3. Remove the motor block assemblies by removing two screws from the top of each ‘A’-frame. This step gives you access to two Weight Retainer Screws that attach the upper weights in the frame assembly (screws 1 thru 4 below).

5. Remove six screws that attach the three circuit boards to the frame assembly (screws 5 thru 10 above)

6. Locate the MU cables (the black pair of wires which run from each end of the power distribution board to each end of the engine frame. Find the white mark on one of the wires close to the circuit board. Cut both wires through the middle of the white mark so that you are left with some white mark on both pieces of the cut wire. This will give you a visual indicator of which wire connects where later in step10.

7. Remove both upper weights by removing a nut, cable keeper, another nut and a washer which attach the weights to the frame assembly. Leave the lower weight in place. Place the shorter weight at the rear of the engine and the long weight at the front of the engine aligning all holes and cutouts. Reattach the weights in their new locations using the hardware in the same order you removed them in. Install the weight retaining screws through the bottom holes of the frame and through the weights. Add the large flat washer and one of the nuts, secure the weight tightly, place the cable keeper on the screw and attach it with the second nut.

10. Clip the MU cables in the wire keepers attached to the screws that hold the weights installed in

step 7. Working with one wire at a time, reattach the MU cables to the circuit board making sure that you match the wire mark on the wires to each other. The rear MU cable will be extra long and the forward MU cable will be too short. Add wire as needed to the forward MU cable and be sure to insulate the splices with heat-shrink tubing or electrical tape. Re-bundle the wires to keep them neat and together, this helps when reattaching the superstructure (hoods and cab).

8. Place the power distribution board on the frame in the opposite the direction it was installed originally. The short wires attached to the small circuit board should be facing the rear of the engine (short weight). Reattach the three circuit boards using the six screws removed in step 5.

9. Reinstall the motor block assemblies by first plugging in the connectors and then using two screws in each ‘A’-frame from step 3.

This completes the frame modification but there is one last thing to do. The engine will run and the on-board TE will now fit in the engine with the speaker but the headlights will be working backwards. That is the front headlight will come on when running backwards and the rear headlight will come on when going forward. To fix this you need to swap two wires attached to the main circuit board in the long hood.