RS-3 Electronics

Being one of the original locos produced by Aristo-Craft, this locomotive has gone through many changes/improvements.

I have gone through the major "spotting" features on the "versions" page, but this page is to help understand the variations on the electronics, especially how to improve and recover from some of the not so well designed issues.

On the improvements page, I do go over recommending additional protection from shorts destroying traces on the main chassis circuit board.

In general, the early RS-3's had a lot of Bakelite circuit boards and more "point to point" wiring.

Later versions were more connectorized.

Chassis board

The earliest units had a small board to connect the motor blocks:

Later this evolved to a long board in the chassis: (the motor blocks connected to it)

g2 chassis board


Later versions had a more compact board:



"Switch board"

There is also a board in the long hood, near the cab, which has switches for motor, smoke, lights.

This board came in several versions:



Very early, the board was Bakelite:

g2 switch3

A daughter board, with a 5 volt regulator was on this board. It was soldered in at right angles. In the picture above you can see the black regulator integrated circuit on the left side of the daughter board. The right side of the daughter board has filter caps. This board was fairly reliable, no issues.


But, for some reason, Aristo changed it in later production, below show the latest version:



You can see the PIC processor integrated circuit in the picture above, it has more pins (because it is really a microprocessor). Unfortunately, using a microprocessor for a task where power can be interrupted often is a poor, even stupid design choice, yes, just plain stupid. This board fails, quite often:



The PIC often locked up, and the output transistor fries.... this is similar to the issue with the PIC processor in the modern smoke unit, and they do a similar meltdown.

Other issues

Another issue is that the internals are assembled backwards, i.e. the main board bolted to the chassis, which can cause interference with anything plugged into the socket, and this requires the board to be unbolted from the chassis and swapped end for end...



Weather Underground PWS KCACARLS78