Photo 1 — Drill #62 holes through board near switch terminals marked with black ink. Feed wires through

holes and carefully solder to indicated points.

Photo 2 — Drill four #62 holes in rear apron of housing, and mount connector (Mouser Electronics Cat. No.

651-1751264 or similar). Solder remaining ends.

Adapting the New Walthers Turntable Controllers for Use with DCC Systems By Paul Turvill

Introduction

While the new European-made 90’ and 130’ HO and N scale turntables from Walthers are masterpieces in terms of me-chanical and electrical performance, it’s probably safe to say that the lack of design considerations for DCC operation is a ma-jor disappointment for many modelers. This document details the way in which the author modified the standard control box to accept DCC switch commands.

Basic Concept

Because the turntable itself is solidly built and resistant to most conventional means of electrical or mechanical modifica-tions, I decided to take the simplistic approach, and concentrate on modifying the control box to allow it to accept DCC switch commands to simulate the pressing of its “turn clockwise” and “turn counterclockwise” pushbuttons. While there are doubtless numerous methods of accomplishing this, I chose to do it by driving a pair of polarity-dependent sensitive signal relays with outputs from a Digitrax DS44 stationary decoder. There are a number of low-cost relays capable of handling the job, but I se-lected a pair of Catalog No. 655-V23026-A1001-B201 relays from Mouser Electronics. These relays will close when a positive voltage is applied, and open when the voltage goes negative; this is a perfect match for the DS44.

Construction

I mounted the relays, the DS44, and a couple of screw-type terminal blocks to a small piece of perforated circuit board. The relays and terminals are designed to match the 0.10”x0.10” spacing of the holes on the perf board. The wiring is arranged so that a “thrown” signal from one DS44 section activates the “CW” relay, and another section of the DS44 activates the “CCW” relay. The relays are released whenever the DS44 sections are set to “closed.”

Next, I opened the control box and installed a 4-position terminal block on the case, and wired it to the pushbutton switches mounted on the circuit board. I used AWG 30 insulated “wire wrap” hookup wire, which fits nicely through #62 holes drilled through the circuit board. The photos below illustrate the location of these holes, the switch terminals to which they must be soldered, and other details. The soldering is moderately delicate, but not impossibly so.

Operation

Once these modifications are made, the turntable may be still be operated manually using the pushbuttons, but it can also be operated by sending appropriate switch commands from a hand throttle. On my layout, operation is fully automated by means of a few Macros and Schedules executed by Railroad & Company’s TrainController software.

Photo 3 — View of completed wiring, showing wires coming through new holes in board and connected to

added terminal block.

Photo 4 — Reinstall board to front of housing, being careful that built-in pushbuttons and LEDs are correctly

oriented .

Photo 5 — Top rear view of modified control box, show-ing relationship of new terminal block to original.

Photo 6 — Add a label to identify the terminal pairs, hook it up and you ’ re ready to go. Any SPST set of

contacts will rotate the bridge in the indicated direction.

Photo 7 — This is the DCC Turntable control module: a Digitrax DS44 stationary decoder and two sensitive re-lays (Mouser Catalog No. 655-V23026-A1001-B201)

mounted on a small piece of perforated board.

Photo 8 — Wired side of control module showing wire runs. Connections at left are track power and relay con-tacts used for CW/CCW activation of the turntable. Re-maining four connections are for the two unused DS44

addresses.