This loco had similar but much milder cyclic motor speed issues as the diesel shunters in article 16, mild enough to not be overly concerned but I felt it could run better as its sister engine with an early non-Ringfield motor. I will not go through the details here as I covered the issue in depth with the shunters, but I will illustrate the decoder installation using the DZ126 and the RoS-6D as the issues may not affect your loco. Very Important - the Ringfield motor was modified as in article 12, failure to do so can destroy a decoder. https://platform1mrc.com/p1mrc/index.php?threads/dcc-loco-conversions-12-dublo-wrenn-ringfield-motor.5993/ 1 - Digitrax DZ126 Straight forward installation as plenty of space for these small wrapped decoders on top of the Ringfield motor casing, the chassis connection is made via a 6BA solder tag under the screw which holds the motion plate in position. The wire from the pickup plate simply connected to the decoder wires. However performance was not as good as expected especially compared to an older sister engine fitted with a Lenz Standard decoder. In light of the issues with the diesel shunters I then fitted a RoS-6D 2 - Rails RoS-6D Mounting possible in the same place as the DZ126 but wires soldered to the pins of the RoS-6D and the two extra pins cropped off. Pins insulated with unshrunk heat shrink sleeving to prevent shorting to each other and the motor housing. The decoder was attached to the motor housing by a double sided sticky pad. This loco then ran smoothly as expected without any cyclic speed variations. The cyclic speed variation issue appears to only affect the Ringfield type motors and only when running on the layout. In the light of these first three Ringfield conversions, two shunters and this 8F I will use the RoS-6D or the larger RoS-218 (which has a wire harness, simpler wiring where there is plenty of space) as the default for the remaining Dublo and Wrenn locos I have for conversion. Other (non-Ringfield) Dublo locos already converted using Lenz Standard, Hattons MD4 or Digitrax decoders will be left as they are as they run well , they will be described in future articles. Discussion always Jim Return to Index
Since the above article was posted I have found that the Rails Connect family of decoders have not performed well on the open frame motors of the 2-6-4 tank locos (I have yet to look at the 0-6-2 tank locos) , this I shall detail in due course. I have found that in general this family of decoders are not suitable for driving worn, low gear ratio mechanisms, other decoders are being tried out. Jim
