Digitizing non DCC-ready (Hornby LMS Fowler 4P 1992-1995 version)

[petertg]

Hi all!
Here I am again, in a different forum but pestering again with questions. Here is a photo of the locomotive in question.

After the problems I have had with cheap decoders which were not up to the task I wanted them to do (the fault was mine for not knowing what the locomotives (old) needed and I should have acquired), I have become an angel (?) and fear to tread. This model is not DCC ready and, according to Brian Lambert, a test should be performed to check the insulation of the brushes from the chassis. He says that the multimeter should be set to ohms and, with one terminal against the chassis, the other applied to the brush terminals, there should be no reading. I set my multimeter to the 200 ohm scale and, in both cases and, after various attempts, I got readings of 0.001, although in one case I got a reading of 0.000. How should I interpret these readings?
Furthermore, it seems to me that if I try and place a layer of insulation under the motor, this might alter its meshing with the drive pinion.
Also, I observe that there is a small space between the rear motor support and the top of the motor, whereby it wobbles slightly. Should I remove this wobble?

[Nigelcliffe]

A reading of 0.00 ohms means "no resistance" which equals short circuit, or piece of wire connecting two things together.  In the test you are doing, you have a "fail" and need to disconnect or insulate things before proceeding.  You need a reading of "infinity". 

 

Looking at the photograph, there are two wires (grey-ish, and black) going onto the motor terminals, and from the motor terminals to the chassis.  At a minimum those have to be broken/disconnected, the resistance re-checked.  If there is no connection between the brushes and chassis, then the decoder can be connected to the pickups and brushes.

[petertg]

I disconnected the items mentioned and got the all clear. I then got the brilliant idea of removing a decoder from one locomotive, with the intention of cutting off the 8-pin plug and, at a later date buying a new dceoder (with guarantee) to re-equip. Unfortunately, with all the fiddling I had to do, the decoder wires had become badly curled, I must have damaged it because, once fitted, it gives a short circuit feedback on the programming track. Having reverted the chassis to DC operation again, it works, whereby I assume (please correct me if I am wrong), that the short was in the decoder and not in the chassis, or the programming track for that matter. Anyway, the upshot is that I now have to purchase two decoders.