Sunday, 13 November 2016

Gremlin hunting

The November meeting started quite well.




David S had brought two loading gauges, one concrete and one rail-built.











Alan S distributed some experimental DG coupling checking devices - black blocks machined to fit on top of the rails, with slots at appropriate positions to check heights of buffing plates and loops.

They also included a jig to mark positions to drill holes in DG base plates, and in the mounting plates on wagon chassis, to allow them to be screwed in and adjusted - but he had found the procedure to be too fiddly to be useful.






One of these in use, checking the heights on Alan's own jinty.







Latest contribution to the layout's wagon collection - box vans and a plate wagon from David S, using some of Keith's cast resin bodies.







This month's unlikely visitor - a part finished Princess Elizabeth, from John Lewsey (himself a rather infrequent visitor to the group). A Nigel Hunt kit, construction described on RMweb here






At this point a smell of burning was detected from the power supply, and the gremlin hunt started. Testing separate parts of the layout isolated the short as being present in the half of the layout away from the fiddle yard - checking the separate circuits for point motors and uncoupling magnets revealed no problems, so the short lay somewhere in the trackwork circuit. Connecting cables were switched, and eliminated as the cause of the problem.



Eventually the short was narrowed down to one position of a specific set of points. Initial diagnosis suggested the switch was at fault, so the control panel was dismantled and the offending switch replaced.








Unfortunately the problem persisted, but eventually poking various parts of the offending set of points dislodged the gremlin and the layout resumed working properly.

By this time there wasn't much time left to attack the "ToDo List" generated from the previous month's experience at Wilmington Exhibition, so this was deferred until next month.

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