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· Just another modeller
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QUOTE (SD40-2 @ 10 Sep 2008, 03:56) <{POST_SNAPBACK}>Well,i`ve cleaned the wheels and track again,but i still have flickering lights.
Could it be the actual light type,the locos have grain of wheat,rather than an actual LED??

***The SD40 is a 12 wheel loco and US prototype diesel loco's usually have pickup on all driven wheels, so if wheels and track are clean and lights still flicker excessively, then the problem is pickups not doing heir job, not the type of bulb.

What brand is the loco? In the absence of this data, some general advice.

I suggest you disassemble the bogies and look closely at the surfaces that make contact between wheel and loco bogie frame/chassis:

If you aren't familiar with this process then look for the Mfrs assembly diagrammes on line and also take the odd digital photo as you disassemble to give you an easy referral point or tw ofor reassembly.

* Polish the backs of the wheels and axles. use very very fine wet and dry used wet (appx 1,000 grit) if needed to remove any blackening.

(Blackening may look good but it always resistive/a partial insulator, and it should be taken off wheel backs as over-blackening is common and this will definately affect pickup badly). Don't over do it.... just enough to get to shiny metal is enough.

* clean and polish carefully the slots the axles move in. (Very fine wet and drywrapped around a thin rod possibly) but don't use overly much abrasion here , again, just enough to make things shine if metal, enough to just remove any fine "dags" if plastic... you do not want to change the shape of this slot)

* clean any phosphor bronze pickups and make sure they make contact where they should, or that any wire that should be attached still is attached.

* check the relationship between pickups and wheels and make sure that contact is made where it shoud be.

Reassemble carefully, checking that all is well and correctly placed as you do it.

make sure all wiring is good, esepcially that both bogies are now properly connected to the decoder red/black wires so pickup gets to where it should go and then turn the loco upside down.

Place one probe of a meter on the place the red wire of the decoder connects to, and test all wheels, making sure every one of them has good contact/shows contact on the meter. Repeat with black wire connection point and the other sides wheels.

It should be better now, but if none of this helps the device you are looking for is called flicker-free, and is available from Euroscale models and Bromsgrove models in UK, DCCconcepts in Australia. All are members of this forum.

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