Skip to main content

Reply to "PS2 3V, speed control off in conventional, shuts itself off"

Lou1985 posted:

….

So back to the hobby shop it goes. It is most definitely speed related. It was tested under DCS and conventional power under 35 scale mph and works fine.

I assume the first thing your LHS will do this time is to run it at >50 sMPH!  Also, I assume the engine gears have been properly maintained-lubed.

Call this nit-picking, but the symptoms suggest a power related issue.  Obviously, speed and power are intimately related.  When you mention time-dependent behavior to get it back to "normal" operation, I think electronic component over-heating...as opposed to electro-mechanical component breakdown when reaching 50 sMPH.

So, two ideas if you're continuing down the DIY diagnostic path.

1) Run the engine without the passenger car load.  For the same 50 sMPH speed, this reduces the power demand on the transistors, diodes, etc. on the PS2 board.  If the shutdown speed increases to, say, 60 sMPH that would be a telling symptom.  Or, if your tests were without load then add as many heavy cars as possible to make the electronics work hard to achieve the same speed.  Then, if the shutdown speed decreases to, say, 40 sMPH that would be an equally telling symptom.

2) Pull the 12-pin harness from the PS2 board and run the engine.  You will not get any smoke or sound since the volume control and smoke switch wires are on that 12-pin harness.  But the engine itself should move fwd and rev.  Does it still shutdown at 50 sMPH?  This is not conclusive but could help isolate (or at least put your mind at ease) as to whether your wiring modifications are related.

To be clear, even if these tests shed new light, if it is indeed a component-related issue you will be hard-pressed to repair it yourself as the components can be difficult to change and MTH does not publish component-level schematics or parts lists.  So it would have to go to your repair shop anyway.  

OGR Publishing, Inc., 1310 Eastside Centre Ct, Suite 6, Mountain Home, AR 72653
800-980-OGRR (6477)
www.ogaugerr.com

×
×
×
×
×