MRC DC throttle -zero setting "drift"

[rrinker]

 The big ones put out a pulse even on stop, it was enough to drive a constant lighting circuit, but no one's locos ever moved The regular type, I used to have a Tech II 1500 and none of my locos ever kept moving at stop, and I hav e a Tech IV 220 or something like that which I use for DC testing, again my locos all stop when the knob is turned all the way to stop. Both use pulse power.

 If they are older, I'm going to suspect a bad capacitor. At most there are probably only a couple of electrolytic capcitors in those. If any are bulged or oozing goo they are bad and need to be replaced. They don;t always leak though and can still be bad. Replace with equal value, same or higher voltage rating. Both numbers are printed ont he capacitor itself.

                                    --Randy

 

[RR_Mel]

We will need a bit more information.  What voltage do you measure at zero throttle?  Do you have a load on the power packs when you check the voltage?  Is the Momentum switch on or off?  What are the MRC model numbers?

 

What kind of meter are you using or how are you determining there is voltage with the throttle at zero.

 

 

Mel

 

 

My Model Railroad   

http://melvineperry.blogspot.com/

 

Bakersfield, California

 

I'm beginning to realize that aging is not for wimps.

 

[Redvdub1]

Our club now has three MRC throttles which don't "shut off" when the throttle is set to "zero".  Two are pulse power throttles and one is a dual throttle 50 watter which I don't think is pulse power. 

Any ideas as to why the "drift"? Are they "fixable".   MRC was no help...they no longer have any bench technicians on board..couldn't find anthing on the web.  The 50 watter has no "trim pots" anywhere...I haven't opened the 12 and 18 watt pulse power units.  

BTW..these are "old" units...at least 15 years old..probably older.