QUOTE (RichD @ 29 Jan 2012, 04:25)
<{POST_SNAPBACK}>This is a fairly common problem with Parma controllers, it is more likely to happen if the wiper button does not ride flat on the resistor. It is a good idea to put a piece or 400 grit sandpaper face up between the button and the resistor and pull the trigger a dozen times to flatten out the contact area. You can salvage the resistor by unwinding the last turn of the wire and soldering it to the back of the full power band.
I'd put good money on it being exactly as Rich has said above.
The "economy" controllers have "uncoated" resistors as standard, so are more likely to have the entire resistor lose tension and unwind wen the wire breaks.
The "PLUS" series resistors are inter-changable if you cannot recover this one, and have a coating on the rear surface, so that when (not if), but when the resistor wire breaks, they don't unwind as much.
You can also paint the rear side of an economy resistor yourself with nail polish or epoxy resin to improve their reliability. - just avoid getting any on the working surface.
How long they will last is "a piece of string" (who knows how long). Old hands have often had a controller for years without problem, newbies who "cruise" cars waround the trakc with the wiper in a fixed position - or anywhere exacpt full power for any length of time, are 100 times more likely to overheat then burn out a resistor.
- I replaced about 30 resistors in club controllers, and repaired about 20 in 12 months - JUNIORS NIGHT was the problem, kids holding the controller in cruise mode......
Being a magnet track the loads were higher than on a non-mag track as well, which didn't help.
You CAN fit "PLUS" resistors to economy controllers. I have done that a few times for folk.
Longer term you are better off buying these.
Negative polarity for home set tracks
http://www.professormotor.com/product-p/pmtr2113.htm
Positive polarity version for most club built tracks
http://www.professormotor.com/product-p/pmtr2120.htm
They do not have resistors, and use a different way to control speed, so they are VERY robust, and apart from cleaning the wiping surface with the proper lubricant (Superlube), need almost zero maintenance.
I have sold something over 100 of these, and the only ones I have repaired have a couple that had been dropped, and for higher end models, I have replaced 2 brake trim-pots in the last 5 years.
Prof Motor are the largest selling controllers in the world these days. - Talking to Andy (The Professor) yesterday, he was saying some dealers take 150 at a time.... makes my "20 mixed please" look like small fry....
or go a bit further up market and grab a Slot.it one, lots of good features.
