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Difalco controller brake contact mod


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#1 dalek

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Posted 09 January 2018 - 06:39 AM

I have a Difalco controller and after I had used it for a year or so, the brakes became intermittent.  
 
After a few wall shots, I discovered that the brass plate on the back of the trigger had a spot that was black and pitted.
 
That plate and the screw head that it touches, is the controller's brake switch.
 
I went back and looked at the instructions and sure enough, it said to clean the plate periodically.
 
But after a while, the plate gets a low spot in it where it contacts the screw head.
 
The plate is relatively large.
 
Has anyone tried using a longer screw so the head could be raised and lowered in order to make contact at different points on the plate and different points on the side of the screw head?  
 
It would be like having a brand new brake switch each time you move it.  Make sense?
 
Also, maybe modify the screw hole so it's a slot so you could move the screw left and right for even more new points of contact?
 

Dale King
 
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#2 Mike Patterson

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Posted 09 January 2018 - 10:50 AM

I soldered a piece of brass tubing to the screw on mine. It gives more contact area, and is easier to clean than the screw head.


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#3 gotboostedvr6

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Posted 09 January 2018 - 11:05 AM

Increasing surface area of the brake contact may result in reduced breaking performance. If you do this without increasing the spring tension resistance across the circuit may actually increase.
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#4 Markomatic

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Posted 09 January 2018 - 11:06 AM

I have had the same issue with the full on contact that activates the relay. I keep them clean but sometimes when I go to full speed the car stops until I press the trigger harder. I was thinking of adding some micro switches in place of the contacts.


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#5 gotboostedvr6

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Posted 09 January 2018 - 11:09 AM

Leaving the brake contact in the stock configuration and cleaning it once a month would be a much simpler solution
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#6 Ramcatlarry

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Posted 09 January 2018 - 11:59 AM

Brass oxidizes.  Clean it well and TIN it with a coat of silver solder. Much less likely to oxidize.


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#7 wjtaylor

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Posted 09 January 2018 - 12:07 PM

If you are having a problem with intermittent brake issues, that is occasionally you will go sailing off into the corner and, no brakes! What I found was the tab that touches the brake button, over time bends and the button on the wiper arm moves further back until it actually is touching the brake band on the resistor and the trace behind it. I have now fixed 3 controllers, including one of mine, all having the same problem in operation and finding the same flaw. I simply rebent the tab and all 3 controllers stopped having the problem. Although I went out and bought a new DiFalco and don't use mine anymore


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#8 Greg VanPeenen

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Posted 09 January 2018 - 01:08 PM

Do what Larry said that has worked for me.



#9 JerseyJohn

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Posted 09 January 2018 - 06:41 PM

Quick fix flatten the brake contact screw allittle to increase contact. Permanent solution . purchase the parma full power and brake contact buttons with the mount and replace it. JJe8d107d6dce9f75179d2f844770ebc71.jpg?11577ed2aa243bd28521abb6db213e99e78.jpg?115 Koford also makes a silver button.


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#10 Greg VanPeenen

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Posted 09 January 2018 - 08:35 PM

Replace the whole works with a micro switch.


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#11 axman

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Posted 21 June 2018 - 02:00 AM

I actually think JerseyJohns solutions is best... but if you want to do it simple and cheap read on.

 

The latest batch of Difalco's we got at our club had Nyloc brass nuts as the brake and full speed contacts.. and we all had intermittent braking problems. 

I put a multimeter on the nyloc nut and showed an open circuit between the bolt and the nut when you twisted it slightly - it was like the nyloc was acting as an insulator.

The same nut is on the full power contact but difalco has soldered a shunt wire to it so he is obviously aware of its shortcomings.

 

Our solution, which has now been done for several member of our club seems to have solved the problem:

Just get a braid and cut most of the clip away. Then put a something pointed lie a pen or pencil and open up the inside of the braid so it becomes a tube again ( Copper braid starts its life round and then is rolled flat )  cut the braid just long enough so you can push it over the nut and it goes all the way to the base of the bolt where it comes out of the circuitboard. Then zip tie the braid under the nut. fold the closed part of the braid to one side ( with clip attached) you've now got a soft copper shroud that gives a nice contact for the wiper arm to hit. You may have to slide the circuit board forward slightly so your wiper button is not bridging the slowest band on your resistor and the brake contact.

I'll post a pic if you want the visual ..

 

Regards,

 

Kim   


Kim Axton

#12 Bill from NH

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Posted 21 June 2018 - 06:09 AM

Kim, why not just use a solid brass nut?


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#13 axman

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Posted 21 June 2018 - 09:15 AM

The solid brass nut also gets the black spot after a while.. Thats why ultimately I like proper buttons like JerseyJohn has posted.. and its the way controllers were built when Parma bought out the first Turbo controller. I think the problem with brass to brass nut contact is electrical arc and thats the black spot that appears. It's not like switch gear that "wipes" the surface which helps self clean. It's just two surfaces "banging " together.  With the copper braid contact against the wiper button it gets a softer landing spot and perhaps because its copper does'nt seem to get the black spot. 

IMG_0686.JPG  

You can see in this pic how the braid provides a larger "softer" surface area. You can also see the full speed nyloc nut is starting also to get the dreaded black spot... I suppose you dont notice poor contact as much on the full speed nut because the wiper arm is still in contact with the full speed band on the resistor block.


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#14 drrufo

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Posted 21 June 2018 - 10:00 AM

The black spot is carbon caused by the arcing when the brake contact on the trigger hits the nut. Just take some fine sandpaper and put it between the two contacts and remove it while putting pressure on the trigger. It will burnish ( Dan's word ) the contact.

The contact will develop a "hole' where the nut makes contact, cleaning with the sandpaper will level it out somewhat.

I have controller that are 20 years old and have the dip and they work fine. Just keep them clean.

 

John Andersen


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#15 Phil Beukema

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Posted 21 June 2018 - 11:32 AM

I have had good luck keeping the carbon off by using a (Q-Tip / alcohol) and following up with a (Q-Tip / braid juice).


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