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More annoying questions...


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#1 strummer

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Posted 07 February 2020 - 12:05 AM

...from someone who doesn't know anything.  :)

 

My questions pertain to some "vintage" controllers; if these have already been asked (and answered) elsewhere, I apologize in advance.

 

I have 2 pair of the K&B/ Aurora "pistol grip" types: these are the same (except for the colors) style as I had back in the '60s. When I first got these, they didn't want to function, but because of their "easy to work on" design (so typical of these vintage items in general) I was able to get them up and working just fine. 

 

Last week I received a small box of stuff, and included was a Cox controller. It has (2) wires with alligator clips, plus a third wire. I figured the 2 with clips would be the ones to connect to my test track, and it also works fine.

 

Controllers.jpg

 

I find the K&Bs to be a little easier to use; (there's less of a stretch for my thumb) but I do like the "hefty" feel of the Cox.

 

Now for the questions: what are the third wires for? The K&Bs' wires terminate with 3 "tabs"; these "tabs" press into the corresponding holes in the Aurora terminal track, so like the Cox unit, they seem to have this third wire.

 

I ask this because I remember the HO scale "T Jet" controllers had but (2) wires each. I think recall one wire from each controller ran to the power pack; one each to the screw-type terminals on the track, with a "jumper" wire between a couple of the track screws(?)...something like that.

 

Also, it appears that the Cox unit is a little "hotter"; that is, the cars respond sooner to this controller than do the same cars to the K&B units. Why is this? A difference in the windings, perhaps?

 

Hey, I told you I don't know anything about this stuff!   :)

 

Mark in Oregon


Mark Mugnai




#2 Ramcatlarry

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Posted 07 February 2020 - 01:34 AM

The earliest controllers only used two wires to control power TO the track/car.  NO brakes, all coast when you let off of the trigger.  In the mid 1960s a third wire was added for a dynamic braking action.  The MRRC (blue hand grenade) has a terminal on top so that you can add this wire.  Early homeset tracks are not wired for a brake circuit. ALL commercial tracks are wired for brakes.  Modern tracks now use a standard WHITE (+ DC); RED (-DC); BLACK (controlled + DC to track).  Early controllers like the Cox are not color coordinated like that and can short out on a modern track if you do not rearrange the color clips correctly.

 

Modern tracks use the left track braid as the (-) DC common Red ground and the right braid as the controlled (+) DC/Black wire...in the direction of motion.  The White (+) DC only goes from the power source to the controller input post.

 

Most early controllers are variable resistors.  Each motor has a relative resistance and matching the controller to the motor is vital for smooth controlled power.  T-jets might use 40-60 ohm, many 1/32 homeset use 15-25 ohm; vintage 1/32-1/24 cars use 5-15 ohms, and most modern commercial cars work best on 2-4 ohm.


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Larry D. Kelley, MA
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#3 Bill from NH

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Posted 07 February 2020 - 09:13 AM

Mark, don't feel stupid or embarrassed because you have questions. I've never met Larry, but over the years, I have come to know he's one of the most knowledgeable people when it comes to slot cars & he freely shares this knowledge with others.  And there are others here just like him too. Remember,"There are no stupid questions, just stupid answers." I don't know if this statement comes from Confucius, but it does apply.


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Bill Fernald
 

I intend to live forever!  So far, so good.  :laugh2:  :laugh2: 


#4 strummer

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Posted 07 February 2020 - 10:54 AM

Bill:

 

Thank you.  :)

 

Larry:

 

Funny you mention the "MRRC" controller. One of those came in the same lot, but I didn't include it in my initial post, because I couldn't get it to work: probably hooked it up incorrectly.

 

Here it is:

 

MRRC.jpg

 

Mark in Oregon

 

EDIT: Right after I posted this, I tried that unit again. It works, but intermittently, so I suspect there's a bad connection somewhere. It looks to be a more or less "sealed" unit, so I don't know if it can be taken apart for repair. Since I don't really need it, I'll just put it on display. The fact that both the K&B and Cox units are assembled with screws is a big plus.  :good:


Mark Mugnai

#5 ajd350

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Posted 08 February 2020 - 09:09 AM

Mark. the bottom snaps off like a tupperware lid and the button on the plunger is just pressed on.


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Al DeYoung

#6 Ramcatlarry

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Posted 08 February 2020 - 04:49 PM

All slot car resistors use TUNGSTON wire for the circuit.  It corrodes easily and usually turns into white powder like steel turns into red powder.  Clean with a wire brush or Scotchbrite and some WD-40 to make it shiny.  It is easy to find a burned out part of the coil also and if you lose a wrap to make a new connection, it is no real big deal.  I know it does not like paste flux to get the wire to tin, so you have to use acid flux to get it done - just wash it down afterward and superglue or epoxy the coil wires down evenly so that the contact pad does not snag.

 

MRRC- Hand grenade - blows up in your hand with too much power (AMPs  or voltage). :bomb:


Larry D. Kelley, MA
retired raceway owner... (for now)
race directing around Chicago-land

 

Diode/Omni repair specialist
USRA 2017 member #404
USSCA  member

Host 2006 ISRA/USA Nats
Great Lakes Slot Car Club member
60+ year pin Racing rail/slot cars in America






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