DR Racing Products

Transistor Controllers

DR-40 Electronic Controller

Operating Instructions

Hookup Operation
Maintenance Disclaimer
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Congratulations!

You have purchased a DR RACING PRODUCTS Model DR-40 Transistor Controller.  This is the instruction sheet for Standard, Choke Bypass, H.O., and Dual Polarity models.

 
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Controller Hookup

You must hook up the red wire to the brake terminal for maximum performance. If you do not hook up the red wire, the full power relay will not work and your car will run slower.  You will also lose controller sensitivity adjustment and it will operate at a higher temperature.  If you do not want brakes, please rotate the brake control knob clockwise for no brakes.

On choke bypass models, the extra white wire with the white heat shrink-tubing marker connects to the white track power post.  The white wire without a white marker connects to the choke.  If you are not using a choke, connect only the white wire without a marker.  When the bypass toggle switch at the front of the controller is pushed forward it will momentarily bypass the choke.  When the switch is pushed toward the rear it will keep the controller in bypass mode.  When the switch is positioned in the center the controller will not bypass the choke.

On dual polarity and single polarity models, you must first determine the track’s own polarity.  To do this, first hookup only the black and white wires.  Then touch your slot cat to the track.  If the slot car motor takes off full blast without engaging the controller trigger on a single polarity model, the controller will not work on this particular track.  However, the dual polarity model will work on this type of track by flipping the polarity switch on the module.  The controller should now work normally.  Hook up the red wire and go! Caution: If switch is in wrong place for a track’s polarity with the red wire hooked up, you will blow the brake fuse or melt the brake pot.  GET IT RIGHT!   THE SINGLE POLARITY CONTROLLER WILL ONLY OPERATE ON INDUSTRY STANDARD POSITIVE GATE TRACKS.  WHITE TERMINAL IS POSITIVE AND RED TERMINAL IS NEGATIVE.

 

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Controller Operation

The controller sensitivity adjustment is controlled using the blue knob.  You turn the knob clockwise for less sensitivity and counter clockwise for more sensitivity.  Group Seven cars tend to require greater sensitivity compared to a scale car which tends to require less sensitivity.

 

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Controller Maintenance

1. The controller has two types of fuses.  The brake fuse is located closest to the trigger. A suitable replacement is a (Radio Shack Part #270-1068 6.3amp slow blow). The transistor fuse for all models is dependent upon the particular transistors installed in each controller.  Refer to the backside of the circuit board for the correct Radio Shack part # for each individual controller. The transistor fuse for both models is located furthest from the trigger.  The transistor fuse is the QUICK BLOW type (A slow blow type or the wrong amperage rating provides no short circuit protection and if the controller sees a shorted load the transistors will blow instantly).  DO NOT USE THE WRONG FUSES OR PERMANENT DAMAGE MAY OCCUR!

2. The controller wiper contact must be kept clean especially between the first and second band.  First clean the wiper contact by putting a small drop of light bearing oil on the contact then work the trigger back and forth several times. Then clean off all remaining oil using a clean and dry Q-tip or rag.  After cleaning hold the circuit board up to a light source and look through it and check for any burned black spots (If maintained properly the black burned spots will not happen).  Remove any black burned spots with a sharp dentist pick.  Do not leave it oily wet as over the years this has created more problems with the DR-40 Controller than any other type of misuse. The excess oil and dirt mixed together creating a conductive paste that electrically connects the dead band and the first power band together causing the car to move without engaging the trigger. All you need is a thin film of lubrication on the copper-clad circuit board to maximize the life of the circuit board. You should perform this operation before every race. If you have a problem with the car moving without engaging the controller trigger, this can usually be traced to a dirty wiper contact. This can also cause overheated modules, brake pots and blown brake fuses. Do not cut away top of handle for easier access! This only makes it easier for unwanted objects to fall into the controller. The entire wiper contact can be accessed without removing the handle by inserting a Q-tip in the back slot between the handle and the circuit board.

3. Once a month lube the oilite bearing. If you don’t a small amount of wear can cause the wiper button to lift off the circuit board causing the controller to not work properly.  Do not install ball bearings yourself with out contacting DR Racing Products first, there is a right way and a wrong way to do it.

  • DO NOT SAND THE CONTROLLER WIPER CONTACT BLOCK!!

  • WARNING: KEEP BOTH HANDLE AND MODULE AWAY FROM POWER POSTS!!

  • DO NOT USE A 1/24 CONTROLLER FOR H.O. AND VICE VERSA!!

  • NEVER RIP ALLIGATOR CLIPS FROM THE POWER POSTS!!

  • YOU WILL BREAK THE TRIGGER OR IT'S STOP IF YOU SQUEEZE TO HARD!!

 

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Disclaimer

WE AT DR RACING PRODUCTS HAVE DONE OUR BEST TO PROTECT OUR PRODUCTS FROM INCORRECT CONTROLLER HOOKUP!  BUT THERE ARE SOME WAYS OF INCORRECT HOOKUP THAT WILL CAUSE MAJOR FAILURES.  WE CANNOT STRESS ENOUGH THE IMPORTANCE OF CORRECT HOOKUP!  ALSO, LOOSE ALLIGATOR CLIPS BANGING AGAINST THE WRONG POWER POSTS CAN ALSO CAUSE DAMAGE, SO BE CAREFUL AND PULL UP ONE WIRE AT A TIME TO THE PANEL.  AGAIN . . . GET IT RIGHT!!

DO NOT LOOSEN TRANSISTOR SCREWS ON THE MODULE OR TRY TO REMOVE TRANSISTORS OR YOU WILL RUIN THEM! THERE ARE NO USER SERVICEABLE PARTS INSIDE THE MODULE.  DR RACING PRODUCTS WILL NOT BE RESPONSIBLE FOR CONTROLLER MODULES THAT HAVE BEEN TAMPERED WITH OR ABUSED.

WE HAVE MADE EVERY ATTEMPT TO PRODUCE A CONTROLLER THAT WILL COVER THE WIDEST RANGE OF APPLICATIONS AND THE CONTROLLER IS EASY TO ADJUST.  IF YOU WANT THE CONTROLLER TO BE MORE SENSITIVE, SOFTER, LINEAR OR PROGRESSIVE JUST CALL US AND ASK HOW.  DR RACING PRODUCTS WILL RETURN EVERY PHONE CALL.

ALWAYS CALL FIRST BEFORE SENDING A CONTROLLER IN FOR REPAIRS OR UPGRADES BECAUSE SOME CONTROLLER PROBLEMS CAN BE HANDLED OVER THE PHONE!

 
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