Ecurie SAMCA controller plug hook up

A picture is worth a bunch of words - this hook up picture is for my own edification and may be useful for anyone else connecting a slot car controller to the current five amp plug system at South African Model Car Association (SAMCA) clubs:

MRRC controller with 1/24 HD30 UPGRADE PCB

The rash of new visitors to Ecurie provides the enjoyable dilemma of how to kit them out with cheapie controllers. Amazing how folk take to electronic controllers once they have driven with them!

Both the Parma Turbo (Plus) unit and the newer MRRC unit provide an excellent base at reasonable cost. Difalco products are Rolls Royce and there is a present window of opportunity to purchase the new 30 band wiper boards complete with resistor banks at an excellent value price. Add two 20 ohm pots and a Tip 36c transistor for pennies and you have a stunning combination for club racing at well under a grand.

The unit above was assembled with the transistor soldered direct to the board and has tested well but not used in track action, yet. Feels luverly, though ;-)

Soldering the unsupported transistor direct to the board is neat but dubious without additional support (see under the right potentiometer) - that may be added later, if necessary. The rest of the soldering reduces to a simple six joints, using this gorgeous board. Reference to the previous posting reveals that there are a host of resistor bank options for the Tip 36c, although experience has shown that the 113 ohm bank will probably be the most suitable.

There will be a latter blow by blow once testing is complete but, in the meantime, these are the sources I used for the various components:

2 x 20hm potentiometers (loudspeaker volume controls) for brakes and start adjustment @ R30 each:
http://www.fort777.co.za/index.php?main_page=product_info&cPath=269_456_552_582_584&products_id=3056

Tip 36c transistor at R20 a pop, from most electronic shops:

http://www.fort777.co.za/index.php?main_page=advanced_search_result&search_in_description=1&keyword=tip36c

Difalco upgrade board with resistor bank from various online sources, or even direct from Difalco, at approx R400 (this one is 148 ohm):

http://www.ncphobbies.com/cgi-bin/vcat/CatalogMgr.pl?cartID=b-2753&SearchField=partnumber&SearchFor=DD261&template=Htx/product_detail.htx&hdr=Product+Details&displayNumber=1

MRRC controller base (normally sourced from Pendleslot for GBP25, under accessories) at approx R300:

http://www.pendleslotracing.co.uk/html/body_track.htm

That makes for an all up cost of about R800 for a larney controller and you can brag to your mates about the smooth as silk 30 band action......!

Scroll back through previus blog posts for the circuit but remember only to connect to the brake stop, never the brake band.

Nigel's MRRC project sorted

Nige’s controller successfully tested after a transistor and wiper board change back to the old standard 108 ohm total for the Tip36c. How I ever worked without this simple tester......? I will try amend the blog postings to drop all references to the ill conceived shorter travel and less ohm spreads, when I have a mo.

Nige’s board soldering attempt suggested for me (personally) that below is a far more logical approach in buying a Difalco pre-made board, complete with resister arrays that can be unplugged to change to a whole range of values – helluva cheap at the price for a Rolls Royce bolt on to the MRRC, with the bonus of 30 bands..... Just fit pots, tranny and hook up wire only – I have ordered my own through North Coast Hobbies.

1/32 HD30 UPGRADE PCB (Suits the Le mans MJ type)
DD553: HD30 Upgrade PCB: Convert. You get the HD30 circuit board with a standard 290 ohm resistor network board installed. Simply unsolder a few wires and remove the old PCB. Transfer the original brake and sensitivity rheostats over to the new HD30 board. Now bolt the PCB to the frame and solder a few wires to their correct positions. Simple instructions included.

Or

1/24 HD30 UPGRADE PCB (Ok for the Tip36C type or use the DD256 113 ohm array for exact)
DD261: HD30 Upgrade PCB: You get the HD30 circuit board with a standard 148 ohm network board installed. Simply unsolder a few wires and remove the old PCB. Transfer the original brake and sensitivity rheostats over to the new HD30 board. Now bolt the PCB to the frame and solder a few wires to their correct positions. Simple instructions included.

DD255: Standard Resistor Network. 180 ohm
DD256: Standard Resistor Network. 113 ohm
DD257: Standard Resistor Network. 78 ohm
DD262: Standard Resistor Network. 290 ohm
DD258: Custom Resistor Network. 136 162 and 192 ohms.
DD260: Custom Resistor Network. 64, 87 and 113 ohms of total resistance.

That completes all my committed or otherwise foisted on projects and no more third party projects will be entertained – it was spoiling my attendance at racing, even if that is spotty;-)

Simple controller checker for three pin plug type

Given my infrequent trips to Ecurie and distance involved, any transistor controller repair or development had ground to an effective halt as a consequence of the tedious delays in testing the units. A simple diagram off the British Darkside slot car site (see link at bottom) suggested that the new three pin plug and socket system now provides an excellent opportunity for a simple test unit.

A chat to Erlo and a tip from flying buddy Mark lead to the purchase of the white 5amp three pin plug socket shown at the left. I flirted with retaining the US controller three colour red/white/back approach but then decided I would stay with black/red colour shown for intuitive ease of hook up to the DC power supply source and test motor/car. When I can actually locate the Brit diagram drawn to controller colours on the net again, I will add that but for now it is actually easier to tell than draw:

1. Two negative black wires twist together and connect to the earth E (bigger) terminal [controller red]. One negative black lead connects to the DC power source and the second negative black lead connects to the test motor or car left negative braid.

2. One positive red wire connects to the live terminal [marked "L" - controller white] and across to the positive lead of the DC power source.

3. A second positive red wire connects to the neutral terminal [marked "N" - controller black] and across to the test motor or car right positive braid.

That's it! The DC source can be max 13.8 volts DC right down to my 8 volts DC unit Lance made us for Dremel cutters etc and worked fine in my case. Obviously mounting the 5 amp socket in to a box would be the next step.

The controller in the second pic down is Jono's, which was a basket case example of why unravelling insulation tape is a poor second to heat shrink tubing. Both adjustment pots and the NPN transistor had been changed without success but it was suspected that the thin red wire to the insulated wiper may have fractured internally under movement load or the intense heat when the the controller cooked. It was simple exercise to check, replace and immediately test the controller on the new tester - with great success. Those up the north coast may have heard the cheer at midnight last night ;-)

The controller savvy folk will by now have twigged why the German slot car racers insist their controller cable colouring is correct and the more common US colours incorrect. Our red "brake" cable is in reality the negative (black) common feed from power source to car!

Now that I at last have this bogey controller repair sorted, I can aim to finish off Nigel's new MRRC project...... ;-)

The useful "build a simple controller checker" article located here:

http://www.darksideracing.co.uk/page19.html
http://www.darksideracing.co.uk/controller%20checker.pdf

Costa's bread board controller - part 3 MRRC addendum

Trotted Costa's new Parma Turbo down to club, only to be greeted with "Ja, but wot about the MRRC". Having motivated the MRRC up front, I was obliged to cobble together the one I had pre-ordered way back. Decided to this as a complete breadboard approach to minimise connection lengths and cable change - the only existing main cable change being to disconnect the red cable to facilitate brake adjustment, with one only cut to the controller case to let the bread board poke through. Note how the bread board is wasted to minimise the case cut.

Both pot terminals poke through to the board front so that connecting up is a breeze and the TIP36c was reverted to in this case to minimise weight and complexity.

It is vital that all cut adjustments are made to the breadboard and nix to the controller case - the internal pimples and bits are for holding the existing board!

The exercise to cut and drill the bread board took one episode of Desperate Housewives and was simply eyeballed, it is really not a tricky exercise. The existing board has four holes perfectly located to hold the home brew bread board. The wiper board is spaced and bolted to the bread board in the space previously used for the resistor.

There are excellent features in the MRRC, like two trigger options, adjustable spring tension, sprung wiper arm and adjustable full throttle stop.

The stock 12 band wiper board had the bottom third trimmed off for clearance of the spring mechanism on the wiper arm. The jury still out on the neat sprung arm as I think the wiper button may be of overly hard material [proved fine] and require a mod, time will tell.

The sensitivity pot is the same 20 ohm volume control pot we have been sourcing for the brake adjustment, through the net from Yebo Electronics in Cape Town. Two 20 ohm pots at forty bucks a pop and a cheapie Tip36c plus heatsink and one can have an adequate transistor conversion of the MRRC unit......

The lightweight heatsink for the Tip36c is widely available and more than adequate cooliing, ignore the mini fan unit in the picture.

The MRRC unit is easily the simplest and quickest way for Ecurie folk to home brew a change to the transistor approach.

The new unit proved a success for all of one and half laps, which is why the picture of the main cable is shown here. It would be crazy to change the magic cable but the colour sequence is white / black / red against our normal white / red / black jack plugs - no problem, simply swapped the red and black cables across but under tension it pulled the red and black jack plug terminals together and instant brakes, no go! Took a while to find and not a big deal, just be careful when fitting a jack plug - the club will be converting to three pin 5 amp plug, which will obviate this issue.

Costa's breadboard controller - part 2 final

Rather than a nuts and bolts view of the hook up wiring, I have rather re-posted the layout schematic with a note that the transistor view on the layout is the bottom of the transistor! Seem obvious but I had it reversed on Gordon's unit that I could never get to function. Most of the wiring tucks away in the unit and the drawing actually does a better job of showing the hook up than I could.

Thanks to the Ecurie guys for slotting me in to a race after a late arrival on Friday night - the controller was truly tested in action from first press and worked fine with a useful third overall, despite the rusty driver.

The pictures illustrate the neat and uncluttered final product. I have also included a cut out of the Gordon economy handle to illustrate how the black lead is bolted to both sides of the transistor top with terminals, one for the contact to the trigger and the other black lead to jack plug. The orange thing is a resettable fuse and well worth the extra precaution if you lend out your controller from time to time. The circuit theory borrowed from the excellent Christ Frost and Le Mans slot car web sites, with the neat artwork off this interesting web site:

http://home.arcor.de/slotracingtechnik/homepage/transistorregler.htm

The sprung button in the MRRC controller is a boon right out the box but, in this Parma Turbo project, I simply bent the end of the wiper arm and bolted on an old brush hood unit off an old can style motor (16D or C Can units fine) - the motor brush being the smoothest approach I have come across for cheapie homebrew units.

My unit will have the two pots facing out rather than in as I found my method of holding had me unintentially winding the sensitivity to zero through the race (not an issue for most other folks). That's it in this series, there may be a further breadboard approach to the interesting MRRC controller, time will tell. In the absence of the metal turbo frame, a small lightweight heat sink and fan (The dinky little Hobbywing RC unit for R85) will be fitted, along with reverting to the Tip36c and a 30 ohm total wiper board to explore the potential of other folk using the existing resistor as a wiper board.

Any net readers are welcome to email the team to find out the component sources etc, although most of mine were from Mantech, locally.

Costa's breadboard controller - part 1

Some gentle persistence from Chairman Costa got me to scratch out the previous start of an "easy to follow Assembly" controller, commissioned by him so long ago. This is the Parma Turbo and it is hoped to do same with the new good value MRRC controller. Thought it worth dealing with the basics without the clutter of hook up wire, first. Of course this is where the steam ran out before so hopefully this motivates the part 2 for final completion. Click on the pic and study the large version closely before reading on. Costa's requirements in bold:

1. Minimum butchering of the controller case. With the above approach there is virtually no dremel cutting of the a Parma Turbo case, although a standard case would have to opened at the top ala the Parma Turbo space for the frame. Three pimples are removed from inside the case to clear the transistor and new spring position. Easy to spot when closing the case together.

2. Simple layout to follow. The brake pot is just above the brake stop and the sensitivity pot is a similar short distance away from the full throttle hook up, requiring very little hook up wire and a circuit layout which can be followed by someone with no electronics knowledge at all. Obviously all the long spiky arms will be cut off the potentiometers after the hook up wiring is complete, so there will be no pricking of precious fingers.

3. Minimum parts count. The transistor uses the Turbo frame as a very efficient heat sink. The frame kindly already provides the necessary holes, which only need a some extra opening up to prevent shorting of the two hook up legs, which are bent over to clear the case. A cheapie transistor insulation kit is a must to prevent electrical shorting against the frame.

4. Minimum drilling. There only two extra holes drilled in to the frame to hold both the fibre potentiometer board and the wiper board. The resistors are first soldered in the back of the wiper board whilst being bent flat. That means the board can be located very low down with no fouling of the upper case by the wiper arm.

5. Relocation of the trigger spring (not specified but essential). This is very important to ensure effective returning back to the brake stop. The frame also kindly already provides another hole in to which a new spring holding point bolt is locked. The original spring locating arm will be bent over to hold the main cables in place. Costa's Turbo controller kit had the best spring supplied that I have ever seen in a Parma controller, by the way - way better than the old barbed wire Turbo springs and saves pinching out of old Economy controllers.

6. Minimum manufacture of parts. The pre-made wiper board is available locally and online and is well worth it to simplify the project. Thus the only element of home manufacture is the small piece of board to hold the two potentiometers and bolt to the controller frame at the two points mentioned. This can really just be eyeballed off with the pots themselves before drilling and cutting the board.

That's it! Roll on part two wiper arm and hook up.