81 replies to this topic

[Martin]

Can anybody advise on this?

Does this look like a good replacement resister for my controller. It says .8 and I not sure what kind of cars it would be good for.

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[zipper]

We used those with Group 7 (Open) cars!

[Phil Smith]

Martin, the resistor in your controller looks really low ohms. Higher than .8 but still really low. Has that been working well for you?

[Bill from NH]

I would think for most scale 1/24 cars, you'd want something in the 2 to 4 ohm range. I used 1 ohm for stop & go, open class wing cars. Parms sold resistors less than 1 ohm, but I didn't use them.

[Isaac S.]

Yeah, around 2 ohms would be good for the vintage pro type cars from the early 70s. I would suggest a modern controller like a Difalco or Ruddock. No worries about ohms and you only need one controller for all your cars.

[MSwiss]

I agree with all the above and will add an .8 would only be (sort of) usable for a 70's, or early 80's, heavy G7 car, where taking off from a stop wasn't much of an issue.

Looking at my scratchbuilt controller, that I used up until about 2004, that incorporates three, 100 watt, 1 ohm resistors, I was running that at approximately 2.3 ohms.

[Martin]

Thanks for the help. I am really just wanting to restore this controller.   I have not used this controller. I use 2.5 ohm for my vintage racing.

Can you tell from my pic what ohm this might be?

 

Mike, what a wild looking piece of equipment you have there. 

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[MSwiss]

Probably took me 40-80 hours to build.

The only production controller pieces on it are the wiper button and trigger spring.

The trigger is a 3/16" thick, solid brass bar, I sculpted.

It has soldered on, a brass strip for the spring, and the wiper button, spring loaded, "shock absorber", which is made from 4 or 5 different diameters of K & S tubing.

Back to you.

Get a hold of a multi-meter and check it across the first small band and the final wide band.

Below is Koford 3 ohm.

[Phil Smith]

 

Mike, what a wild looking piece of equipment you have there.

 

Yes looking at all those wires gives me headache. I can't imagine building something like that. I'd miss-wire and toast the first dozen attempts.

[MSwiss]

Each wire has a little number tab on it, made from strapping tape.

Getting them hooked up to the three resistors in order was not an issue.

If I made a mistake, all that would happen, is the car would operate weird.(not accelerate smoothly)

The biggest challenge was the homemade 24 band switch block, and keeping the bands and wires coming off the bands, insulated from each other.

I rigged a simple drilling fixture on the drill press bed, and drilled 2 diagonal holes through the 24 pcs of K & S 1/2" X 1" strip, and 25(?) pcs of matching size mylar, I cut from Koford precut diaplanes.

The 2 Koford 3/32" axles that ran through the bands and insulators, had tight fitting Plastistruct tubing over it.

The alternating tab design worked just as I envisioned, and everything went together way easier than I hoped.

It was just tedious, time consuming work.

[Phil Smith]

I've been looking at all 3 photos and I mostly (but not completely) understand your controller. Very ingenious! I bet it was a bit of an arm workout. What are open heats? 5 minutes?

[MSwiss]

Yes, very heavy, but not a dealbreaker.

I won both my over 45 / Senior, G7 titles, and my Pro G27 one, with it.

[Martin]

Get a hold of a multi-meter and check it across the first small band and the final wide band.

Below is Koford 3 ohm.

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Thanks Mike, I will see if I have a multi-meter (that works)

[Mark Onofri]

Mike S. That controller is over the top ! I'm sure it only played a small part in you being world champion. A lot of people have been mislead into thinking the controller is the answer to " lack of skill". I've found that (in my case) it's usually a problem with the nut that holds the trigger. After struggling with a (name ommited not DiFalco) controller since 2004, I went back to my 1989ish Gordy Root built Parma ~=.2ohm external resistor with a recently added (last year) Kofford choke. On the blue king @ Speedies my lap average dropped from ^5s to 4.3's. Note: mossetti chassis,LMP body, bb mid America motor.

[Mark Onofri]

But, I just can't seem to get that nut holding the trigger right.

[Bill from NH]

Try some Loctite. your choice of red, blue. or green. 

[Mark Onofri]

Martin, from what I remember, that type of resistor was prone to overheating. That's why you see the aluminum barrel heatsink that inserts through the top hole. Are they efficient or effective ? Who knows. The important thing is , they look bitchin. As for the resistor you posted, the amount of corosion on the bands would render it useless in a short time. Hardly worth the time & effort of installing it . If you're adamant on using a ceramic resistor, look for one of the "wet wound epoxy

[Mark Onofri]

Stupid phone. One of the "wet wound epoxy" variety. The one you posted is prone to shorting at the last band before full power.
Further more, based on the posts of your most excellent cars, a 1.5-2 ohm with a KOFORD break will work better than spending big$ on a state of the art controller designed for new motors.

[Mark Onofri]

Ps: if you really, really want to go all out, use (2) two Kofford (except no substitute) adjustable breaks @ $65 US . 1st one for the break,2ond one for sensitivity. Although they sell a break and sensitivity sepreatly, the break ones are nearly indestructible.

[Mark Onofri]

Bill NH, what colour locktight do you use 😁?

[Bill from NH]

I use green heat retaining compound 609.

 

You can easily make other resistors "wet wound".

 

 You can use two of the barrel heatsinks with the double barrel resistors. I built one of the Parma kits shown in post #57, during the 70s with them, & it still works great. I got two more in bag of parts for the next controller build. Someone recently named a famous racer responsible for making those heatsinks. It wasn't important enough at the time for me to recall the name. 

[Mark Onofri]

Martin,I missed the part of you wanting to restore that controller. When you ascertain the ohm rating of the resistor, post it. I have a few I won't use. F

[Mark Onofri]

I will , without a doubt,kill this phone .For the price of postage & a pint I'll send you one.

[Martin]

What a nice offer Mark, I will PM you.

 

At least its cleaner in this pic.

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[TSR]

Martin,
your controller is a Parma "Double Micro" of which resistor is held by a "Green Bolt", the product of the great Bob Green himself. It is an after market accessory that did not come with the Parma controller.
From 1970 and until the Parma "Turbo" was introduced in 1974 with a one-piece aluminum frame, such controllers built by John Gorski's father, Bob Cotton, Johnny Ng and of course in large volumes by Parma, all derived from the original Russkit model, were used by just about every single "pro" racer in the USA and abroad, and also by "amateur" and "semi-pro" racers which made up the fields. They all burned the heck of your trigger finger despite all the "mods" such as the rubber paint on the Parma or wooden trigger on the Ng, among other heat-cheating trickery.