21 replies to this topic

[peter m]

Hi guys! I have just recently purchased a circuit master controller (the one armchair racer sells).

I have used it a couple of times now and have found that with the sensitivity set to it slowest setting it is still to quick for me! I read on armchairs site that you can change the resistors to change the sensitivity but i dont know what to change them too. I tried emailing armchair but they haven't got back to me about anything, probably very busy! So if there is anyone there that knows anything about these controllers or where i could find the info it would be greatly appreciated!

peter

[kalbfellp]

Do you have a circuit diagram of the controller?

[peter m]

It didn't come with any circuit diagrams but i will take a photo tomorrow and post it, it might be of some help.

[peter m]

The numbers are the resistance values in ohms. The larger resistor is 22ohms between each leg.



I was thinking if i can get the values lower by using the correct resistors , this would lower the sensitivity?

any electronic gurus out there that might know?

[kalbfellp]

Without having a diagram and some more info, I would simply make up a new resistor pack using some 33 ohm resistors and see how it goes,the cost is very little only your time.Use some epoxy to join them. I am assuming that the resistors simply plug in to the socket.
I am also assuming that you feel that the first step gives to much go with your cars. You can also vary any of the resistors in the pack to change the progression of the power.

[peter m]

yeah i reckon i will give that a go! So you think i should go higher in ohms?

I might try making a resistor pack that when measured between the bars like in the photo shows (start)10,10,33,33,33,33,33 OHMS (top speed) or do you think i should be going the other way for example 2,2,15,15,15,15,15,15ohms? i hope that makes sense to you?

[slots]

Peter, I've had one for years. You just need to pull the resistor packs out and get a larger ohmage to plug in. Try a 330. I'll call John who designed them and check. What cars are you running with it?

[tooter]

Are you using an adapter for use on your home track? Is it positively wired?

Is it too sensitive on the Armchair track? or just on your track

[peter m]

i am using it at thunderbirds in adelaide, positive wired track with 1/32 scale car, mainly nc5 motors.

I am use to using a cheap parma 25 ohm controller with a brake pot. which the power comes on just perfect for my liking! At the moment i cant use the other one because it is to hard for me to drive smoothly because the power just comes on to quick for me even with it on the slowest setting.

It would be great if you could give john a call for me and find out what i can do or where i can get the other resistors from!

thanks heaps

peter

[tooter]

Won't be hard to fix ,sorry didn't realize you were in Adelaide. The resistors are available from a company called Farnell. I'm sure Jim at Armchair will have them.

[kalbfellp]

I think I am correct is saying increase the resistor value,decreases the tensitivity.

[peter m]

Just thought i would let you know that i got it all sorted now! i ended up replacing the 2 large resistor banks with some single 33 ohm resistor. Eager to try it i went down to Thunderbirds raceway today and gave it ago.
It works great now! Before it would launch like a top fuel drag car on the slowest setting , But now i can make it feel like my 25ohm controller.
I did ring armchair for some advice but he said i was the first one to have this problem so i would be curious to know if anyone else had to change there resistors.

Have attach a pic to show you.

[tooter]

I have three of them and have never had this problem. They are great controllers enjoy.

[kalbfellp]

Glad that you managed to get it sorted. It would now be easy to try some variations to tune the response even more if you wanted to.

[slots]

Peter, I spoke to John and he said you can do what you did no problem. Personnally, I'm perplexed as I have run everything from an AFX car right up to and including an open wing car with mine and no problem. It is possible one of the resistor pack's is bad. You might try replacing them as one of them could be shorting out. I own unit number 1 and the only problem I have had is I didn't clean the wiper block causing a short through the brake system. Otherwise a durable, reliable controller. Won't get rid of it.

[peter m]

Thanks for doing that for me stu! I did give it to a vetran driver at our club and he said the same thing as i did. so it may have been a bad resistor or something i dont know. But it is all sorted now! One thing i did notice is the resistors in my controller are different to the one on armchairs website. Anyway i have to go tinker with my cars because i have racing tonight!!

[slots]

Peter, I see what you mean about the resistor packs. I would say that he can't get the original 5 unit packs any more so went with the 4 unit packs with a single at the end. It's quite common for electronic suppliers to end a particular unit with no notice but the controller design is the same with a few minor upgrades since I got mine.

[Orakei Racer]

slots, on Sep 12 2009, 11:38 AM, said:

Peter, I've had one for years. You just need to pull the resistor packs out and get a larger ohmage to plug in. Try a 330. I'll call John who designed them and check. What cars are you running with it?

I found this discussion after doing a quick search.

I have number 16 from the first batch produced. Have been happy with it's performance over the yrs, but have found over the last 12 months that it is becoming more over sensitive, even with the sensitivity dial turned down to maximum slow.

I will likely go down the same track of changing the resistor banks to a larger rating.

I noticed that of the 2 banks of resistors, one had a resistor range of 2 to 100 and the other bank had a 2 to 220 resistor "chip".

I'm interested to know why there are 2 banks of resistors when there only appears to be a 10 band range and also whether each bank should mirror the resistor range of the other or why you would use different resistor ranges for each bank.

Thanks

Orakei racer

[stoo23]

Hi there,

I just noticed this 'Post' and although the Original Post creator appears to have 'sorted' his Problem,..I had a somewhat similar situation !!

Having known John had produced these and needing an affordable controller to race my Retro's with I purchased one from Armchair, after getting John to Ring Wayne as he wanted some to sell at HSC,..(Bit I couldn't wait till HSC's stock arrived,..in Hindsight, I wish I had,..sort of).

Compared to the Older unit I had tried and Liked,..the New unit was (By comparison), a Real Disappointment!

The Wiper had been Changed from the Older Parma Metal style, to a Thin Polycarbonate one !! and as that was Mounted differently on the Trigger, the Main board was also in a slightly different Position.

First time I tried it, The Brake adjuster Did Not Work Properly at all, Which I quickly worked out with a Multimeter, was due to a Dead 'Track' at One end of the Pot !!
I Made a 'Quick and Dirty' Fix at the Track, by Reversing the Wiring to the Other 'Tag' on the Pot and it Works, (In Reverse!!,..lol) as long as I don't go to THAT Dead Part of the Track, as then I Have Nooooo Brakes at all !!,..lol

At the time I rang Armchair,..to No avail, in fact it developed into 'One of Those' Conversations/arguments and all I wanted to Know was whether they had any Spares.

Suitable replacements Can be purchased from Dick Smith btw.

BUT, apart from the Controllers Mechanical 'Foibles', like the Triugger and Wioer button being able to 'Lift' off the Wiper Block, there were Other things about it's Construction and Setup, that I was Not Happy with,..as One older slotting acquaintance put it,..It's Like a Fully Built 'Kit' !!!,..ROFL,..Well,..atleast Mine was !!

So,..as I also Found the supplied Resistor 'Blocks' to provide a far less than 'suitable' or even remotely Ideal progression across the Wiper,..Well it didn't Suit My driving style and I also found the Overall Low end sensitivity to be Suss,..Plus it Suddenly Jumped in Response as one Progressed up the Wiper Block.

Like the Original Poster, I too replaced them with Individual Resistors and have been Quite Happy with the Overall Peliability and Performance of the Controller after Basically 'Blueprinting' it !!


As far as Why there are Two Resistor Blocks/sockets, is Quite Simple, if you Follow the Circuit Board 'Tracks' and Use the Above Photos as a Reference, you Can See How the Individual Resistors 'Connect' between the 'Bands' on the Wiper Block.

Lift the Wiper Of and Put some Paper under it and have a Play with a Multimeter and the 'Penny Will Drop' !!,..

The Basic Electronics/Output etc of the Controller all seems Quite sound, (although with the Unit I have, I have Not tried anything 'Hotter' than a current Group 15).

If you Purchase one and you are Technically Minded, it WILL be Worth putting in some Time Getting it all lined up and working smoothly and Linearly, I Moved the Circuit Board and Replaced the Poly Wiper arm with a Real one and a New Wiper Button and Re-Wired the Trigger,..and I had to Pay Quite a Bit of attention to the Whole Trigger Mechanism as Neither were the Trigger bearings 'Seated' well, but the Whole Mechanism Needed a Bit of TLC and Alignment.

As I said, All is Good and has Proven Fine running Scalextric, Aussie Retro's and both 1/32 and 1/24th Plafit cars,..good enough for a fair share of Podium Places and Wins, so it Can't be all that Bad !!!,..lol

That said,..Having driven with one or two of the More Recent DiFalco 30 Band controllers with the Changeable 'Plug In' Resitor 'Arrays', I AM Impressed.

It's somewhat Hard to describe, But the Whole 'Feel' of the Controller and it's Power delivery, is So smooth, it is beginning to become a somewhat serious consideration as an alternative/ Prime Controller.

But for the Bucks, The Circuit Master ain't too Bad.

Mind you John did suggest he would give me the details, so I must chase him up again, as iy Would be Nice to have a Circuit Diagram. I sure Ain't going to start Building 'Copies' !!!,..ROFL

Cheers,
Stewart

[slots]

Stoo, I'm saddend to here about these defects in the later models as John's idea at the time was to design and build a better and more versatile controller and not worry about profit. The only problem I have ever had was I blew the brake pot but that was a case of I missed some muck in between the wiper segments. My own fault as I know better about cleaning them. Other than that, I have not had a problem. Still a reliable unit even though it is getting old. When I upgrade my controller next, I'm going Scorpius analogue set up. Really want to be able to drive from where ever I want around a track. Will still have the Circuit Master as a back up though.