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I have been searching to find some decent replacements for the manky pots used in my G25 pedals and have come up with a couple of solutions.

Firstly these: http://www.ebay.co.uk/itm/370852871606?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Which appear to be a direct replacement but at £22 each it gets a bit steep for three, although there is the option to make them an offer.

I have also found a cheaper solution but they will take more "fitting" but will provide a good long-life cermet pot if I can do it.

I'll let you know.

(http://www.planet-venom.co.uk/PnG/G25Pots/G25 Pots 001.jpg)

(http://www.planet-venom.co.uk/PnG/G25Pots/G25 Pots 002.jpg)

(http://www.planet-venom.co.uk/PnG/G25Pots/G25 Pots 003.jpg)

Cannot see the pictures?

Me neither but I'm fighting it.  ;-)

As you can see, I have made use of some parts of the manky old pots to provide mounting and connection compatibility.

The black plastic bit in the last picture is a bit mangled because I ended up cutting the centre hole in the wrong place, after hitting the E-Stop, but it is all held in the right place by the hole in the steel plate anyway.

I used the black plastic bit so that I didn't have to do anything to the steel chassis. 

These pots come without a flat on the shaft so I had to machine that on too.

Down side of using the black plastic bit is that the length of the shaft is marginal when it comes to refitting the retaining clip.  But I made the flat a good fit so it may not matter.

Well that's me out of action for the foreseeable future.

Everything is back together and none of the pedals will work!  Not even registering on the Wingman utility.

They are 10k pots, as were the ones that they replaced, there is a nominal 5v being supplied to either end and they appear to be functioning as a voltage divider.

Looks like it is all heading for the bin!

Been a while since I moved my pots around, but does it use one end to wiper?
if you've accidentally wired to both ends then pot turn will do nothing useful
Appologies if that insults you intelligence  ::)

The pots have 5v across them and the wiper moves over a limited arc at the middle of its travel.  So the wiper sees a proportion of the 5v, about 2v at zero travel.

I took pictures of the original wiring to make sure that I ended up with the same circuit.  Top and bottom connectors on all of the pots are red and black, whilst the signal wires are white, orange and something else that I can't remember.  ::)

I expected to have to reverse the controls but I'm stumped as to why they don't work at all!

There's probably a clip on You Tube of someone doing it correctly

I am Southport Saturday if you want to compare against mine.

Thanks Matt but for now I have thrown everything in the corner of the room until such time that I can face the eleventy million screws again!

I suspect that I haven't machined the flat on the shaft such that the pot uses exactly the centre section of the track.

Thus the voltage signals may be out of range.

I shall test with some standard pedals to make sure that the A-D board in the wheel is still healthy before doing anything else.

I might try one of the Leo Bodnar USB cables, if all else fails, as surely that can be configured to use any voltage values?

Thanks again for the offer Matt but we are out on Saturday.  ;-(

Think that I may have found out what the problem is.

The original pots are 10K ohm but they sweep through this in 70 degrees of travel.  So the analogue voltage signal will start somewhere near 0V and end up somewhere near 5V, or vice versa.

My voltage signal goes from about 2V to about 3V and so the A/D board inside the wheel is rejecting the starting point and just not recognising the pedals.

I'm hoping that either a Leo Bodnar adapter or something from Basherboards my be able to take my puny 1V variation in signal and turn it into enough digits to give me a decent pedal response.   ::)

Hi Clive,

I am absolutely not an expert on electronics. In fact I have no knowledge at all on that really.

But I am pretty sure its not a matter of matching exactly amount of Volt like you say, as only the differences between start and stop are measured.

But I could be wrong on that and these G25 circuitboard indeed only works in that Volt areas you mentioned.

However here some thoughts/idears:

Looks like your new potentiometers do match 10k +-10% ,like the original G25 pedals pots have.
But if the originlas are linear or non-linear ( no idear what that really is ) could be important to know. To be on save side the new pots may should match these parameter as well.

Antoher thing important to know, is the working range of the potentiometers. Some do have a  dead zone on their travel range. Mostly those who come without an mechanical start and stop.
However , to check that I did used the tiny programm called DIView.
It makes the movement of pots visible and allows calibration/configuration.

http://www.leobodnar.com/shop/index.php?main_page=page&id=12



Dunno if that helps you, as your pedals run via G25 circuitboard, if I understood right.
At least your wheels axis movement should be displayed.
If your pedals arent recognized by diwiew then , even if you did move the pots axis by hand , to got free from the limitted travel way given by the gearing of the G25 pedal construction, I am clueless.
But if, then you are able to figure out the right position of  how each axis has to been mounted to the gearing of the pedals. ( working range of potentiometers ).

I never did run pedals via G25 circuitboard. ( never did have an G25 wheel ).
I always used LeoBodnar USB chip stuff to run my wheels and pedals.

Actually I run G25 pedals wired to that kinda chip.
It could be that these Bodnar chip is more forgiven than G25 circuitboard, if pots are on that dont match exactly the originals in all therms. I dont know....


So in case your new pots could not go to work via G25 wheel,  for sure its an good alternative to run for an LeoBodnar BUO836 12bit joystick controller.

Good luck and do not hesitate to ask more.


Btw. If I am lucky, today my new Clubsport V3 pedals do arrive. Wonder if I can get used to that hall sensor magnetic stuff so....

kindly regards
Nicky

Thanks for the response Nicky.

I believe the original pots to be linear but it's the 70 degree bit that is the problem.

By my calculations, the original pots will give a voltage signal that varies from 0.9v to 4.1v whereas my pots will only give me, say, 2.17v to 2.83v.

I don't know how adaptable the Leo Bodnar system is but it should be possible to convert it to digital with something! 

I suppose that I could just use the analogue signal and stuff it in the game port to start with.  ;D

Even if you got your new pots working I'd have thought the lower voltage range would result in lower resolution. Are you seeing this limited range because once mounted the pots have a reduced physical travel? If unrestricted you should see 0 to +5V on the wiper as you move it from one extreme to the other.

The pots must be of same value and range/steps.
Maybe a bit to late for you, but found this replacement pot-meter, that is used by others http://www.digikey.com/product-detail/en/450D103F7/450D103-6-ND/183274?cur=USD
I cleaned G27 pots with CRC contact cleaner WD40. All I did was do as the guy in this video https://www.youtube.com/watch?v=0QvOepREO4k Now all pedals have full range again and don't even stutter any more. You might want to use an air spray to let the contact spray dry out faster.

You might NOT want to use WD40 period. Use a purpose made electrical contact cleaner like this (http://www.maplin.co.uk/p/servisol-super-10-switch-contact-cleaner-200ml-jp17t)

EDIT: Apologies, you did state that is was the contact cleaner version. However I think most folk only know of one WD40 product.

I highlighted it, so it's more clear that it's a contact cleaner, made for electronics that needs to be used  ;)

The shaft only moves through about 45 degrees.  On a 70 degree pot that gives about 1v to about 4v variation.

On a 340 degree pot there is naff all in the way of change.

The Bodnar system uses 10 bits rather than Logitech's 8 and I have asked them what resolution I could expect.

Failing that, it must be possible to take the available signal and convert it to something useful before feeding it into the Bodnar adapter.

Anything to get away from Logitech's awful pots!!!!

EDIT:  I have ordered a Bodnar cable.  Apparently, with the signal as it is, it will provide around 132 steps for full pedal travel, which isn't as good as the original Logitech but better than a kick in the teeth.  I then plan to use an Instrumentation Amp to modify the signal back to its original value.  That should give in the order of 600 to 700 steps via the Bodnar cable.  Plus the wheel will no longer have to deal with the pedals and may give a better response too.

That pot is still 300 degrees rotation so there would only be around 0.75 volts variation for full pedal movement.  :-(  It is also a carbon tracked device, which in my book is the worst type.
If I can make mine work the pots are rated at 5 million cycles, which is way better than the standard ones.


I have cleaned mine in the past but I do not feel that the faffing about justifies the short period of use that it gives you before it needs doing again.

 ??? do not understand why the new pots have a shorter travel way.  as long they connected to the gearing of the G25 pedals, travel way should be the same.

only thing I can imagine is : if the new pots dont have an mechanical start & end stop, but an 360° turn, then theer must be a dead zone between start&end position. Means if your shape of the shaft is accidently wrong positioned, wrong area of the pot travelway is at work. worst case would be if that dead zone is in the working range of the new pot then..

The 45 degree travel is standard, no matter which pot you have.  But since the original pots sweep through 70 degrees for their full 10k, they use 64% of their travel.  As a voltage divider, that means that they give a change of 3.2v when connected across 5v rails. 

45 degrees of movement on a pot with 340 degrees of travel only uses 13% of their travel, thus just 13% of 5v = 0.66v


The original pots are designated as 10K/70  meaning that the track has a resistance of 10K and  that the wiper goes from zero to 10K in 70 degrees.

I can't do anything about the gearing between the pot and the pedal so the 45 degrees has to stay.

well ,then its these circuit board inside the G25 wheel wont accept the new pots so.

I never ever had any kinda trouble on my selftuned pedals run via LeoBodnar BUO836 12bit joystick controller.
No matter if I run the ( same ) pots with selfbuild gearing or with none gearing at all.

of course geared pots serve more resolution ( as the travel range of the wiper increase ) = very little more smooth feeling e.c. inside GPL .

Means that these nice chip simply accept, recognized and count right , so the Volt output fits right again to any calibration menue of any PC racing sim.
( selfcalibration ? )


still dont understand why your new pots (340 degrees as you said ) wont run 70 degrees once they ruled by the gearing of G25 pedals

A 12-bit A/D would give eight times the resolution of the standard Logitech 8-bit system.  So even with the signal that I currently have, the Bodnar unit would convert that to around 264 steps.  So given that the Bodnar calibration system will work over a much greater range of inputs, you would never notice.

The current Bodnar cable is 10-bit and will give me an estimated 132 steps, before I fit an instrumentation amp, and anything that I want thereafter.  ;-)

Pedals are working with the Bodnar cable.   :thumbup1:

Clutch calibation is being a tad strange but it works in the game.  I have also managed to bin all my previous wheel setup stuff on the profiler.  In fact I binned the profiler and now need to find the disc so that I can re-create the same feel that I had before. 

Personally I wouldn't bother looking for the old Logitech disc I'd just download the latest software from their website

and buy a new wheel and pedals whilst your there  ;)

Hmm.........  I did that but it isn't called Wingman anymore and I wasn't sure that it was the right thing.


@ Tony  ;-P  It's all right for you rich folks!

OK Done that.

Just wish I could remember what I had all the settings at.   :(

I think that I have the wheel sorted and the pedals seem to be behaving themselves.

In testing I'm about a second and a half slower than Geoffers at Goodwood in an Alpine, so just about normal I'd say, after a six week lay-off!

UPDATE

These pots have not required any attention since the last post!!!