potentiometer centering when swapping?

[Matthew Fisher]

I have a Happ's analog stick and I swapped the 5K pots for 100k and wired it up to go to the gameport.  The darn thing just won't calibrate correctly, however.   Symptoms: (best explained by behavior in Star Wars) no matter what I do, when the stick is at rest, the cursor sits about 2/3 of the way up the screen and I cannot get it to aim at anything in the bottom third of the screen.  I have tried calibrating in MAME and using JCENTER, an old CH utility that came with their flight yokes. 

My question is (before I take this thing apart), how important is it to physically center the pots when swapping?  I guess I assumed this would all be worked out in calibration, so I wasn't too careful to center the pots when I swapped them.  Was I wrong?  Thanks in advance. 

[Kremmit]

Have you calibrated through the Windows Control Panel?

If that doesn't work, then it's probably time to center those pots.

[Matthew Fisher]

Sorry, forgot to mention, I am running in DOS.  I guess I will take it apart (again  ) to center the pots. 

[u_rebelscum]

Sorry, forgot to mention, I am running in DOS.  I guess I will take it apart (again  ) to center the pots. 

Yes, DOS is a pain to center, even with good drivers.  (Windows98 on come with "good drivers", AFA centering goes.)

Check what type of "taper" your new POT has:

• you should NOT use "audio", the resistance is logarithmic
• "S-curve", like happs, has a "dead spot" in the middle, and thus needs to be centered, good driver or not
• "linear", with a good driver shouldn't have to be centered, but it you don't have that driver, you'll have to center it.

[Matthew Fisher]

Ah, I forgot about the s-taper!  I have the Happs, so I will just pull out the trusty multimeter and get those things centered, like I should have done when I put them in...   

[Matthew Fisher]

OK, I am bumping this because I am at my wit's end.  I centered my pots on my stick physically, ensuring this through use of my meter and also in JCENTER, which displays raw data from the pots.  I then dutifully calibrate in VPPRO, which is a calibration and centering program.  Good full range travel, good centering, good buttons.  The darn thing still won't calibrate properly in MAME, though!  What's more, I can't get a regular PC stick to work anymore, even though one worked great before I tried to hook up this new stick. 
 
My questions are this:  If anybody knows, how exactly are the calibrations in my separate utility and MAME interrelated?  Are the data stored in the .cfg file for each game?  My understanding was that sticks have to be calibrated for each game in DOS, in which games the calibration is stored; if so, how would a separate centering and calibration program make any difference?  I have searched the web in vain for some explaination of how this might work.   It would be pain to recalibrate every time I opened a new game in MAME, but I'll do what I have to do...  Again, I'm limited to DOS and the gameport (unless someone knows of a USB joystick driver for DOS).