Replacement pots for Apple brand joysticks

[telengard]

I 3 of these and all of them don't register in certain directions (usually goes out to about 212 of the full 255 when testing).  Taking the joysticks apart, the total resistance of the non-working pots are less than the working ones (~133 ohms for working, ~122 not working, some even lower like 95).  My CH Premium IIs do not have this issue at all once calibrated. 

 

Certain games seem to be tolerant of this, others like my favorite Loderunner, are not.

 

Are these pots available somewhere?  They'd need to have the same resistance value, shaft diameter/threading, etc.  Or would a larger resistance value work, like a 150?

 

Also, these joysticks are NOT fun to disassemble, tons of little mechanical parts, and a plastic nut shaft. 

Edited October 10, 2021 by telengard

[MarkO]

On 10/10/2021 at 2:16 PM, telengard said:

I 3 of these and all of them don't register in certain directions (usually goes out to about 212 of the full 255 when testing).  Taking the joysticks apart, the total resistance of the non-working pots are less than the working ones (~133 ohms for working, ~122 not working, some even lower like 95).  My CH Premium IIs do not have this issue at all once calibrated. 

 

Certain games seem to be tolerant of this, others like my favorite Loderunner, are not.

 

Are these pots available somewhere?  They'd need to have the same resistance value, shaft diameter/threading, etc.  Or would a larger resistance value work, like a 150?

 

Also, these joysticks are NOT fun to disassemble, tons of little mechanical parts, and a plastic nut shaft. 

The Apple ][ JoySticks are 150K Ohms, as I recall...  Which is an uncommon value, but it probably has something to do with the Charging Circuit that is used..

 

MarkO

[GameGeezer]

150K confirmed

[telengard]

Thanks for the info everyone.  I have other joysticks to use (CH, Suncom, Kraft) but I liked how these look.  Too bad they don't work so well, all 3 are now on a shelf until I can find some 150K pots.

[Baldrick]

19 hours ago, telengard said:

Thanks for the info everyone.  I have other joysticks to use (CH, Suncom, Kraft) but I liked how these look.  Too bad they don't work so well, all 3 are now on a shelf until I can find some 150K pots.

You probably won't find any 150K pots.  Those are unicorns.

 

You'll have better luck maybe finding 100K pots or even 10K pots.

They will work if you add compensation capacitors in parallel with the pot.

 

The 150K pot forms an R-C "network" with some 0.022 uF capacitors on the motherboard to make some timed-pulses out of the 556 timer that the pot is connected to.

So if you use some (quite common) 10K pots, you'll get the equivalent performance with a 0.3 uF cap in parallel with the pot.  Or substitute any other value according to the formula example:

 

10kΩ * (x + 0.022μF) = 150kΩ * 0.022μF

x + 0.022μF  = (150kΩ * 0.022μF) / 10kΩ

x  = (150kΩ * 0.022μF) / 10kΩ – 0.022μF

 x = 0.308μF  

[MarkO]

On 11/24/2021 at 7:03 AM, Baldrick said:

You probably won't find any 150K pots.  Those are unicorns.

 

You'll have better luck maybe finding 100K pots or even 10K pots.

They will work if you add compensation capacitors in parallel with the pot.

 

The 150K pot forms an R-C "network" with some 0.022 uF capacitors on the motherboard to make some timed-pulses out of the 556 timer that the pot is connected to.

So if you use some (quite common) 10K pots, you'll get the equivalent performance with a 0.3 uF cap in parallel with the pot.  Or substitute any other value according to the formula example:

 

10kΩ * (x + 0.022μF) = 150kΩ * 0.022μF

x + 0.022μF  = (150kΩ * 0.022μF) / 10kΩ

x  = (150kΩ * 0.022μF) / 10kΩ – 0.022μF

 x = 0.308μF  

Thanks for the Formulas...  I know when adapting JoySticks from One computer System to another, "adjustments" might need to be made..

 

MarkO

[GameGeezer]

Rubbish. I recently ordered about 20 150K pots.

 

https://www.mouser.com/ProductDetail/TT-Electronics/P230-1FD20BR150K?qs=sGAEpiMZZMukHu%2BjC5l7YT77tCcQpo3bZhrL7abqNgY%3D

 

https://www.amazon.com/Uxcell-a11121400ux0234-Electrical-Wirewound-Potentiometer/dp/B0169OOLV4/ref=sr_1_3?gclid=Cj0KCQiA-qGNBhD3ARIsAO_o7ynlnyWIXb4lRTctnu3G0oDnpRzjDpcDR9S3D43j9HOlfH8fru4Kz2QaAmAjEALw_wcB&hvadid=409909999188&hvdev=c&hvlocphy=1013452&hvnetw=g&hvqmt=e&hvrand=4180624490516709794&hvtargid=kwd-27997994916&hydadcr=514_1012844948&keywords=150k+potentiometer&qid=1638457566&sr=8-3

 

https://www.newegg.com/p/2YK-005K-00HU6

 

https://www.mouser.com/ProductDetail/BI-Technologies-TT-Electronics/P270-SF11R150K?qs=sGAEpiMZZMukHu%2BjC5l7YT77tCcQpo3bhw45jJVHiTo%3D

 

 

Edited December 2, 2021 by GameGeezer

[Papalapa]

15 hours ago, GameGeezer said:

Rubbish. I recently ordered about 20 150K pots.

 

https://www.mouser.com/ProductDetail/TT-Electronics/P230-1FD20BR150K?qs=sGAEpiMZZMukHu%2BjC5l7YT77tCcQpo3bZhrL7abqNgY%3D

 

https://www.amazon.com/Uxcell-a11121400ux0234-Electrical-Wirewound-Potentiometer/dp/B0169OOLV4/ref=sr_1_3?gclid=Cj0KCQiA-qGNBhD3ARIsAO_o7ynlnyWIXb4lRTctnu3G0oDnpRzjDpcDR9S3D43j9HOlfH8fru4Kz2QaAmAjEALw_wcB&hvadid=409909999188&hvdev=c&hvlocphy=1013452&hvnetw=g&hvqmt=e&hvrand=4180624490516709794&hvtargid=kwd-27997994916&hydadcr=514_1012844948&keywords=150k+potentiometer&qid=1638457566&sr=8-3

 

https://www.newegg.com/p/2YK-005K-00HU6

 

https://www.mouser.com/ProductDetail/BI-Technologies-TT-Electronics/P270-SF11R150K?qs=sGAEpiMZZMukHu%2BjC5l7YT77tCcQpo3bhw45jJVHiTo%3D

 

 

Interesting...

 

Are fully compatible with the original Apple pots? I mean, some adaptation is necessary to install them in the Apple joystick?

 

[Baldrick]

They'd be compatible if they were 3/4 turn pots like most of the ones used in joysticks. 

Sizing and fitting become obvious issues.  But it's nice to see that they are available in one form or another.

For a while they could not be found.

 

If your joysticks pots are lower in resistance and they are reliably precise (that is, they have smooth transitions and don't change in total value) you can easily correct for the lower resistance with the capacitor formula above.

 

[telengard]

I had yet another joystick start to not work and investigated the issue a little more.  This was for a Kraft Premium II (love this particular joystick).

 

It seems the travel of the shaft with the joystick handle/ball mechanism might be part of the issue.  When I remove the pot completely from the joystick, it registers the full close to 0/150k on my bench meter.

 

My issue now is, I have all these joysticks that are apart and are, to me at least, pretty intricate, and getting them back together after futzing with them is challenging.   

[telengard]

I managed to repair one of my Apple joysticks using a cap parallel to the pot as suggested, took a bit to dial in the correct value, but it is working great now.

Putting these things back together is a REAL pain, so if taking apart take pictures.   

 

thanks everyone for the help!