Case 4890 front steer sensor.

[Kollebo]

Hello over there.

im hunting for an front steer sensor to my Case 4890.
Part no:A149696 or A185743.
no one in Sweden can get them.
I also search on E-bay and the web but without any luck.
does anyone have one or know who does?

i could also be happy with only the potentiomer inside because that is only what is broken but i cant find that ither.

Thanks C-J from Sweden

 

[Kollebo]

 

[John Saeli]

We can furnish a new sensor. $$$ e-mail is open.

 

[Kollebo]

Hello

i cant find e-mail to you.
could you send me Pictures?

 

[Bob]

(quoted from post at 04:27:10 07/09/19) Hello over there.

im hunting for an front steer sensor to my Case 4890.
Part no:A149696 or A185743.
no one in Sweden can get them.
I also search on E-bay and the web but without any luck.
does anyone have one or know who does?

i could also be happy with only the potentiomer inside because that is only what is broken but i cant find that ither.

Thanks C-J from Sweden

Looks like a new unit is some $1200.00USD.

You say you could repair it if you had a new potentiometer.

It doesn't need to be a "SPECTROL" brand, not sure if they are around anymore, but there's lots of sources for "precision potentiometers".

Here's what we know...

It has 5000 Ohms resistance.
Tolerance is +/- 5%.
Linearity us +/- 5%.
We need to know what it's "range of motion" is, and some idea of wattage.

below is a link to one that would probably do the job IF a
"one turn" range of motion is suitable.

https://www.mouser.com/ProductDetail/Vishay-Spectrol/140B00502?qs=M7yXsciANIXgACOI3pm7hw==

 

[kevinthefixer]

Take that pic to any electronics supply store, they should be able to fix you up. Looking at that pot it is almost certainly a 270-degree sweep, 5K is clearly readable, it's near-certain to be linear taper. It probably needs to be calibrated while installing so be sure you know how to do that. It's a bit late to tell you to do that before you take it apart!

 

[4435]

Several years ago I contacted Vishay, they could not sell to me. Case still had a strangle on that particular one.
It is a million turn continuous rotation. I had another company make me a half dozen. They are + or -10% I also had to cut the connector board and move the resistors into the cab. Not as happy with them as I would like but don't have anywhere near $1200 in 6 of them.

Don't have a shot of the cut, used a dremel saw to do it.
If you don't come up with something over there I would part with one or two. HTH Tom

 

[Kollebo]

Hello and thank you for your answers.
im searching the wed for potentiometers.

What did you mean with "cut the board and move the resistors into the cab"?

im now thinking of this solution.
i will put a 2kohm resistor in the red wire and will then move the centerpoint 1/4 turn.

then i have 1/2 turn to use in the potentiometer and also the correct ohm Reading at the right time.

has anyone tried this?

thanks C-J

 

[Kollebo]

Hello

This could actually work.
do you have this?

Thanks C-J

 

[4435]

Yes that could work, I would start with a a 1000 ohm maybe even a 500.
The metal connector with two screws in it where the wire from the sensor and to the steering module are connected (what I pictured). That is what I cut and moved the two resistors from the bottom of the potentiometer. Those are 1400 ohm 1/4 watt resistors in series with the winding in the pot.
So you could potentially use two resistors of different values to unbalance the pot. and move the centering point. Having them on the board in the cab makes them much easier to change and modify if needed. I would buy new resistors so you have a nice long lead. HTH Tom

 

[Kollebo]

Hello Tom.

You seem to know this things.
The two resistors that are mounted on the potentiometer.
what are they doing?
are the sinking the V from 8v to 5v or what?

Thanks. C-J

 

[Kollebo]

(quoted from post at 04:59:20 07/09/19) We can furnish a new sensor. $$$ e-mail is open.

Hello

Could you send me an E-mail
i cant find your email.

Thanks C-J

 

[4435]

The resistors are the only difference between front and rear sensors.
Yes the voltage would be a little different but there is not any load to cause voltage drop.
The way I understand the purpose of said resistors is so the module in cab knows if it is front or rear sensor. HTH Tom