Cat 226b thumb wheel switch replacement

[quiksilvr]

after having fixed a few of these for people, im beginning to notice that on some of the thumbwheel switches, when the magnet goes bad, its not too long after, that the sensor inside the switch ends up going bad. and thats the point of no return for the switch.

 

[pbd05]

Not yet, but that's where I was heading. I'm just trying to remember if I have to lift the cab to get that vent/trim out.

 

[quiksilvr]

no u dont have to, i used a torx bit with a pair of vise grips to turn it and u can squeeze between the cab and the cover not much room but it is do-able

 

[pbd05]

after having fixed a few of these for people, im beginning to notice that on some of the thumbwheel switches, when the magnet goes bad, its not too long after, that the sensor inside the switch ends up going bad. and thats the point of no return for the switch.

My switch has a fair amount of "wear" in the potting from the blown out magnet rubbing against it, so I wouldn't doubt it could be going bad too. We have 3 x 216B in the scrap pile at work that I should try a new joystick from. I'm not sure if those would even have auxiliary switches on them though.

 

[quiksilvr]

if you are referring to the concave indentation on the sensor portion, that is from the factory.

 

[pbd05]

if you are referring to the concave indentation on the sensor portion, that is from the factory.

That's the one, that's good to know! I thought mine was worn down from the magnet. Hopefully the weather holds out after work sometime this week so I can take things apart a little further.

 

[quiksilvr]

there is a way to check the sensor portion of the thumbwheel switch, if you have a spare magnet laying around. you can run a magnet along the bottomside of the switch. with the switch connected to the machine and the machine running. if the sensor is still good, then you should get some kind of response from the machine.

 

[wriggconst]

It's been awhile since I have been on here. Ohio weather bites.Thank you quiksilvr for trying to fix my thumb roller switch. It still didn't work so I ended up getting a new joystick and in the initial test that seems to have fixed the problem. Thanks to everyone for their advice and suggestions. Wayne

 

[wriggconst]

By the way some of Cat engineering is kinda suspect. lol

 

[pbd05]

I got some time to work on mine today. I pulled the joystick and harness out of the machine and tested it on the bench. I ended up finding no continuity in the output circuit (yellow wire) which lead me to finding a break in it. I repaired the wire with what I had on hand and put everything back together. It's now working consistently in both directions which is awesome. However, the positive flow output is very weak/slow while the return is overly quick.

I'm not sure if there's a calibration I have to do on the auxiliary circuit?

 

[pbd05]

I pulled the negative terminal in hopes of resetting any sort of calibration on the machine, no luck. I looked into what the purple wire does and it looks like that might just be for a factory calibration, it doesn't actually connect to anything on the machine side of the harness. I'm debating on removing everything again, and redoing my splices with crimps instead of solder. Maybe I have some excess resistance from the repair? I guess the other issue could be the one magnet on my switch being in worst shape than the other, but it's very minute.

 

[stefuel]

A soldered connection is way better then a crimped one. That said, you probably couldn't measure the difference between a soldered connection and a properly crimped connection. The soldered connection is less likely to fail down the road.

 

[Nige]

I looked into what the purple wire does and it looks like that might just be for a factory calibration, i

Do you have an electrical schematic.? If you don’t and you want one pls supply a serial number.

 

[pbd05]

Do you have an electrical schematic.? If you don’t and you want one pls supply a serial number.

Thanks for the offer! I still have the one you got me from the drive motor/parking brake thread!

 

[Nige]

So what is the reference number of the purple wire of which you speak.?

 

[pbd05]

I'm not sure what the reference number is, but it's the Violet (VI) wire coming off ROLLER - PROPORTIONAL A1/A2. It doesn't have a pin on the machine side of the harness so I figured it doesn't have a use while in the machine.

 

[Nige]

That must be either the complete handle assembly is designed to be externally calibrated in another type of application, or just the thumbwheel switch (from an outside supplier) is designed for external calibration in another application. No calibration required in your application, it either works or it doesn't

 

[pbd05]

That must be either the complete handle assembly is designed to be externally calibrated in another type of application, or just the thumbwheel switch (from an outside supplier) is designed for external calibration in another application. No calibration required in your application, it either works or it doesn't

Is it possible that Cat ET needs to be used when replacing the switch to set some calibration in it? I'm still planning on re-doing my repair, I ended up putting 3 repair joints on the yellow wire and would like to bring that down to one.

 

[Nige]

Is it possible that Cat ET needs to be used when replacing the switch to set some calibration in it?

No. There is no calibration for the thumbwheel switch. If it has been correctly manufactured it will put out a voltage output that varies from around 5.7v in the centre, and increases/decreases by up to approx 0.8v depending on whether you roll the switch forward or back.

 

[pbd05]

I was blessed with 18 inches of snow yesterday so got a chance to use the machine again. It looks like the issue might have corrected itself, and/or the switch wasnt really the issue. Everything works like it should now, both open and close functions on my bucket seem balanced now. One of the hydraulic hoses on the bucket got damaged (pinched) from bad routing some time ago, I'm thinking that was really my issue after all.