Repairing Linear Shock Potentiometers

[Dave Petzko]

I've got Pi linear shock pots on the car. One of the sensors is outputting a lot of spurious voltages...creating some nonsensical position readings. I tried spraying contact cleaner into the sensor housing, but the only thing that seemed to do was reduce friction of shaft movement. Bad data was still being output.

I switched the bad pot from RR to LR to confirm that it wasn't the wiring loom...but could still be the connector attached to the pot.

Anyone know whether it's possible to disassemble a linear shock pot and clean/repair? If yes, are there any tricks for disassembling?

Thanks...

[S Lathrop]

The issue is that the range the pot has been operating in damaged. This is a problem with linear pots. Years ago I went with rotary pots instead of linear post, They are less expensive, give better resolution and last a lot longer.

Say a bell crank rotates 30 degrees. I can gear a linear pot so that the pot rotates 270 degrees for the 30 degree rotation of the a bell crank.

When I used linear pots I had a bracket that I tie-wrapped the body of the pot to a mount on the shock body. I then could change the position of the body if I ran into the problem you are having.

[romoman]

I haven't tried repairing too many, but it's never been successful. They are pretty simple - it's a wiper and a track. It's already no good, so pull it apart and see if you can fix it.

[Dave Petzko]

Thanks guys. I'll pull it part and see if there is anything obvious.

Steve - are you using hall effect rotary sensors? If yes, whose are you using? I'm aware of CDS sensors, but not sure I want to go there. MoTec has a contactless rotary pot but I can't figure out how it would be mounted. I'm sure there are other options such as Penny & Giles.

[romoman]

The CDS sensor went the way of the company - gone. I've heard that Veracity has a replacement, but not positive. I'd ask them.

[S Lathrop]

Thanks guys. I'll pull it part and see if there is anything obvious.

Steve - are you using hall effect rotary sensors? If yes, whose are you using? I'm aware of CDS sensors, but not sure I want to go there. MoTec has a contactless rotary pot but I can't figure out how it would be mounted. I'm sure there are other options such as Penny & Giles.

I used Novotechnik SP2800 non-contacting angle sensors. When I was buying these sensors they were about 1/3 the cost of a linear sensor and I never had one of them go bad.

[problemchild]

Thanks guys. I'll pull it part and see if there is anything obvious.

Steve - are you using hall effect rotary sensors? If yes, whose are you using? I'm aware of CDS sensors, but not sure I want to go there. MoTec has a contactless rotary pot but I can't figure out how it would be mounted. I'm sure there are other options such as Penny & Giles.

Dave, Any data guy I have worked with complained about a dirty signal with those linear sensors when new, and pretty useless once used very longl. Perhaps you can salvage it, or move it to another area of travel, but I would avoid investing in those. I switched to the CDS sensors which have proven quite reliable. I would look for something similar.

Just a note. I went with rotary pots on one car, as Steve suggested, to try and save cost. By the time I bought all the pots, gears and did the machine work, I had more money invested than the CVS sensors cost.