Problem with 2008 gear tooth sensor

[roborat]

My second sensor also seems to be bad with a reading of 3.69 on the signal wire. Guess that we will order a new honeywell sensor this morning.

[SuperBK]

One of ours sits at 3.6 volts too! We are hooked up the other one before putting the other gearbox together. It works. So one good, one bad here too.

[RyanN]

I'm with most of you saying that one of the GTSs is bad. We wired ours up yesterday, one worked, the other did not. We got one of the ones from last year, and it worked, so we're sticking with that. I guess that would be legal since in the KOP they included two, and we are only using two. The one from last year is identical to this years except the fact that the colors changed.

[MrForbes]

We have one good sensor, one bad one too. The bad one is the one at the outer end of the "full" board...that is, it only has one edge cut. Maybe there's a manufacturing or design problem with the circuit board itself? or a part on wrong? that could be fixed?

Also has anyone asked on Q&A if they'll make an exception and allow using previous year KOP sensors because of the apparent systemic problem with the new boards?

[Eugene Fang]

Hey everyone! i think our team found the source of the problem.

check out R3 on the two boards. the number on them is different.

Apparently, R3 on the end gear sensor board is marked 4001, R3 on the other gear sensor board is marked 4004. Our mentor assumed that one is 400 and 40k Ohms, but he was not sure how to read the surface mount resistor markings. It is clear they made a mistake in the factory and built all of one of the two boards incorrectly.


Hopefully, more information will be posted later today about this problem.

[MrForbes]

We found that R4 is different, I did not look at R3 yet.

let's see how this picture came out? oh, I have to split it up....

[Eugene Fang]

OH! R3 AND R4 ARE SWITCHED!

[Tim Skloss]

Originally Posted by RyanN

I'm with most of you saying that one of the GTSs is bad. We wired ours up yesterday, one worked, the other did not. We got one of the ones from last year, and it worked, so we're sticking with that. I guess that would be legal since in the KOP they included two, and we are only using two. The one from last year is identical to this years except the fact that the colors changed.

It would be legal only if the sensors from last year are freely available to ALL teams as a commercially available part. So if you can prove that they can be purchased today by any team, then you are OK.

[Dad1279]

Markings per http://www.vishay.com/docs/20020/smdmark.pdf

4001 - 4k ohm
4004 - 4 meg ohm

[Tim Skloss]

Originally Posted by Pikat

Hey everyone! i think our team found the source of the problem.

check out R3 on the two boards. the number on them is different.

Apparently, R3 on the end gear sensor board is marked 4001, R3 on the other gear sensor board is marked 4004.

It would be great for someone to swap the resistors so they match the working GTS board and verify that it fixes the problem.

All of us want to know if there is an easy way to fix the bad board!!!

[usbcd36]

I can verify that swapping the resistors fixes the board. Don't attempt it without the right equipment, though.

[baop858]

Which one is the working one?

[Brian C]

The bad one is the end board on the sensor strip. The good one is the next one in. If you have already separated your boards (and I'm thinking that by now you should have) the board with one smooth edge is the bad one and the one with 2 small nibs on opposite edges is the good one.