Probing Oddity? Help-What's going on?

[jim_stadtlander]

The probe only works when NOT in the Collet.

I have been using the probe with successs until this morning. I had the pattern in to be traced and it punched a hole into it. Last night it was working fine.

It continued to not react to anything in its way, no matter what I tried with wires, etc. I take it out of the Chuck and start messing around and it works fine!!! Place it back into chuck and nothing works. I have put a layer of tape around the probe and it is working again. What has happened? Why is it doing this? Should I paint the probe's body, is the black that's on it an insulator for current?.........Jim

[Brady Watson]

Jim,
Check to make sure that the wires from the probe are going to the correct inputs & power spots on the terminal blocks in the control box. I know that there was at one point a small miscommunication which resulted in a few probes being wired wrong from the factory. If you are using a newer probe, verify that ground is properly seated & in the right spot, the input line is in input #1 & properly seated, and that the power wire is going to +5 or +12v depending on model. If your Zzero plate is working, then Input 1 should be good.

FYI - There is another spot to hook up ground in the control box than the one in the same input block as input #1.

-B

[jim_stadtlander]

The Zzero plate is working fine. Which should(?) mean the wires coming to the connector for the probe are working right. No loose connections in the probe wiring, unlees it is the green wire deep inside the black box that can't be gotten to. The input light is works fine at the computer screen. And everything was working as it should, yesterday. The probe is older, I am guessing in the 2 -8 year old range. I cleaned the chuck and collet this morning with WD40, could that have some kind of bearing on it? I will check that control box as you suggest, but it was working before and I have not opened that up to possibly creat a new problem.....Jim

[Brady Watson]

If this is a 1st Gen probe with brass styli, then it should only have 2 wires. One to ground & one to input 1. IMO the old school ones are the best. If it is the 1st gen, loosen it up a bit so that it requires some movement of the stylus to trigger. If you make it too tight, it causes reliability problems where the probe won't clear.

-B

[jim_stadtlander]

I will try to explain the problem again, because I may have confused the question. Above, I said that I wrapped the probe---- what I wrapped is the shank that goes into the collet (not the styli). I wrapped it with a layer of plastic tape to "insulate" it from the collet. That makes it work, but it is tricky to get it in and out of the collet. If I remove the tape, install the entire probe mechanism back into the collet it don't work!!! If I remove the shank(thus the whole probe unit) out of the collet hold the body of the probe in one hand and very gently touch the styli with my finger from the other hand,....the Z moves up and reacts until I stop touching the stylus. Why would touching the probe to the collet/chuck keep the probe from working???? Could the green wire inside the aluminum body have a fault? Can't get at it to see it.

Brady-- Yes, it is a two wire probe, so I will assume that it is a first gen. probe. Thank you for all your help to this forum. It seems as if you are always there to help anyone out....Jim

[Brady Watson]

Hey Jim,
Make sure that whatever probing routine you are running works with a normally closed probe, like the 1st Gen you have. The correct condition with the probe should be that input 1 will ALWAYS be ON when you have the probe hooked up and the stylus is hanging there not touching anything. Input 1 should go OFF when you move the stylus.

Check to make sure that you have whatever program running the probe set up correctly for a normally closed probe.

-B

[bill.young]

Hey Jim,

It's hard to tell without being there, but it sounds to me like you have an internal short in the probe that's grounding to the body of the probe, so that when you put the probe in the collet it completes the input switch connection. Maybe a chafed spot where the wire enters the body of the probe?

It's been a while since I messed with one of the earlier probes, but I believe the bottom end of the probe (the one with the stylus) can be removed with a couple of screws and might let you see a problem.

Bill

[jim_stadtlander]

Bill-- I disassembled the probe with the three screws. Took it all apart(carefully)down to the screw that holds in the internal spring. Spring would not come out easily even with that deep screw removed, so I left it ay that. The rest of the aluminum body with the triangle hole in it looks like it is all one piece. Is it??? The green wire goes inside that. Blue goes in and then comes back out. How do they get those wires in it if it is one piece?

Brady--- I did try the other setting for the probe(on the computer screen) and as soon as I switched to it, an error came up saying that it is set wrong. So I went back to the original setting. Hope that makes sense.

Happy Easter to all!!!!!! Jim

[Brady Watson]

Jim,
Yes - the probe body is one piece. It's pretty simple, and as Bill points out, one of the wires could be chaffed. You should be able to thread new wires in there if you have to.

-B