posted 01-16-2010 07:26 PM            

Well I first changed cables as I have an extra one. That did not work. So, I called Karen at Lafayette. She told me to upgrade the system to see if that would work(I did not upgrade in three years). I also called my local rep and he agreed. That did not work. I then attached another, brand new, DAS box to my Dell Laptop and even that did not work. I then used an old cable with the finger plates. That worked fine and all of the other components worked fine. So, I concluded that I had two damaged cables. Its not out of the question since we run them over with chairs from time to time.

So, I have been running the tests with the finger plates for the last month and had no problem with it until I got around to ordering a new cable.

Well, we are sending a guy to Backster so I ordered a new cable for myself so I can use the electrodes and give him the old finger plate cable. I ordered the cable with both electrodes and finger plates--pretty cool.

Anyway, even this cable does not work with my electrodes, but the same cable works with the finger plates. So there must be a setting that I can not find that has the electrode disabled, but not the finger plates---is there?

posted 01-17-2010 12:54 PM         

I use the LX4000, and I do not believe there is a setting that "disables the electrodes but not the finger plates".

Lately I've been using four EDA sensors (two electode style and two fingerplate style)on four fingers of one hand. Then combine the signal through a Radio shack "Y" into the DAS unit. I'm finding there is less non-specific EDA activity and distortion due to minor finger pressure changes.

posted 01-18-2010 02:54 AM         

If the snap-on cable works for the snap-on fingerplates, there is no reason for that same cable not to work with the snap-on electrodes.

I can only think of two potentional reasons for the electrodes not to work: 1: Lafayette’s snap-on disposable electrodes come pre-gelled on a sponge- like- material and are moist for conduction. If you are using disposable electrodes that have become old, that gel may have become ‘dried out’ and the sponge becomes ‘stiff’ to the touch; therefore no contact via conduction is being made to the subjects skin (and therefore unresponsive). If you pull the dried out sponge off, and don’t use any kind of gel, the electrode may still not come into contact with the skin because the electrode is off-set and below the adhesive portion. Also, in the past I seem to recall getting a ‘bad’ batch of electrodes that were dried out when I received them. So, just because their 'new'- doesn’t mean they are not dried out.

And 2: You have a bad batch of disposable electrodes in that the 'snap' is not in actual contact with the sensor

Can you describe how you are making the determination electrodes 'don't work'? I mean, what exactly happens when use them?

posted 01-18-2010 07:55 AM            

My GSR is a flatline and as soon as I snap on the fingerplates it is fine. (Yes it is the dual cable you described).

posted 01-19-2010 04:42 PM         

I mentioned the other day that the snap-on disposable electrodes come pre-gelled on a sponge material and are moist for conduction; and thought if you were using ‘dried out’ electrodes that might be the problem your experiencing.

Today I happened to have a couple ‘dried out’ electrodes, and did a self-test just to see what would happen when I connected the cable; sure enough- the EDA trace line was absolutely flat without even a twitch. I must have been dead.

Even though you said you used ‘new’ electrodes, you might wanna check the sponge on the bottom for dryness or simply pull the sponge sponge off before using.

posted 01-21-2010 08:54 AM            

Thanx to Bob and those of you that emailed me with solution tips.