7i76e defect (poti on TB4)

Hi,

I got my 7i76e 3 weeks ago.
First dry runs with inputs and outputs together with linuxcnc were successful. Until now
Yesterday I tried to play with TB4 potentiometer, but without success.

I connected a 9V Battery (9.2V) between Pin 1 and 3. And I always measure 4.55 V between Pin 1 and 2.
Regardless of the status of hm2_7i76e.0.7i76.0.0.spinena and hm2_7i76e.0.7i76.0.0.spinout.
Even when 7i76e is powered off, I measure 4.55 between Pin 1 and 2.

Am I'm doing something wrong?
Or does that indicate a defective 7i76e?

Thanks in advance.

If you get more than 100 mv or so on TB4 pin 2 relative to pin1
when not enabled its likely that the output buffer Op Amp is damaged

What pin was connected to + ?

Hi tommylight,
+9.2V connected to pin 3
- connected to pin 1
4.55V (always) between pins 1 and 2

Hi PCW,
how do you know all the things about Mesa cards?
Do you own schematics of this cards?

Anyway, thanks for your answers.
Then I guess I'll have to exchange the card.

---
I contacted eusurplus.com today, where I bought the 7i76e card 3 weeks ago.
They told me, first to contact Mesa (pcw@mesanet.com) with full description of the issue.
Let's see what happens next ....

Just in case you haven't put 2 and 2 together, the pcw@mesanet.com you were told to contact is the same PCW that replied to this thread a couple of messages up.

Now it works! I cannot believe that!

I wanted to make card ready for shipment and I removed 1st time *all* plugs (green and orange, also the ones I had never used before) from card, in order to better remove wires.
Give it a last try, was my thought.
I plugged only the connector with the battery into TB4 without powering the card itself.
Now I measured 5.9mV between pins 1 and 2.
Exactly as Peter said it should be.

Could the other plugs have had something to do with the issue?
At least I didn't see anything strange thing.
I removed and plugged TB4 several times. But not the other plugs.

I'll send separate email to pcw@mesanet.com about this.

Hi Todd,

meanwhile I put 2+2 together
I already noticed the similarity when I was told to contact pcw@mesanet.com.
This explains Peter's outstanding knowledge about Mesa cards.