[sdiy] Odd OTA behavior

[Aaron Lanterman]

I just got this e-mail from a student:

>  I took the remaining 13700 and the 082 I was using and tried them  
> on another board and found that the 13700 wouldn't keep a steady  
> ~-13-14V at the Icon terminal - placing a resistor between +15 and  
> the terminal (trying with 520kOhm) would rise the voltage at Icon to  
> ~1.4V.

I thought the voltage at a control pin of an OTA typically hung out a  
diode drop or two above the negative rail. What could he have done to  
make it measure at 1.4?

(I'm thinking he probably hosed the chip somewhere along the line -  
blowing up a 13700 seems to be a rite of passage in my class; either  
that or he's flat out screwing up the measurement somehow.)

- Aaron