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Chassis LED polarity . . . Phantom power voltage T15

PostPosted: Thu Nov 13, 2008 9:02 pm
by buenavista
I just finished a T15, my first SCA module. I also bought the chassis, PS03, and harness. Everything works great, but I have a couple quick questions:

1) When I first wired up the power LED, I wired the negative terminal to pin 1 (PGND) of J1, and the postive (white stripe) of the LED to pin 2. I measured zero resistance of Pin 1 to CGND to verify correct pin. But the LED did not function in this position. I reversed it, and it worked. . . . Was I wrong in my original thinking, or was my LED not marked correctly.

2) When phantom power is in the off position, my DMM is settling at around .2 or .3 volts. Should it be at zero, or is this OK?

PostPosted: Mon Dec 01, 2008 6:06 am
by tpryan
1) When I first wired up the power LED, I wired the negative terminal to pin 1 (PGND) of J1, and the postive (white stripe) of the LED to pin 2. I measured zero resistance of Pin 1 to CGND to verify correct pin. But the LED did not function in this position. I reversed it, and it worked. . . . Was I wrong in my original thinking, or was my LED not marked correctly.


Note that in step 25 of the assembly instructions, the positive lead is shown connected to pin 1. Pin 2 is -30V, not +30V, so your initial connection was backwards.

2) When phantom power is in the off position, my DMM is settling at around .2 or .3 volts. Should it be at zero, or is this OK?


0.2V or so is normal.