Final Readings are off...

[landontucker]

So, I just completed my second T15, and I'm doing my final measurements, and it looks like I'm not up to specs.

Measurement between PGND & -18V = 18.21V
Measurement between PGND & +18V= -28.52V


What should I be checking first?

[tpryan]

First, make sure your meter has a fresh battery. Measure the voltage of a 9V battery to make sure it's not lying to you.

Second, make sure you're measuring with respect to PGND. There are several points that are clearly marked on the board, see the schematic for others.

Third, if the voltages are still wrong, make absolutely sure that you have installed the correct parts around U5 and U6, especially resistors R30, R31, R33, and R34. Verify that the electrolytic caps and diodes are installed the right way round.

Let us know what you find.

[landontucker]

Alright, after a short look, it was clear D10 was backwards. After kicking myself, I fixed it, and it looks like we are reading within a volt for all readings. The only problem is that I'm reading the exact opposite for all voltages. +18 is reading -18. -18 is reading +18. And my phantom power is reading -46.5V.

Any ideas?

[tpryan]

Any ideas?

You've probably got your meter probes reversed. Black is "GND" or "Common", red is "volts/ohms/mA" or similar. Check the manual.

[landontucker]

Any ideas?

You've probably got your meter probes reversed. Black is "GND" or "Common", red is "volts/ohms/mA" or similar. Check the manual.

Sadly, this is true.

So it's good to know that I'm within the right readings. Officially, here is where I'm at:

PGND and +18V: +17.97V
PGND and - 18V: - 18.19V
PGND and Pin 2: +46.5V

Is 46.5V an adequate reading for Phantom?

[tpryan]

Is 46.5V an adequate reading for Phantom?

Yes