HD I/O calibration question

[David Sandwisch]

I can't seem to get anything to change when I turn the adjustment screws on the back of my HD I/O. I am running -20 dbfs signal through them from the calibration session and looking at the meters on my sound board. I don't have a volt meter to calibrate them to -20dbfs = 1.228V but I think looking at a sound board meter should see the meters go up and down as I turn the pots. I have wildly turned them and nothing changes on the meters on my sound board. I can see that my output 2 is lower than all my other outputs and I need to bring it up but I can't get it to change. Everything on my sound board is the same per channel and I've eliminated the sound board as the issue.

Ideas? I should be seeing the meters change that are reading the output signal if I turn the output trim pots right?

[Craig F]

you should see a change
are you sure you're turning the output pots and not the input pots?
a 6dB difference is most likely a dropped leg in the signal path

[David Sandwisch]

Yes I am turning the output pots. They are at the bottom of the unit with the input pots towards the top. I have turned output 1 and 2 several rotations and nothing changes on the output level of the sine wave on my sound board meters.

I have never attempted this since I purchased it new and the only reason I need to is for some reason my output 2 dropped several DB in strength compared to the other 5 outputs that make up surround. All my surround channels output the same level except output 2, the center. This is evident in every session I test including the calibration session. Somehow the I/O appears to not be putting out enough on output 2 and I can't get turning the pots to do anything.

More thoughts or questions or things I can try?

Thanks,
David

[David Sandwisch]

So I swapped my input DB25 with my output DB25 and flipped the genders and then the signal on output 2 was much stronger and matched the other channels. I also turned the trim pots and after many full 360 degree turns, the levels on the sound board did change. This tells me the trim pots are extremely fine adjustment. It also tells me that my output DB25 cable has a busted leg on the XLR end like you suggested above. I put the DB25 cables back in their original configuration and wiggled the back of the channel 2 XLR connector and I could get the signal to jump up and down on my monitor board.

Looks like I will be repairing a cable tomorrow. Thanks for the information!

Thanks,
David