Help with MOTU 2408 mkii and PCI 424 Card - Right Channel

[peacemaster]

Hello:

It seems that my right audio channel has become very dull, with a kind of blown-out sound (most noticeable when panning any instruments hard right). I'd thought it was my speaker, then the external mixer, but the same issue occurs when I plug headphones directly into the 2408. Is there any way to A) fix this with a driver configuration or B) determine whether the issue is with the 2408 itself or the PCI 424 card, before I try to replace? The items are often sold separately on ebay.

Thank you for any help!