There is probably some kind of IC chip for each preamp and #1 is probably gone bad. I would also not bother spending money on repairs. If you can live without 1 channel, then just tape over #1 and move on. If you are not using the digital inputs, you could put them into service for more inputs. On a budget, the ART Digital MPA on the SPDIF input would be a solid performer(easily equal or better than the 003 preamps). Still in budget land, the Behringer ADA8200 on the lightpipe input is also as good or better than the 003(both these options would be $300 or less on the used market). Both of those units could still be useful with many newer interfaces(and someday soon, you may NEED to upgrade the interface anyway, even if not right now)
I am selling a Presonus Studio 1810c right now as I stepped up to HDN. PM me if you are interested
