I'm sure you can get them from Mackie. They have free parts manuals at their site, but I didn't see one for the SRM-450. They do list email and phone technical support. I would drop them a note or give them a call and I'm sure they can take care of your problem: Their contact info is on this site: http://www.mackie.com/scripts/contact_support.asp Hope this helps
Answers & Comments
I'm sure you can get them from Mackie. They have free parts manuals at their site, but I didn't see one for the SRM-450. They do list email and phone technical support. I would drop them a note or give them a call and I'm sure they can take care of your problem:
Their contact info is on this site: http://www.mackie.com/scripts/contact_support.asp
Hope this helps