From the ARRL ARES E-letter:
Something that every ARES® team needs is a “fixer” – a skilled tech equipped not so much with radios, but with test equipment and supplies of tools, wire, connectors, and repair materials. The team “fixer” is a person who can fix or jury-rig just about anything and who can improvise as needed to keep things running.
With a majority of team members focused on communications and organization, this function needs attention during planning and training for response and deployment. It’s a great path for mentoring hams from non-technical backgrounds so they are better prepared to maintain operational status under field conditions.
In addition, this function is a natural for hams from a “do it yourself” (DIY) background – a prime source of recruitment to Amateur Radio. — Ward Silver, N0AX, ARRL QST Contributing Editor