End of Line Technician

Mainspring Energy
Mainspring Energy

Menlo Park, CA, USA

USD 28-37 / hour + Equity

Posted on Feb 6, 2026

About Mainspring

Mainspring Energy manufactures and delivers fuel-flexible, low-emissions local power solutions that rapidly add new capacity and deliver reliable, affordable, and sustainable electric power. The company began commercial shipments of its Mainspring Linear Generators in 2020 and today has hundreds of megawatts in advanced development and field operations for leading Fortune 500 companies, data centers, and utilities. Mainspring also partners with global energy leaders including AEP, NextEra Energy Resources, Schneider Electric, and more.

The core values that ground our work, guide our decisions, and connect us together:

  • Pragmatic Optimism
  • Excellence without Ego
  • Proactive Collaboration

Job Overview

Mainspring is seeking a motivated and technically skilled End of Line Technician to join our growing Product Testing team. This role is ideal for individuals who thrive in a fast-paced, hands-on environment, enjoy mechanical and electromechanical work, and are energized by troubleshooting, testing, and continuous improvement.

As an End of Line Technician, you will play a critical role in the assembly, testing, validation, and occasional field deployment of our next-generation linear generator technology. You will perform mechanical and electronics assembly, diagnostics, retrofits, functional testing, core validation, emissions testing, and electronics box (eBox) testing, primarily in-house, with limited field work to support on-site testing or retrofit activities.

Responsibilities

  • Collaborate: Partner with cross-functional build and test teams in a dynamic, fast-paced production and test environment, and provide support for limited on-site field activities
  • Mechanical & Electronics Assembly: Assemble mechanical and electromechanical generator components and subassemblies following established procedures, identifying opportunities for process improvements
  • Troubleshoot, Repair & Retrofit: Diagnose and repair mechanical systems and electronic control/power electronics boxes, perform in-house and field retrofits as needed, and implement design updates with engineers
  • Testing & Validation: Execute comprehensive testing, including core validation, emissions testing, eBox testing, and general generator system functional testing across lab, production, and limited field environments
  • Inspect & Document: Perform thorough inspections, document test results, failures, retrofit actions, and corrective measures, providing actionable feedback to the engineering team
  • Continuous Improvement: Contribute to process improvements focused on safety, throughput, retrofit efficiency, and operational effectiveness in a high-tempo environment

Qualifications

  • Minimum 3 years of hands-on mechanical assembly and/or repair experience; experience in fast-paced manufacturing, automotive, power generation, or heavy equipment environments is a plus
  • Experience with electronics diagnostics, troubleshooting, and retrofit implementation, including control boxes, sensors, wiring harnesses, and connectors
  • Knowledge of or experience with core validation, emissions testing, and eBox testing is a strong plus
  • Willingness and ability to perform limited field work, including occasional on-site testing or retrofit support
  • Proven ability to manage multiple tasks, adapt to changing priorities, and maintain a strong commitment to safety and quality
  • Proficiency with precision measurement tools (micrometers, bore gauges, gauge blocks) capable of measurements down to 0.001”
  • Familiarity with software tools, data logging, and test documentation systems is a plus
  • Forklift or heavy equipment operation experience is a plus
  • Possession of a California Class A Commercial Driver’s License (CDL) is a plus

Does your experience not meet all of our posted requirements? Studies have shown that some people are less likely to apply to positions unless they meet every listed requirement. At Mainspring, we are committed to building a diverse, inclusive, flexible, and collaborative environment, so if you want to help us transition the world to clean and affordable electricity, and don’t meet all posted requirements for a particular role, we’d still love to hear from you. Mainspring can sometimes be flexible enough to shift responsibilities for the right person, or otherwise identify open or upcoming roles that may better fit your professional background.

In more traditional words, Mainspring Energy, Inc is an Equal Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, or protected veteran status and will not be discriminated against on the basis of disability.

This compensation and benefits information is based on Mainspring Energy's estimate as of the date of publication and may be modified in the future. We generally do not negotiate on salary once we have made an offer. The level of pay within the range will depend on a variety of job-related factors that may include location, relevant prior experience and/or education, or particular skills and expertise. New hires joining the company tend to be paid within the starting base pay range noted above, with opportunities to increase pay over time based on development of additional skills, competencies, and company-specific knowledge.

28 - 37 USD

This position is onsite at our Menlo Park HQ. The hourly rate will be adjusted to reflect local market conditions based on employee location as well as the experience of the employee. Along with the base hourly, Mainspring offers pre-IPO stock options + benefits + bonus.