AP4 Services

Established in 2009, by John Downing and Chris Rychcik, Turbine Controls & Excitation Group (TC&E) was created to fill a void in the controls, exciter, and LCI field engineering services sector for large gas and steam turbines.  TC&E has since grown from a small services company focused on troubleshooting and outage support, to performing complex control system upgrades.

In 2018, in partnership with TMEIC™, TC&E introduced the first non-OEM LCI digital front end (DFE) upgrade in the industry.

In 2019, in conjunction with Basler™, TC&E introduced the first non-OEM digital front end retrofit for an EX2000 excitation system, the DECS-2100.

As the TC&E brand and reputation continued to grow, TC&E was acquired by AP+M Holdings LLC, at the end of 2020, to form AP4 Group.  TC&E continues to build its brand, under the AP Energy Group, and expand its abilities by working with other well known equipment providers throughout the power generation space.


Expert Powerplant Support

AP4 Services is focused on the ever-changing needs of our customers. It is our mission to provide the highest quality Field Engineers with the correct skill set to support our customers’ requests.

Controls & instrumentation

AP4 Services provides expert support in all GE™ Turbine Control Systems, Excitation, and LCI Static Starters. We also have a wide range of knowledge of other platforms including but not limited to Instrumentation, PLC, Protection Relays, BOP and Mechanical systems.

Mechanical Field Services

In today’s changing power market, the reliability of starting your Gas Turbine is now more important than ever. Every Summer and Winter AP4 Services answers multiple Forced Outage Calls to repair issues. It is our mission to help our customers keep these systems 100% reliable.



Using the latest technology, components, and lessons learned through decades of experience, TC&E can ensure complete reliability for both start-up and continuous operation.


This is the key to success in today’s competitive power markets. Heat Rate, Capacity, Start-Up, and Maintenance Costs are critical to the success of aging power plants.


Spending good money where it makes the most difference! We understand that O&M budgets are shrinking, so we work with the plants to understand where and when to repair, replace, or upgrade for maximum return.


Aging systems can continue to provide reliable service for many years to come with the proper service, maintenance, and repairs. Push your upgrades out 5-10 years with confidence.