From January to March 2009, turbine 2 was undergoing scheduled repairs and modernization. It was the first and only turbine in the station which was equipped with a new electro-hydraulic regulator of its rotational speed supplied by the Promavtomatika company.[3] During the course of the repair, the turbine blades were welded, because after a long period of operation, cracks and cavities had appeared. The turbine runner was not properly rebalanced after these repairs.[4] After the repairs, turbine 2 had increased vibration, ca 0.15 millimetres (0.0059 in) for the main bearing at the full load of the turbine. While that did not exceed specifications, the increased vibration was unacceptable for long term use. The elevated vibration compared to other turbines was apparent for turbine 2 before the repair as well. The vibration exceeded the allowed specification in the beginning of July[2] and continued to increase with accelerated speed.