public Program()
{
    Runtime.UpdateFrequency = UpdateFrequency.Update100;
}

public void Save()
{
}

public void Main(string argument, UpdateType updateSource)
{
    List<IMyTerminalBlock> welders = new List<IMyWelder>();
    GridTerminalSystem.GetBlocksOfType<IMyWelder>(welders, block => IsSameConstructAs(Me));

    foreach (var welder in welders)
    {
        if (!welder.Enabled)
        {
            welder.ApplyAction("OnOff_On");
        }
    }
}