question: how to replace filter fans for autosonde? 
 context: ['AUTOSONDE contains two identical axial fans. Electrical cabinet fan (M1) is in the main\nelectrical cabinet and the overpressure fan (M3) is inside the filter box next to the entrance\ndoor.\n6.8.2.1\u2002Replacing Electrical Cabinet Fan (M1)\n1. Switch off power by turning the main switch to OFF position and lock the switch with a\npadlock.\n2. Open the main electrical cabinet.\n3. Disconnect cable X22-M1-W1 from the fan. \nTake note of the order of the wires before disconnecting them.\n4. Pull out the clip (number 1 in the figure) and rotate the fan (2). \n1\nClip\n2\nFan\nFigure source: EC Fan-and-Filter Unit Assembly and Operating Instructions (Rittal)\n5. Replace the fan with a new one and reconnect cable X22-M1-W1.', "6.8\u2002Electric System Maintenance\n6.8.1\u2002Replacing Axial Fan Filters\nAUTOSONDE contains three axial fan filters. Two are in the main electrical cabinet fan and\none is in the overpressure fan box next to the container entrance door.\nCheck the filters at regular intervals and replace when necessary.\nMake sure the fan rotor is stationary before changing the filter mat. Never\ninsert your fingers into the fan rotor.\nWARNING!\n1. To release the louvred grille, press the catch on the grille slightly upwards with one\nfinger. \nFigure source: EC Fan-and-Filter Unit Assembly and Operating Instructions (Rittal)\n2. Drop the grille open by approximately 70 or 90 
degrees.\n3. Make sure that the open (roughened) side without the manufacturer's logo faces\ntowards the louvred grille.\n4. Insert the filter mat.", '2. Open the air intake filter box next to the entrance door.\n3. Disconnect cable F12-M3-W2 from the fan. \nTake note of the order of the wires before disconnecting them.\n4. Pull out the clip (number 1 in the figure) and rotate the fan (2). \n5. Replace the fan with a new one and reconnect cable F12-M3-W2.\n6. Close the air intake filter box.\n7. Unlock the main switch and turn it to ON position.\n8. Test the fan:\na. Activate Maintenance Mode.\nb. Turn the fan on in Maintenance > System Overview > Gas System > Overpressure \nfan. \nThe fan should start blowing fresh air into the container.\nc. Turn the fan off.\nd. Exit Maintenance Mode.\nAUTOSONDEâ AS41 Maintenance Manual\nM212011EN-C\n60', "3. Make sure that the open (roughened) side without the manufacturer's logo faces\ntowards the louvred grille.\n4. Insert the filter mat.\n5. Make sure that the open (roughened) side faces towards the louvred grille.\n6. Push the l