Boot lid and bottom, in the condition of belt box down, reference NV - SD50 movement (or K) maintenance manual mechanical assembly program, check the mechanical drive mechanism positioning marks without dislocation occur (especially to check mode switch on the triangle sign and borders on whether the gap of alignment, the base connected to the gear and rack with warehouse base positioning marks are aligned). If you check the mechanical drive mechanism positioning logo misalignment does not occur, large in the resistance load mechanism failure is mostly due to tape or mode switch internal dirt caused by poor contact. In this case, can use manual loading method to observe the loading mechanism transmission is smooth. If resistance is big, then check the load motor shaft for dirt, turbine, and vortex rod meshing rotation is normal. If the load transmission smooth, then check the load motor driver IC IC6501 / BA6219B 2, 10 feet of the output load motor driving voltage is normal, internal contact mode switch are in good condition. If the mode switch internal poor contact, from the mode switch aperture place drip into the anhydrous alcohol, turned on the power switch, let the tape after loading and unloading a few times you can resume normal mode switch internal contact.zjgservice manual download site