Plug in the power plug, check the switch position of the panel. When a "VTR" key is pressed, a red small alarm clock shape mark and time / week alternately beating shows. This shows that the machine is in "regular video" state. The "timing video" switch from "ON" to "OFF" position, with a warehouse port has been able to add / uninstall normal. Connected to the TV, tape playback appear full screen clutter (different from the ordinary signal noise wave point) and the normal image cannot be rendered, but go with and sound normal. Analysis is not a tape and tracking bad reasons (rotation tracking button ineffective), hence open the top cover plate, careful observation of the drum, no obvious dirt, just a head has defect was estimated to be caused by the improper cleaning. For a new drum (model VJB0001b), the image has improved, but still some noise wave and noise wave band and go with process, fault phenomenon heavy light, adjust the sound control head height, inclination, azimuth and horizontal position are invalid, doubt go tape tension system problems, promote the tension arm, change the tension in the process of operation of the magnetic tape, fault was reduced. Check the tension system. It is found that the tension arm traction felt the Copperbelt is off, AB glue the felt stuck in, to be cured after replay the tape, and further adjust the sound control head (because of the replacement of a drum, if not adjusted to form tracking adverse), picture and sound are basically normal.

Further inspection record system, such as audio and video input socket input signal from the record, then everything is normal, and direct the TV receiving system into signals were recorded, the image correctly but no sound, carefully check the audio channel. The results for audio input jack poor switch, after adjustment and repeated plug, reproducing all normal.

In TV receiver tuner process, also found that the machine receives the image and sound quality can not be taken into account, hence take if box, fine tuned intermediate frequency detection in the week (t703), aft in the week (T704), audio demodulation in weeks (t752), troubleshooting.

The video recorder is a mechanical and electrical integration of precision electrical appliances, in the repair should be very careful, not blind demolition. When replacing the drum, we should pay attention to the two opposite side of the upper and lower drum of the white mark; green two also relative, otherwise it can not reproduce normal images.