Common fault detection of pressing pulley of Panas

The mechanical control of the pressure pulley of Panasonic NV M series camera is mainly composed of the main rod, the pressure pulley rod, the return spring, the pressure pulley support, the pressure pulley and the driving arm only punch rod. The control process is that in the playback or recording state, the loading motor drives the main rod to move through the cam gear, and then the main rod pushes the belt pressing wheel assembly to press the tape to the surface of the main shaft. The mechanical parts of NV M series cameras are installed on the upper and lower sides of the cast aluminum chassis. The parts are assembled accurately and the control process is complex. For the sake of narration, this paper talks about the rotation or movement direction of a mechanical part, which refers to the installation surface of the part. UL also sent a team of professional technical experts to participate in this rubber and plastic exhibition.

the mechanical control process of pressing pulley is the same when the camera is in playback or recording state. This paper takes playback state as an example to introduce the mechanical control process of pressing pulley. Turn on the power switch, insert the tape box, press the replay key, the system controls the microprocessor to output the tape loading instruction, the loading motor immediately drives the cam gear to rotate in the anti clock direction, the curve groove at the bottom of the cam gear drives the main rod and the mode state selection switch to move to the right, and the control rod a fixed on the main rod pushes the contact of the belt pressing roller rod to move in the anti clock direction, And drive the belt pressing roller support to drive a position clockwise. As the main rod moves to the right, the main rod pushes the control rod B fixed on the belt pressing rod to move to the left, and drives the belt pressing roller support to move to the direction of the main shaft, and then the belt pressing roller presses the tape to the surface of the main shaft, as shown in Figure 1. While the main rod drives the belt pressing wheel to move to the right, the control rod B on the belt pressing rod moves to the position C in Figure 2 (looking from the side of the main circuit board to the chassis), and the recoil rod of the drive arm locks the belt pressing control rod B within a certain range. When the main rod drives the mode state selection switch to the replay state position, the loading motor stops rotating and the machine enters the replay state

when the machine replays normally, press the stop key, the loading motor drives the cam gear to rotate clockwise, the curve groove at the bottom of the cam gear drives the main rod and mode state selection switch to move to the left, and the belt pressing pulley gradually leaves the main shaft. Under the action of the return spring force, the belt pressing pulley rod drives the belt pressing pulley support to return to the stop state position. When the mode state selection switch moves from the replay state and position to the stop state position, The loading motor stops rotating, and the machine is in the stopped state, so as to complete the mechanical control process of the belt pressing wheel. Here are some examples of common troubleshooting

example 1. Model NV m9000

fault phenomenon: turn on the power switch, the power indicator light is on, insert the cassette and press the replay key. After the tape is loaded, a still image appears in the electronic video recorder, and then unload it after 3 seconds. This kind of ceramic particles (bimolecular polyurethane material) is composed of red and green color matching

analysis and maintenance: after the tape is loaded, a still image appears in the electronic video recorder, and then unloaded after 3 seconds. It is estimated that the fault exists in the tape walking mechanism. Eject the cassette, remove the two fastening screws on the cassette cover and remove the cassette cover. Check the belt moving mechanism. It is found that when the machine is in the stopped state, the belt pressing pulley has been pressed against the surface of the main shaft. Pull the belt pressing pulley support by hand, and it is found that the plastic hook of the return spring on the take-up disc brake has been broken. Therefore, the belt pressing pulley assembly cannot be reset when it is in the stopped state. Press the replay key, and the belt pressing pulley cannot press the tape against the main shaft when the tape is loaded, so the above fault phenomenon occurs. After replacing the take-up disc brake and hanging the return spring on the belt pressing rod, the mechanical control of the belt pressing wheel returns to normal

after the take-up disc brake is damaged, it is difficult to buy accessories in the market. In this case, remove the take-up disc brake, drill a through hole near the original hook with a 0.8mm drill bit, and then hang the spring lug in the drill hole. Nearly 50% of the domestic market is always occupied by imported products

example 2. Model nv-m1000

fault phenomenon: insert the tape box for shooting, the tape makes a squeak when moving, and there is a noise band on the screen of the video recorder, which will be shut down for protection after a few seconds. Analysis and maintenance: when the tape moves around, it can reanalyze the curve and make a squeak, which is suspected to be caused by the poor mechanical performance of the tape box. Eject the tape box, replace it with a tape box with good mechanical performance, insert it into the tape bin and replay it. The above fault phenomenon still exists. Judging from the direction of the squeak, it is estimated that the fault is in the mechanical control mechanism of the belt pressing wheel. In order to observe the mechanical transmission process of the pressing pulley, eject the belt box, remove the cover of the belt bin, and simulate the loading of the belt box into the bin when the belt bin is ejected. The steps are as follows: ① turn on the power switch; ② Use a small screwdriver to press down the bin locking rod (white) installed at the lower right of the bin frame, and at the same time, extend your left hand into the bin to press down the bin locking plate, and the mechanism will immediately make a "snap" sound, indicating that the bin has been lowered in place and locked, and the bin lowering switch has been turned on; ③ Take two small pieces of black adhesive tape and seal the head and tail detection holes installed on the left and right sides of the bin frame; ④ Press the box out key, wait until the microprocessor sends out the bin position detection command, and then press the replay key to simulate the tape loading and enter the replay state (note that using the above simulated tape loading method, when pressing the stop key, the black tape on any detection hole at the head or tail of the tape should be immediately removed when the tape is unloaded, and resealed after unloading, so as to press the replay key again to simulate the tape loading), and observe the mechanical control process of the belt pressing wheel, It was found that after the tape was loaded, the upper part of the pressure pulley did not fully lean against the surface of the main shaft. Further observation showed that the pressure pulley had been tilted and deformed, resulting in uneven pressure between the pressure pulley and the surface of the main shaft, so the above failure occurred. Remove the belt pressing pulley support, carefully calibrate the belt pressing axle and reinstall it, and then release the simulated belt box into the warehouse. The steps are as follows: ① remove the black adhesive tape on the head and tail inspection holes; ② Take a hook to hook the bin lock pin (black) of the locking plate, then press the box key with your left hand, and hook the lock pin up with your right hand at the same time (don't use too much force). Insert the box and replay, and the machine will return to normal operation