Panasonic NV - SD50 video recorder, can complete the tape into the box, loading, occasionally can enter a state of video reproduction, but it can't work properly, there will be no time automatic stop, sometimes even after loading is automatically entered into a state of downtime, no regularity. knFservice manual download site
 knFservice manual download site
After being shut down, press the "EJECT" at the same time, "FF" and "designs" key, start the automatic fault detection circuit, the screen shows the failure information is: "if 1:5. According to the display information: the first part of the said maintenance mode number, "5" on behalf of the main shaft motor for testing: the second part number maintenance data, according to different testing content, "91" on behalf of the replay works; The third part of the said maintenance information number, "5" on behalf of the main shaft motor does not turn or its rotation detection circuit fault. The machine in the condition of the replay, did not turn or its dominant shaft rotation detection circuit failed. knFservice manual download site
 knFservice manual download site
Open the chassis, power, join tape, into the box, after loading the machine, press "PLAY" button, find fault occurs, first is wheeled a halt, and then the machine automatically unload, and recover the cassette tape can't, that is not turn caused as a result of the main shaft. Is the main shaft is not spindle motor assembly, system control circuit and driver circuit fault occurs. knFservice manual download site
 knFservice manual download site
Replace "substitution" spindle motor assembly, the fault is still. Specify in the drive circuit or system control circuit. knFservice manual download site
 knFservice manual download site
Panasonic NV - SD50 spindle motor drive using IC2502 (BA6439P) integrated circuit, the peripheral circuit diagram as shown in the figure below. Its working voltage is provided by Q1503 voltage stability after. From IC2502 Q1503 base voltage stability provided by the hall, the power supply voltage. The working voltage of hall IC, provided by Q2506 voltage stability after the working voltage of FG head is provided by after Q2505 voltage stability. By measuring the voltage is normal. Work in replay mode, the system control chip IC6001 from its (27), input (28) feet of FG signal after frequency division, as the comparison of the speed servo signal, the mixing speed servo voltage and phase servo voltage output from the (23) foot, after after R2521 into IC2502 (16), is used to adjust the output current, motor driver control of main shaft in order to achieve the purpose of motor rotating speed and phase. When need to rewind, as well as make the spindle in a reversed way of working, IC6001 (62) feet output high level; When need to fast forward, as well as make the spindle is rotating, IC6001 output is low level (62) of the foot, after R2038 into IC2502 (11) feet; When need spindle stalling, IC6001 (62) feet of the output level of 2.4 V, control of main shaft halt. When failure occurs, the measurement of IC2502 (11) foot as low level, indicates that system control circuit is working properly. Obviously, the fault must be IC2502 drive circuit. In the state, each foot IC2502 dc voltage is measured with a multimeter, compared with normal found (13) foot (normal: 0 V, the measured value: 2.1 V), (14) foot (normal: 0.4 V, the measured value: 0.4 V), (17) foot (normal: 0.3 V, the measured value: 0.3 V) voltage is on the high side. Check grounding capacitance (14) foot (C2528), (13) feet grounded capacitor (C2529), (17) foot grounding resistance (R2516) without exception. Doubt IC2502 performance is bad, replaced, the fault still, maintenance trouble at this time. Try measuring C2528, C2529, R2516 three resistance capacity components of public ground terminal voltage of main circuit board, to found a positive voltage, ground contact undesirable. Measured with a multimeter ohms range when the power is cut off, it happens. These three components through a wire to the public grounding and motherboard end connections, failure completely ruled out.

 2    1 2 Next Last