VIDCAM's Maintenance Pages

1.Required Maintenance

The recording density of a VCR is much higher than that of an audio tape recorder. VCR components must be very precise to ensure compatibility with other VCR's. If any of these components are worn or dirty, the symptoms will be the same as if the part is defective. To ensure a good picture, periodic inspection and maintenance, including replacement of worn-out parts and lubrications, necessary.

2.Scheduled Maintenance

Schedules for maintenance and inspection are not fixed because they vary greatly according to the way in which you (the customer) uses your VCR, and the environment in which the VCR is used. But in general home use, a good picture will be maintained if inspection and maintenance is done every 500 hours of use. The Table below shows the relation between time used per day and inspection period.
  When inspection is necessary
Average Hours
Per Day		 6 Months 9 Months 18 months
One Hour  
Two Hours    
Three Hours      

3.Simple Maintenance Checks

The faults occurring in the playback picture as shown in the table below, some can be remedied by cleaning and lubricating. Others will depend on the machine's use and type of tapes used.
Phenomenon Inspection Location
Poor Signal to Noise,no colour Tape Oxide on Video Head/s or worn Video Heads
Tape does not run or tape is slack. Tape Oxide on Pinch Roller,
Video Drum or in the Tape path.
Vertical Jitter Tape oxide on Video Head or Tape path.
Audio Distorted or low volume Tape oxide on the Audio Heads or Audio Heads or Tape path are worn.

4.Maintenance Procedures

4.1 First try a Cleaning Tape, you never know your luck it MIGHT work. (In 90% of cases it won't). Providing it is a good quality brand it won't do any damage, but be careful because there are lot of abrasive type's out there. But most of the time the Tape oxide will be too stubborn to be removed by a cleaning tape, so you will have to take your machine to a authorised Service Centre , They will dismantle the Machine removing the cover and get access to the Upper Video Drum (the big silver thing that is sitting at an angle). The top part will spin around, its called the Upper Drum and contains the two Video Heads, it may also contain more than two if for example the VCR has LONG PLAY, HI-FI, S-VHS or Trick functions, like SLOW motion ,Video Insert or very good pause ,it could have up to 10 Heads. Then Moisten a cleaning Stick or Chamois with Pure Alcohol. Place the damp chamois up against the upper drum and carefully turn the Upper drum around, making sure NOT to move the Chamois up or down when the Head tip is underneath the Chamois or you risk snapping the brittle head tip off and that will cost you a new Video Drum, (From $50 upwards). Thoroughly dry the Drum/head, if any fluid is left when you insert a tape it will stick to the Drum and get spun into the Tape mechanism, usually damaging the Tape and Dirtying the Video heads again. We DO NOT recommend you do this your self as you may chip your heads or even get electrocuted by touching the wrong thing !  

If you do not know what you are doing, give it to someone who does.

Cleaning the tape transport system and drive system.

Wipe with gauze or cotton buds moistened with alcohol.

  • The tape transport system is a number of tape guides that come into contact with the tape when playing etc.

  • Make sure that during cleaning you do not touch the tape transport system with the tip of a screwdriver and that no force is applied as this may deform it.

    Lubrication

    Greasing
  • Greasing Tape guide tracks and loading gears.
    Apply grease (use only Froil or Molicoat) with a small cotton bud or brush. Do not use excess grease. It may come into contact with the tape transport or drive system. Wipe any excess and clean with alcohol and dry.

    Parts to be Maintained/Inspected and Maintenance/Inspection Schedules

    Caution:The following table does not apply to all units, it depends on how the unit is used and the environment in which it is used.
    Component\ Hours 500 1000 1500 2000 2500 3000
    Video Heads (Cylinder Assy) C C/R C C/R C C/R
    Supply guide roller C C C C C C
    Supply Guide Pole C C C C C C
    Take-up guide roller C C C C C C
    Pull-out Pole C C C C C C
    Back Tension Arm C C C C C C
    Back Tension Band   R   R   R
    Supply Reel hub C C C C/R C C
    Take-up reel hub C C C C/R C C
    Pinch Roller C C C C/R C C
    Impedance Roller C C C C C C
    Capstan/Drive geared belts       R    
    Capstan/Drive Rubber belts C C/R C C/R C C/R
    Reel Idler       R    
    Capstan Shaft ie Capstan Motor C C C C/R C C
    Loading Motor       R    
    C Check & Clean
    C/R Check, Clean or Replace
    R Replace
    8 Mil VTR Mechanism
    Sony's 8 Mil VTR Mechanism.
    VHS VTR Mechanism
    VHS VTR Mechanism

    This is the Layout of a VHS tape. Showing the position of Audio Tracks,Control tracks and Video tracks 1 &2.(CLICK for FULL PAGE).
    Magnetic tape pattern for VHS PAL Tapes
    KEY Items Standard Remarks
    A Tape Width 12.65 ± 0.01 mm  
    Vt Tape Speed 23.39 ± 0.5% mm/sec  
    Ø Drum Diameter 62 ± 0.01 mm Upper Drum
    Vh Writing Speed 4.85 m/sec  
    P Video Track Pitch 0.049 mm  
    B Video Width 10.60 mm  
    W Video Effective Width 10.07 mm  
    L Video Track Center 6.2 mm Measured from Reference edge
    V Video Track Width 0.049 mm  
    C Control Track Width 0.75 mm  
    R Audio Track Width 1.00 mm Single track (MONO)
    D Audio Track Width 0.35 mm Ch-2 (Right channel)
    (NOT HI-FI)
    E Audio Track Width 0.35 mm Ch-1 (Left channel)
    (NOT HI-FI)
    F Audio Track Reference-line 11.65 mm Measured from Reference edge
    h Audio to Audio Guard Width 0.3 mm  
    Øo Video Track Angle 5º 56' 7.4" (Stopped)
    Ø Video Track Angle 5º 57' 50.3" (Running)
    . Video Head Gap Azimuth Angle 6º ±10'  
    X Positions of Audio & Control Head 79.244 mm  
      Positions of front edge V-Sync 5~8 H Inside the W bottom
      Tape Back tension 30 ~ 45 grams At tape beginning.

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