Judging the condition of your Video Heads
A great deal of video playback quality depends on the condition of your video heads. This is why many VCR manufacturers used to suggest changing the video heads after 1000 hours of use.
Now that there's no new video heads available, we all have to get by with used ones. With a used video head, wear is sometimes hard to judge without the right equipment. At TGrant Photo we test Panasonic AG1980 video heads very carefully. The video head drum is removed from the AG1980, then there's a close visual inspection of the video head tips. We look for chips and other mechanical damage to each head tip. The video heads are then installed in our AG1980 test VCR. Connected to a waveform analyzer, we're able to tell a lot about the condition of the heads. As the video heads wear, the output level of the video heads decreases and can be seen on the waveform analyzer display. The greater the wear, the lower the output level,.
Without special equipment, there's still some tests that you can use to get an estimate of your video head's condition. The video head drum contains several "head tips" some are used for the video signal, and others are used for the HiFi sound. A good indicator of the video head's condition is the ability to play back tapes with HiFi sound. A worn video head starts to be fussier about setting up the HiFi sound.
Test your VCR using several HiFi tapes. With the TBC turned "off", load a tape and don't adjust the tracking. If your VCR sets up both the HiFi sound and the picture within 4 seconds of loading, it usually has good heads. It's important to mention, however, that a VCR that is out of alignment, can often produce a clear video picture but no HiFi sound.
Tip: when playing back HiFi sound, look for an illuminated "HiFi" icon on the front of your VCR. Don't assume the HiFi heads are working, because if the HiFi heads are bad, the sound defaults to the linear mono audio soundtrack.
The ability to play different EP (SLP) tapes is another important test. EP is the 6-hour tape mode, the videotape travels at a slower speed so playback problems become more obvious. After loading a video cassette, most EP(SLP) tapes should lock up the tracking within 4 seconds. If you see a "watery" or unstable picture, even after adjusting the tracking, then the video heads might be worn or very dirty.
At TGrant Photo, the reconditioned Panasonic AG1980s that we sell always have the very best available video heads installed. Heads in poor condition or heads that won't play HiFi always end up in the trash!
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