VCR Demagnetizing

[NYC Film]

I am still new to the forum, and I'm just getting the hang of posting threads. The forum has been very helpful these last 6 months that I became interested in VHS restoration, but I am curious about Demagnetizing a VCR.

I have in the past demagnetized VCR's in a electronics repair courses I took 12 years ago, I still own my VCR demagnetizer tool (and haven't used it in as many years, and could probably use a little refresher). In doing a bit of research it sounds like some say that with the newer VCR's demagnetizing is not necessary, particularly the JVC 7000 and 9000 series decks. I never worked on the newer JVC 9000 or 7000 series decks (or anything manufactured after 1997). I am just looking for some clarification on whether this holds true, or if I should not bother to add it to my routine VCR maintenance.

[lordsmurf]

Not a modern problem, to my knowledge.
Read more: http://richardhess.com/notes/2006/03/24/demagnetizing-recorders-and-heads

While early machines may have had an issue with magnetization, most late-model machines rarely become magnetized.

Note: Richard Hess is a name you'll see mentioned in restoration/forensic recovery.

[lordsmurf]

This gets interesting...

Take the first two. This has always been my understand, as well:

http://broadroot.com/content/blue/smarts/chapter6.htm

VCR SMART: Demagnetize VCR heads? Audio heads in a cassette tape deck require periodic demagnetization, but video heads do not. Never attempt to demagnetize the video heads in a VCR. Any type of demagnetizer used inside a VCR improperly can easily shatter the video heads, ruining the video drum assembly. Demagnetizing VCR components is an extremely rare requirement and should only be done by a professional.

http://www.tapeheads.net/showthread.php?t=3291

Here we go again-
Degaussing of an aluminum cylinder is NOT needed. The ferrite heads on the drum are ferrite and are demagnetized when you record with them. The only head that would need this might be the stationary CTL head or audio head. It depends on what material these are made of. With VCR parts- heads and the like, it is more likely that you will cause damage by cracking off the heads off the drum than doing any good. There is more good done by cleaning the drum and the edge areas of the guides on the drum and moving guides.

It sounds like recording a tape every now and then is essentially how a VCR degausses/demagnetizes itself.


But then I see this:

http://www.videomaker.com/article/1105/

One final internal maintenance function is head demagnetization. Demagnetization of recording and playback heads is important because over time, the heads can gain an unwanted magnetic charge from the tapes played over them. A magnetized recording head can cause some hiss and distortion during both playback and recording, and this limits high-frequency response during playback. Demagnetization should occur after around every 200 hours of VCR or camcorder operation. And if you're a serious enthusiast, that number rolls up quite quickly. It's a fairly simple process, one that involves placing an electronic probe very near, but not touching, the heads. But be careful when demagnetizing video heads, especially when using demagnetizes that were designed for use with audio recorders. Some are strong enough to damage the much smaller video heads. Professional video head demagnetizers from Markertek and Comprehensive Video Supply are available for $35 and $55 respectively.

However, this wouldn't be the first time I've seen a stupid article at VideoMaker. Articles are only as good as their writers, which are only as good as their research, sources, knowledge and experience. That one article alone is flawed several times over! For example, the static electricity created by a vacuum cleaner (even the tiny ones) can cause big damage. Using a mini-vacuum in a computer, VCR, etc -- boneheaded move.

That kit they mention -- http://www.markertek.com/Chemicals-Cleaning-Supplies/Cleaning-Tapes/VHS-Cleaning-Tapes....xhtml?32-3080 -- reminds me of DVD rewinders, DVD sticky labels and "DVD safe" markers. It's just crap that is sold because somebody is dumb enough to buy it.

[NYC Film]

This gets interesting...


That kit they mention -- http://www.markertek.com/Chemicals-Cleaning-Supplies/Cleaning-Tapes/VHS-Cleaning-Tapes....xhtml?32-3080 -- reminds me of DVD rewinders, DVD sticky labels and "DVD safe" markers. It's just crap that is sold because somebody is dumb enough to buy it.

http://www.studiosoundelectronics.com/cleaning.htm

At least Studio Sound Electronics has angled chamois head cleaners (which is the easiest and safest way to clean video heads)... the markertek kit looks ridiculous and expensive. The Problem with these kits is that you can damage the video heads by demagnetizing them, and they don't explain that (maybe the one with the video does). What your supposed to demagnetize are capstans, pinch rollers and etc which can become slightly magnetized over time as tape passes over them. However I think I will refrain from demagnetizing any JVC deck I have unless absolutely necessary, which will hopefully be never.