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VCR head cleaning

 
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crosstalk



Joined: 30 Apr 2006
Posts: 45
Location: PA

                    
PostPosted: Thu Apr 02, 2009 9:44 am    Post subject: VCR head cleaning Reply with quote

Hello. I am in the process of transferring old VHS tapes to DVD and would like some advice on vhs cleaning.

(1) How often should I clean the heads and tape path?
(2) What solvent should be used on the video head and rubber parts?
(3) What should be used to clean the video head and rubber parts?

I have read that ethanol, denatured, or isopropyl alcohol should be used to clean the video head, but it might dry out the rubber parts. So what does one use on the rubber parts? Also is a white piece of paper ok for the video head or is a chamois swab better?

I realize that this subject has been covered to death on the internet, but I trust your opinions more than random internet articles.

Thanks,
Rich
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zaphod7501



Joined: 02 Aug 2004
Posts: 533
Location: Peoria Illinois

                    
PostPosted: Thu Apr 02, 2009 6:27 pm    Post subject: Reply with quote

I've run my own shop for 30 years and serviced the first VCRs to hit the US market, so I have some pretty definitive ideas on the subject.

Cleaning: When they are dirty. Cleaning is not preventative maintenance. Heads get dirty when a contaminant comes off of the tape, sticks to the heads, and doesn't just wipe itself clean almost instantly. Heads get clean with use, not dirty. You will have an obvious problem like no picture.

Rubber parts: What rubber parts? You've got an ancient machine if it has rubber drive parts. (other than a belt or two) Belts are either good and will last indefinitely, or they crack and break, or they stretch and slip. Any belt problem: change them. Attempting to clean them is probably a waste of effort. If they get contaminated with oil or grease, then a chlorine based solvent works best. (chloroclean?)

Head cleaning: Isopropyl alcohol (plain, no oils or aromatics) is preferred with a fine chamois (no dyes or softening agents) There are some fine Egyptian cotton cloths but I don't think you are going to find any of that. Worst case - you played across a splice. (you can't splice consumer video tape anywhere the heads touch) and you have glue on the heads. Acetone is the next stage solvent but only on the video heads, never the audio/control track head. (stationary head assembly) Last resort - toluol since I don't think you can get MEK anymore.

First step with a suspected dirty head. Take a good, newer tape. Put it in. Hit play. Wait several minutes. It may self-clean.

Problems with VHS transfers:
Tracking.: Best results when played with the machine that recorded the tape. Tapes will stretch with use and if that happens, you will not be able to get correct tracking. (it's actually "tape path" errors but everyone mislabels it "tracking")
Quality: If your recordings were SP, then you will get watchable DVDs. LP, SLP - you will be very disappointed. Transfer only what you can't replace. Prerecorded - you may need a MacroVision stripper. (depends on the recording method) For best quality, a TBC (time base corrector) would be best. Note that a TBC won't correct tracking, tape path, or audio errors.

Good luck, but many people are unhappy with the results of VHS to DVD. BetaMax works pretty well however.
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Just call me Zaphod (or Steve) --- I never should have started using numbers in a screen name but I just can't stop now.
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crosstalk



Joined: 30 Apr 2006
Posts: 45
Location: PA

                    
PostPosted: Thu Apr 02, 2009 7:15 pm    Post subject: Reply with quote

Thanks for the detailed post, Steve. So far I have gotten good transfers with a panasonic ag-5710p and a sony TBC (and SP tapes). I'm using a hauppauge pvr-250 for the mpeg2 encoding.

I haven't looked inside the ag-5710p yet, but I had thought there would be some rubber parts (like a pinch roller) in the tape path.

Anyway, I guess I will wait until I notice some visual/audio degradation before cleaning anything (particularly the video/hifi heads).

Thanks,
Rich
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zaphod7501



Joined: 02 Aug 2004
Posts: 533
Location: Peoria Illinois

                    
PostPosted: Fri Apr 03, 2009 7:29 am    Post subject: Reply with quote

I have a pair of the PVR250's and an HVR1600. The cards provide a number of video processing functions internally, so you should get fairly decent transfers. As long as you are not using Windows Media Center, you can copy anything regardless of copy protection.

The pinch roller is pretty indestructible and contacts the back of the tape. It's failure mode is "bent" and would roll the tape up or down on the capstan.
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crosstalk



Joined: 30 Apr 2006
Posts: 45
Location: PA

                    
PostPosted: Fri Apr 03, 2009 9:21 am    Post subject: Reply with quote

Yes, the pvr250/350 has a number of options, especially when used in linux. The temporal filter does a good job of removing noise (especially when tweaked for each capture--usually a value of 7-11 produces a good result). I've experimented with the other adjustments, but can't really figure out any improvements. Any comments on the spatial/median filters? I posted all the filtering options below.

Thanks,
Rich


spatial_filter_mode (menu) : min=0 max=1 default=0 value=0 flags=update
0: Manual
1: Auto
spatial_filter (int) : min=0 max=15 step=1 default=0 value=0 flags=slider
spatial_luma_filter_type (menu) : min=0 max=4 default=0 value=1
0: Off
1: 1D Horizontal
2: 1D Vertical
3: 2D H/V Separable
4: 2D Symmetric non-separable
spatial_chroma_filter_type (menu) : min=0 max=1 default=0 value=1
0: Off
1: 1D Horizontal
temporal_filter_mode (menu) : min=0 max=1 default=0 value=0 flags=update
0: Manual
1: Auto
temporal_filter (int) : min=0 max=31 step=1 default=0 value=8 flags=slider
median_filter_type (menu) : min=0 max=4 default=0 value=0 flags=update
0: Off
1: Horizontal
2: Vertical
3: Horizontal/Vertical
4: Diagonal
median_luma_filter_minimum (int) : min=0 max=255 step=1 default=0 value=0 flags=inactive slider
median_luma_filter_maximum (int) : min=0 max=255 step=1 default=255 value=255 flags=inactive slider
median_chroma_filter_minimum (int) : min=0 max=255 step=1 default=0 value=0 flags=inactive slider
median_chroma_filter_maximum (int) : min=0 max=255 step=1 default=255 value=255 flags=inactive slider
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zaphod7501



Joined: 02 Aug 2004
Posts: 533
Location: Peoria Illinois

                    
PostPosted: Fri Apr 03, 2009 7:10 pm    Post subject: Reply with quote

I use WinTvCap, a Windows command line application developed by Kevinkiller over at the shspvr.com forum. It has all of those options but I don't have any suggestions. Most of them seem to be undocumented and many have been hard-coded into the drivers and middleware so they no longer work. Each driver revision would change how the card reacted to the various options with no warning or explanation.

I never saw any real changes when altering the filters so I gave up and left them alone. Even things like sharpness would work with some driver revisions but not others.
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Just call me Zaphod (or Steve) --- I never should have started using numbers in a screen name but I just can't stop now.
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crosstalk



Joined: 30 Apr 2006
Posts: 45
Location: PA

                    
PostPosted: Fri Apr 03, 2009 8:04 pm    Post subject: Reply with quote

Thanks for telling me about the windows command line option. That might come in handy some day when I upgrade the linux capture cards and stick the pvr250 in a windows box. I agree that the settings seem to depend on the firmware that is loaded and some of the settings have limited useful ranges even though the min/max values have a wide range.
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