Sound problem during vhs capture

[monks19]

Hi, I've been doing some vhs captures with my svhs unit (JVC SR-V101US) for a while now without any trouble until recently. The issue I'm having is that some kind of noise happen when a vhs tape is rolling during capture. I dont know what's causing this, but I know that it doesn't apear at the the same places (whem playing the tapes) and that the issue is gone momentarilly when I'm plugging and unplugging the rca cable (which has been replaced 3 times this week) and when I eject the vhs to put it back in the vcr. I tried to play some the same tapes on another unit (Panasonic AG-W3) and the issue is no longer there. I did the same with a Sanyo unit (VHR-H532) with the same results with the Panasonic. So, what could be causing this ? I've thought that the JVC unit might need a good internal clean up, but I prefer to ask some advices to some of the experts here (Lordsmurf & all) before doing so.

Here's an audio sample to download so you can hear (7zip file). Let's hope that this issie can be solved.

Thanks to answer as soon as possible

[jman98]

You have NOT attached an audio sample. Try again.

[monks19]

It has been correctected now.

[mike20021969]

It sounds like a tracking issue.

[hech54]

So, what could be causing this ? I've thought that the JVC unit might need a good internal clean up, but I prefer to ask some advices to some of the experts here (Lordsmurf & all) before doing so.

What is so hard about opening up the VCR and "going at it" with a Q-Tip and rubbing alcohol that you need advise on it?
I'll never understand that.

[monks19]

hech54, go back read my message carefully.

mike20021969, I'll try to check on the tracking control and let you know if that's it or not.

[hech54]

hech54, go back read my message carefully.

Not only did I read it....I quoted it.

[mike20021969]

Not only did I read it....I quoted it.

You misunderstood what he said.

He's looking to try other things first. He'll clean inside if all else fails.

[jagabo]

Yes, it's a tracking problem.

[monks19]

Thanks mike.

ok, I've tryed the tracking control but excepting the image, I didn't see much change on the sound though... I'll try later with anothe tape, see if it gets the same results.

[monks19]

Me again. I tryed another tape and ajusting the tracking control, but no success. I don't know what's triggering the reagtion, but one of the consequences is the fact that the audio keep changing mode at times (hi-fi to normal). So seriously, I dont know. Can the fact that some pieces inside this unit trigger the reaction because they ar dirty ? Any ideas ?

Thanks to answer

[mike20021969]

the audio keep changing mode at times (hi-fi to normal). So seriously, I dont know.

It's probably time to open up the VCR and clean the (entire) tape path with isopropyl alcohol and an appropriate applicator (I use numerous cotton buds to apply, clean and polish stationary heads, guides and capstan - but never use cotton buds on the drum heads). Pay special attention to the stationary heads. All it takes is a speck of dirt to mess up playback.

If things don't improve, it maybe time for a professional service, or possibly new drum heads or another machine.

[monks19]

Ok. I'll see about that. Thanks.

[turk690]

On VHS decks, hi-fi audio is recorded & played back by separate audio heads that spin on the drum along with the video heads. It is therefore possible for video to track perfectly but hi-fi audio to rattle and/or cut in and out, or vice-versa. Although VHS track dimensions are much bigger and longer than, say, those on 8mm tapes, compatibility issues can still arise between tapes being played on machines that didn't record them. These machines may have problems on the extreme: worn out or very dirty pinch rollers & idler wheels, tape guide paths that have been ever so slightly gouged out, dirty video heads and hi-fi AND normal audio heads. There are natural breaks in a video signal such as horizontal and vertical blanking where video head construction can be made to coincide with as they spin and so playback appears smooth. For hi-fi audio though, audio is broken & reconnected 60 clips a second; there is circuitry that mutes these joints and should ideally switch from one head to the next seamlessly. Ever so slightly misaligned audio & video heads (in relation to one another) because of any of the reasons I mentioned above can cause this circuitry to not mute and we hear the motorboating sound (actually a series of spikes at 60Hz). Even worse, there is another circuit that switches between hi-fi and normal tracks (depending on the condition or presence or absence of any of them) that compounds the problem. Video & hi-fi audio heads are fragile and can be destroyed by sledgehammer-fingered people, but that shouldn't prevent them from being cleaned manually, along with everything on the tape path, applying dragonfly-like delicacy. I'd get a piece of paper for example, douse it in isopropyl alcohol, set it against a rotating head, and manually twist them against the paper. A plastic knife can be used to scrape off built-up oxide on stationary heads (normal audio & control) and rollers. It could be done simple in the past, but VHS tape cleaners have gone extinct.