Muffled audio, bad tracking on rarely used VCRs?
 

I suddenly out of nowhere am having trouble with two VCR units, both are DVD/VHS combo units.

VCR one (SAMSUNG VR330) started to out of nowhere have high pitched sound, choppy video, and uncontrollable tracking. After cleaning and realigning the unit, I was able to fix the high pitched audio and choppy video, but I still have muffled sound and minor uncontrollable tracking. I can typically get it under control by slightly playing with the alignment, but the second I rewind or fast forward, the issue comes back. With this unit in particular, I am also dealing with slowing rewind times and a somewhat glitchy counter.

VCR two (SONY SLV-D380P) randomly had a bit of tracking issues that I was able to fix. It now just has muffled audio.

Oddly enough... In both of these units I can put in a VCR cleaning tape and the video/audio will be perfectly fine. I do though know it is not the tapes. One tape for example, I digitized a few days ago and it had good sound. I pop in that tape now and it no longer does. Also, since the cleaning tapes work perfectly fine, I know it isn't my converter either.

Any ideas?

Only thing I can think of is tape speed. Could it be possible that the cleaning tapes run at a different speed than most other tapes? The rewind/counter issue on VCR one could be a lose belt?

VCR one is about 10 years old but lightly used. VCR two is about 5 or 6 years old but only used a handful of times. Both units I have used multiple cleaning tapes, used air electronics duster, and did the paper rubbing alcohol clean people were doing on Youtube.

I don't know what the exact issue is, but muffled sound + tracking and counter issues all indicate an issue with the Audio/control head, or accompanying electronics (the stationary heads similar to the you would find in a audio deck to the right of the video drum). Did you clean that when cleaning the video heads? (it's fine to use a cotton bud on the A/C head.) A/C head misalignment (not the same as tape guide alignment!) could also be a cause though it's much less common for that to go out of alignment than tape guides and can be tricky to adjust.

VCRs age, used or not. Most people assume it's just the lube and rubber bands, but it's also affected by gravity (misaligns itself over time) and chemical changes (breakdown of plastics, caps). This is why NOS ("new" old stock) VCRs, ones claimed to have "never been opened" (or " never used") is nonsense for newbie suckers. I've seen many "new" VCRs that didn't perform correctly, and that extends all the way back into the late 90s and early 00s when these were all still produced. Decks were rarely 100% accurate off the assembly line, and it just degraded from there.

DO NOT USE VCR "CLEANING" TAPES. Even the term "cleaning" is nonsense. All those tapes do is push around dirt, not remove it. Worse yet, some are too abrasive, ruin the VCR heads. By using those multiple times in each of your decks, you may have made the initial problems worse.

You're also using junky low-end consumer VCRs, which can have variable quality on each play. No consistency.

@hodgey: I'm not readily aware of easy ways to realignment the audio control head. And sadly, I think the "less common" is becoming more common as we enter the 2020s. I've seen far too many audio issues in recent years, and I have to extra scrutinize for it.

Wouldn't I have seen a degrade over time though? Here it just all happened at once, with both units, in a matter of a day or two.

I mentioned the cleaning tapes because when playing them the units are perfectly fine. So, if it is an overall degrade, wouldn't I be experiencing the same with those tapes as well? I never am.

Just trying my best to fix them before spending money to have someone with real knowledge look at them.

Not necessarily. Age can weaken, usage can quickly further the weakness.

A lot of cleaning tapes were nothing more than 'clean', high-grade tape. Hence the dire warnings about rewinding etc, the idea being the machine would just be subject to continual fresh tape when playing the tape. The better quality ones I understand were not abrasive at all. There were some 'wet' systems, they always looked like a recipe for distaster.

Professional machines were sometimes cleaned by simply running a box-fresh tape through them, I don't understand the mechanism but this would often pull off some detritus from the heads. A basic first-pass clean.

None of them will come close to a conventional manual clear, but a good quality cleaning cassette (3M etc) are mostly likely to simply be just plain high-grade videotape.

All it takes to clog the heads is one short section of crinkled/creased tape. The oxide and binder gets scraped off the tape at the high points. In this case there is no substitute for manual cleaning of tape path and sometimes repeatedly on the one tape. If at all possible identify the damaged section of tape and don't play it. Often the section can be identified by the hissing noise it makes as it hits the fast spinning video heads. The sequence is often a poorly maintained machine damages a tape which tape now repeatedly clogs the heads. There is no substitute for a machine in top mechanical condition, avoiding even minor tape damage in the first place.

Neither unit gives off any hissing noises.

As I think I have already said, I have done a clean of each unit aside from using the cleaning tapes.

Muffled audio can also indicate the VCR defaulting from HiFi to linear audio track when video tracking is incorrect or the HiFi heads are dirty.

Which are the HiFi heads?

They look like another pair of video heads on the rotating aluminium drum. In practice we just clean them all.

Another possibility for intermittent tracking and linear track audio issues is a slightly loose control/linear audio head that moves into and out of alignment.

Slow rewind may be caused by worn or hardened rubber drive wheels, or possibly an issue with the VCR thinking it is near the end of the reel and slowing to protect the tape from sudden stop from high speed.

After watching this guy's video I am sure it is both units not getting HiFi sound. What he is dealing with I think isn't the same I am though. I wonder if cleaning that area would change things? Had to think units that are rarely used would have parts go bad so easily.

https://www.youtube.com/watch?v=MaLZCopEbwo&t=892s

If I have time tonight I'll open one up again and give it a try.