What I am about to post may or may not be relative to the JVC issues so take it for what it is worth-
Considering the many reports people are posting about the JVC mechanical problems after only a 100-200 hours of use, pinch roller issues etc. I decoded to examine my maintenance records on my VHS duplicator rack over the past 18 years. There was an interesting observation here. I have used a number of Panasonic VHS VCR's and a few JVC VCR's but in recent years, I have used Mitsubishi VCR's. These decks all get about 6 hours of record time per day and then rewind on each tape recorded about 6 days a week.
The maintenance records on the JVC machines I used about 8 years ago all had tape transport failures, requiring replacement within 9 months to a year of use.
Maintenance records on the Panasonic decks I had in use back in the mid 80's and then again in '95-'96 all indicate failures with the eject mechanisms.
I began to use Mitsubishi VCR's in my duplicator rack about '94 and these all failed after about 4 years use with problems in the power supply breakdown, the mechanics never failing except I did replace the pinch rollers on an annual or as needed basis, ie 9 months to 1 year. I now have 2 MItsubishi HD59 machines that are over 4 years old that have both had 5 pinch rollers and the power supply is still working and just this past month the rewind system is beginning to make rather loud noise during rewind but the VCR still produces very good recordings as scoped evaluated.
Based on the above, I would conclude that different manufacturers have unique weaknesses in their VCR design. I don't have recent data on the JVC, nor Panasonic in this business but I will tell you that based on my maintenance records the duplicator bay gets Mitsubishi VCR's as replacements now when a Mits goes bad and these usually go bad in the breakdown of the electronics, particularly the power supply and voltage regulation circuits while the mechanical side lasts much better than the competitors I had used.
I have a MItsubishi SVHS VCR that I installed new in my HT about 4 years ago and it has had several frequent needs to have it's head cleaned, far more often than those same machines in my duplicator rack. I believe this to be caused by the fact that most of the tapes played in this HT Mitsubishi VCR were rental tapes or tapes belonging to someone else. I never really used that VCR for recording much here. IT's main on time was spent with it as a cable tuner. The need for head cleaning, therefore, I have concluded is more related to the quality of tape passing the heads than the type machine. My duplicator VCR's need head cleaning after nearly 60 times as much record time as play time on the home theater same model VCR.
My Panny and Mits DVHS machines have never had the heads cleaned. They also have never had a tape in them that has had more than about 7 passes. And these HDTV tapes with that many passes has been rare. I believe mu most played HDTV tape has been the Startrek tapes ( I'm not a trekkie fanatic, I just like those movies and can watch them over and over) and my last demo tape I made up (which I get out when I have guests over who want to see a variety of HDTV programming available). Most of the time my DVHS VCRs have only had tapes with mostly 2 passes. Thus, the main reason why I probably rarely have the need, actually never had the need to clean the heads on the DVHS machines.
Considering the above observations, do any of you use the same tape over and over for time shifting? Then, need to clean the heads? Maybe you should consider using a more robust tape for time shifting, like Broadcast Master grade SVHS tape that is made especially for the rigors of lots of jogging and shuttling back and forth. It may last longer for time shifting and produce less head clogging. Do you play rental tapes or tapes made by others of unknown origin in your DVHS VCR? Maybe you need to consider a second machine for this purpose and leave the one machine for critical recordings only for your own tape exposure.
Finally, I do know that any VCR in a smoking environment or one where you may have a popcorn machine will have atmosphere pollution that will deposit a film of contaminates on the VCR mechanics and in this environment, will suffer more frequent mechanical failure.
I know this is not really an avx issue but decided to post it here since the JVC problems have been discussed here and these have been a part of the problem from many in using the AVX.