JVC VCR Rewinds and Then Wouldn't Play

While watching a movie my JVC (HR-VP710U) stopped 3/4 of the way thru, and rewound the tape.

It then ignored the play function.
It also did not show any status info on the screen when the menu was pressed.

When the tape was removed and reinserted, it brought the tape to the head and then ejected the tape without playing.

With the top off and after a cleaning, it still did not work.

The belt in this machine is viewable from the top portion. There is no belt at the bottom. The belt looks fine (machine is only about 5 years old).

After reassembling the bottom back on the next day. The vcr worked.

It played through one tape of the Godfather but may have rewound again near the end, for we suspect that we did not see the entire tape one.

Anyway, once tape two was inserted, again the problem. It refuses to play and ejects the tape.

Is there a heat sensor or something? I am wondering if heat is causing this problem? I just tried it again after it has been shut off for a couple days, and it is working again.

For how long, I do not know.

Could heat be stretching the belt after an hour or so of play, causing it to go into rewind and then not playing again?

Would appreciate any input on this.

 

There is no heat sensor although there is a Dew sensor. Is it extremley humid where you are? Look down in between the two reels that the tape sets on. (These are the take up/supply reels.) There is another wheel assembly between the two take up reels, this is the idler tire. If this tire is wore out it could do what you are describing. This tire turns the takeup/supply reels which sends a pulse to the servo chip and tells the unit it's working. If it would lose the pulse during play back the unit would auto rewind if so set up. If it is a gear assembly the clutch in the assembly could be failing. If the dew sensor is active you would not be able to do anything. 5 years of service is pretty good without any trouble. You can take some rubbing alcohol on a Q-tip and clean that tire, if it works then there is your problem. But it wont last long. That tire assembly can be a hassle to get out. You may be able to change it while it's in the machine but that is a royal pain too. Anyway, I think that is what's wrong, clean the tire and go from here.

 

Your VCR is not old enough to be giving you any kind of rubber drive problems, unless some foreign matter got on the belt or pulleys. Your VCR model tells me that you have a gear driven idler assembly. Remove the top cover and watch to see if the right-side reel stops turning at all, during playing a tape. Sometimes fine sand-type particals get caught in between the teeth. Although rare, I have seen these same make VCR's with a defective Servo Controller I.C.
Usually not worth the repair, even if it's a hi-fi VCR. Belts on average, tend to last around 9-10 years.

Good Luck!

 

Actually in 26 years of bench experience I have seen manufactures put whatever they want in their units. What is available. Back order of parts from ROC/Taiwan etc. According to the use of the unit, 5 years is not uncommon for belts/tires to get soft. If this is and it should be a gear type idler, the clutch has or is failing and will need replaced or rebuilt. Replacing is the easiest. Felt clutches can be purchased but it isn't the easiest thing to do.

 

Thanks guys.

I'll have a look see and see if I can find anything.

I have ordered another one, so if and when this one gets fixed, I'll use it as a backup, or give it away.

It is interesting what you said about the humidity, for where I live, summers are humid, and it has been like that for the past few weeks.

Perhaps thats it.

Thanks again.

 

Temperature variances, humidity, salt in the air for our coastal friends all have a bearing on how long everything from a plant to an automobile last and work. There are different settings for vehicles in high altitudes as well as cooking differences. Belts/tires in an inexpensive VCR may only last a year or two. In a more expensive unit they may last 10 years but in my experience, especially if you use the VCR allot, and allot is actually considered one movie a day. Setting also has a bearing, a VCR that sits and is only used once a week/month, the belts/tires get flat spotted and also dry rot just like the tires on your car. Practically the same type of rubber. I think I said that belts/tires get soft the actually get hard as manufactures no longer use live rubber, they use neoprene. Linseed oil actually does a very good job of cleaning neoprene tires etc. (2% linseed.) Anyway, check that clutch, watch the take up reel and see if it is skipping.

 

Smokey says:
You folks are getting too complicated on this problem.

The machine uses tape tension to determine when it has reached the end of the tape. The tape is not reaching the end before it goes to rewind. Assume the brake on the supply hub has failed and remains in contact all the time.
The tape motor reaches a point where it can no longer pull tape against a brake on the hub, so it recycles.

So, check the brake on the supply hub. I bet the solenoid is bad.

Smokey

 

...with all due respect Smokey, this machine does not use tape tension to determine the end of tape, nor does any other consumer type VCR. VCR's use two methods for determining the end of tape and they are called E.O.T.(end of tape sensors). Some VCR's also monitor and compare the received pulses from the supply and take-up sensors to speed up or slow down while in rewind/fast-forward modes). The brake on the supply hub is activated simultaneously with the take-up brake and these solenoids wouldn't cause the machine to rewind. ...I agree, let's not complicate the issue.

 

Good evening, lucman2:

Smokey says "Bull Biscuits". Tape counter determines speed during rewind. Tape tension determins end of tape. I've been working on consumer, commercial, and broadcast machines for years. It's all the same.

If the supply hub brakes fails, this a common failure in consumer VCR's. Tape motors will drag the tape until the "take up hub" is almost full. Then, there isn't enough verve in the system to pull it any further. Tape tension increases, the rider arm connects, and the tape goes into rewind. The VCR thinks it has reached "tape end".

And, if you can prove me wrong, the forum is upen.


Smokey

 

You show me a single VCR without back tension and I'll kiss what you want on Main street and give you ten minutes to draw a crowd. I don't know how many VCR's I have repaired over the years with tensioner problems. Especialy in the consumer grade stuff. Cheap nylon devices that fail from heat or just plain old wear. If the back tension is off the unit will rewind. There are end of tape sensors, infrared pickups that "See" thru the leader of the tape. But the back tension is critical in every VCR on the market today. Lucman, can you give us an idea of how long you have been in the buisness? Not knocking or wanting to start any crap but I am curious as to how long and what your background is? Your profile mentions several things among which is electronics tech. Thanks dude...

 

bigmike, Did you mis-read the postings...I never said that vcr's don't use back tension...of course they do and it is a very critical adjustment. Smokey say's tape tension determines the end of tape...do you agree? just answer that for me.

 

Tape speed is determined by comparing the difference between the two reels and it is also read back from the take-up reel (for those vcr's that don't monitor the supply reel)
Back tension is a very important part of the vcr mechanisms but has nothing to do with determing the end of tape...on many machines, the back-tension lever isn't even in the picture during FF/RW modes.
How does tape tension determine the end of tape????
How is tape tension even measured?????
The end of tape happens when the optical sensors detect the IR light...and this happens when the EOT sensors detect the clear section of tape which causes the machine to halt.
Supply hub brakes failing is not very common at all.
Who knows, maybe they sell a totally different version of VCR's in your part of the world.

 

If it were an EOT problem, the machine would not ignore the play function when it goes into REW mode. Check the mode switch, try cleaning it first but it may have to be replaced.

 

Mode switches are a big culprite with some vcr's...I too have had alot of success just cleaning and re-greasing them.
Although most mode switch failures I've seen showed up when the tape was inserted or when it is ejected.