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Crumbtrail TV Forums: TV Equipment: VCR Repair Forum:
Panasonic VCR stops mid tape?

 
 


tundrawolf
New User

Dec 16, 2009, 3:24 AM

Post #1 of 12 (3345 views)
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Panasonic VCR stops mid tape? Can't Post
Hello,


I think my Panasonic VCR is packing the tapes wrong. I can rewind and fast forward a video tape about twice before it won't play it at all. But, when I turn the cassette reels by hand after inserting the lock, they turn freely and easily.

When I put a new tape in the vcr it plays fine, once, then the same thing happens.

Please help!



Dave



jts1957
Veteran


Dec 16, 2009, 8:50 AM

Post #2 of 12 (3338 views)
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Re: [tundrawolf] Panasonic VCR stops mid tape? [In reply to] Can't Post
Check take-up and supply reel torques in all modes.
Panasonic made a couple of different units during the VHS era. Can you at least give us a hint as to 70's, 80's, 90's or 00's?


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Location: Far, Far Away


tundrawolf
New User

Dec 16, 2009, 4:36 PM

Post #3 of 12 (3335 views)
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Re: [jts1957] Panasonic VCR stops mid tape? [In reply to] Can't Post
I am very mechanically inclined, but new to VCRs, to a degree. How do I check the torque?

The VCR was made in 2001. I had another VCR like it that I have used to cannibalize parts when I needed to. So far just the mode switch on the motherboard and the motor that actuates the cassette load mechanism.


jts1957
Veteran


Dec 16, 2009, 8:28 PM

Post #4 of 12 (3334 views)
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Re: [tundrawolf] Panasonic VCR stops mid tape? [In reply to] Can't Post
Torque gauge? Expensive, very precise.

A "Dummy" tape and two fingers? Little or no cost, will tell your "experienced fingers" if is sufficient enough to pull tape correctly.Wink


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Location: Far, Far Away


tundrawolf
New User

Dec 16, 2009, 9:42 PM

Post #5 of 12 (3332 views)
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Re: [jts1957] Panasonic VCR stops mid tape? [In reply to] Can't Post
Before this incident, when playing, the tap would slow down intermittently, like someone playing a record and applying pressure to the turntable to slow the music down. I thought "Binding", so I took the unit apart, and applied oil and grease to areas where it was needed.

During this, though, I discovered a sort of "torque converter" connected to the drive motor, so that if the tape reaches its end, it will not over stress the drive band, and will allow for slippage.

I studied the mechanism, and found that it only took very light pressure to stop the mechanism from turning, and that my donor VCR allowed a lot less slippage.

So, I took a Q-tip and covered it in some very thick grease, and grease the internal contact points. It allows slippage now, but it is stronger, definately.

Could it be possible that the cassette tray mechanism isn't seating fully and allowing the tape to pack at an angle? Would this cause the binding I am experiencing?


jts1957
Veteran


Dec 16, 2009, 10:13 PM

Post #6 of 12 (3331 views)
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Re: [tundrawolf] Panasonic VCR stops mid tape? [In reply to] Can't Post
If looks anything like this: NO grease should ever touch!

Also see:
http://books.google.com/...n%20band&f=false


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Location: Far, Far Away


tundrawolf
New User

Dec 17, 2009, 1:09 AM

Post #7 of 12 (3328 views)
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Re: [jts1957] Panasonic VCR stops mid tape? [In reply to] Can't Post
The item I grease was a disc, that had another dist spring loaded. A spring pressed one disc on top of the other. The lower disc had grooves cut into it, and the upper disc had a sort of felt. The amount of torque that was transmitted was very very little, and I felt may have slowed down the cassette.

That band, are actually two arms that are pressed against the outside of the contacts (That contact the tape reels) didn't get any oil or grease.

This is very frustrating to me, I seem to have gone through everything.

But, I have taken the donor vcrs mechanism out and have been applying power to the motor and watching the mechanism work both ways, and studying what every moving part does. I'll figure it out somehow, I hope. Any suggestions?


jts1957
Veteran


Dec 17, 2009, 1:38 AM

Post #8 of 12 (3327 views)
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Re: [tundrawolf] Panasonic VCR stops mid tape? [In reply to] Can't Post
What's the Model Number?


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Location: Far, Far Away


tundrawolf
New User

Dec 17, 2009, 1:50 AM

Post #9 of 12 (3325 views)
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Re: [jts1957] Panasonic VCR stops mid tape? [In reply to] Can't Post
Model: PV-C2020


tundrawolf
New User

Dec 22, 2009, 5:47 AM

Post #10 of 12 (3314 views)
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Re: [jts1957] Panasonic VCR stops mid tape? [In reply to] Can't Post
AH HA! I took the unit apart and watched it play, everything seemed fine. Then, I stopped and hit rewind, and saw that the capstan (The rubber pad that pinches the tape against a rotating metal rod) was pinching the tape and pushing it DOWNWARDS!

Please give me a suggestion as how I can fix this!


jts1957
Veteran


Dec 22, 2009, 9:09 AM

Post #11 of 12 (3313 views)
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Re: [tundrawolf] Panasonic VCR stops mid tape? [In reply to] Can't Post
The capstan is (usually) the center shaft of the capstan motor. The pinch Roller/Pressure roller pinches the tape between to pull tape at precise speeds.
If pinch roller is extremely shiny in center (Top & Bottom 1/8 inch being much less so), you could try roughening its surface with the fine side of an emery board. Clean residue.

The Capstan and pinch roller only pinch the tape in "Record," "Play," "Forward search" (with a picture) and "Reverse search" (with a picture).
The tape free runs in "Fast Forward" (NO picture) and "Rewind" (NO Picture).


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Location: Far, Far Away


tundrawolf
New User

Dec 22, 2009, 7:10 PM

Post #12 of 12 (3310 views)
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Re: [jts1957] Panasonic VCR stops mid tape? [In reply to] Can't Post
Thank you so much, jts1957! You have been a huge huge help to me. I looked in that book you posted for the capstan, and found out that using alcohol to clean the capstan in excess will destroy the lubrication on the bushing. Sure enough, I took it apart, and there was visual wear on the bushing.

So, I took the capstan keeper and the capstan rotor from the donor VCR, and mic'd each part. One capstan had a diameter of 3.43MM, and the other had a diameter of 3.50! This measurement was taken at the wearing surface of the lower bushing. I used a high quality synthetic oil and lubricated both bushings, and used the capstan keeper with the least amount of wear. I have learned so much about VCRs from attempting to repair this one.

I can now go through every mechanism and understand where it goes, how it works, and what it does. Previously, the tracking would consistently 'vibrate' once every second or so, now the tape views perfectly with no problems. Thanks a lot, I appreciate your help! Merry Christmas!

 
 
 


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