VCR Drive Belt and Pulleys Get Slippery

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MrAl
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Post by MrAl » Thu Sep 04, 2008 12:00 pm

Hi Janitor,

Oh i see, i thought you meant that there was a switch on the front
panel that was the function switch. From what you are saying it
sounds like you are talking about a switch that is activated internally
when the unit shifts modes (pushed by the gearing).
I'll check this out too.

Hopefully ill be back a little later with some results.
LEDs vs Bulbs, LEDs are winning.

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MrAl
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Update

Post by MrAl » Thu Sep 04, 2008 2:37 pm

Hello again,


I took the thing apart again, finding the belt slipping again.
This time i put two turns of medium coat thread around the two
pulleys, forming it into two circular loops and then tying a knot.
Well actually, i used a slip knot and then after i pulled it into
place around the two pulleys and it was fairly tight i put a tiny tiny
bit of Super Glue on the knot to hold it permanently. I didnt want
to tie too big of a knot because the knot too has to go around the
pulleys.
Put the belt back on over the threads and it works fine again.
I'll have to see how long this fix lasts.

For the future i was thinking of constructing a mechanism with a
take up pulley and a lever. The lever will be spring loaded keeping
the pulley tight against the belt half way between the two pulleys.
This will keep tension on the belt even if it stretches a bit more.
I dont think i want to buy another belt because the same thing
will happen again anyway. The belts arent that expensive but
it seems like such a waste to do that.
LEDs vs Bulbs, LEDs are winning.

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MrAl
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Re: VCR Drive Belt and Pulleys Get Slippery

Post by MrAl » Mon Nov 30, 2009 3:38 pm

Hi again,


Little update for this VCR.

I was thinking of junking it, then replacing the belt. Well, i finally got around to ordering
a belt (or 2) and got the new ones in the mail today and replaced it and now it works
just fine again!

There is another web site (i ordered from Studio Sound) i think it was MCW or something
that had a belt on their site back last year in August, and it was 9.5 inches in circumference.
That would not have worked on my VCR even though they linked to it. This thing needs
a belt 8.5 inches in circumference.

The funny thing is, the old belt was 9.5 inches in circumference while the new belt is
only 8.5 inches in circumference.
Could it really stretch THAT much?
Could it be that they put the wrong one on at the factory?
Any ideas?
LEDs vs Bulbs, LEDs are winning.

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Janitor Tzap
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Re: VCR Drive Belt and Pulleys Get Slippery

Post by Janitor Tzap » Mon Nov 30, 2009 6:02 pm

Yup,
They sure can!

Belts can stretch quite a bit before they break, or simply fall off.

I've replaced the belts on Turn Tables, and 8-Track players with the factory replacement belts.
When comparing the new belt to the old belt.
I would find the old belt had stretched a good inch, too 1 1/2 inches.

Makes me wonder how the stupid things stayed on as long as they did.


Signed: Janitor Tzap

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MrAl
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Re: VCR Drive Belt and Pulleys Get Slippery

Post by MrAl » Tue Dec 01, 2009 5:27 am

Janitor Tzap wrote:Yup,
They sure can!

Belts can stretch quite a bit before they break, or simply fall off.

I've replaced the belts on Turn Tables, and 8-Track players with the factory replacement belts.
When comparing the new belt to the old belt.
I would find the old belt had stretched a good inch, too 1 1/2 inches.

Makes me wonder how the stupid things stayed on as long as they did.


Signed: Janitor Tzap
Hi Janitor,

Thanks for the verification here.
One of the reasons i asked is because i had lots of VCR's in the past, from the 1980's
or around that time, and i dont remember one stretching that much so fast. I had
the VCR's for years before i had a problem, and more importantly, i *used* them a
*lot* more than i used this one before the problem started to occur.
(The main problems i had though were in the sliding mechanisms, that would wear
and needed a new surface to work again).
I think i bought this one in the late 1990's, and although i didnt use it that much
after 6 months or so the rewind stopped working (unit would shut off).
Maybe the belt stretches by just sitting there? I guess that is possible.
But another thing that caught my attention is that the other web site i talked about
showed their belt replacement for this VCR as having a circumference of 9.5
inches, while the belts i got were 8.5 inches, and the old one measured 9.5 inches
and it didnt work anymore and was not actually worn out as the belt thickness
was still ok being the full belt thickness required.
Isnt it strange that a website is selling this larger belt for the same VCR, and the
one i took off (that doesnt work) was the same total length?

Just to note, i did a lot of rework on my older VCR's in the past, rebuilding
a sliding mechanism with a large copper wire threaded into the plastic (looked
strange but worked for years) and even once building into it a pulley system
that would put a little more pressure on the capstan to keep the tape moving
correctly. I was going to put a little belt pulley for the old belt on this newer
VCR but there is *so* little room under the chassis where the belt is that this
was not going to be possible without owning a machine shop to make the
special parts that would be required. That would allow me to tighten the
belt up for a number of months or years as the belt got looser, and i think
if the belt wears out that fast then they should build this kind of thing into
the VCR or else not use belts in the first place, or maybe a steel reinforced
belt.

Know of any VCR's that do not use any belts?
LEDs vs Bulbs, LEDs are winning.

Bear
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Re: VCR Drive Belt and Pulleys Get Slippery

Post by Bear » Tue Dec 01, 2009 11:58 am

Mr. Al... In one of my many incarnations I used to buy specialty chemicals from a company by the name of "VanWaters & Rogers". I'm sure that they would have an office that you would be able to purchase from. I sure that they would have 200 proof (medicinal) alcohol. They also have other items that would be of interest to yourself and other members of this forum.
It was great when (in the olden days) you could go to the neighborhood pharmacist & purchase a quarters worth each of carbon, sulfur and saltpeter for various pyrotechnical "experiments".

Take care all

Dennis

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Janitor Tzap
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Re: VCR Drive Belt and Pulleys Get Slippery

Post by Janitor Tzap » Tue Dec 01, 2009 4:28 pm

MrAl wrote:
Janitor Tzap wrote:Yup,
They sure can!

Belts can stretch quite a bit before they break, or simply fall off.

I've replaced the belts on Turn Tables, and 8-Track players with the factory replacement belts.
When comparing the new belt to the old belt.
I would find the old belt had stretched a good inch, too 1 1/2 inches.

Makes me wonder how the stupid things stayed on as long as they did.


Signed: Janitor Tzap
Hi Janitor,

Thanks for the verification here.
One of the reasons i asked is because i had lots of VCR's in the past, from the 1980's
or around that time, and i dont remember one stretching that much so fast. I had
the VCR's for years before i had a problem, and more importantly, i *used* them a
*lot* more than i used this one before the problem started to occur.
(The main problems i had though were in the sliding mechanisms, that would wear
and needed a new surface to work again).
I think i bought this one in the late 1990's, and although i didnt use it that much
after 6 months or so the rewind stopped working (unit would shut off).
Maybe the belt stretches by just sitting there? I guess that is possible.
But another thing that caught my attention is that the other web site i talked about
showed their belt replacement for this VCR as having a circumference of 9.5
inches, while the belts i got were 8.5 inches, and the old one measured 9.5 inches
and it didnt work anymore and was not actually worn out as the belt thickness
was still ok being the full belt thickness required.
Isnt it strange that a website is selling this larger belt for the same VCR, and the
one i took off (that doesnt work) was the same total length?

Just to note, i did a lot of rework on my older VCR's in the past, rebuilding
a sliding mechanism with a large copper wire threaded into the plastic (looked
strange but worked for years) and even once building into it a pulley system
that would put a little more pressure on the capstan to keep the tape moving
correctly. I was going to put a little belt pulley for the old belt on this newer
VCR but there is *so* little room under the chassis where the belt is that this
was not going to be possible without owning a machine shop to make the
special parts that would be required. That would allow me to tighten the
belt up for a number of months or years as the belt got looser, and i think
if the belt wears out that fast then they should build this kind of thing into
the VCR or else not use belts in the first place, or maybe a steel reinforced
belt.

Know of any VCR's that do not use any belts?
The old piano key style VCRs had Idler Pulleys for the main drive belt.
Thou, the belts on them were really heavy duty.
Later, manufacturers to cut the cost, and weight of the VCR.
Replaced metal components with plastic made ones.
Plus a redesigned the belt drive and pulley setups to eliminate the need for Idler pulleys.

Rubber belts need to be used so they stay pliable.
If they sit for too long, they stretch, stiffen, and eventually break.
So it is a good idea too check the belts on a VCR that has been sitting unused for long
periods of time{A year or longer}.
Give them a cleaning with Isopropyl Alcohol, and clean the pulleys as well.

Yup,
Panasonic PV-8000 & PV-9000 Models.
No belts.
Only rubber that is in them is the pinch roller. :smile:
These are portable VCR's that fit into docking stations.
Both are Stereo 4 Video Head.
But the PV-9000 Model is a HIFI Version.
But good luck trying to find one.
These were made circa 1984-1987.


Signed: Janitor Tzap

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MrAl
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Re: VCR Drive Belt and Pulleys Get Slippery

Post by MrAl » Sat Dec 05, 2009 8:49 am

Janitor Tzap wrote:
MrAl wrote: Know of any VCR's that do not use any belts?
The old piano key style VCRs had Idler Pulleys for the main drive belt.
Thou, the belts on them were really heavy duty.
Later, manufacturers to cut the cost, and weight of the VCR.
Replaced metal components with plastic made ones.
Plus a redesigned the belt drive and pulley setups to eliminate the need for Idler pulleys.

Rubber belts need to be used so they stay pliable.
If they sit for too long, they stretch, stiffen, and eventually break.
So it is a good idea too check the belts on a VCR that has been sitting unused for long
periods of time{A year or longer}.
Give them a cleaning with Isopropyl Alcohol, and clean the pulleys as well.

Yup,
Panasonic PV-8000 & PV-9000 Models.
No belts.
Only rubber that is in them is the pinch roller. :smile:
These are portable VCR's that fit into docking stations.
Both are Stereo 4 Video Head.
But the PV-9000 Model is a HIFI Version.
But good luck trying to find one.
These were made circa 1984-1987.


Signed: Janitor Tzap

Hi Janitor,

Oh ok i guess i should look into those Panasonic units then. No belts sounds good
to me!

I tried cleaning with alcohol first, and that seemed to work for about 5 minutes.
Now i know the belts were stretched or the wrong size installed at the factory.

You know what else bites: if they want to make VCR's (or anything else for that
matter) that use belts like this at least they should make the unit serviceable
without having to remove the entire chassis first. I have to take out screws,
unplug various connectors, and lift the chassis out of the box and turn it over
before i can even think about checking or replacing the belt. One of my old
VCR's at least had a bottom cover that could be removed that gave access
to some stuff like this. A few screws removed and the cover came off.
This RCA thing is really the worst design i ever saw for servicing.
LEDs vs Bulbs, LEDs are winning.

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Janitor Tzap
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Re: VCR Drive Belt and Pulleys Get Slippery

Post by Janitor Tzap » Sat Dec 05, 2009 10:51 am

Yeah,

From 1999 and up the VCR's got to be less service-able.
I tried cleaning with alcohol first, and that seemed to work for about 5 minutes.
Now i know the belts were stretched or the wrong size installed at the factory.
Rubber belts are only designed to last I believe 5-6 years maxium.
Thus, when you clean the VCR's Video/Audio Heads, and tape guides.
Check and clean the belts as well.
Many people will let cleanings slide till the VCR starts to act up.
By this time it will need more than just a cleaning.

One thing you can try for worn or stretched belts is some rubber rejuvenator.
http://www.mcmelectronics.com/product/2 ... =220225260

It may not help if the belt is to badly stretched.


Signed: Janitor Tzap

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Re: VCR Drive Belt and Pulleys Get Slippery

Post by ideas101 » Sun Dec 20, 2009 10:26 pm

Great post!!! looking forward on sharing my expertise and learning new ideas here at the same time..i'll see you around guys...

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