VCR Drive Belt and Pulleys Get Slippery

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Janitor Tzap
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Post by Janitor Tzap » Mon Sep 01, 2008 4:30 pm

MrAl wrote:Hi again,

Janitor:
The fix i was talking about with the spring and pulley and cord was to
help keep more pressure against the capstan by the capstan roller.
Maybe the roller was what was worn? I say this because i dont
remember the capstan itself being worn and i think i would have
noticed that because it is basically a straight shaft and if it was worn
i would have seen a shoulder where it wore narrower, and i dont
remember seeing anything like that. The roller on the other hand im
not sure of because it's just a roller and the whole surface would
have worn.
Hmm....
The Capstan itself sounds like it was OK.
More likely it was the Pinch Roller and the Arm it was mounted on that wore out.
The pivot point on the Pinch Roller Arm is under a lot pressure.
After awhile the hole at the pivot point gets elongated.
Thus, it stops putting the Pinch Roller correctly against the Capstan.
BTW, my newest VCR (the RCA unit i just fixed) has a 'time' based
counter rather than a simple up/down counter like my old VCR's had
and i liked better. I was thinking of installing my own simple up/down
counter using some sort of sensor and a uC chip and display.
Have you done anything like this before or mounted some sensor
for this kind of thing before?
Yeah, the newer VCR's use the timing pulse that is put onto the tape
when it is recorded for the Hour, Minute, and Second for the Tape Counter.

The old mechanical Tape Counters had a belt that came off of the right Reel Hub driving it.

Later, they used just the right Reel Hub, with black & white stripes on it.
The stripes past in front of a photo sensor just under the Reel Hub.
The pulses from the sensor then went to a uC chip and then to the display.

The most simple solution is go with a old mechanical Tape Counter.
Find an old junk VCR that has one, and then figure out how to mount into your RCA VCR.

The other is to tap off the signal from the photo sensor to a uC Chip, then to a 4 digit display.
But the uC Chip will need to get a pulse from the MPU.
{Or tap off of the FF and RW buttons}
Which will dictate the direction (Counting up/Counting Down).


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Externet
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Post by Externet » Mon Sep 01, 2008 10:17 pm

Al:
Glue a piece of aluminium foil to the capstan flywheel and read its passing with a reflective optocoupler out of a defunct fax machine. It has a tape speed constant, rpm not dependent on the amount of tape on the hubs.
Miguel
- Abolish the deciBel ! -

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MrAl
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Post by MrAl » Tue Sep 02, 2008 5:19 am

Hi again,


Janitor:
I threw out all my old VCRs a few years back, so i only have this one now.
I guess i dont mind mounting some sort of sensor though. The idea
of using a uC is so that the calculations can be done right inside the
VCR, so the time can be displayed right then and there.
Yeah i guess it was then arm pivot that wore then. I never did figure
out what actually caused the problem but that's sounds good to me.

Miguel:
Thanks for the tip about the capstan flywheel, i had a guess that it might
always be the same speed. The thing is though, using the take up reel
revolutions allows me to calculate where the tape is no matter where the
last user left it rewound to using the Spiral and it's derivative with time.
What i really dont like is that when i plug a tape in to a VCR (at least
any i have had so far) it reads either 0000 or 00:00:00 no matter where
the tape actually is, and i dont want to have to rewind it just to get where
it really is on the counter.
BTW i dont have any old fax machines around, maybe i could order a
part on the web for this?
LEDs vs Bulbs, LEDs are winning.

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Externet
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Post by Externet » Tue Sep 02, 2008 6:20 am

Oh, no, no need to order. I will send you one on mail.
Tell me the mailing address to externet at inorbit dot com.
Miguel
- Abolish the deciBel ! -

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MrAl
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Post by MrAl » Tue Sep 02, 2008 7:43 am

Hi Miguel,


Oh really? That's very generous of you, and i might take you up
on that!
BTW, did not you and i trade some parts a short while ago where
i sent you something (HP LED) and you sent me something (caps) ?

I really appreciate your offer much. One thing i would have to
know i guess is what the part number is, or if you have any data
on it so that i would know how to hook it up. I would think there
should be a +5v supply somewhere inside the VCR that i could
use if the current draw isnt too high.
LEDs vs Bulbs, LEDs are winning.

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Externet
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Post by Externet » Tue Sep 02, 2008 9:43 am

Yes, we did trade toys. The LED is now a happy ignition timing tool.

Don't worry about ease of use for the optocoupler. I will include some data.
Miguel
- Abolish the deciBel ! -

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Janitor Tzap
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Post by Janitor Tzap » Tue Sep 02, 2008 10:33 am

Externet wrote:Al:
Glue a piece of aluminium foil to the capstan flywheel and read its passing with a reflective optocoupler out of a defunct fax machine. It has a tape speed constant, rpm not dependent on the amount of tape on the hubs.
Miguel
Hi Miguel,

That maybe a problem.
On some VCR's the Capstan keeps turning while the "Pause" Function is used.
So your counter would be off if you were pausing the tape or had it paused before starting a recording.

It would work better to put the foil on the right Cassette Reel Hub instead.


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Post by Externet » Tue Sep 02, 2008 10:41 am

You are absolutely right !
Luckily the sensor / counter can be paused / disabled with the same VCR pause signal too :grin:
Miguel
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Post by Janitor Tzap » Tue Sep 02, 2008 10:51 am

Externet wrote:You are absolutely right !
Luckily the sensor / counter can be paused / disabled with the same VCR pause signal too :grin:
Miguel
Ok,
That's one way to solve that problem. :cool:


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Post by MrAl » Tue Sep 02, 2008 11:57 am

Hi again,

Sorry to say but the point is moot because i cant put it on the capstan
because that goes at a constant speed regardless of where the tape
is rewound to. As i was saying before, i need to have the sensor get
the takeup reel revolutions to make this trick work at all.
Perhaps someone else may wish to do the capstan though on their
VCR.

Now that you guys got me thinking about this reflective light sensing,
maybe i'll draw up a disk with sectors and print it to blue paper and
transfer it and etch it on some brass or stainless steel, or even a
copper board perhaps if i can get enough reflectivity. With several
sectors i'll improve the resolution at least 10 fold and that will make
the tape sensing calculation go that much faster than it would sensing
only one revolution per true revolution. I could use the high resolution
count for the calculation and divide it by 10 to send to the display
counter. Should work pretty nice!

I have to wonder now if there are any VCRs out there that already do
this?
LEDs vs Bulbs, LEDs are winning.

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Janitor Tzap
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Post by Janitor Tzap » Tue Sep 02, 2008 12:57 pm

MrAl wrote:Hi again,

Sorry to say but the point is moot because i cant put it on the capstan
because that goes at a constant speed regardless of where the tape
is rewound to. As i was saying before, i need to have the sensor get
the takeup reel revolutions to make this trick work at all.
Perhaps someone else may wish to do the capstan though on their
VCR.

Now that you guys got me thinking about this reflective light sensing,
maybe i'll draw up a disk with sectors and print it to blue paper and
transfer it and etch it on some brass or stainless steel, or even a
copper board perhaps if i can get enough reflectivity. With several
sectors i'll improve the resolution at least 10 fold and that will make
the tape sensing calculation go that much faster than it would sensing
only one revolution per true revolution. I could use the high resolution
count for the calculation and divide it by 10 to send to the display
counter. Should work pretty nice!

I have to wonder now if there are any VCRs out there that already do
this?
Well there are the Professional or Studio VCR's that have a Time Stamp Base Generator built into them.
Thus, every tape recorded on it has a time code on it.

I've done a little bit of work with 1/2inch Studio Sony VTR's.
When some one had a tape that we needed to use from a consumer recorder.
It first had to be played through a Time Stamp Base Generator,
and the video now with the time code attached.
Recorded to a new tape, so we could then do editing with it.

Consumer VCR's have a timing code that is put on to a tape.
But the consumer VCR isn't setup to read it.

Maybe with the newer equipment that has come out in the past 10 years, a consumer version does exist.
But, I'm rather doubtful that one does.
Being the cost, and if the consumer market really wants, or needs such a feature in a consumer VCR.


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Post by MrAl » Wed Sep 03, 2008 9:59 am

Hi Janitor,

Ok, im not sure mine does that or not, but for sure it does not
read it back if it does :smile: as when i put the tape in it resets to
00:00:00 which isnt what i want it to do.
Too bad i cant think of a way to set the time counter, rather than
have it reset to zero. If i could enter in 03:00:00 for example, that
would help a bit too. I wonder if there is any way to rig this up...
maybe send more pulses to the control chip somehow.

Anyway, last night i put the unit into fast REW (rewind) and it
stalled again. Stopped dead, then shut off. After turning it back
on the tape popped out (as usual) and after i put it back in the
rewind worked again. Strange. It's like it got stuck for a second.
Maybe it's time for a new vcr? But i hardly used this thing over
the past 10 years. Also, i have read that the manufacturers are
making the new vcrs really really cheap (like mine ha ha) so
maybe it wont even help to buy a new one.
I'd possibly give up on vcrs totally, but i have quite a few tapes made
up from over the years of some of my favorite movies.
I'd also consider putting them on DVD, but i dont have a converter
to pump the video into the computer. Any ideas there?
LEDs vs Bulbs, LEDs are winning.

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Janitor Tzap
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Post by Janitor Tzap » Wed Sep 03, 2008 4:03 pm

MrAl wrote:Hi Janitor,

Anyway, last night i put the unit into fast REW (rewind) and it
stalled again. Stopped dead, then shut off. After turning it back
on the tape popped out (as usual) and after i put it back in the
rewind worked again. Strange. It's like it got stuck for a second.
Maybe it's time for a new vcr? But i hardly used this thing over
the past 10 years. Also, i have read that the manufacturers are
making the new vcrs really really cheap (like mine ha ha) so
maybe it wont even help to buy a new one.
I'd possibly give up on vcrs totally, but i have quite a few tapes made
up from over the years of some of my favorite movies.
I'd also consider putting them on DVD, but i dont have a converter
to pump the video into the computer. Any ideas there?
Hmm.......
That sounds like a dirty Function Switch to me.

See if you can locate the Function Switch on the chassis.
Then see if you can't spray some "Tuner Cleaner" inside the switch.
Then work the switch too get the contacts inside it to rub off the oxide that has build up.
If that doesn't work.
You'll need to carefully disassemble the gearing around the Function Switch.
Then possibly pulling apart the Function Switch, cleaning the contacts with an eraser, and the wiper.
Put a thin layer of "Tuner Lub" or "Tuner Spray" on the contacts.
Then re-assemble the Function Switch.
If that fails. Then just replace the Function Switch.
You can go too: http://www.studiosoundelectronics.com/indexfrm.htm
There you will find step by step information on how remove, and replace the Function Switch.

Transferring tapes are we? :wink:
Well single unit VCR's have all but dried up now.
You can still get VCR/DVD Comb Units.
But I'm finding that with old tapes that were recorded in EP/SLP or LP on older VCR's.
Just won't play right.
I can't get the some tapes to track, or the screen blanks off & on when the signal gets weak.
I know a friend went through several different brands till he found one that would work.
{I think it was a Sony.}

But that is just the VCR part.
If you want to do this right.
You need a Time Base Corrector & Video Enhancer.
A Video Capture Card or USB Video Capture Device.
Note: the USB unit works only with XP or Vista.

The Video Capture Cards, or USB Video Capture Devices aren't expensive.
$30 to $80 dollars.
But the Time Base Corrector & Video Enhancers.
They start at $250 and up, depending on the style you need.

You can just go with the Capture Card, or USB Device.
But I found that if the Video Signal going into the Video Capture Unit is unstable, or too weak.
It automatically blanks or "Blue Screens" the Picture.

Here, go to this address:
http://thehaisho.com/forums/viewtopic.p ... 5&start=20
Scroll down to the last posting.
There you will find an attachment WheelerVideo.PDF.
Go head and down load it.
{It's 765K, but the info is excellent.} :)


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MrAl
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Post by MrAl » Thu Sep 04, 2008 6:33 am

Hi again Janitor,


Hmmm, the USB video thing sounds interesting. Maybe i should look
into that.

For the VCR i now have, i run it with the remote control so i am not
actually operating any switch of any kind. Also, i am pretty sure it
is the belt / pulleys i talked about earlier because after i cleaned that
belt and two pulleys it started working very well again, every time
i used it. I will crack open the case again later today (hopefully)
and see if anything happened to that belt again, as last night it acted
up again several times and would not rewind again with the exact
same symptom.
LEDs vs Bulbs, LEDs are winning.

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Janitor Tzap
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Post by Janitor Tzap » Thu Sep 04, 2008 8:07 am

MrAl wrote:Hi again Janitor,


Hmmm, the USB video thing sounds interesting. Maybe i should look
into that.

For the VCR i now have, i run it with the remote control so i am not
actually operating any switch of any kind. Also, i am pretty sure it
is the belt / pulleys i talked about earlier because after i cleaned that
belt and two pulleys it started working very well again, every time
i used it. I will crack open the case again later today (hopefully)
and see if anything happened to that belt again, as last night it acted
up again several times and would not rewind again with the exact
same symptom.
There has to be a "Function Switch".
How would the CPU know which mode it was in?

Many of the VCR's that came out in the passed 10 years sometimes
bury the "Function Switch" under the gears to save space.
You can go too: http://www.studiosoundelectronics.com/indexfrm.htm
There you will find step by step information on how remove, and replace the Function Switch for your model of RCA VCR.

Note: Frank tries to cover the most used brands and models.
So, if it's not on his site.
You can E-mail him, and ask where the "Function Switch" is located on your model.:grin:
Franks E-mail: [email protected]

It could still be possible that your belts are still giving you problems.
Since you cleaned them with Rubbing Alcohol in stead of Isopropyl Alcohol, or methyl Alcohol.

But don't be surprised if the belts have gotten stretch out because of the Rubbing Alcohol,
and that cleaning them with Iso, or Methyl Alcohol doesn't help.
Thus, you will have to replace the belts. :(


Signed: Janitor Tzap

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