VCR Drive Belt and Pulleys Get Slippery

This is the place for any magazine-related discussions that don't fit in any of the column discussion boards below.
User avatar
MrAl
Posts: 3862
Joined: Fri Jan 11, 2002 1:01 am
Location: NewJersey
Contact:

VCR Drive Belt and Pulleys Get Slippery

Post by MrAl » Fri Aug 29, 2008 12:51 pm

Hello,

My VCR is about 10 years old now but as little as 6 months after
purchasing it it developed a problem. The problem was that the
fast (non play mode) rewind would not work anymore. I finally
got around to gutting it and found that cleaning the drive belt
and related pulleys fixed the problem. It took a bit of disassembly
however, taking out screws and unplugging various connectors so
the main drive subassembly could be removed to get at the bottom
of it where the belt and pulleys are located.
What i was wondering was what do you think would cause the belt
and pulleys to become slippery after only 6 months use?
I left a few screws out in case i have to do it again in 6 months.
LEDs vs Bulbs, LEDs are winning.

User avatar
Externet
Posts: 1842
Joined: Fri Feb 01, 2002 1:01 am
Location: Mideast USA
Contact:

Post by Externet » Fri Aug 29, 2008 1:20 pm

Hello Al
Typical misbehavior on VCRs. Before tackling anything, it is better to try different cassettes as they can get 'lazy' and mislead the trouble.
Being late for that, I have had success by scraping with an x-acto blade, the plastic surfaces against the felt clutch, and the V grooves on pulleys.

The idler wheel mechanism was since day one, prone to failure. They never came up with a decent engineering and millions of units ended in the trash because of simple 'slipping' of rubber-to-plastic surfaces.
Stronger springs sometimes help.

It helps to have a cassette with no tape and no cover to see where the slipping happens when a 'test cassette' is not on hand. There is photosensors that do not allow the mechanism to work for troubleshooting without it. Such modified cassette body lets you do the visual checking.

Good luck,
Miguel
- Abolish the deciBel ! -

User avatar
Janitor Tzap
Posts: 1468
Joined: Sat Aug 12, 2006 5:17 pm
Contact:

Post by Janitor Tzap » Fri Aug 29, 2008 2:18 pm

Hmm........
What is the make and model?

Years ago I ran into that problem with the FISHER 720-900 Series VCR's.
The RW/FF Idler Assembly was poorly made.
So, I was replacing a lot of belts on those units, as well as rebuilding the RW/FF Idler Assembly, or just replacing it.
I sold a lot of Tape Rewinders too those customers.

Here....
Just look up the Make and Model of your VCR on this web site.
http://www.studiosoundelectronics.com/indexfrm.htm
Frank Fendley runs this site, and he has a lot of knowledge of VCR's.
His site has just about everything you need to know about how to service, and maintain your VCR.
As well as parts. :)


Signed: Janitor Tzap

User avatar
MrAl
Posts: 3862
Joined: Fri Jan 11, 2002 1:01 am
Location: NewJersey
Contact:

Post by MrAl » Sat Aug 30, 2008 1:36 pm

Hi again,

Miguel:
Yes i tried a couple other cassettes to make sure it was not a
bad cassette. They both did the same thing and stopped rewinding
when the cassette got down to about 2 hours. It did work from
6 hours down to 2 hours, but then would stop and shut off.
Roughing up with a knife sounds like a good idea, i'll have to
keep that in mind for next repair time.
The belt and pulley system for this one doesnt have any springs
to tighten. I would have expected on such a drive system for
them to have a slack busting pulley and spring, but they dont
for this unit. I thought about adding one myself. I've done
such mods on other VCRs (much older units) and got 10 more
years out of them. Now that you got me thinking about it again,
on one unit i installed a tug wire and related spring to keep
more tension on the capstan...got several years more out of it.
That was a big job however, had to install a tiny 1/8 inch diameter
pulley that i made from the end of an old guitar string (the
things at the end are made of brass i think and they make nice
tiny pulleys). Funny, the holder for the tiny pulley was made from
an old Leggos plastic block, using the inside for the pulley and
putting a steel shaft through one side and out the other. Made
a nice and small block and tackle.
I dont have a test cassette, never got one, even with all the work
i have done in the past on these things, but maybe i should make
one. Would be nice. I would have been able to see what was going
on first time i opened the cover i think. I couldnt see anything
until i removed the whole chassis subassembly with this unit.
Older units i took off the bottom and could see almost everything.

Janitor:
Thanks for the link. It looks like they sell almost anything
for a VCR, which is nice, and they had my belt too, but not the
idler arm. Lucky i dont need that, but maybe a belt in the
future.
LEDs vs Bulbs, LEDs are winning.

User avatar
dacflyer
Posts: 4482
Joined: Fri Feb 08, 2002 1:01 am
Location: USA / North Carolina / Fayetteville
Contact:

Post by dacflyer » Sat Aug 30, 2008 2:40 pm

i used to clean slippery belts with either contact cleaner or some alcohol, and as for slipping clutches, i'd take them apart and dab some heatsink grease on the felt pad, and that seemed to help...customers never came back with any complaints...

User avatar
Janitor Tzap
Posts: 1468
Joined: Sat Aug 12, 2006 5:17 pm
Contact:

Post by Janitor Tzap » Sat Aug 30, 2008 4:52 pm

dacflyer wrote:i used to clean slippery belts with either contact cleaner or some alcohol, and as for slipping clutches, i'd take them apart and dab some heatsink grease on the felt pad, and that seemed to help...customers never came back with any complaints...
HeatSink Grease on the felt pad!?!
Woundn't that make the clutch slip more than normal? :???:

Normally you.....
First I take a part the clutch assembly, and clean it with Isopropyl Alcohol, and a tooth brush.
NOTE:Don't use Rubbing Alcohol, it has oils in it, and leaves a film of oil on the parts.

Then I ruff up the felt pad with a razor blade, and ruff up plastic hub it sits against.
NOTE: You may not need to ruff up the plastic part of the hub.
Some have molded groves already in them.

The belt pulley can just be cleaned with Isopropyl Alcohol, and a Q-tip in its groove.
If there is some gunk really stuck on it.
Then use a razor blade knife, or some fine grit sand paper, 900 or higher.
To remove the gunk.

Normally, I don't recommend resurfacing the pulley.
Because the belts are designed to fit the pulley grooves exactly.
So, ruffing up the pulley surface would shorten the life of the drive belt.

When you clean the belts, use Isopropyl Alcohol as well.
I've used lint free paper towels, but clean sheet of paper will work too.
For belts that are greasy, or slightly stretched.
I use "Rubber Renew" on them.


Case History:
I have seen problems with belts on 80's type Panasonics.
The load belt, drive belt and drive tire were wearing out faster than normal.
The fix that Panasonic came up with: was to replace the belts with slightly
thicker square belts, and replace the pulleys with ones that had a wider V-Slant.
This solved the belt problem, but it took longer for the drive tire problem to be solved.
I and several others, who were seeing this problem got flyers from PRB.
They claimed that their replacement tires lasted longer than the OEM ones.
Well we got some, and put them in the Panasonics.
They worked as PRB claimed, lasting 3-4 years instead of 1 to 2.


Signed: Janitor Tzap

User avatar
dacflyer
Posts: 4482
Joined: Fri Feb 08, 2002 1:01 am
Location: USA / North Carolina / Fayetteville
Contact:

Post by dacflyer » Sat Aug 30, 2008 5:45 pm

actually the heatsink grease is very thick.and doesn't slip like thinner greases or oils..it seemed to work good for me..and as for belts, i always used a size smaller belt to give that little extra grip.

User avatar
MrAl
Posts: 3862
Joined: Fri Jan 11, 2002 1:01 am
Location: NewJersey
Contact:

Post by MrAl » Sun Aug 31, 2008 7:16 am

Hi again,


I used rubbing alcohol but i guess i'll have to try to find some
iso alcohol next.

I've never tried heat sink grease for anything other than heat sinks.
Doesnt that stuff get slippery?

The unit is an RCA unit from the late 1990's. I found out it has
a Daewoo chassis from that site link provided by Janitor. I was
surprised to find this out, as i thought Daewoo got their stuff from
somebody else.
LEDs vs Bulbs, LEDs are winning.

User avatar
Janitor Tzap
Posts: 1468
Joined: Sat Aug 12, 2006 5:17 pm
Contact:

Post by Janitor Tzap » Sun Aug 31, 2008 10:14 am

MrAl wrote:Hi again,


I used rubbing alcohol but i guess i'll have to try to find some
iso alcohol next.
I normally buy it at the local pharmacy, or at Walmart. :)
I've never tried heat sink grease for anything other than heat sinks.
Doesnt that stuff get slippery?
Yes, it starts out quite viscous, but over time it will dry out, and get like glue!
There is a black graphite grease that was used a lot by the manufacturers on VCR gears {Molydenum?}Spelling?
When it dried out it would act like glue as well.
I've pulled a part countless VCRs that used that stuff on the gears.
It recked the gears, burned out motors.
Worse case I saw was on a Zenith VCR.
Not only did it destroy the gears, and motors.
It caused the drive IC to burn out, and damage the Power Regular IC.
Sometimes I got lucky, and the stuff hadn't completely dried.
Thus, I could pull the gears a part, and clean them up, and re-grease
them with white lithium grease or "Tuner Lub".
The unit is an RCA unit from the late 1990's. I found out it has
a Daewoo chassis from that site link provided by Janitor. I was
surprised to find this out, as i thought Daewoo got their stuff from
somebody else.
Well that's not uncommon.
I've pulled apart RCA's, GE's, Panasonic's that were basically the same machine.
I have to laugh sometimes at how the manufacturers sell parts to one another.
Or going down a line of DVD Players at Best Buy, and seeing that they are basically the same. :lol:


Signed: Janitor Tzap

User avatar
MrAl
Posts: 3862
Joined: Fri Jan 11, 2002 1:01 am
Location: NewJersey
Contact:

Post by MrAl » Sun Aug 31, 2008 11:24 am

Hi again,


That grease might help explain a problem i had a long time ago
with an 1980's Sharp VCR. One of the plastic cam grooves (for
mode switching) wore out rather fast, and i had to run a piece of
heavy solid copper wire along the inside edge to make up the
guides edge like when it was new, and attach and epoxy the ends
to hold it in place. Lucky it worked ok, and got lots more years
out of it. I dont remember what kind of grease i used after that
though. The copper wore a little flat over time but still lasted long.
The symptom was the unit would jam up when it was put in record
mode and that was because of the cam follower jamming into the
worn out side wall of the cam groove. What junk that thing was.
You would not believe the disassembly required to do that repair
either! Wow, what a mess, taking off all kinds of mechanical stuff
to get to the cam. Glad now i finally junked that thing when i got
the RCA unit. BTW, the RCA (or should i say 'Daewoo') unit has
the mode cam stuff right on top of the chassis. It's just the belt
that's underneath.
LEDs vs Bulbs, LEDs are winning.

User avatar
Bob Scott
Posts: 1192
Joined: Wed Nov 20, 2002 1:01 am
Location: Vancouver, BC
Contact:

Post by Bob Scott » Sun Aug 31, 2008 11:56 am

Janitor Tzap wrote:
MrAl wrote: I used rubbing alcohol but i guess i'll have to try to find some
iso alcohol next.
I normally buy it at the local pharmacy, or at Walmart. :)
Ya, the rubbing alcohol has lanolin in it, and leaves a greasy film. 99.99% Isopropyl is recommended. At my TV station, the operators ran out of VTR head cleaner for the Ampex 2" quad head machines. The maintenance supervisor bought rubbing alcohol as an emergency measure. It's a good thing I caught them before they used it! It would have gummed up those expensive(!) heads.

I've used methyl alcohol successfully. Has anyone else? Come to think of it, in a pinch I've used scotch or rye whisky for cleaning the heads of a friend's 8-track.

I worked for Sony back in the days of 1/2" reel-to-reel tape machines. I learned quickly that cleaning belts and scraping rubber idlers parts like I did in my amateur days, doesn't last as long as doing it the right way, by installing new unstretched and unaged belts or rubber idler wheels.

Cleaning and roughing up a belt pulley sounds like a good idea, but I'd use very fine 600 grit sandpaper, not by scraping it with a knife.

I date myself when I mention that to fix shiny 8-track capstans shafts, after masking the bearing surfaces with electrical tape, I used to soak the shafts in ferric chloride etchant for an hour to get rid of the shine and restore the grip. This worked but was only a temporary and inadequate solution. It lasted even less time than cleaning an old stretched-out belt. I thnk that those capstans were case hardened at the factory. Etching them ruined the hardening and made them wear much faster. The only real solution was capstan shaft replacement.

User avatar
Bob Scott
Posts: 1192
Joined: Wed Nov 20, 2002 1:01 am
Location: Vancouver, BC
Contact:

Post by Bob Scott » Sun Aug 31, 2008 11:59 am

MrAl wrote:Now that you got me thinking about it again,
on one unit i installed a tug wire and related spring to keep
more tension on the capstan...got several years more out of it.
That was a big job however, had to install a tiny 1/8 inch diameter
pulley that i made from the end of an old guitar string (the
things at the end are made of brass i think and they make nice
tiny pulleys). Funny, the holder for the tiny pulley was made from
an old Leggos plastic block, using the inside for the pulley and
putting a steel shaft through one side and out the other. Made
a nice and small block and tackle.
I'm stunned! That is absolute genius!

I guess this was before the time that you could just get another another VCR for Walmart for 50 bucks.

User avatar
MrAl
Posts: 3862
Joined: Fri Jan 11, 2002 1:01 am
Location: NewJersey
Contact:

Post by MrAl » Mon Sep 01, 2008 7:15 am

Bob Scott wrote:
MrAl wrote:Now that you got me thinking about it again,
on one unit i installed a tug wire and related spring to keep
more tension on the capstan...got several years more out of it.
That was a big job however, had to install a tiny 1/8 inch diameter
pulley that i made from the end of an old guitar string (the
things at the end are made of brass i think and they make nice
tiny pulleys). Funny, the holder for the tiny pulley was made from
an old Leggos plastic block, using the inside for the pulley and
putting a steel shaft through one side and out the other. Made
a nice and small block and tackle.
I'm stunned! That is absolute genius!

I guess this was before the time that you could just get another another VCR for Walmart for 50 bucks.

Hi Bob,

Yes, that was when VCRs were 250 bucks.
Gee thanks for the complement (chuckle) but i guess i didnt realize
that the capstan had maybe worn a bit?

I cant find any links that state that the regular rubbing alcohol sold in
the US has anything other than 70 percent straight alcohol mixed with 30
percent water. I know they make stronger concentrations, but i've
never seen any other ingredients mentioned either on the web or on
the bottle itself. The bottle i happen to have right now says 70/30 but
nothing else. Perhaps different brands put in some other stuff too?
I've seen stronger concentrations at the local WalGreens, but i dont
think i've ever seen 99 percent even there. Not sure where i would
get any pure (or almost so) alcohol now that i think about it. Any
ideas?
LEDs vs Bulbs, LEDs are winning.

User avatar
Janitor Tzap
Posts: 1468
Joined: Sat Aug 12, 2006 5:17 pm
Contact:

Post by Janitor Tzap » Mon Sep 01, 2008 11:50 am

Bob Scott wrote:
Janitor Tzap wrote:
MrAl wrote: I used rubbing alcohol but i guess i'll have to try to find some
iso alcohol next.
I normally buy it at the local pharmacy, or at Walmart. :)
Ya, the rubbing alcohol has lanolin in it, and leaves a greasy film. 99.99% Isopropyl is recommended. At my TV station, the operators ran out of VTR head cleaner for the Ampex 2" quad head machines. The maintenance supervisor bought rubbing alcohol as an emergency measure. It's a good thing I caught them before they used it! It would have gummed up those expensive(!) heads.

I've used methyl alcohol successfully. Has anyone else? Come to think of it, in a pinch I've used scotch or rye whisky for cleaning the heads of a friend's 8-track.

I worked for Sony back in the days of 1/2" reel-to-reel tape machines. I learned quickly that cleaning belts and scraping rubber idlers parts like I did in my amateur days, doesn't last as long as doing it the right way, by installing new unstretched and unaged belts or rubber idler wheels.

Cleaning and roughing up a belt pulley sounds like a good idea, but I'd use very fine 600 grit sandpaper, not by scraping it with a knife.

I date myself when I mention that to fix shiny 8-track capstans shafts, after masking the bearing surfaces with electrical tape, I used to soak the shafts in ferric chloride etchant for an hour to get rid of the shine and restore the grip. This worked but was only a temporary and inadequate solution. It lasted even less time than cleaning an old stretched-out belt. I thnk that those capstans were case hardened at the factory. Etching them ruined the hardening and made them wear much faster. The only real solution was capstan shaft replacement.
Hi Bob,

Nice to know I wasn't the only one tinkering with these. :lol:

But yeah,
I and several of the people I worked with at this Repair Shop.
Came up with some fixes that were pretty weird.

The 8-track repair of the Capstan that you mention sounds extreme.
I've used polishing compounds like "Mothers" to remove the build up of oxides, that the tapes left.
Then used Isopropyl to remove residue from the "Mothers" polish.
But a lot of times the brass bearings in the 8-Track Players were worn out.
Or both the Capstan & Bearing were worn to the point that they were grooved.

I found in an old manual on cleaning Reel to Reel Audio Tape decks.
It stated that after you finished cleaning the heads.
You were to take a Q-Tip and a Lite Machine Oil and lightly coat the Audio Heads,
then wipe off the excess leaving just a film on them.
I guess the thinking was.
The Audio Tapes at the time didn't have a lubricant mixed in with the oxides and binding material.
Thus, they would wear down the heads quickly if there wasn't some kind of lubricant on the heads.

Yes,
Replacing the stretched out belts, worn out Tires, and Pinch Rollers is the best way.
But while I was working at the shop, we got in VCR's that were only months old.
So, replacement Belts, Tires, or parts weren't yet available,
and the customer wanted his VCR back, and working ASAP.
So, we came up with a lot of quick fixes.

One trick that worked pretty good was turning Tires inside-out.
This would give us up to a year before the machine would come back in.
By that time we could then get the replacement parts in from our suppliers.

By the way......
I don't advocate roughing up a belt pulley with a Razor Blade knife either.
Normally I will use a Q-tip and Isopropyl to clean it.
But, I've run into one or two really gummed up pulleys.
{This guy tried to cleaned the belts with WD40!} :lol:
The belt broke, and pieces were stuck to the pulley.

One thing that we used a lot was the Ultra Sonic Cleaner.
It was great for gears, and the occasional badly clogged Video Head.

Case History:
I wish I could remember the Panasonic VCR that was the size of a book.
It was Panasonic's attempt to make a VCR that had only one motor to
run every function. Play/FF/RW and Load and Eject the tape.
We saw a lot of those, that the gears had tore up, burned out the motor,
burned out the drive IC, or Power Supply Failed.
A lot of them end up in the parts pile in the back room. :lol:


Signed: Janitor Tzap

User avatar
MrAl
Posts: 3862
Joined: Fri Jan 11, 2002 1:01 am
Location: NewJersey
Contact:

Post by MrAl » Mon Sep 01, 2008 12:02 pm

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.

BTW, the cord was a piece of that old time radio cord i think they call
it 'dial cord' as it was used to connect the dial to the large tuning capacitor
in old style radios. That stuff was tough and held up for years.
What else might work is some heavy duty 'coat' thread, made for
sewing winter coats. That stuff is tough too.
The fixed i used might have to be modified too though for other
types of mechanical mechanisms in other types of VCRs. You
would have to engineer something slightly different to keep more
pressure on the capstan roller.

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?
LEDs vs Bulbs, LEDs are winning.

Post Reply

Who is online

Users browsing this forum: Joseph and 7 guests