Sony VCR enters weird state after rewind or fast forward

D

Diomidis Spinellis

Guest
My Sony SLV-E470EG VCR is now operating in a weird manner after
rewinding or fast-forwarding the tape. All functions behave OK, until
stop or play is pressed during a fast-forward or rewind operation.

At that point a noise of a motor running without effect is heard for
about 4 seconds. From that point onward the play, rewind and fast
forward commands do not produce any action. An eject command will start
rewinding the tape (at relatively low speed) for about 20 seconds.
After that point the tape will be ejected. When the tape is loaded
again the cycle (normal play / eject, until play / stop is hit during
rewind / fast-forward) can be repeated.

I have read the VCR part of the Sci.Electronics.Repair FAQ and tried the
various suggestions. The VCR has only a single belt, which has gears
and appears to be OK. The only visible problem I could see was a
partially unglued rubber break pad on the supply spindle, which I fixed.
All gears appear to be intact, and no foreign materials appear to be
blocking them.

I would appreciate any ideas you may have.

Diomidis Spinellis - http://www.spinellis.gr
 
A warn idler assembly and or a bearing or bushing that is failing or jamming
can cause this type of effect. This is the only thing I can think of from
guessing at a probably cause. The best thing would be to have someone who
has a lot of VCR service experience to look at it for you. There machines
can be a challenge to service.

--

Greetings,

Jerry Greenberg GLG Technologies GLG
=========================================
WebPage http://www.zoom-one.com
Electronics http://www.zoom-one.com/electron.htm
=========================================


"Diomidis Spinellis" <dds@aueb.gr> wrote in message
news:c6tjga$87b$1@nic.grnet.gr...
My Sony SLV-E470EG VCR is now operating in a weird manner after
rewinding or fast-forwarding the tape. All functions behave OK, until
stop or play is pressed during a fast-forward or rewind operation.

At that point a noise of a motor running without effect is heard for
about 4 seconds. From that point onward the play, rewind and fast
forward commands do not produce any action. An eject command will start
rewinding the tape (at relatively low speed) for about 20 seconds.
After that point the tape will be ejected. When the tape is loaded
again the cycle (normal play / eject, until play / stop is hit during
rewind / fast-forward) can be repeated.

I have read the VCR part of the Sci.Electronics.Repair FAQ and tried the
various suggestions. The VCR has only a single belt, which has gears
and appears to be OK. The only visible problem I could see was a
partially unglued rubber break pad on the supply spindle, which I fixed.
All gears appear to be intact, and no foreign materials appear to be
blocking them.

I would appreciate any ideas you may have.

Diomidis Spinellis - http://www.spinellis.gr
 
Jerry, many thanks for taking the trouble to reply. You are the
newsgroup's wise man!

You are right, the machine is difficult to service. I placed a gear
assembly at the wrong tooth position, and it took me four hours to
understand how to assemble it in the right position (there was no
apparent timing mark, and it fell off by mistake). The gear in question
had teeth around 3/4 of its periphery. Apparently the trick is to
engage the gear in a "toothless" position and then rotate the gear that
drives it. At some point the driving gear "catches" the partially
toothless gear and engages it at exactly the correct position.

Back to the original subject. I may be getting closer to the problem's
cause: I decoded the error message on the display as: "05 Abnormal
reverse cam motor rotation", and I noticed that a large gear-driven
plastic plate is in a different position (by one tooth) when the problem
manifests itsself, than when the tape is originally put into the VCR. I
assume that the plate should be in the same position when the tape is
first inserted, and after stop is pressed. I will experiment engaging
this plate at different gear teeth, assuming it was somehow missaligned
(e.g. by someone forcing the tape into the VCR).


Cheers,

Diomidis

Jerry G. wrote:
A warn idler assembly and or a bearing or bushing that is failing or jamming
can cause this type of effect. This is the only thing I can think of from
guessing at a probably cause. The best thing would be to have someone who
has a lot of VCR service experience to look at it for you. There machines
can be a challenge to service.
Click to expand...
 
I have now found the source of the problem, and sort-of solved it. The
transport control system has a mechanism for rapidly aplying the brakes
to the take-up and supply wheels when the system goes from fast-forward
to stop. This mechanism consists of a small metal lever and is armed
when the plastic transport control plate moves into the fast forward
position: the lever moves in sync with the rest of the transport control
plate and removes the brakes, while also applying tension to a spring.

When a stop command occurs the motor triggers the armed brake lever, not
via the normal gear mechanism that controls the positioning of all other
parts (and its initial arming), but via a separate system. The
transport control motor, appart from the transport control gear, has on
its axle a paddle-wheel structure consisting of three paddles. When
stop is pressed, a small part of the control motor rotation causes one
of the three paddles to trigger the armed break lever. On my system I
could cause this action by hand, but the motor did not apply enough
torque to trigger it via the paddle. I "solved" this problem by
removing the the lever's spring and extending it beyong its limit of
elasticity, thus increasing its length and decreasing the pressure it
applied on the triggering mechanism. The system works ok now, though I
am not entirely happy with the solution.

Diomidis Spinellis - http://www.spinellis.gr


I wrote:
My Sony SLV-E470EG VCR is now operating in a weird manner after
rewinding or fast-forwarding the tape. All functions behave OK, until
stop or play is pressed during a fast-forward or rewind operation.

At that point a noise of a motor running without effect is heard for
about 4 seconds. From that point onward the play, rewind and fast
forward commands do not produce any action. An eject command will start
rewinding the tape (at relatively low speed) for about 20 seconds. After
that point the tape will be ejected. When the tape is loaded again the
cycle (normal play / eject, until play / stop is hit during rewind /
fast-forward) can be repeated.
Click to expand...
[...]
 
The load motor needs to be replaced. It comes with the gear, etc.

Mark Z.

--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"Diomidis Spinellis" <dds@aueb.gr> wrote in message
news:4092C8ED.7070106@aueb.gr...
I have now found the source of the problem, and sort-of solved it. The
transport control system has a mechanism for rapidly aplying the brakes
to the take-up and supply wheels when the system goes from fast-forward
to stop. This mechanism consists of a small metal lever and is armed
when the plastic transport control plate moves into the fast forward
position: the lever moves in sync with the rest of the transport control
plate and removes the brakes, while also applying tension to a spring.

When a stop command occurs the motor triggers the armed brake lever, not
via the normal gear mechanism that controls the positioning of all other
parts (and its initial arming), but via a separate system. The
transport control motor, appart from the transport control gear, has on
its axle a paddle-wheel structure consisting of three paddles. When
stop is pressed, a small part of the control motor rotation causes one
of the three paddles to trigger the armed break lever. On my system I
could cause this action by hand, but the motor did not apply enough
torque to trigger it via the paddle. I "solved" this problem by
removing the the lever's spring and extending it beyong its limit of
elasticity, thus increasing its length and decreasing the pressure it
applied on the triggering mechanism. The system works ok now, though I
am not entirely happy with the solution.

Diomidis Spinellis - http://www.spinellis.gr


I wrote:
My Sony SLV-E470EG VCR is now operating in a weird manner after
rewinding or fast-forwarding the tape. All functions behave OK, until
stop or play is pressed during a fast-forward or rewind operation.

At that point a noise of a motor running without effect is heard for
about 4 seconds. From that point onward the play, rewind and fast
forward commands do not produce any action. An eject command will start
rewinding the tape (at relatively low speed) for about 20 seconds. After
that point the tape will be ejected. When the tape is loaded again the
cycle (normal play / eject, until play / stop is hit during rewind /
fast-forward) can be repeated.

[...]
Click to expand...
 
Mark D. Zacharias wrote:

The load motor needs to be replaced. It comes with the gear, etc.
Click to expand...

Thanks Mark! I thought this could be the case when I found the motor
also had problems opening the front door latch swiftly enough. Now I am
working with the break spring hacked to exert less pressure, and the
front door latch spring removed, but, as you say, I should better hunt
for a load motor replacement.

Cheers,

Diomidis
--
Diomidis Spinellis Associate Professor
Department of Management Science and Technology (DMST)
Athens University of Economics and Business (AUEB)
Patision 76, GR-104 34 Athens, GREECE +30 2108203682
http://www.dmst.aueb.gr/dds/ mailto:dds@aueb.gr
 
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