Notes on the Troubleshooting and Repair of Video Cassette Recorders


Chapter 20) VCR Sensors and Tape Counters

  20.1) Tape start/end sensors

VHS cassettes use a clear leader and trailer for the purposes of detecting
beginning or end of tape.  A light source that pokes up in the center
of the cassette illuminates photodetectors on either side of the cassette
through passages in the plastic passing through the tape as it leaves
and enters the cassette.

The light source can fail - this is common on older VCRs where this
was an incandescent lamp but rare on modern VCRs which use a special IR
LED.  The failure of this light source can produce a number of symptoms:

* The VCR may simply shut down and refuse to do anything.  VCRs with
  incandescent lamps often were able to figure out that the light bulb was
  burnt out since it was drawing no current and then shut down or flash an
  error code.

* The VCR may go through the motions of playing a pre-recorded tape thinking
  that a tape is present because the sensors return signals indistinguishable
  from what it would see if a tape were present.  Eventually, it may give
  up and probably shut off power.

* The VCR may do strange things when you attempt to load a cassette since the
  microcontroller is receiving conflicting signals - the cassette is
  out but the sensors think otherwise.

If your VCR uses an incandescent lamp and it is not lit when power is on,
then the bulb is most likely burnt out.

If either sensor fails open, then similar symptoms may result.

If the sensor on the supply side fails shorted, then it will appear as
though the tape is at the end.  The VCR may refuse to play or FF or will
attempt to rewind as soon as a cassette is inserted.

If the sensor on the takeup side fails shorted, then it will appear as
though the tape is at the beginning.  The VCR may refuse to REW.

In both cases, sometimes you can trick the VCR into cooperating and
confirming that there is a sensor problem by pulling the connector
for the appropriate sensor once the cassette is loaded.

If you can get at the connectors, you can test the sensors by monitoring
the voltage on the outputs.

One test you might try if the VCR attempts to play an imaginary pre-recorded
tape as soon as power is turned on is to locate the microswitch for record
lockout protection - it will be located near the front (where the record
protect tab would be once the cassette is loaded).  Press this in while you
turn power on.  If the VCR now just initializes and displays cassette-in
without trying to play, then it really thinks there is a cassette in place
most likely due to a faulty sensor.

In some cases, there could be other problems like a faulty mode switch
or microcontroller producing symptoms that might be mistaken for faulty
start/end sensors.

  20.2) Start/end sensor testing

The start and end sensors are usually a combination of a light source
(IR LED) and IR photodiode.  With a little effort, these can be tested
for functionality.

* For an incandescent lamp (older VCRs), if it is not lit with VCR power
  on, it is most likely burnt out.  Test with an ohmmeter.

* For an IR emitter, an IR detector like the circuit provided elsewhere
  in this document or an IR detector card can be used to determine if
  the LED is operating.

You can also try powering the LED with a low voltage supply and 500 ohm or
so resistor using the IR detector to see if it works.  Disconnect it from
the circuitry first!  Try both polarities to be sure you got it right.

The sensors themselves can be tested by disconnecting them from the
circuitry and shining an IR source on them (a remote control or
incandescent bulb) while monitoring the resistance with a VOM or DMM.
Use the polarity which give the higher reading (reverse bias).  This
resistance should drop dramatically if they are functional.

If the start and end sensor assemblies are interchangeable, swapping them
may be instructive.  For example, this may shift the symptoms from play to
rewind or vice versa.

  20.3) Tape counters

There are two kinds of tape position counters: reference and real-time.

What I call a reference counter is what all VCRs used up until a few years
ago.  A sensor counts revolutions of the takeup reel (usually) either
directly or via a belt drive.  A mechanical or electronic counter displays
an arbitrary number which provides some idea of location.  Since the
rotation rate of the reel is not constant with respect to the actual
time of the tape, it is not possible to use this for anything other than
a reference.  In addition, the tape may slip a bit and be wound tighter
or looser depending on whether it was wound in play, FF, or REW.  Thus,
even the reference is not accurately repeatable.

Failures can be caused by a broken or weak belt for the mechanically
operated counter or defective circuitry for the electronic display.  A
failed sensor would most likely also cause the VCR to shut down and
unload the tape as this is what is used to confirm that the takeup reel
is rotating and that tape is not spilling into the bowels of the VCR.

Real-time counters - which really are a vast improvement - operate off
of the control track pulses from the control head.  Tape location is
measured in hours, minutes, and seconds though it is still relative
and must be reset at the beginning of the tape if an absolute location
is to be determined.

The only disadvantages of real-time counters are that:

* They do not operate with a new or bulk erased tape since there is no control
  track.  Thus, it is not possible to leave a specific length section of such
  a tape unrecorded by using the counter to space over it.  You must lay down
  a control track first by recording something - anything - for the time you
  want.  However, it is advisable that this be a valid video source so that
  the sync pulses occur with the proper timing.

* The tape must be in contact with the control head for all operations.  In
  principle, this results in more head (and tape) wear though I know of no
  cases of the A/C head stack requiring replacement because of this design.

Failure of the real-time counter on a VCR that otherwise works normally
is quite unlikely and is probably an electronic problem since the
control head must be functional for all record/play modes to work properly.
However, it is possible that a failure of a half loading arm to fully
extract the tape would result in problems in (non-search) FF or REW.

  20.4) Reel rotation sensors

Reel rotation is detected most often using optical sensors under the
reels though some older VCRs may use mechanical or optical interrupters
driven off of belts from the reel spindles.

* There will always be a takeup reel sensor - even on a VCR with a real-time
  counter.  It has two functions: to (1) confirm that the reel is rotating and
  that tape is not spilling into the bowels of the machine and (2) to operate
  the (non-real-time) tape counter.

  Failure of this sensor will cause the machine to shutdown almost immediately
  and will result in a stuck tape counter.

* Some VCRs will have a similar sensor on the supply reel.  The output
  from this sensor can be used to confirm proper rotation of both reels
  both during modes involving tape motion as well as during the tape load
  and unload operations.  Exactly when each is used will vary by design.

  If your VCR has identical sensors monitoring both reels, swapping the sensor
  assemblies may be instructive: the behavior will change if one is bad.  For
  example, a VCR that would shut down in a couple of seconds in play mode may
  continue to operate correctly but now have problems with rewind.

* Some fancier VCRs will display an estimate of tape remaining using
  the difference in rotation rates of the supply and takeup reels
  based on assumptions about tape thickness, hub size, and total length
  (which you may have to tell it).  

* Sometimes, reel rotation sensor problems are simply due to accumulated
  dirt on the reflective surfaces - clean them.  In other cases, replacement
  sensors will be needed.  While you are at it, replace both sides where
  appropriate - most of the cost to you is in your time, the cost of the
  sensors themselves is modest.

Note that on VCRs with real-time counters, the real-time display as well
as possibly the tape movement sensing operates off of the A/C head control
pulses.  Failure here could be due to dirt, a bad A/C head, tape path
alignment problems, or failure of a half loading arm to properly extract
the tape so that it contacts the A/C head.

  20.5) Reel rotation sensor testing

The counters on some VCRs are active at all times - rotate the appropriate
reel and the counter will change (count up or down depending on its default
mode - the direction of rotation probably will not matter).  If your VCR is
of this type, testing is particularly easy.  Slowly rotate the takeup (usually)
reel by hand.  The numbers should change several times - probably 4 - per
revolution.  There should be no missed counts and there should be no positions
where the counter free runs - the display increments or decrements on its own
very quickly.  Any of these could indicate a problem with the sensor or LED,
a buffer amplifier, bad connection, or the microcontroller or other IC that
actually drives the counter and display.

For electrical tests, first, locate the LED and photodiode.  You can tell
the difference by testing with a DMM on its diode test scale - the LED will
have the higher forward voltage drop.  Sometimes, the connections are even
marked.  What a concept!

Momentarily touch and remove a resistor (1K ohms or so should work) across
the sensor leads (while the VCR is in PLAY mode before it quits if needed).
This should make the counter change if the the LED is bad or the photodiode
is open.  Alternately, a remote control may be able to activate it providing
pulses that will look to the counter exactly like reel rotation.

If this has no effect, unsolder the sensor (or unplug the sensor assembly
from the main board if there is a connector) and try the resistor across
the terminals where it was connected.  If you now get a response, the
sensor was shorted (or the connection was bad).

If you do not get the counter to change in either case, there is a problem
with an intermediate buffer amplifier, the electronics on the main board, or
a bad connection leading to the main board.  You will need to obtain the
service manual or trace the circuit leading to where the sensor signal is

It is possible that the counter will only change when the microcomputer expects
the reel to be moving, so a test while in STOP mode may not be valid.

An alternative test is to use an ohmmeter across the photodiode on a high
ohms scale.  Use the polarity which gives the higher resistance and shine
a light on the sensor.  The resistance should drop dramatically with a bright
incandescent light (these put out a good amount of IR).  If it is infinite
in both directions, the photodiode is open.  If it is low in both directions,
it is shorted.  You may be able to make a measurement while the sensor is
still in circuit, though other components may mask the resistance change.
As noted, the IR sensor/LED combination is often a pluggable assembly.
Using my VOM on a photosensor, I read infinite ohms with no light and 200 ohms
with a bright light.  However, your mileage may vary.

If you have an oscilloscope, monitor the sensor output.  If it is a voltage
signal at this point (likely), then you should see it go high and low as you
rotate the reel or shine light on it.  With the reel rotation, the low and
high periods should be roughly equal.  There may be a buffer amplifier driven
by the sensor - check its output as well.  The signal there should be a
cleaned up version (low pass filtered and possibly inverted) of the sensor
output.  In all cases, the signal should be a DC value without noticeable
ripple or noise (block external light as fluorescent lamps in particular may
add a 120 Hz ripple to your detected signal).  Even at transitions between
low and high or high and low, the level should change smoothly.  You may
be able to trace the signal to its final destination, the microcontroller
or other large multilegged part, and monitor it there as well. 

Play a T120 tape recorded at EP speed near the end of the tape.  This will
result in the slowest takeup reel rotation.  Or, if your VCR has the counter
active in stop mode with the cassette out, rotate the takeup reel by hand
very slowly.

If the counter skips or 'free runs' at certain positions of the reel, there
may be a problem with the hysteresis circuit.  If this is external to the
microcontroller, a resistor may have opened or there may be some other easily
identified bad component.  If it is internal to the microcontroller - either
an actual circuit or firmware - then replacing the microcontroller may be
the best solution unless you want to add your own circuit - I have done this
to repair a Sears VCR with an erratic counter problem.  It is a simple 1 or 2
transistor circuit (depending on what external circuits are already present).

Monitor the sensor output when rewinding a T120 tape to the very end - this
will be the worst case test as the pulses will be at the highest rate.  There
should be no missing pulses and the high and low times should still be similar.
A bad sensor might result in unequal high and low times and dropped pulses
at high speed.

  20.6) Stan's tips on reel sensors

(From: Stan Cramer (stvcrm@Gramercy.ios.com)).

Try removing the take-up reel disk. Look on the bottom surface to see if 
there are a series of pie-shaped vanes - shiny, dark, shiny, dark, etc. If
the shiny vanes get misted with smoke or general grak, the symptom is the
same  as if the sensor itself is faulty. Use some Windex or some such mild 
cleaner on the vanes and test the machine again.

On some earlier machines, the take-reel disk might have a series of evenly 
spaced slots - blank,solid,blank,solid etc.-that interrupt the flow of IR 
light creating an electronic pulse stream.  If your machine has this type 
of motion sensor, you can try brushing or blowing out the dust that may 
have accumulated in the small recesses surrounding the IR emitter and 
receiver devices on the sensor assembly.

If these attempts don't do the trick, you probably have a faulty sensor.

Chapter 21) Motors and Rotors

  21.1) Types of motors in VCRs

There may be anywhere from 2 to 6 or more motors in your VCR.  Some
designs use a single motor to power all functions except the video
head drum.  Others have separate motors for each function.  Most
typical are 3 or 4 motors.  Motors perform the following functions:

1. Cassette loading (front loaders only).
2. Tape loading (position tape around video head drum, etc.).
3. Video head drum rotation (servo controlled).
4. Capstan rotation (servo controlled).
5. Takeup reel rotation (PLAY, REC, FF, CUE).
6. Supply reel rotation (REW, REV).

The video head drum (3) always has its own motor.  It is internal to
the lower cylinder or above the upper cylinder (except in the very
oldest VCRs) and directly drives the spinning upper cylinder.

Most consumer VCRs use a single motor for the capstan and the takeup
and supply reels.  Some also use this same motor for cassette and/or tape
loading.  Several possible types of small motors are typically used in VCRs:

1. Small brush-type permanent magnet (PM) DC motors similar to those found
   in small battery operated appliances, CD and tape players, and toys
   may be used for cassette loading and/or tape loading.

2. A similar but larger PM motor may provide power for the capstan and
   reel rotation and possibly multiple other functions (older VCRs). 

3. A single low profile or 'pancake' brushless DC motor may provide power
   for a direct drive capstan, reel rotation, and possibly multiple other

4. Brushless DC or 3 phase direct drive motors are usually used for the
   video head drum.  Some of the very earliest VCRs used a belt drive for
   the video head drum.

  21.2) Testing and repairing small motors

Aside from obvious mechanical problems and lubrication if needed, you usually
cannot do much to repair defective motors.  If you enjoy a challenge, it is
sometimes possible to disassemble, clean, and lubricate a motor to restore it
to good health.  However, without the circuit diagram, even knowing what the
proper voltages and signals should be on (2) or (3) type motors would prove

The following are some of the possible problems that can occur with the basic
permanent magnet motors:

* Open or shorted windings or windings shorted to case.

* Partial short caused by dirt/muck or carbon buildup on commutator.

* Burnt out armature due to defective driver, power supply, controller, or
  mechanical overload.

* Dry/worn bearings.

An open or shorted winding may result in a 'bad spot' - a position at which
the motor may get stuck.  Rotate the motor by hand a quarter turn and
try it again.  If it runs now either for a fraction of a turn or behaves
normally, then replacement will probably be needed since it will get stuck
at the same point at some point in the future.  Check it with an ohmmeter.
There should be a periodic variation in resistance as the rotor is turned
having several cycles per revolution determined by the number of commutator
segments used.  Any extremely low reading may indicate a shorted winding.
An unusually high reading may indicate an open winding or dirty commutator.
Cleaning may help a motor with an open or short or dead spot but most likely
it will need to be replaced.  Note that unlike a CD player which uses
some motors constantly, the small PM motors in VCRs are only used for loading
operations and are generally quite reliable unless damaged by other problems.

For more information on small PM motors, see the chapter: "Motors 101" in the
document: "Notes on the Troubleshooting and Repair of Small Household
Appliances and Power Tools".

  21.3) Capstan problems

Capstans are expensive especially if they are integral with the capstan motor,
but unless it is bent (very unlikely), or the bearings are totally shot, or it
is direct drive and the motor is bad, the capstan should not be a problem
as long as you **carefully** clean off all of the black tape oxide buildup
with alcohol and a lint free cloth or Q-tips.  Don't get impatient and
use anything sharp!  The black stuff will come off.  A fingernail may
help.  A dry bearing may need a drop or two of light oil (electric motor or
sewing machine oil).  Sometimes, there is a bearing cover washer that works
its way up and interferes with the tape movement.  Push it back down.

Some Sony VCRs have had problems with defective capstan motors resulting
in intermittent pausing or stopping of video playback when hot.  The entire
motor or just the bearing assembly needs to be replaced in this case.

  21.4) Some capstan motor information

From: whitmore@jila.colorado.edu (Mike Whitmore)

VCR capstan motors are servo-controlled to allow precise speed and phase
control. Typical signals are:

VCC  - power to chip/motor- probably 9-12V
FG - frequency generator output from motor to servo loop
CTL - control track pulse from Audio/Control head
F/R - forward/reverse (one high, one low)

There will probably be other connections for a variety of servo voltages,
braking, grounds, etc. - You may need to find service literature for this VCR
or the datasheet for the particular driver chip to get more info.  Data will
also tell if motor is 3-phase.  This is common for many capstan motors and
would require this IC to run it. 

Chapter 22) Items of Interest

  22.1) Why is a tracking control needed

In order for the video to be read off of the tape properly, the spinning
video heads must be centered on the very narrow diagonal tracks.  The
width of these tracks is as small as .019 mm.  The actual reference point
is not on the video heads but the A/C head - several inches away.  The
control pulses put down during record are used to phase lock the capstan
to the spinning video heads.  The distance between the control head and the
video heads determines whether the required centering will be achieved.  In
the ideal world, the distance would be identical for all VHS VCRs - that is
the goal.  It is part of the VHS specification.

However, whether from wear and tear, or even if the technician doing the
setup in the VCR factory had an off day, this distance may not be quite
identical on the VCR that the tape was recorded on and the machine being used
for playback.  Therefore, a way is needed to adjust the effective distance.
A mechanical control would be possible but not very elegant.  Therefore, an
electronic tracking control is provided.  This basically allows adjustment
of the time delay or phase of the control pulses from the control head during
playback.  Record tracking is fixed.  Actually, there may be as many
as three tracking controls: (1) the user tracking knob or buttons, (2) an
internal master tracking adjustment, and in fancier models, (3) an
autotracking servo system.  (Note: tracking is always automatically reset
to the default when a cassette is inserted.)

  22.2) VCRs with 2, 4, 6 or more heads - what is the difference?

A single pair (2) of heads is needed for basic record and playback.  With
more heads, various aspects of these functions can be optimized to improve
picture quality - usually for the special effects like CUE and REV.  For
example, a 4 heads are usually needed to produce decent quality playback in
CUE and REV modes for SP recorded tapes.

Another set of heads is required for HiFi audio.

The only possible difference for record or at normal playback speeds is in
picture quality since with 4 or more heads, head widths/gaps can be better
optimized for each speed.  For example, a wide track width can be used at SP
speed and a narrower one for EP speed.  Which VCRs do this, I have no idea.
In fact, such differences might only be visible to the average viewer in an
A/B comparison under controlled conditions.

The stability of the video playback has nothing to do with the number of
heads.  A jumping picture during playback is due to a servo system problem.
With problems of this type particularly on a new VCR commercially recorded or
rental tapes, it is more likely that the VCR is having problems with some kind
of copy protection scheme.

  22.3) Which combination of heads are used for what modes?

The quick answer is: "almost any combination which includes at least one head
of each azimuth angle on each side of the video drum" :-).

For a 4 head VCR, this may even include all 4 at once.  In this case, signals
from both heads of the pair on each side of the drum are monitored and the one
with the greatest amplitude is sent to the video circuitry.  This provides
clearer special effects for SP recorded tapes in particular - CUE, REV, SLOW,
and PAUSE - where the video heads may be crossing tracks of both azimuth
angles.  Such an approach may be called a 'double azimuth' design by the

For record and play modes, an opposing pair will be used but which pair will
depend on speed - EP, LP, SP.

Thus, almost anything is possible and it gets to be confusing very quickly!
Don't count on finding this information in the service manual either.

  22.4) More on 6 head VCRs

(From: Paul Weber (webpa@aol.com)).

A six head (VHS) vcr has 4 video heads and 2 audio heads on its rotating
upper cylinder.  The 2 audio heads record VHS Hi-Fi.  They are about 1/3 the
width of the most narrow video heads (about 6 microns).  A four head
machine lacks the audio heads and is therefore incapable of playing or
recording Hi-Fi.  There are also 2 head machines on the market.  They use
the same pair of video  heads for all tape speeds.  4 and 6 head machines
use the 28 micron  wide heads for SP (highest speed), and the 19 micron
heads for LP (middle) and EP or SLP (slowest) speed.  Some machines have a
7th head: the flying erase head.  It is about 40 microns wide, and when
activated, can erase the recorded tracks of both video fields that make up
a frame.  Most vcrs use all 4 video heads to smooth out the picture when
scanning in fast forward and rewind.  This is why 2 head machines have
much more noise in the picture when scanning. 

Machines that have a switch to turn off the 19 micron heads do so in an
attempt to improve the playback of tapes made on old 2-speed (SP and LP)
machines.  These machine had video heads that were something like 22
microns wide, and scanning them the narrower heads of a modern machine
sometimes produces unacceptable results.

Compatibility problems between machines are a fact of life because of
mechanical differences.  Recording at the highest possible speed minimizes
problems, but hi-fi audio tracking problems can happen even then because
the tracks are so narrow.  If you have video tracking problems between 4
and 6 head machines on tapes recorded at the highest speed, it is because
of mechanical differences, not because of the number of heads on the
machine; the number of video heads is identical.  The differences are in
the alignment of the audio/control head that controls synchronization of
the video upper cylinder, and in alignment of the video heads themselves.

  22.5) Choice of SVHS or high quality 4 (or greater) head VHS VCR

SVHS won't be better than a good 4 head (+2 HiFi) unless:

1. You use high quality (read: expensive) SVHS type tapes (usually, there may
   be exceptions and some people claim that premium VHS tapes will work for
   SVHS recordings if the proper hole is drilled in the case but don't count
   on it).

2. The recordings are actually made in SVHS mode.

3. They are played back on another SVHS deck.

Since few people have SVHS decks, there is probably little benefit if the
objective to to make high quality recordings to share.

I would probably go with a good 6 head (including 2 HiFi) since it will be
compatible with everyone.

However, just saying it has 4 or 6 or 25 heads doesn't mean it will produce
a high quality result - there is a lot of variation in video and to some
extent HiFi audio quality.

  22.6) About VISS and VASS

I assume VISS stands for "VHS Index Search System" or something similar.  In
any case, VISS and VASS provide the means to mark the start (usually of a
video segment so that it can be accessed quickly later on.

"How standard is this system?  My Goldstar VCR has VISS and now I see
 reference to an LXI brand with the same system.  I've heard of other VCRs
 with functionally similar features, but never had the opportunity to try
 exchanging tapes.  Do they use the same marks?  When my Goldstar finally
 bites the bullet (beyond my powers to resuscitate it), will the collection
 of indexed tapes I've built up be useless, or will another VCR with indexing
 features find the marks that Goldstar put on them?"

(From: Ed Ellers (kd4awq@iname.com)).

VISS is a real standard, issued by JVC in 1986.  There is also a VASS -- VHS
Address Search System -- using the same techniques, but it was taken off the
market in 1988 after a patent infringement suit by a German company; JVC
settled that case, but VASS never came back (at least not in North America);
JVC later developed a more sophisticated system called CTL Coding, but it's
not used on consumer VCRs over here either.  VASS records four-digit codes
instead of a single index mark; CTL coding records an actual time code on
the control track, and also provides for VISS and VASS use.

Incidentally, VISS and VASS work by altering the duty cycle of the 29.97 Hz
square wave recorded on the control track; the servos still work on the
average phase of the signal, but the changes in duty cycle are decoded into
a slow bit stream.  Before VISS was developed a number of VHS VCRs had a
different indexing system that recorded a low-frequency signal across the
entire tape, using a special head on an arm that contacted the tape while it
was rewound into the cassette; these index codes could only be placed at the
beginning of a recording and couldn't (then) be read except during rewind
and fast forward modes.  Theoretically a modern VCR could be made to read
this signal using the control head, but this would require a special circuit
to be added; I don't know of any VISS-capable decks that can do this, and
given the small number of recordings likely to still exist with the old
index signal it wouldn't seem to be worth the trouble.

  22.7) How does the "commercial skip" feature work?

(From: Matt Kruckeberg (sackmans@ndak.net)).

My understanding of commercial advance is that the program is monitored
during recording for fade to black and silent audio between programming and
commercials and between commercials.  The microprocessor stores these events
in memory until the recording session is over.  It then analyzes these
events to determine whether an event was part of a group of commercials or
just a dark silent passage of programming.  The tape is then rewound and the
beginning and end of the commercial groups are marked with special start and
end signals recorded on the control track, similar to index search marks.
During playback with the feature activated the unit will automatically
forward search when a start signal is detected and resume normal play when
an end signal is detected.

  22.8) Old clunkers and the march of technology

It always amuses me to listen to comments about how anything older than
6 months (or 30 minutes) should be tossed in favor of some newer, more cheaply
made piece of crap.  Yes, convenience features and HiFi audio have made newer
VCRs a lot nicer in many ways.  But for time shifting and the kids, that
old clunker will do just fine, thank you. Some of the older VCRs will just
keep going and going and going and going with a cleaning and a few rubber
parts from time-to-time.

On the other hand, I had to repair my high-end (for 1990) moderately used
Mitsubishi VCR because a 10 cent plastic part broke (their cost, my
cost - $10) - clearly an exercise in design-to-fail engineering.  For
about .5 cents more, it could have been built never to fail.  The
replacement part was identical to the original, so I give it about 4 years.

  22.9) Comments on quality of consumer electronic equipment construction

(From: Stan Cramer (stvcrm@Gramercy.ios.com)).

In recent years, the rapid decline in the quality of construction of VCR's
has been  widely chronicled here and in other forums.  Through all of this
criticism, I have staunchly defended JVC as the last bastion of construction
integrity! Alas - no more!

Tonight, I had the occasion to open up a JVC HR-J620U and was shocked at what
I saw!  I am sad to announce that even the once venerable JVC has sold out to
the concept of making machines really light and really, really crummy! This
new JVC transport is the epitome of designing "throw away" machines - even
worse than the transports offered by Matsushita or Funai! Glaringly absent
is the modular power supply. You may no longer fall back on the last resort -
replace the power supply!  Folks, this is just an unmitigated piece of
unadultered crap!

As both a consumer and a VCR technician, I am truly offended by the shoddy
construction of all new VCR transports and, in particular, by the caving in
of JVC to make machines geared to the lowest common denominator. All of us
should be outraged!

(From: Greg Monbourquette (gregm@globalserve.net)).

I too am concerned about the lack of care that the engineers who put these
things together take when considering the amount disassembly required in order
to only clean a lousy belt.  (I'm talking mostly about the RCA/GE models with
a plastic plate covering the bottom of the VCR) And yes there was once a time
when you could buy/sell a vcr and KNOW that the customer won't have any
problems for at least 5 years . I tell my customers all the time when they
finally decide that the 15 year old TV that finally died ( for the first time)
will be replaced by a new one, " don't expect 15 years out of any TV you buy
today. Oh well we've (I've) ranted long enough.  I now know my feelings
aren't only mine. 

  22.10) Can I add an S-Video input to my VCR?

Possibly, but why bother?  You will most likely be limited by the VCR's
circuitry anyhow.

All S-Video means is (1) a special connector and (2) separate luminance (Y)
and chrominance (C) rather than composite video.

In a VCR, you will need to bypass the input circuitry and get to the place
where Y and C are separate.  This may or may not be possible depending
on its design.

It is probably not worth it as you will likely not gain much in picture
quality but if you really are determined, a schematic will be essential.

If all you want to do is allow for an S-video input, there are single
chips which will combine the Y and C into a normal composite video

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Written by Samuel M. Goldwasser. | [mailto]. The most recent version is available on the WWW server http://www.repairfaq.org/ [Copyright] [Disclaimer]