Vertical Deflection Problems

23.
8) Vertical squashed
This is a vertical deflection problem - possibly a bad capacitor, bad

connection, flyback/pumpup diode, or other component. None of these
should
be very expensive (in a relative sort of way).
If the symptoms change - particularly if they become less severe - as

the set
warms up, a dried up electrolytic capacitor is most likely. If they get
worse, it could be a bad semiconductor. Freeze spray or a heat gun may
be
useful in identifying the defective component.
It is often easiest to substitute a good capacitor for each electrolytic

in
the vertical output circuit. Look for bad connections (particularly to
the
deflection yoke), then consider replacing the vertical output IC or
transistor(s).
A defective deflection yoke is also possible or in rare cases, a bad

yoke
damping resistor (e.g., 500 ohms, may be mounted on the yoke assembly
itself).
The following are NOT possible: CRT, flyback, tuner (except for the
famous
RCA/GE/Proscan or Sony models where the controller is at fault - see the
sections on these specific brands). I am just trying to think of really
expensive parts that cannot possibly be at fault :-).
Note that some movies or laser karaoke discs are recorded in 'letterbox'
format which at first glance looks like a squashed vertical problem.
However,
the picture aspect ratio will be correct and turning up the brightness
will
reveal a perfectly normal raster above and below the picture.
23.11) Single Horizontal Line
CAUTION: To prevent damage to the CRT phosphors, immediately turn down

the
brightness so the line is just barely visible. If the user controls do
not
have enough range, you will have to locate and adjust the master
brightness or
screen/G2 pots.
A single horizontal line means that you have lost vertical deflection.
High voltage is most likely fine since there is something on the screen.
This could be due to:
1. Dirty service switch contacts. There is often a small switch on the

located inside on the main board or perhaps accessible from the back.
This
is used during setup to set the color background levels. When
flipped
to the 'service' position, it kills vertical deflection and video to
the
CRT. If the switch somehow changed position or got dirty or corroded
contacts, you will have this symptom. Flip the switch back and forth
a couple of times. If there is some change, then replace, clean,
resolder,
or even bypass it as appropriate.
2. Bad connection to deflection yoke or other parts in vertical output

circuit. Bad connections are common in TVs and monitors. Check
around the pins of large components like transformers, power
transistors
and resistors, or connectors for hairline cracks in the solder.
Reseat
internal connectors. Check particularly around the connector to the
deflection yoke on the CRT.
3. Bad vertical deflection IC or transistor. You will probably need

the service manual for this and the following. However, if the
vertical deflection is done with an IC, the ECG Semiconductor
Master Substitution guide may have its pinout which may be enough to
test it with a scope.
4. Other bad parts in vertical deflection circuit though there are not
that many parts that would kill the deflection entirely.
5. Loss of power to vertical deflection circuits. Check for blown

fusable resistors/fuses and bad connections.
6. Loss of vertical oscillator or vertical drive signals.
The most likely possibilities are in the deflection output stage or

bad connections to the yoke.
23.17) Vertical foldover
The picture is squashed vertically and a part of it may be flipped over

and
distorted.
This usually indicates a fault in the vertical output circuit. If it
uses
an IC for this, then the chip could be bad. It could also be a bad
capacitor
or other component in this circuit. It is probably caused by a fault in
the flyback portion of the vertical deflection circuit - a charge pump
that
generates a high voltage spike to return the beam to the top of the
screen.
Test components in the vertical output stage or substitute for good

ones.
23.18) Comments on vertical problems
(From: Bert Christensen (bert.christensen@rose.com)).
As a general rule, vertical faults can be divided into two types: ones
that
cause geometric distortion (a circle will not be round) and those that
simply
black out a portion of the screen. The former are faults in the vertical
oscillator, drive, or output stages. The latter are blanking faults.
Blanking
faults are almost always caused by electrolytic capacitors changing
value and
thereby changing the timing of the pulses which blank the screen during
vertical retrace. In other words, the pulses are turning off the video
signals
at the wrong time.
The most common true vertical fault is geometric distortion and a

foldover of
white lines at the top of the screen. This is almost always caused by
the
electrolytic capacitor on or near the collector of the vertical output
transistor or part of the IC which has the supply voltage (B+) on it. In
the
old tube days, the general rule was that bottom distortion was in the
cathode
of the output tube and distortion at the top was caused by a fault in
the
drive circuit.
21.3) Focus adjustment

On a decent TV, you should be able to make out the individual scanning
lines. If they are fuzzy, especially in bright areas, then focus may
need
to be adjusted.
The focus pot is usually located on the flyback transformer or on an

auxiliary panel nearby. Where there are two adjustment knobs on the
flyback
transformer, the top one is generally for focus and the bottom one is
for G2.
The focus wire usually comes from the flyback or

the general area or from a terminal on a voltage the multiplier module
(if used). It is usually a wire by itself going to the little board
on the neck of the CRT.
Let the set warm up for at least half an hour. Display a good quality
signal. Turn the user color control all the way down and the brightness
and contrast controls all the way up. This will be the worst case.
Adjust
the focus control for best overall sharpness - you may not be able to
get it
perfect everywhere - center as well as corners. If best focus is at one
end of the focus pot's range and still not good enough, there may be a
problem in the focus divider, focus pot, or some related component.
21.4) Adjustment of the internal SCREEN and color

controls
The screen should be adjusted with a white pattern (snow from the tuner
should do or turn the user COLOR control all the way down to get a
black and white picture). Put the set in Service mode (horizontal line)
if it has such a switch in the back or inside. If not, just use
the raster in a darkened room. Adjust screen for a dim white
line (raster). If the line is not white at its dimmest point, you will
need to adjust the drive and cutoff controls for R, G, & B.
Alternatively, you can use the following procedure:
Turn R, G, and B screen (or background) controls down. Now turn color
control fully counterclockwise -- off. Now turn up red screen until the
screen just shows a red hue. Now turn red gun down until red tint just
goes
away. Now do the same with the green and blue screen controls. Now
adjust the
two DRIVE controls for the best black and white picture. That`s all
there is
to it. I don`t like to work with just a thin "SETUP" line. Cartoons seem
to
be the best thing to have on while doing the above procedure. You can
also use just plain snow (no program) if you prefer. If you can obtain a
good b@w pic. when you`re done, the tube is good and the set if most
likely functioning properly. Be patient and go slow while watching the
large mirror that you are using during this procedure. (LEE)

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23.

This is a vertical deflection problem - possibly a bad capacitor, bad

If the symptoms change - particularly if they become less severe - as

It is often easiest to substitute a good capacitor for each electrolytic

A defective deflection yoke is also possible or in rare cases, a bad

23.11) Single Horizontal Line

CAUTION: To prevent damage to the CRT phosphors, immediately turn down

This could be due to:

1. Dirty service switch contacts. There is often a small switch on the

2. Bad connection to deflection yoke or other parts in vertical output

3. Bad vertical deflection IC or transistor. You will probably need

5. Loss of power to vertical deflection circuits. Check for blown

6. Loss of vertical oscillator or vertical drive signals.

The most likely possibilities are in the deflection output stage or

23.17) Vertical foldover

The picture is squashed vertically and a part of it may be flipped over

Test components in the vertical output stage or substitute for good

23.18) Comments on vertical problems

(From: Bert Christensen (bert.christensen@rose.com)).

The most common true vertical fault is geometric distortion and a

21.3) Focus adjustment

The focus pot is usually located on the flyback transformer or on an

The focus wire usually comes from the flyback or

21.4) Adjustment of the internal SCREEN and color

Alternatively, you can use the following procedure:

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