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Hello, dear soldering enthusiasts!
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Today I will tell you why you need to...
start repairing the TV. And start it
it is necessary to carefully study the principles
nal scheme, well at least it does for me
taught, although I would put it first
rough determination of the malfunction, and
otherwise why do you need this circuit? Towards
to the best of my ability, the TV is fine: well
the image is simply perfect, synchronized
tion does not break down, there is no false capture of co-
middle channels... But there is no sound. Here
Now you will need a diagram. Per-
First thing to do is check if power is being supplied
at ULF and UPChZ, then check with an ohmmeter
speaker is broken. If everything is in order, then-
yes, according to the diagram, find the ULF input, take it
by the tip of a small screwdriver and touch-
go to this input. In dynamics there should be
a characteristic background appears. The most advanced
those interested can take their multimeter, turned on
use it to generate a signal and send it
this same signal to the ULF input. If sig-
cash goes through, then you have toyou have to tinker
with this box. And if you don’t hear anything -
but then pick up the same tester
and check the block modes. If there are any
will differ, then it is necessary to find out
thread, why they are different and the problem
eliminate. Let's consider what can be said
swearing in ULF.
As a rule, a condenser is placed at the input of the ULF -
torus to remove the constant component
signal. If this capacitor breaks, then
the amplifier either will not work or will
kids fart so much that you just feel sick
no. It is logical to assume that if in con-
the condenser will break or leak
electrolyte, then you won’t hear anything either -
those Next, the resistor may burn out by installing
applying bias at the base of the transistor. B
In this case, the modes will differ from
norms. Breakdown of transitions is also possible
transistor or their break. This is being verified
using an ohmmeter. If the ULF is assembled according to
transformer circuit, and the box itself is enough
definitely old, then check the transform-
torus If the ULF contains field-effect transistors
ry, and a considerable layer has accumulated on the board
dust, then check them at the same time. And what if
The ULF is assembled like all normal people on
chip K17ChUN7 or similar, then either
the capacitors were covered there, or the
microcircuit. The microcircuit breaks quite
often. Well, if the whole board is burned out, then
don’t worry and replace the ULF completely with
anyanother, for example, from an imported mag-
nitophone. Just put the speaker there
at 30 watts and check the reliability of the circuit
demagnetization of the kinescope, otherwise with such and such
it will be quickly magnetized by the speaker.
Well, in general, you have adjusted the ULF for the television
sound appeared. And here is an image of
fell. Then first of all check the presence
What is the voltage on the second anode of the kinescope.
This is done as follows: rear
Touch the screen with the side of your palm.
If the hairs are attracted and you feel
characteristic tingling, which means lowercase
the scanner is working fine, the kinescope is just locked
some kind of signal. But it’s definitely because
you know that you don't have to buy a lamp
for the output stage of the BSR, which costs
about a hundred. If the screen has a bright vertical
cal or horizontal stripe, then not
either lowercase or frame is correct
scan, look in the corresponding blocks.
If the general synchronization is disturbed, then
Check the modes of the K17CHHA11 chip. If
they are different, then you can safely change it
No, it crashes often. By the way, this mic-
When the circuit malfunctions, it disrupts the re-
control unit presses. If the image
has the shape of a trapezoid, this indicates
break in the OS windings or its contacts
connector. And here's another joke: if...
change the phasing of one (I don’t remember which)
TVK windings, then the image will be re-
reversed. Well, in general, you don’t haveimage
marriage. Then check the video gain modes
tel, as well as UPCHI and VD. If violated
line or frame synchronization, then
crawl around the corresponding task
general sawtooth voltage generator.
Check the lamp modes, paying attention to
leaked capacitors and burnt resistors
tori. By the way, if the lamp comes to ruin,
for example, in case of loss of emissions or inter-
electrode short circuit, then the modes are violated -
and the resistors around it burn. If you
the lamp has shorted the cathode with the heater, then
voltage on the cathode and heater
they sound the same. If there is on the screen
raster, but no image, then pick it up
screwdriver, grab the tip and check
all cascades of the UPCH, starting directly from
places where the inverter goes from the PTC. If all cascades
are working properly, then disassemble the PTC and replace it
There is a burnt resistor on it. By the way, the lamps in
Always install new PTCs!
Now let's talk about the common fo-
bii of some fans of soldering, expressing -
I am in an incomprehensible fear of losing the setting
TV blocks. I hasten to reassure you:
if absolutely all potentiometers and re-
knock down the replacement resistors, then at least half-
in an hour you will get everything back to normal and it will work out
even better than it was. That's just me
I don’t advise you to twist the circuits in the UPCHZ and
UPCH. Without oscilloscope and frequency meter
will bring the frequencies back to normalnot easy.
And so - feel free to twist any adjustments -
ki, because, in fact, that’s what they are for
appointed. Take my word for it - you are without
Work will bring everything back to normal.
And now I will tell you how to check
lineman on a tube TV. But if
there is voltage on the second anode, you can
don't do this. Take a piece of insulated
bathroom wire and wind it somewhere
be in the free space of the ferrite ser-
TVS dechnik. Make four to five turns and
measure alternating voltage. If there
at least 5 volts, then everything is in order with the fuel assembly.
If there is no voltage, then touch
use a screwdriver (just don’t touch the hot
lo!) to the anodes of the output stage lamps
line scan. If the cascade works -
et, then between the electrodes and the screwdriver
a spark discharge occurs. Availability of the latest
th means the BSR is working properly. If
the vertical size of the image is small and
if it doesn’t help, then change TVC to for-
known to be serviceable.
Well, what if the TV has nothing at all?
works, then start with the power supply. Pro-
check the fuses, then the network windings
transformer, diode bridge, filter
rubbing capacitors and soldering quality.
If the voltage at the KPEHSA output is from -
is present, but at the entrance it is, then boldly
You can change the microcircuit. Further, if
the bilitron in the power supply breaks through, then the output voltage
dressing up becomes4 times less, and at
Some blocks somehow manage to do this
work. In a word, if the weekend is
charging power supply when the load is off differs
are too far from the norm, remove this power supply - that's it
exactly in it. It happens that the brightness of the image
niya is too small or too large -
check if there is no voltage
-250V.
As you can see, there is nothing complicated about this.
The main thing is don’t be afraid to touch anything if
you have an insulated screwdriver. The main thing is
to understand which block is responsible for what:
PTK - adjustment to frequency and selection
intermediate frequencies of image and sound.
UPCHI and UPCHZ - strengthening of intermediate hours
that of image and sound respectively.
(I just want to say - highlighting colors -
out subcarriers).
ULF - amplification of the AF signal.
VD - this is a video detector locatedbetween
UPCHI and VU.
VU - amplifies the video signal to the desired level
amplitudes. Here you can adjust
video signal range.
BSR - the master oscillator is located here
line scan and its terminal station
stump. A high voltage is immediately formed
tion for the second anode.
BKR is also a generator and final stage
stump.
BP - mains voltage conversion
into feeders, their stabilization and filtration.
In the most advanced TVs everything
made simpler - there are synchroprocessors
ry, karaoke processor, TV processor
text, processor in the operating control unit
melts on the OSD too, the IC2 bus is damaged - when
Having an oscilloscope is no problem.
Well, that's all for today.Next time
I'll tell you about something in more detail.
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