Download high voltage probe

Using High Voltage Meter or Probe to
Repair Equipment Problems Fast
A high-voltage meter or probe is the tool needed to test high voltage circuit such as
the picture tube of a Monitor and Television. Besides measuring the anode voltage of
a cathode ray tube, it can also be used to check the focus voltage of the flyback
transformer. A normal maximum voltage a high voltage meter can check is about 30
to 45 kilo volts.
The ranges is marked in front of the voltmeter panel. Majority of our multimeter
maximum voltage range is from 600 volt ac/dc to 1000 volt. Due to the low range of
our multimeter whether an analog or digital meter is, it can’t test any voltages that is
higher than the maximum voltage or else your meter may becomes faulty!
There are some types of
multimeter where you could
connect an external probe which
is specifically designed to
measure the high voltage of
equipment. . In order to take the
measurement, simply connect the
high voltage meter ground cable
to the chassis or cold ground of
the Television or Computer
Monitor. Then, slip the probe tip
underneath the flyback
transformer anode cap. The high
voltage reading can be read from
the meter’s panel.
I don’t always use high voltage meter to troubleshoot Monitor. I will only use it when
there is a symptom of no high voltage, high voltage shutdown, focus out problem,
small and big horizontal size display. By using only the high voltage probe I can tell
at which section of a Monitor is faulty.
With this meter, it really saves me a lot of my precious time because I don’t have to
guess anymore which portion of a Monitor is giving problem. In Monitor
troubleshooting, one of the most frustrated complaint is the Monitor shut down when
switch on. You do not know where to begin and if you are a beginner, you may take
lots of time to troubleshoot this type of problem. That’s why understanding how an
equipment work is very important before you start to repair it.
Using this high voltage meter you could clearly see if the Monitor is shutting down
before it reached 24 kilovolt or after 24kv. If the Monitor shutdown when the voltage
reached 15 kilovolt then you have to check the horizontal oscillator circuit because
the horizontal drive pulse was cut off when it reached 15 kilovolt.
All my concentration was upon this
horizontal oscillator circuit which
includes the surrounding components.
After troubleshoot for sometime I
managed to locate a faulty resistor
nearby the horizontal oscillator ic that
turned into high ohms.
Assuming if the high voltage shutdown
when it reached the 28-30 kilovolt scale
then you can suspect the B+ voltage
could be too high, internal flyback
transformers capacitor value has
became too low or open circuit, safety
capacitor (hold down capacitor) value
run or open and suspect also the
flyback transformer feedback circuit.
Many repair technicians and engineers
confused about the section that they going to check if there is a complaint of small
horizontal width. A small horizontal width can be caused by two sections in a Monitor
i.e.; the B+ and horizontal size circuit.
If the picture horizontal size is small and measured only 14-18 kilo volt with the high
voltage meter then suspect the problem in the B+ boost circuit. It could be a defective
B+ fet, dry joints, a missing gate pulse to B+ fet, an open filter capacitor, a faulty
current sense resistor or even a partially shorted B+ coil. A small horizontal size also
can be caused by a faulty horizontal size and s-correction circuit (circuit that controls
the resolution width). Even though there are problems in the horizontal size circuit,
the high voltage will still maintain at 24 kilo volt. Thus, by using the high voltage
meter I could easily know which section is having problem and this will make my
repair job a lot faster.
Testing the focus voltage of a flyback transformer can also be done with the help of
high voltage meter. With the help of this probe, knowing the focus voltage will easily
tell if the focus out problems was due to a faulty picture tube, flyback transformer or
even the crt socket. Focus voltage is about 5 to 10 kilo volts. Warning! Do not use
your multimeter to measure it. Suspect a defective flyback transformer if the voltage
that you checked rising after the Monitor switch is ‘on’ for sometimes.
For a good flyback transformer, the focus voltage should maintain the same even
though the Monitor has switched ‘on’ for a very long time. Currently I’m using the
Kaise-SK9000 high voltage meter probe that is made in Japan. I’ve already used it for
more than eight years and I can say that it is a very good meter and reliable too. Invest
one if you are in the Monitor or Television serving line and see how this high voltage
meter can cut down your troubleshooting time.