Ryan Atong from Philippines send in a few questions on CRT television repair course
Thank you for the books.....I’ve started reading it already
and got some few questions ...I’m gathering it. .so I just email it to you one
time…
Thank you Teacher
Okay, no problem Ryan
Hi Humphrey, I have few questions upon reading the book
1. The snubber capacitor (is it snubber caps by the way)
which is
rated 400v...
This is not snubber Ryan, it is called S-correction
capacitor, all snubbers are rated between 1200volts-2000volts.
Is there any effect
on the HOT in case they got faulty?
S-capacitor fault? NO effect on HOT, but if S-capacitor open
there will be a single vertical line on the screen.
Sometimes the television may go into shutdown for safety
purposes, it is a serious problem and therefore don’t put the television on
with this kind of problem because it can cause more damages.
Also if S-capacitor shorts it will load down the horizontal
supply and this can cause the television not to start.
Read page 66 and 67 for more info on this.
2. How can I measure the voltage of the new replace snubber
capacitor? Can I just put 2 probes on the caps? It AC right. Because snubber
caps has no polarity?
As you have noticed from your book, Snubbers have one leg on the
middle leg (collector) of the H.O.T and the other leg on the emitter (GND),
therefore if you test the Voltage at the middle leg of the HOT you are actually
sitting on the snubber leg, if the horizontal circuit is not working then you
will get the B+ voltage at that point.
The B+ is Direct current(Dc) and therefore your meter should
be in DC range, as you know capacitor block DC and pass AC and therefore the
snubber capacitor has no effect on this DC voltage, now if the horizontal
output is working( this you can tell by watching the screen) as in if there is
something on the screen it is assumed that the HOT/snubber/flyback is working
and should not be considered for any troubleshooting…in fact it is not allowed
to test the voltage at the collector of the HOT if there is something on the
screen, you can even destroy the meter instantly
3. If I change the snubbers and the driver transistor and
still the
HOT become shorted I have to change already the FBT...but do
i still
change again the snubbers and the transistor or just FBT
alone.
Not a must but it is good to confirm if they are okay or not
4. How do I know the snubber is short or open?
For short just use any meter set to low ohms, if you get any
reading even at the highest range then it is considered the snubber is shorted.
If open you cannot tell with a meter because usually a good snubber capacitor
test open using any meter. Here the best is substitution. But again as I said
if the HOT tested okay, that is good enough test that the snubber is also
okay.(NB if the snubber goes it will go with HOT)
Cause i went to the market to buy these capacitors and i
broguth my FBT for testing
also...as for my surprise, the FBT is breaking down when
loaded.so i conclude that the reason why
the HOT get shorted is because of the FBT.
Could be, though this is not clear to me.
5. How can I test the degaussing coil? Is it continuity,
cause in your
book I see 2 reading, 1 is 13.3 and the other is 0.12. by
the way I am using auto range digital multi-meter
You can use your meter set to low ohm, as you have rightly
put it expect low ohms, the example I used in my book is 13.3 ohms and the
other was 12 ohms but not 0.12 ohms, kindly consider 12 ohms and 13 ohms.
If you get infinite reading then the degaussing coil is
considered open and therefore faulty..
Finally the best test for degaussing coils is fly back tester
Thank you Humphrey..
Ryan
