In data Sun, 18 Jun 2006 05:41:26 +0200, ha scritto:
Approx a month ago, when you would turn on the TV each day for the
first time, the top of the screen would be shrunk down a few inches.
As TV warmed up, the screen would return to normal. Color and clarity
of picture has been excellent throughout.
You have a vertical problem.
The other day, turned it on, just get a line thru the middle of the
tube. So, whatever was going bad, has definitely gone bad. I do not
have TV repair experience, but I have experience repairing other
high-voltage items, such as many Tube Guitar Amps, antique radios,
PC's, and even rebuilt a Video Game monitor once (installed a capacitor
kit). So I am familiar with the voltages involved.
Hantarex ?
I talked with a friend of mine who repairs TV (lives several hours away
from me...), and while he is hesitate to tell me a lot (he never tells
the secrets of the trade, so to speak...), he said that this a typical
problem with Mitsubishi TVs, and that the problem is probably in the
Vertical output circuit, then said 'maybe 5 capacitors, probably a
chip, and maybe a fuse'.
Here are some photos of the boards inside the set:
(mainboard)
http://mysite.verizon.net/cowman136/tv1.jpg
(closeup of area that may be the problem...)
http://mysite.verizon.net/cowman136/tv2.jpg
(power supply board)
http://mysite.verizon.net/cowman136/tv3.jpg
You guys can tell me whether my friends general advice is accurate or
not. For starters, I have proceeded assuming his advice was good, and
did some searches to try to narrow down what I am looking for.
Doing some Google searches based upon part numbers on the transistors
that I see on the mainboard (picture "tv2.jpg" above) , I found that
TA8427K is apparently my Vertical Deflector chip, that C2073 is
apparently my Vertical Output chip. In this circuit, I see the
following components (and checked them in-circuit, where noted:
- fuse (checks good)
- 15K ohm 3 watt resis. - checks good, approx 14K ohms in circuit
- 4700uF at 10V cap - did not test
- 2.7 ohm resistor - good
- 2700 ohm resis - good
- red capacitor approx 1 inch size with numbers (2A : 335K S) - value
unknown, not tested
- resistor with bands of "yellow - purple - gold - gold" - tests approx
4 ohms.
This resistor was good ! (yellow-purple-gold = 4,7 ohm)
Changing components without measures isn't a good idea.
Start from changing all electrolytic caps in that zone, then
My photo tv1.jpg above highlights this area of the board. I do not see
any visibly burned components or exploded/leaking caps.
Assistance is MUCH appreciated. I really need to fix this myself, as
cash is very tight. I do not mind installing a few "extra" parts,
shotgun approach is fine. Also, advice as to where is best to buy the
parts (the IC's, as I probably have the caps & resistors) will be
appreciated. THANKS.
BJ
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Inty.Evolution
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