Re: Viewsonic E653 Monitor. Squashed picture II

Arfa Daily wrote:
hi

[quoted text clipped - 43 lines]

thanx

Seems to me that the advice being given on that forum, whilst not
definitive, is never-the-less exactly right. I would suggest that the first
thing to do would be to check the pincushion amp, and its drive. Also, if
any caps *have* leaked (and you are not confusing the glue that's often
found around their bases, with leaked electrolyte), then they need to be
replaced. Just because they had enough go in them to just about do their job
three days ago, doesn't mean that one of them hasn't gasped its last today.

To use a car analogy, you can drive around today with half a millimetre of
lining material on your brake pads, that stop the car today, and squeal
metal on metal tomorrow ...

The 24C08 is an EEPROM, where all of the setup parameters are stored. It's
not at all unusual for these to get corrupted in TV sets, and to produce
symptoms like you describe, which are not correctable. However, it's often
necessary to pre-program a new blank one with a basic set of parameters,
before it will work.

Finally, a warning. If you are not used to working on monitors, take extreme
care, as they employ switchmode power supplies, which are (literally)
potentially lethal. Also the high voltage generation circuits for the CRT
can give you a nasty bite, as can the CRT itself, long after you have
switched off.

Arfa



hi and thanx for your reply.....

i'm sorry my post didn't show the fourth chip which is;

4. KA3842B and also there was a fifth one......
E009C

i wrote it's data on the back of the paper containing all the data of the
chips i found, it's data are;

5. PM02AF
LM this one i couldn't get any datasheet about
358N

the fourth chip is smps controller, this makes me know only three out of five
chips and i don't know exactly which is the pincushion amp, or where is it's
drive. it's kind of making me handicaped not having the service manual for
this piece of hardware. also i don't have the proper test equips, only an avo
meter, the data sheets and my personal experience.

today i replace the caps that i suspected of having leaked, and the truth to
be said, the pincushion became less by 8mm which is small but positive result.
also i tried to replace the ATMEL 24C08 EEPROM with a new blank one, but i
got a white screen with horizontal bright lines across it, it looked like a
writing paper and i didn't see any thing but shadows of what really was to be
shown behind this new look so i turned back to the old one and every thing is
fine relatively.

the first chip i mentioned "no. 1" is a big ic and since the begining i
suspected it but i don't have it's data sheet as to decide whether or not to
replace it. also it's said to be discontinued which makes me unsure whether
will i find it on the market or not.

as a matter of fact the monitor is eight years old and all of it's capacitors
are probably if not surely much older, so it needs all of it's caps to be
replaced. but i need to have it working as not to be throwing mony away for
nothing.

you are right about being extra careful while working with this type of
hardware, but the smps isn't what i fear. what really makes me sweat my
juices out is the tube itself, when i'm working on it while online i know
that there is a 25+ kv infront of me. one mistake and i might be history and
so i take emergency precautions while working with it. also i have proper
grounding which calms me down a little.

this is all i've got,

hope for the best solution.


thanx all

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