I've got an RCA F27689, built in 2001. Not the world's best 27" TV,
but decent enough for me right now.

I'm a bit of a tweaker, so I've already found out how to get into the
service mode of my TV. I'm also a fairly cautious type, so I also
wrote down all the default values for my set before attempting to mess
with anything. I've also read some horror stories that suggest if
you're going to be fiddling with things in the service menu, you'd
best be prepared for the consequences of messing something up
permanently (or at least enough to require a visit to a service
technician). You may consider me a fool, but the potential benefits of
tweaking make that a risk I'm willing to take.

Using a Digital Video Essentials test pattern as a guide, I can see
that some parameters make visible changes: I've found vertical
position, vertical size, and horizontal position, for example.

However, the one thing I really want to change -- horizontal size, to
correct for what I feel is an awful lot of horizontal overscan -- has
thus far eluded me. I'm beginning to think maybe it can't be adjusted
at all (!), but I don't really want to believe that just yet. I'm
hoping maybe there's another password to set, and further parameters
to adjust. Or that one of the parameters I don't see doing anything
can be made to do something, somehow. I don't know -- I'm grasping at
theoretical straws here.

Could somebody with a little (or a lot) more experience than I've got
give me a couple of pointers? Thanks kindly...

[crossposted to sci.electronics.repair and rec.video]

I wrote:

I've got an RCA F27689, built in 2001.

Quick update: the chassis number is CTC197A8.

[crossposted to sci.electronics.repair and rec.video]

I don't know your set in detail, but I have some suggestions.

I would think it would be a good idea for you to invest in the service
manual. They should give instructions for the complete set-up of your set.
There will be test equipment necessary to do all of the set-ups to any great
detail. What you want to do, is mainly visually referenced, using a test
pattern on the screen.

In some models of sets, they use some resistors with jumpers that are
soldered to them to set the width. Some sets have a connector that is
selectable for the width. Another way of doing this, is that there may be a
pot or width coil on the main chassis in the horizontal output area.

--

JANA
_____


"Karyudo" wrote in message
...
I've got an RCA F27689, built in 2001. Not the world's best 27" TV,
but decent enough for me right now.

I'm a bit of a tweaker, so I've already found out how to get into the
service mode of my TV. I'm also a fairly cautious type, so I also
wrote down all the default values for my set before attempting to mess
with anything. I've also read some horror stories that suggest if
you're going to be fiddling with things in the service menu, you'd
best be prepared for the consequences of messing something up
permanently (or at least enough to require a visit to a service
technician). You may consider me a fool, but the potential benefits of
tweaking make that a risk I'm willing to take.

Using a Digital Video Essentials test pattern as a guide, I can see
that some parameters make visible changes: I've found vertical
position, vertical size, and horizontal position, for example.

However, the one thing I really want to change -- horizontal size, to
correct for what I feel is an awful lot of horizontal overscan -- has
thus far eluded me. I'm beginning to think maybe it can't be adjusted
at all (!), but I don't really want to believe that just yet. I'm
hoping maybe there's another password to set, and further parameters
to adjust. Or that one of the parameters I don't see doing anything
can be made to do something, somehow. I don't know -- I'm grasping at
theoretical straws here.

Could somebody with a little (or a lot) more experience than I've got
give me a couple of pointers? Thanks kindly...

[crossposted to sci.electronics.repair and rec.video]

On Tue, 26 Apr 2005 03:27:08 -0400, "JANA" wrote:

I would [...] invest in the service manual.

Sounds good. Where can I find one? I've heard something like Thomson
something-or-other, but that's not quite enough detail. Any more
hints?

In some models of sets, they use some resistors with jumpers that are
soldered to them to set the width. Some sets have a connector that is
selectable for the width. Another way of doing this, is that there may be a
pot or width coil on the main chassis in the horizontal output area.

All three of these are strategies I would pursue. Changing out a
jumper -- or even a resistor -- is within my cautious capabilities, I
think. If I were to take the back of the set off, what would I be
looking for, and where would I look for it? Any hints on what sort of
label (e.g. printed on the PCB?) I'd see? (Oh, and don't worry: I'm
not going to touch anything metal until it's been off for the better
part of a day, lest I fry myself or something else).

Thanks for your help!

Ok!
Its time for you to take the TV to a service shop before you kill the set.
definitely this is way above you.
kip
"Karyudo" wrote in message
...
On Tue, 26 Apr 2005 03:27:08 -0400, "JANA" wrote:

I would [...] invest in the service manual.

Sounds good. Where can I find one? I've heard something like Thomson
something-or-other, but that's not quite enough detail. Any more
hints?

In some models of sets, they use some resistors with jumpers that are
soldered to them to set the width. Some sets have a connector that is
selectable for the width. Another way of doing this, is that there may be
a
pot or width coil on the main chassis in the horizontal output area.

All three of these are strategies I would pursue. Changing out a
jumper -- or even a resistor -- is within my cautious capabilities, I
think. If I were to take the back of the set off, what would I be
looking for, and where would I look for it? Any hints on what sort of
label (e.g. printed on the PCB?) I'd see? (Oh, and don't worry: I'm
not going to touch anything metal until it's been off for the better
part of a day, lest I fry myself or something else).

Thanks for your help!

Do not try to alter the horizontal width in hardware. You obviously do not
understand the operation or design of the circuits enough to do so without a
high probability of damage to the set.

Leonard

"Karyudo" wrote in message
...
On Tue, 26 Apr 2005 03:27:08 -0400, "JANA" wrote:

I would [...] invest in the service manual.

Sounds good. Where can I find one? I've heard something like Thomson
something-or-other, but that's not quite enough detail. Any more
hints?

In some models of sets, they use some resistors with jumpers that are
soldered to them to set the width. Some sets have a connector that is
selectable for the width. Another way of doing this, is that there may be
a
pot or width coil on the main chassis in the horizontal output area.

All three of these are strategies I would pursue. Changing out a
jumper -- or even a resistor -- is within my cautious capabilities, I
think. If I were to take the back of the set off, what would I be
looking for, and where would I look for it? Any hints on what sort of
label (e.g. printed on the PCB?) I'd see? (Oh, and don't worry: I'm
not going to touch anything metal until it's been off for the better
part of a day, lest I fry myself or something else).

Thanks for your help!

You obviously do not
understand the operation or design of the circuits enough to do so without a
high probability of damage to the set.

You misunderestimate me. *Of course* I don't understand the circuits
enough -- yet. I'm not going to do a damn thing until I do, and until
there's a much lower probability of damage to the set (preferably
hovering around 'nil').

What I really need now is not dire warnings, but more information
about either the circuits themselves, or where to find the
information. I know service manuals exist; I'd like to know how to get
one. I'm educated, bright (enough), and cautious. I'm not going to
mess anything up, because I won't touch anything until I'm pretty
positive I'm touching the right thing.

One observation: TVs suck. Computer monitors (and I mean *all of
them*) have allowed the end user to adjust just about every damn thing
-- including horizontal width, of course -- for at least about a dozen
years. This is not rocket science, it's just crappy engineering. The
fact that I've even got to consider some dangerous hardware mod just
to get the whole picture on the screen is ludicrous.

How much overscan are you talking about? The set is designed with between 5
& 10 percent, and closer to 10 is not uncommon.

You can get the manuals from Thomson Consumer Electronics or their
distributors, such as Tritronics. Be sure to get the training manuals as
well as the service manual.

Leonard

"Karyudo" wrote in message
...
You obviously do not
understand the operation or design of the circuits enough to do so
without a
high probability of damage to the set.

You misunderestimate me. *Of course* I don't understand the circuits
enough -- yet. I'm not going to do a damn thing until I do, and until
there's a much lower probability of damage to the set (preferably
hovering around 'nil').

What I really need now is not dire warnings, but more information
about either the circuits themselves, or where to find the
information. I know service manuals exist; I'd like to know how to get
one. I'm educated, bright (enough), and cautious. I'm not going to
mess anything up, because I won't touch anything until I'm pretty
positive I'm touching the right thing.

One observation: TVs suck. Computer monitors (and I mean *all of
them*) have allowed the end user to adjust just about every damn thing
-- including horizontal width, of course -- for at least about a dozen
years. This is not rocket science, it's just crappy engineering. The
fact that I've even got to consider some dangerous hardware mod just
to get the whole picture on the screen is ludicrous.

If it needs to be adjusted you will need Chipper Checker
and if its really got overscan then the set needs to be repaired.

kip
"Karyudo" wrote in message
...
I've got an RCA F27689, built in 2001. Not the world's best 27" TV,
but decent enough for me right now.

I'm a bit of a tweaker, so I've already found out how to get into the
service mode of my TV. I'm also a fairly cautious type, so I also
wrote down all the default values for my set before attempting to mess
with anything. I've also read some horror stories that suggest if
you're going to be fiddling with things in the service menu, you'd
best be prepared for the consequences of messing something up
permanently (or at least enough to require a visit to a service
technician). You may consider me a fool, but the potential benefits of
tweaking make that a risk I'm willing to take.

Using a Digital Video Essentials test pattern as a guide, I can see
that some parameters make visible changes: I've found vertical
position, vertical size, and horizontal position, for example.

However, the one thing I really want to change -- horizontal size, to
correct for what I feel is an awful lot of horizontal overscan -- has
thus far eluded me. I'm beginning to think maybe it can't be adjusted
at all (!), but I don't really want to believe that just yet. I'm
hoping maybe there's another password to set, and further parameters
to adjust. Or that one of the parameters I don't see doing anything
can be made to do something, somehow. I don't know -- I'm grasping at
theoretical straws here.

Could somebody with a little (or a lot) more experience than I've got
give me a couple of pointers? Thanks kindly...

[crossposted to sci.electronics.repair and rec.video]

Kip, why do you need the Chipper Check to make adjustments on this set?

I don't recall any horizontal size adjustment on the 197 chassis. This is
not uncommon on 27" televisions.

Leonard

"kip" wrote in message
.. .
If it needs to be adjusted you will need Chipper Checker
and if its really got overscan then the set needs to be repaired.

kip
"Karyudo" wrote in message
...
I've got an RCA F27689, built in 2001. Not the world's best 27" TV,
but decent enough for me right now.

I'm a bit of a tweaker, so I've already found out how to get into the
service mode of my TV. I'm also a fairly cautious type, so I also
wrote down all the default values for my set before attempting to mess
with anything. I've also read some horror stories that suggest if
you're going to be fiddling with things in the service menu, you'd
best be prepared for the consequences of messing something up
permanently (or at least enough to require a visit to a service
technician). You may consider me a fool, but the potential benefits of
tweaking make that a risk I'm willing to take.

Using a Digital Video Essentials test pattern as a guide, I can see
that some parameters make visible changes: I've found vertical
position, vertical size, and horizontal position, for example.

However, the one thing I really want to change -- horizontal size, to
correct for what I feel is an awful lot of horizontal overscan -- has
thus far eluded me. I'm beginning to think maybe it can't be adjusted
at all (!), but I don't really want to believe that just yet. I'm
hoping maybe there's another password to set, and further parameters
to adjust. Or that one of the parameters I don't see doing anything
can be made to do something, somehow. I don't know -- I'm grasping at
theoretical straws here.

Could somebody with a little (or a lot) more experience than I've got
give me a couple of pointers? Thanks kindly...

[crossposted to sci.electronics.repair and rec.video]

I don't have the exact CTC197A8 scematic, but other 27" CTC197 use
parameter 5 as horiz size adjustment in the service menu.

This is correct. The set does have horizontal size adjustment, parameter 5.

Leonard

"RonKZ650" wrote in message
oups.com...
I don't have the exact CTC197A8 scematic, but other 27" CTC197 use
parameter 5 as horiz size adjustment in the service menu.

Yes
But did the set develop a fault that now gives excessive
scan or not, or does he want to reduce what is normal
on those TV,s.
Has the TV always been like it ???
Gotta tell us more info.

kip


"Leonard Caillouet" wrote in message
...
This is correct. The set does have horizontal size adjustment, parameter
5.

Leonard

"RonKZ650" wrote in message
oups.com...
I don't have the exact CTC197A8 scematic, but other 27" CTC197 use
parameter 5 as horiz size adjustment in the service menu.

On 27 Apr 05 01:37:15
Karyudo wrote:

But did the set develop a fault that now gives excessive
scan or not, or does he want to reduce what is normal
on those TVs. Has the TV always been like [that]?

Yeah, it's always been like that, and no, there's no fault per se. But
I still feel that there's too much stuff being cut off. Titles on some
movies or TV shows, for example, are butted right up against the edge
of the screen -- and sometimes they're even cut off a bit. So I'm
guessing I'm missing part of the 'TV title safe' area?

I can change the horizontal position adjustment (P:04) from one
extreme to another, and still not see the very edge of the picture on
either side. I mean, this is *acceptable*, but it's not *optimal*.
It's disappointing to learn that this is likely not an easy tweak to
make. But I'm a persistent geek if nothing else, so I'd still be
interested to hear what I might have to do "under the hood" to have a
shot at reducing the overscan on my set.

Any further ideas?? (Thanks, everyone!)

There might be an off-value or mislabelled part in the deflection
circuitry. If there is a non-polar electro in the deflection circuitry
this may be the culprit affecting the width.

Another thing that may affect width is the high voltage being too low.
Recall that as the electron acceleration in the crt is increased the
beam becomes stiffer and requires more magnetism to deflect. This was
a classic case of a bad crt in the old days since as the beam got
weaker the width would increase. It would even follow the scene
brightness changes. I guess with better supply regulation this effect
is rarely seen in modern sets.

Well, if all else fails you might try robbing some power from the
horizontal deflection coil by adding a parallel load to it. Perhaps an
experimentally selected flame-proof resistor in series with a NP cap?
This is only a suggestion and not a known fix.

M*i*k*e


.... If all else fails, hurl it across the room a few times!

On Tue, 26 Apr 2005 06:45:17 GMT, Karyudo
wrote:

I've got an RCA F27689, built in 2001. Not the world's best 27" TV,
but decent enough for me right now.

However, the one thing I really want to change -- horizontal size, to
correct for what I feel is an awful lot of horizontal overscan -- has
thus far eluded me. I'm beginning to think maybe it can't be adjusted
at all (!), but I don't really want to believe that just yet. I'm
hoping maybe there's another password to set, and further parameters
to adjust. Or that one of the parameters I don't see doing anything
can be made to do something, somehow. I don't know -- I'm grasping at
theoretical straws here.


The horizontal size can't be adjusted on most RCA 27" TVs. You'll
have to live with the horizontal overs canning. You probably could
modify it, but it would be easier and cheaper in the long run to
replace it with a better set. For example, all Sony 27" TVs from the
early 90's on have a horizontal size adjustment.
Andy Cuffe

-- Use this address until 12/31/2005

-- Use this address after 12/31/2005