Hatachi tv problem

B

Bubba Jones

Guest
I have Hitachi tv manufactured in 1981.

For several years now, when white text is displayed, bright streaks
appear to right of the high brightness area. The streaks are of the
same height as the text and is translucent over image that should be
there. This looks like brightness is bleeding over vs. echo of text
characters.

This effect also occurs if there is any high brightness image area
anywhere on the screen.

I am using satellite receiver for signal source, so it is reasonably
high quality. However, the problem happens with CATV as well.

Adjustment of contrast & brightness controls do not eliminate problem.

Any ideas what may be causing this?

I would like to fix this so I have a tv to use in the basement.

Thanks for any suggestions on how I may fix this.

Bubba
 
This can be either from some components in the video amp sections that are
going off value to cause frequency response problems, or the CRT may be
going weak. The most common cause is a weak CRT.



--

Greetings,

Jerry Greenberg GLG Technologies GLG
=========================================
WebPage http://www.zoom-one.com
Electronics http://www.zoom-one.com/electron.htm
=========================================


"Bubba Jones" <Smelly@hotmail.com> wrote in message
news:ids4qvolaqrojsqlnh26voc7u6l0fc0aqf@4ax.com...
I have Hitachi tv manufactured in 1981.

For several years now, when white text is displayed, bright streaks
appear to right of the high brightness area. The streaks are of the
same height as the text and is translucent over image that should be
there. This looks like brightness is bleeding over vs. echo of text
characters.

This effect also occurs if there is any high brightness image area
anywhere on the screen.

I am using satellite receiver for signal source, so it is reasonably
high quality. However, the problem happens with CATV as well.

Adjustment of contrast & brightness controls do not eliminate problem.

Any ideas what may be causing this?

I would like to fix this so I have a tv to use in the basement.

Thanks for any suggestions on how I may fix this.

Bubba
 
1981 ? On the newer ones I'd say the COMB filter, but in this case I think
Jerry's right. If it is flaring (that's what I call it) there are two options.
If it isn't really bad you might get away with turning the G2s higher. If not
you can raise the filament voltage, just like a brightener used to do in the
old old sets. In a bigscreen you'll need a good tech to accomplish this.

IIRC, it is pretty difficult to boost the filament on some of these, but it can
be done.

Where are you geographically ? If you're near NE Ohio I might be able to come
do it.

JURB
 
I adjusted focus & hi-voltage controls on flyback transformer and this
has reduced bleeding problem when brightness is not too high.

There are vertical grayish bars in screen, each about 2 inches in
width. These are more visible from a distance.

The TV has not been in use for about 5 years, but these bars were in
the display well before it was set aside in favor of a new tv. The
vertical bars seem to influence the white bleeding problem.

There is a slight 60hz buzz in the audio when white text appears on
screen.

The model for the TV is Hitachi 2140, manufactured in Feb 1982.

Anyone have a schematic for this unit?

Any ideas what may be causing these bars?

Thanks for all ideas.

Bubba



On Fri, 31 Oct 2003 16:50:48 -0500, "Jerry G." <jerryg50@hotmail.com>
wrote:

This can be either from some components in the video amp sections that are
going off value to cause frequency response problems, or the CRT may be
going weak. The most common cause is a weak CRT.



--

Greetings,

Jerry Greenberg GLG Technologies GLG
=========================================
WebPage http://www.zoom-one.com
Electronics http://www.zoom-one.com/electron.htm
=========================================


"Bubba Jones" <Smelly@hotmail.com> wrote in message
news:ids4qvolaqrojsqlnh26voc7u6l0fc0aqf@4ax.com...
I have Hitachi tv manufactured in 1981.

For several years now, when white text is displayed, bright streaks
appear to right of the high brightness area. The streaks are of the
same height as the text and is translucent over image that should be
there. This looks like brightness is bleeding over vs. echo of text
characters.

This effect also occurs if there is any high brightness image area
anywhere on the screen.

I am using satellite receiver for signal source, so it is reasonably
high quality. However, the problem happens with CATV as well.

Adjustment of contrast & brightness controls do not eliminate problem.

Any ideas what may be causing this?

I would like to fix this so I have a tv to use in the basement.

Thanks for any suggestions on how I may fix this.

Bubba
Click to expand...
 
Bubba Jones wrote:

I adjusted focus & hi-voltage controls on flyback transformer and this
has reduced bleeding problem when brightness is not too high.

There are vertical grayish bars in screen, each about 2 inches in
width. These are more visible from a distance.

The TV has not been in use for about 5 years, but these bars were in
the display well before it was set aside in favor of a new tv. The
vertical bars seem to influence the white bleeding problem.

There is a slight 60hz buzz in the audio when white text appears on
screen.

The model for the TV is Hitachi 2140, manufactured in Feb 1982.

Anyone have a schematic for this unit?

Any ideas what may be causing these bars?

Thanks for all ideas.

Bubba
Click to expand...
Vertical bars means that something is showing up that's happening at the
horizontal rate. It may be that some filter cap that's driven off a
flyback-derived supply is going bad, or it may be that a diode off the
flyback is possibly starting to go leaky...

No way I can say more without looking at a schematic, though.
 
Roy, thanks for your help.

I found a bad 10uf 160v capacitor next to flyback.

I replaced it, and problem is fixed.

No more gray bars or flaring on white video. The only bars I like, are
the ones I drink in ;-))

Thanks to all who have responded and help me get this tv set back in
viewable order.

Bubba


On Sat, 01 Nov 2003 03:25:43 GMT, "Roy J. Tellason"
<rtellason@DONTSPAM MEpa.net> wrote:

Bubba Jones wrote:

I adjusted focus & hi-voltage controls on flyback transformer and this
has reduced bleeding problem when brightness is not too high.

There are vertical grayish bars in screen, each about 2 inches in
width. These are more visible from a distance.

The TV has not been in use for about 5 years, but these bars were in
the display well before it was set aside in favor of a new tv. The
vertical bars seem to influence the white bleeding problem.

There is a slight 60hz buzz in the audio when white text appears on
screen.

The model for the TV is Hitachi 2140, manufactured in Feb 1982.

Anyone have a schematic for this unit?

Any ideas what may be causing these bars?

Thanks for all ideas.

Bubba

Vertical bars means that something is showing up that's happening at the
horizontal rate. It may be that some filter cap that's driven off a
flyback-derived supply is going bad, or it may be that a diode off the
flyback is possibly starting to go leaky...

No way I can say more without looking at a schematic, though.
Click to expand...
 
Bubba Jones wrote:

Roy, thanks for your help.

I found a bad 10uf 160v capacitor next to flyback.
Click to expand...
If it's connected to a diode that's driven off the flyback, I'd change the
diode too. Not a standard rectifier, that needs to be a higher-speed
part...

> I replaced it, and problem is fixed.
 
Thanks for suggestion.

The capacitor I replaced was not connected to a rectifier diode.

The capacitor connected to the rectifier diode tested okay.

Thanks again.

I bought tv new in 1982 and have brought it with me through two house
moves since replacing it with another (14 years ago). I hate throwing
stuff away and am really glad to have this unit restored to service.

Bubba



On Sat, 01 Nov 2003 21:05:44 GMT, "Roy J. Tellason"
<rtellason@DONTSPAM MEpa.net> wrote:

Bubba Jones wrote:

Roy, thanks for your help.

I found a bad 10uf 160v capacitor next to flyback.

If it's connected to a diode that's driven off the flyback, I'd change the
diode too. Not a standard rectifier, that needs to be a higher-speed
part...

I replaced it, and problem is fixed.
Click to expand...
 
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