Pioneer SD-P5065 Blue barely visible

[jon smith]

I have an old Pioneer SD-P5065 projection TV. Using my laptop I ran a few
monitor tests, and all the tests/colors checked out except for the color
blue. All other colors displayed fine. The blue is barely visible. On
normal CRT's I know I should try to adjust the screen pot on the flyback to
brighten a dark picture, but this flyback has nothing and it would matter
little since the CRTs are in series. I do not have schematics for this set.
So any ideas would be helpfull. I am thinking each CRT may have its own
screen adjustment, but I have yet to locate them.

thanks for any help

 

[Jerry G.]

Most likely the tube for that channel is weak. It is possible that the
signal level to it is low, or the bias to it is weak. This can be checked
with a scope, and a DVM.

From my past experience, most of the time the CRT's fail, thus causing the
fault you see.

--

Jerry G.
=====

I have an old Pioneer SD-P5065 projection TV. Using my laptop I ran a few
monitor tests, and all the tests/colors checked out except for the color
blue. All other colors displayed fine. The blue is barely visible. On
normal CRT's I know I should try to adjust the screen pot on the flyback to
brighten a dark picture, but this flyback has nothing and it would matter
little since the CRTs are in series. I do not have schematics for this set.
So any ideas would be helpfull. I am thinking each CRT may have its own
screen adjustment, but I have yet to locate them.

thanks for any help

 

[[email protected]]

The screen controls are usually in front. You may need to remove the
speaker grille and one other panel. You will see the focus block with 6
controls. Three are focus and three are the screen controls for the
red, green and blue crts respectively. If the blue is weak, you may
need to adjust the focus also.

R Thomas

 

[James Sweet]

The screen controls are usually in front. You may need to remove the
speaker grille and one other panel. You will see the focus block with 6
controls. Three are focus and three are the screen controls for the
red, green and blue crts respectively. If the blue is weak, you may
need to adjust the focus also.

R Thomas

In my experience the blue tube usually goes weak first, I think the phosphor
is the least efficient so it gets driven harder and wears out the gun, but
try turning it up a bit, might be able to squeeze more life out of it.

 

[Bill Jr]

It has been my experience that when all adjustments net very little
difference that the CRT can be rejuvenated quite successfully.
These old Hitachi CRT's usually come back to life very well.
Your mileage may vary.

Good Luck,
Bill Jr

 

[James Sweet]

It has been my experience that when all adjustments net very little
difference that the CRT can be rejuvenated quite successfully.
These old Hitachi CRT's usually come back to life very well.
Your mileage may vary.

Good Luck,
Bill Jr

Good to know, I've never tried rejuvenating a projo CRT but I was under the
impression that it's rarely successful.

 

[jon smith]

Thanks for the help guys. When I went to adjust the blue the TV had already
been on for quite some time (Kids+ video games). To my suprise the blue was
close to perfect and needed little adjustment. I going to let the set cool
down over night and see how it looks tomorrow.
Do any of you know of any problem CAPs or transistors in this model?

 

[James Sweet]

Thanks for the help guys. When I went to adjust the blue the TV had already
been on for quite some time (Kids+ video games). To my suprise the blue was
close to perfect and needed little adjustment. I going to let the set cool
down over night and see how it looks tomorrow.
Do any of you know of any problem CAPs or transistors in this model?

Capacitors are a common problem with just about any older TV, a bit of
freeze spray could help you track down temperature sensitive parts.

 

[Leonard Caillouet]

Good to know, I've never tried rejuvenating a projo CRT but I was under the
impression that it's rarely successful.

We do it all the time. The success rate varies, probably more than with
direct view CRTs. Projection tubes are run with a great deal higher beam
current and age phosphors much faster. They are often in much worse shape
when we get them than direct view tubes. I have not had a great deal of
success with the Hitachi RPTV CRTs once they start going weak in emission.
Not much way to tell other than to try it. Not much to lose on a set this
age.

Leonard