Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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  #1   Report Post  
Mike
 
Posts: n/a
Default Zenith SR2765s no blue

Anyone have a euras account on here? i have a zenith sr2765S that has no
blue.

output transistor checks fine.

it lists this issue in euras, but i had to cancel subscripton.


help...please....


  #2   Report Post  
David
 
Posts: n/a
Default Zenith SR2765s no blue

27" Zenith crt from 1993 through late 96? Troubleshoot for bad crt FIRST as
that is the most likely cause.

Then do standard troubleshooting of the video output stage and pre-driver
stages.

David

Mike wrote in message
...
Anyone have a euras account on here? i have a zenith sr2765S that has no
blue.

output transistor checks fine.

it lists this issue in euras, but i had to cancel subscripton.


help...please....




  #3   Report Post  
Mike
 
Posts: n/a
Default Zenith SR2765s no blue

not CRT. subbed it.




"David" wrote in message
...
27" Zenith crt from 1993 through late 96? Troubleshoot for bad crt FIRST

as
that is the most likely cause.

Then do standard troubleshooting of the video output stage and pre-driver
stages.

David

Mike wrote in message
...
Anyone have a euras account on here? i have a zenith sr2765S that has no
blue.

output transistor checks fine.

it lists this issue in euras, but i had to cancel subscripton.


help...please....






  #4   Report Post  
Jerry G.
 
Posts: n/a
Default Zenith SR2765s no blue

Just a suggestion here... The best way to troubleshoot this is to first see
if the bias volts to the CRT elements are okay. If so, use a scope and trace
back the video signal along its path in the blue channel.

--

Greetings,

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


"Mike" wrote in message
...
Anyone have a euras account on here? i have a zenith sr2765S that has no
blue.

output transistor checks fine.

it lists this issue in euras, but i had to cancel subscripton.


help...please....



  #5   Report Post  
David
 
Posts: n/a
Default Zenith SR2765s no blue

Then it looks like you just need to do basic crt drive voltage and
waveform troubleshooting.

"Mike" wrote in message ...
not CRT. subbed it.




"David" wrote in message
...
27" Zenith crt from 1993 through late 96? Troubleshoot for bad crt FIRST

as
that is the most likely cause.

Then do standard troubleshooting of the video output stage and pre-driver
stages.

David

Mike wrote in message
...
Anyone have a euras account on here? i have a zenith sr2765S that has no
blue.

output transistor checks fine.

it lists this issue in euras, but i had to cancel subscripton.


help...please....






  #6   Report Post  
Ken G.
 
Posts: n/a
Default Zenith SR2765s no blue

not CRT. subbed it.


It will be tomorrow :-)

  #7   Report Post  
Mike
 
Posts: n/a
Default Zenith SR2765s no blue

found the problem.

2 open resistors feeding the base drive. and feedback.

you are right about the CRT. the colors are funky. and in dark scenes, the
green lacks, such as when watching twister, the grass and trees are sorta
dark purple. but at certain scenes, the green is there. like in whites,
whites have too much green. and yellows are there. peoples faces are too
red. if i drop the red gain, it takes out the red from teh darker scenes.
the colors are hard to describe. but its teh green that lacks in darker
images. and the picture is somewhat dim. even when the green drive is all
the way up, the whites are swamped in green. and the blacks are sorta faint
red instead of black.


go figure.









"Jerry G." wrote in message
...
Just a suggestion here... The best way to troubleshoot this is to first

see
if the bias volts to the CRT elements are okay. If so, use a scope and

trace
back the video signal along its path in the blue channel.

--

Greetings,

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


"Mike" wrote in message
...
Anyone have a euras account on here? i have a zenith sr2765S that has no
blue.

output transistor checks fine.

it lists this issue in euras, but i had to cancel subscripton.


help...please....





  #8   Report Post  
Mike
 
Posts: n/a
Default Zenith SR2765s no blue

no bleeding or blooming, and the convergence is fine. the corners arnt out
of focus. commonly, i see bad convergence, and out of focus corners when bad
CRTs are present.




"Mike" wrote in message
...
found the problem.

2 open resistors feeding the base drive. and feedback.

you are right about the CRT. the colors are funky. and in dark scenes, the
green lacks, such as when watching twister, the grass and trees are sorta
dark purple. but at certain scenes, the green is there. like in whites,
whites have too much green. and yellows are there. peoples faces are too
red. if i drop the red gain, it takes out the red from teh darker scenes.
the colors are hard to describe. but its teh green that lacks in darker
images. and the picture is somewhat dim. even when the green drive is all
the way up, the whites are swamped in green. and the blacks are sorta

faint
red instead of black.


go figure.









"Jerry G." wrote in message
...
Just a suggestion here... The best way to troubleshoot this is to first

see
if the bias volts to the CRT elements are okay. If so, use a scope and

trace
back the video signal along its path in the blue channel.

--

Greetings,

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


"Mike" wrote in message
...
Anyone have a euras account on here? i have a zenith sr2765S that has no
blue.

output transistor checks fine.

it lists this issue in euras, but i had to cancel subscripton.


help...please....







  #9   Report Post  
Mike
 
Posts: n/a
Default Zenith SR2765s no blue

there isnt any bleeding or blooming, and the convergence is fine. the
corners are not out
of focus. commonly, i see bad convergence, and out of focus corners when bad
CRTs are present.

There are purity problems in the extreme corners. i cant get that out
whatsoever.



"Mike" wrote in message
...
found the problem.

2 open resistors feeding the base drive. and feedback.

you are right about the CRT. the colors are funky. and in dark scenes, the
green lacks, such as when watching twister, the grass and trees are sorta
dark purple. but at certain scenes, the green is there. like in whites,
whites have too much green. and yellows are there. peoples faces are too
red. if i drop the red gain, it takes out the red from teh darker scenes.
the colors are hard to describe. but its teh green that lacks in darker
images. and the picture is somewhat dim. even when the green drive is all
the way up, the whites are swamped in green. and the blacks are sorta

faint
red instead of black.


go figure.









"Jerry G." wrote in message
...
Just a suggestion here... The best way to troubleshoot this is to first

see
if the bias volts to the CRT elements are okay. If so, use a scope and

trace
back the video signal along its path in the blue channel.

--

Greetings,

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


"Mike" wrote in message
...
Anyone have a euras account on here? i have a zenith sr2765S that has no
blue.

output transistor checks fine.

it lists this issue in euras, but i had to cancel subscripton.


help...please....







  #10   Report Post  
Shoreline Electronics
 
Posts: n/a
Default Zenith SR2765s no blue

Usually the 120k 1/2 watt resistors are open on these.........CRT may still
look like crap. Evaluate with a CRT tester to be sure.



--
==========================
Jeff Stielau
Shoreline Electronics Repair
344 East Main Street
Clinton,CT 06413
860-399-1861
860-664-3535 (fax)

========================
"If you push something hard enough it will fall over."
Fudd's First Law of Opposition - Sir Sidney Fudd


"Mike" wrote in message
...
Anyone have a euras account on here? i have a zenith sr2765S that has no
blue.

output transistor checks fine.

it lists this issue in euras, but i had to cancel subscripton.


help...please....







  #11   Report Post  
Mike
 
Posts: n/a
Default Zenith SR2765s no blue

it does look like crap. the green gun is too weak. the whites are flooded
with green, and the 50% or less required of green, it doesnt show.





"Shoreline Electronics" wrote in message
. com...
Usually the 120k 1/2 watt resistors are open on these.........CRT may

still
look like crap. Evaluate with a CRT tester to be sure.



--
==========================
Jeff Stielau
Shoreline Electronics Repair
344 East Main Street
Clinton,CT 06413
860-399-1861
860-664-3535 (fax)

========================
"If you push something hard enough it will fall over."
Fudd's First Law of Opposition - Sir Sidney Fudd


"Mike" wrote in message
...
Anyone have a euras account on here? i have a zenith sr2765S that has no
blue.

output transistor checks fine.

it lists this issue in euras, but i had to cancel subscripton.


help...please....







  #12   Report Post  
Mike
 
Posts: n/a
Default Zenith SR2765s no blue

so basically, browns look purple. and dark greens look like a dark purple.

you can only see the first 3 shades of green. the rest are just shades of
purple.



"Mike" wrote in message
...
it does look like crap. the green gun is too weak. the whites are flooded
with green, and the 50% or less required of green, it doesnt show.





"Shoreline Electronics" wrote in message
. com...
Usually the 120k 1/2 watt resistors are open on these.........CRT may

still
look like crap. Evaluate with a CRT tester to be sure.



--
==========================
Jeff Stielau
Shoreline Electronics Repair
344 East Main Street
Clinton,CT 06413
860-399-1861
860-664-3535 (fax)

========================
"If you push something hard enough it will fall over."
Fudd's First Law of Opposition - Sir Sidney Fudd


"Mike" wrote in message
...
Anyone have a euras account on here? i have a zenith sr2765S that has

no
blue.

output transistor checks fine.

it lists this issue in euras, but i had to cancel subscripton.


help...please....









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