Zenith SR2765s no blue

[Mike]

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....

 

[David]

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]

not CRT. subbed it.

 

[Jerry G.]

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.

--

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Jerry Greenberg GLG Technologies GLG
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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....

 

[David]

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

 

[Ken G.]

not CRT. subbed it.


It will be tomorrow

 

[Mike]

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.

 

[Mike]

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]

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.

 

[Shoreline Electronics]

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

 

[Mike]

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.

 

[Mike]

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.