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Need schematic for Sony KV-1380R TV
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Chuck
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Need schematic for Sony KV-1380R TV
On Tue, 29 Dec 2009 18:17:47 -0800 (PST), "hr(bob)
"
wrote:
On Dec 29, 10:40*am, Andy Cuffe wrote:
On Sun, 27 Dec 2009 21:54:47 -0800 (PST), "hr(bob) "
wrote:
Just had a Sony Model KV-1380R given to me a couple of days ago. *Only
problem is simultaneous but intermittent horizontal and vertical
shrinkage of about 20%, on a random basis. *Removed the set back,
problem is still intermittent, but appears to be less frequent. *Tried
beating on anything related to power supply, both in normal and
trouble modes, no effects. *I suspect something in the power supply
since both H & V are affected. *Currently running the set with a
voltmeter on B+ which is running about 155V, waiting for something to
go wrong. *But I can't sit around watching the set, just check it
intermittently. *Anyone had similar problems with this or similar
Sonys. Photofact folder is 2564, putting manufacture date at sometime
in 1987 or early 1988. *If anyone has a pdf of this folder, please let
me know.
My money would be on the STRXXXX voltage regulator that most Sony's of
that era had. *They are a common failure, although they usually do go
intermittent. *
Andy Cuffe
Today the picture had shrunk when I went to my workshop. The
rectified line voltage had risen to 150 V from 140 V when the picture
was full-size. This might be due to a decreased load on the power
supply since the scanning current has gone down. Next thing to do
will be to see what if anything I can do about turning the set off and
on after a failure and see if the picture restores to correct size or
not. This seems to be a bottom-line Sony, so I don't know if there is
anything adjustable from a memory chip that might affect the picture.
I am also going to move my voltmeter to the CRT cap and see what the
HV does when the failure occurs. Stay tuned
This unit doesn't have adjustments stored in a EEprom. Mark
Zacharias' solution is the most common failure mode causing this
symptom. Rarely the STR IC goes intermittent and even rarer, a
resistor changes value in the regulator circuit. I'd replace the 33
uf cap he mentioned before further troubleshooting. Chuck
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