Sony TV contast problem
 

Hi,

I am experience a problem with my Sony KV-32XBR51. Sometimes when I change
channel or watching DVD, the TV instantly darkens color like someone lowered
the contrast dramatically and then it would come back to normal in a flick
of second...or sometimes, it would stay for some time (several minutes) then
come back normal. I am trying to get this fixed but don't know where to
start troubleshooting...any help is appreciated!

Bill

You will need the service manual, a DVM, and a scope. First check that the
voltages to the video stages through to the output drives are all correct.
Also verify the bias volts to the electron gun assembly are correct. If so,
follow the video signal path with the scope to locate the area of
variations. Since it is on all three colours, you are looking for something
that is common.

If it is the brightness that is changing, this is sometimes caused by the HV
multiplier going defective. Don't rule out the possibility of a cold solder
connection as well.

If you are not properly trained and equipped to work in TV servicing, I
would strongly suggest you give your set out for proper service. The Sony
sets are fairly complex to work on, and it is recommended to give it to a
service centre that is familiar with working on your type of set.

If you venture in to the set, there are some serious safety issues. The set
will have to be operating while the tracing is done. The chassis will have
to be jigged up in a position where the readings can be taken on both the
underside, and top side will it is running. A very good knowledge of the
operation of the circuits involved will be necessary to troubleshoot your
set.

--

Jerry G.
======


"Bill" wrote in message
...
Hi,

I am experience a problem with my Sony KV-32XBR51. Sometimes when I change
channel or watching DVD, the TV instantly darkens color like someone lowered
the contrast dramatically and then it would come back to normal in a flick
of second...or sometimes, it would stay for some time (several minutes) then
come back normal. I am trying to get this fixed but don't know where to
start troubleshooting...any help is appreciated!

Bill

Bill,

Has this set ever been serviced? If not.....there are a few common spots
on these to have faulty connections.

Regulator IC's Ic581, Ic582 , D659 & the IHVT.


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

========================

"Bill" wrote in message
...
Hi,

I am experience a problem with my Sony KV-32XBR51. Sometimes when I
change channel or watching DVD, the TV instantly darkens color like
someone lowered the contrast dramatically and then it would come back to
normal in a flick of second...or sometimes, it would stay for some time
(several minutes) then come back normal. I am trying to get this fixed but
don't know where to start troubleshooting...any help is appreciated!

Bill

Jeff,

Thanks for the reply, the set has been serviced before. Last time it got
serviced was because my "all-mighty" Dad decided to attempt to fix the set
himself and some circuit shorted and the set end up sitting there for
several years before we hired some service guy who finally fixed it.

Seems like I need a service manual or at least a schematic for the board to
start with.

Bill


"Shoreline Electronics" wrote in message
m...
Bill,

Has this set ever been serviced? If not.....there are a few common
spots on these to have faulty connections.

Regulator IC's Ic581, Ic582 , D659 & the IHVT.


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

========================

"Bill" wrote in message
...
Hi,

I am experience a problem with my Sony KV-32XBR51. Sometimes when I
change channel or watching DVD, the TV instantly darkens color like
someone lowered the contrast dramatically and then it would come back to
normal in a flick of second...or sometimes, it would stay for some time
(several minutes) then come back normal. I am trying to get this fixed
but don't know where to start troubleshooting...any help is appreciated!

Bill