View Single Post
  #7   Report Post  
Posted to sci.electronics.repair
John F Miller
 
Posts: n/a
Default Sony TV - Picture Problem

Thanks, Jeff!

I followed your suggestions yesterday and, after being on continuously for
more than 20 hours, the problem seems to have gone away.

Regards,

John.

--
John F. Miller
http://www.enosoft.net
high performance tools for music and video


"Shoreline Electronics" wrote in message
...
Resolder your vertical output IC561.

This will solve your problem.

Resolder the Horizontal Driver Transformer while your in there for good
preventive maintenance


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

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

"John F Miller" johnATenosoft.net wrote in message
...
Hello,

I have a Sony Trinitron KV27S22 (December 1997). A couple of days ago,
it developed a picture problem. Rather than try to describe it, I have
placed the following photos on the web:

Image of color bars: Behaving OK -
http://www.enosoft.net/kv27s22/Bars%20-%20OK.JPG
Image of color bars: Exhibiting problem -
http://www.enosoft.net/kv27s22/Bars%20-%20Problem.JPG

The problem will set in anything from a few seconds to a few minutes
after cold-starting the set. The problem will persist for a few seconds
before the display completely disappears. Only a cold reset will restore
the image. Audio is fine.

I have done some troubleshooting and have narrowed the problem to what I
think is a capacitance issue. Using a painter's stick (wooden!), I
tapped the various components on the main board and found that the
tapping could induce the problem. However, if I hold the ground of the
audio connectors, the tapping does not create the problem. When the
problem is present, grabbing the ground of the audio connector clears the
problem.

The most sensitive part of the board is shown at:

http://www.enosoft.net/kv27s22/Main%20Board%20(Part).JPG

I have a copy of the Sony service manual for this set but, before I
merrily begin replacing all the capacitors, I would like to know if
anyone knows a specific cause and/or that I am barking up the right tree.

Many thanks in advance,

John Miller.