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Sony TV Standby Light Blinking - Trouble cleared on testing

A

AnyOl'Joe

Jan 1, 1970
0
Sony TV Standby Light Blinking - Trouble cleared on testing

Sony TV Standby Light Blinking (continuously - no error code), No Video -
Audio Fine - many models, mine is KV32S66, MFG date October 1999, problem
date July 2007. TV use - low to moderate.

I did a lot of searching/Googling the net. It eventually became obvious that
many of the "helpers" in forums have a convenient link to a website for
parts/docs sales and their diagnosis involved a product they sell (ie: CD or
a kit). Thank you all for that but it seems TV repair mystique hasn't
changed much since the fifties (a fool and his money are soon parted). Even
the experts can be dumbfounded by all of the possibilities and resort to the
shotgun approach, complete assembly replacement, rebuild kits (I do it too).
Rumor has it that Sony has stopped selling certain boards to protect their
reputation. Sony is encouraging component replacement. The boards are
expensive - result is customers get mad at product mfg, not the repair tech
although labor time for component diagnosis may make the repair cost higher,
especially for those shops that rarely do component diagnosis.

In the case of the Sony standby light blinking (no code, just regular warmup
blink) there seemed to be four common answers. Most all agree this is a
moderate to serious problem/repair, $150 - $400+.

1. No reply from the jungle IC301 (data bus is busy, shorted to ground or
held high), IK video path is defective.
2. Weak CRT (usually "Dakota"), sometimes rejuvenation recommended
3. Cold solder joint
4. Screw adjustment on HVT/Flyback (marked "screen")
5. (not so common) Main board has bad design where heavy components not
supported upon removal of back causing cracks. Of course, the back panel
needs to be removed to cause this problem.

My "solution" has worked so far. The first thing tried was the "screw"
adjustment. That did little to help the problem. The next alternative was to
remove the motherboard and all related boards and inspect for cold joints.
Once all the boards were removed, I gave all of them a good air blow and
inspected the joints for at least an hour in direct sunlight using double
magnifying glasses (one pair reading glasses, one hand held). All joints
looked whole, bright and shiny. A few joints demanded a "wiggle" test but
passed well. Frustrated I reassembled knowing full well nothing had really
been done to remedy the problem. Before ckt board installation, I took a can
of air and blew off the dust from the yoke and back of picture tube,
especially around the anode and gently wiped the anode area with dry paper
towel. Reinstalled boards & triple checked connections before installing
back cover. To my surprise, it now works... for how long I don't know. I am
understandably frustrated, not knowing what is going on and if/when this
problem will return. More frustrating is the several posts that the expert
said "I've never seen dust cause a problem". I have fixed many computer
problems by reseating connectors & boards but that seems unlikely the
problem here. I've also found cases where bugs caused shorts near higher
voltage areas, no bugs in this case. Thank you Jesus for fixing the TV for
me but I wish you'd tell me what happened to cause it. (Want cake and eat it
too)
 
D

Dave

Jan 1, 1970
0
AnyOl'Joe said:
Sony TV Standby Light Blinking - Trouble cleared on testing

Sony TV Standby Light Blinking (continuously - no error code), No Video -
Audio Fine - many models, mine is KV32S66, MFG date October 1999, problem
date July 2007. TV use - low to moderate.

I did a lot of searching/Googling the net. It eventually became obvious that
many of the "helpers" in forums have a convenient link to a website for
parts/docs sales and their diagnosis involved a product they sell (ie: CD or
a kit). Thank you all for that but it seems TV repair mystique hasn't
changed much since the fifties (a fool and his money are soon parted). Even
the experts can be dumbfounded by all of the possibilities and resort to the
shotgun approach, complete assembly replacement, rebuild kits (I do it too).
Rumor has it that Sony has stopped selling certain boards to protect their
reputation. Sony is encouraging component replacement. The boards are
expensive - result is customers get mad at product mfg, not the repair tech
although labor time for component diagnosis may make the repair cost higher,
especially for those shops that rarely do component diagnosis.

In the case of the Sony standby light blinking (no code, just regular warmup
blink) there seemed to be four common answers. Most all agree this is a
moderate to serious problem/repair, $150 - $400+.

1. No reply from the jungle IC301 (data bus is busy, shorted to ground or
held high), IK video path is defective.
2. Weak CRT (usually "Dakota"), sometimes rejuvenation recommended
3. Cold solder joint
4. Screw adjustment on HVT/Flyback (marked "screen")
5. (not so common) Main board has bad design where heavy components not
supported upon removal of back causing cracks. Of course, the back panel
needs to be removed to cause this problem.

My "solution" has worked so far. The first thing tried was the "screw"
adjustment. That did little to help the problem. The next alternative was to
remove the motherboard and all related boards and inspect for cold joints.
Once all the boards were removed, I gave all of them a good air blow and
inspected the joints for at least an hour in direct sunlight using double
magnifying glasses (one pair reading glasses, one hand held). All joints
looked whole, bright and shiny. A few joints demanded a "wiggle" test but
passed well. Frustrated I reassembled knowing full well nothing had really
been done to remedy the problem. Before ckt board installation, I took a can
of air and blew off the dust from the yoke and back of picture tube,
especially around the anode and gently wiped the anode area with dry paper
towel. Reinstalled boards & triple checked connections before installing
back cover. To my surprise, it now works... for how long I don't know. I am
understandably frustrated, not knowing what is going on and if/when this
problem will return. More frustrating is the several posts that the expert
said "I've never seen dust cause a problem". I have fixed many computer
problems by reseating connectors & boards but that seems unlikely the
problem here. I've also found cases where bugs caused shorts near higher
voltage areas, no bugs in this case. Thank you Jesus for fixing the TV for
me but I wish you'd tell me what happened to cause it. (Want cake and eat it
too)

must be a bad solder joint. all that wiggling has helped it. for now
 
A

AnyOl'Joe

Jan 1, 1970
0
Dave said:
must be a bad solder joint. all that wiggling has helped it. for now

I was thinking the same thing.

One thing I failed to mention is that when the TV was acting up it would
respond to the "whack" test favorably but usually not for long. If the
picture was allowed to go black then no amount of hitting had any effect
(like scr controlled). When it went black, the pic shrunk from every side up
towards the top with dark lines streaking throught it. Eventually it went
all the way up to nothing, then blackness with normal audio, the stanby
light remained unlit. At the next power cycle, if pic didn't return, the
standby light would just blink at the normal POST rate.

Thanks for your comments.
 
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