Hello,
I'm trying to diagnose a fault that just developed,
I get sound, and I can feel/here the static electricy
that's generated on the screen when it's turned on.
The screen remains black.

I took the back off the TV and I can see that all
of the neck filamants are unlit.

Please advise. This is a 1992 Sony 27 inch XBR
(kv27-xbr35) Thanks for any assistance.

Dave

"davexnet02" wrote in message
...
Hello,
I'm trying to diagnose a fault that just developed,
I get sound, and I can feel/here the static electricy
that's generated on the screen when it's turned on.
The screen remains black.

I took the back off the TV and I can see that all
of the neck filamants are unlit.

Please advise. This is a 1992 Sony 27 inch XBR
(kv27-xbr35) Thanks for any assistance.

Dave

Dry joint, heater supply off the line ouput transformer?

David

On Tue, 14 Dec 2004 19:58:27 -0000, "David Sewell"
wrote:


"davexnet02" wrote in message
.. .
Hello,
I'm trying to diagnose a fault that just developed,
I get sound, and I can feel/here the static electricy
that's generated on the screen when it's turned on.
The screen remains black.

I took the back off the TV and I can see that all
of the neck filamants are unlit.

Please advise. This is a 1992 Sony 27 inch XBR
(kv27-xbr35) Thanks for any assistance.

Dave

Dry joint, heater supply off the line ouput transformer?

David

LOPT = flyback?
There's the thick wire that goes to the anode,
and a thinner wire that goes to the small circuit board
at the back of the tube. Is that the heater?
I thought it was the focus.

Dave

Loss of +200 VDC to the video driver/output. Defective Video driver/output.
Defective CRT, Etc Post the diagnostic measurements you have actually made
so we may asset what you have done already then render assistance.
"davexnet02" wrote in message
...
On Tue, 14 Dec 2004 19:58:27 -0000, "David Sewell"
wrote:


"davexnet02" wrote in message
. ..
Hello,
I'm trying to diagnose a fault that just developed,
I get sound, and I can feel/here the static electricy
that's generated on the screen when it's turned on.
The screen remains black.

I took the back off the TV and I can see that all
of the neck filamants are unlit.

Please advise. This is a 1992 Sony 27 inch XBR
(kv27-xbr35) Thanks for any assistance.

Dave

Dry joint, heater supply off the line ouput transformer?

David

LOPT = flyback?
There's the thick wire that goes to the anode,
and a thinner wire that goes to the small circuit board
at the back of the tube. Is that the heater?
I thought it was the focus.

Dave

On Tue, 14 Dec 2004 15:58:17 -0500, "Art"
wrote:

Loss of +200 VDC to the video driver/output. Defective Video driver/output.
Defective CRT, Etc Post the diagnostic measurements you have actually made
so we may asset what you have done already then render assistance.
Hi Art, thanks for responding.
Alas, I have not made any "diagnostic measurements", just some
observations. I am not a qualified TV servicer, but I do have some
electronics background, and I have a copy of the service manual.

I have not done anything except resolder all the pins on the
power supply board transformers. (Sony G board).
Problem remains.

Perhaps the TV has reached the end of it's useful life,
or at least it's cost effective life.

Dave

"davexnet02" wrote in message
...
On Tue, 14 Dec 2004 15:58:17 -0500, "Art"
wrote:

Loss of +200 VDC to the video driver/output. Defective Video
driver/output.
Defective CRT, Etc Post the diagnostic measurements you have actually
made
so we may asset what you have done already then render assistance.
Hi Art, thanks for responding.
Alas, I have not made any "diagnostic measurements", just some
observations. I am not a qualified TV servicer, but I do have some
electronics background, and I have a copy of the service manual.

I have not done anything except resolder all the pins on the
power supply board transformers. (Sony G board).
Problem remains.

Perhaps the TV has reached the end of it's useful life,
or at least it's cost effective life.

Dave



Don't condemn it just yet, it's quite likely it can be brought back to life
for a bit more, and perhaps much more useful service.

On Tue, 14 Dec 2004 18:47:23 GMT, davexnet02
wrote:

Hello,
I'm trying to diagnose a fault that just developed,
I get sound, and I can feel/here the static electricy
that's generated on the screen when it's turned on.
The screen remains black.

If the red LED flashes, the set may be in IK blanking. Try turning the
screen control up slightly. If the picture comes in, it *could*
indicate a weak CRT. However, we had a Sony KV27EX25 in the shop today
that had no raster. Turning up the screen restored the pix, which is
often associated with a weak picture tube. But the CRT on this set
checked good. Further checking showed a low screen (G2) voltage. We
found an open 1 meg resistor on the CRT board in series with the
screen control. Replacing the resistor restored an excellent picture.

Alan Harriman




I took the back off the TV and I can see that all
of the neck filamants are unlit.

Please advise. This is a 1992 Sony 27 inch XBR
(kv27-xbr35) Thanks for any assistance.

Dave

On Wed, 15 Dec 2004 04:16:15 GMT, Alan Harriman
wrote:

On Tue, 14 Dec 2004 18:47:23 GMT, davexnet02
wrote:

Hello,
I'm trying to diagnose a fault that just developed,
I get sound, and I can feel/here the static electricy
that's generated on the screen when it's turned on.
The screen remains black.

If the red LED flashes, the set may be in IK blanking. Try turning the
screen control up slightly. If the picture comes in, it *could*
indicate a weak CRT. However, we had a Sony KV27EX25 in the shop today
that had no raster. Turning up the screen restored the pix, which is
often associated with a weak picture tube. But the CRT on this set
checked good. Further checking showed a low screen (G2) voltage. We
found an open 1 meg resistor on the CRT board in series with the
screen control. Replacing the resistor restored an excellent picture.

Alan Harriman
Hi Alan, never seen a flashing LED on this set.
Was that implemented in the 1992 models?

I had suspicions about a weak CRT prior to this failure.
The grey scale was off (too blue) and it was satrting to wash out.

As I mentioned, the CRT filaments are not lit at all.
I'll check the CRT board to see if anything shows up there.
Thanks,
DAve

On Wed, 15 Dec 2004 04:27:24 GMT, davexnet02
wrote:

On Wed, 15 Dec 2004 04:16:15 GMT, Alan Harriman
wrote:

On Tue, 14 Dec 2004 18:47:23 GMT, davexnet02
wrote:

Hello,
I'm trying to diagnose a fault that just developed,
I get sound, and I can feel/here the static electricy
that's generated on the screen when it's turned on.
The screen remains black.

If the red LED flashes, the set may be in IK blanking. Try turning the
screen control up slightly. If the picture comes in, it *could*
indicate a weak CRT. However, we had a Sony KV27EX25 in the shop today
that had no raster. Turning up the screen restored the pix, which is
often associated with a weak picture tube. But the CRT on this set
checked good. Further checking showed a low screen (G2) voltage. We
found an open 1 meg resistor on the CRT board in series with the
screen control. Replacing the resistor restored an excellent picture.

Alan Harriman
Hi Alan, never seen a flashing LED on this set.
Was that implemented in the 1992 models?

I had suspicions about a weak CRT prior to this failure.
The grey scale was off (too blue) and it was satrting to wash out.

As I mentioned, the CRT filaments are not lit at all.

Ooops...read your first post too hastily...maybe they have voltage but
you can't see them as being lit. Have you looked at them in the dark?
It is possible to "roll your own" filament transformer, but you should
have a qualified TV repair person do it, as the filament voltage's
value may be critical to the life of the CRT.

Tom
I'll check the CRT board to see if anything shows up there.
Thanks,
DAve

On Tue, 14 Dec 2004 18:47:23 GMT, davexnet02
wrote:

Hello,
I'm trying to diagnose a fault that just developed,
I get sound, and I can feel/here the static electricy
that's generated on the screen when it's turned on.
The screen remains black.

I took the back off the TV and I can see that all
of the neck filamants are unlit.

Please advise. This is a 1992 Sony 27 inch XBR
(kv27-xbr35) Thanks for any assistance.

Dave

Have you checked the IK voltage on the CRT board? If .6 or so, the CRT
likely has a weak cathode. If 2.2 or so, there is likely another
problem.

Tom

On Wed, 29 Dec 2004 21:47:22 GMT, Tom MacIntyre
wrote:

On Tue, 14 Dec 2004 18:47:23 GMT, davexnet02
wrote:

Hello,
I'm trying to diagnose a fault that just developed,
I get sound, and I can feel/here the static electricy
that's generated on the screen when it's turned on.
The screen remains black.

I took the back off the TV and I can see that all
of the neck filamants are unlit.

Please advise. This is a 1992 Sony 27 inch XBR
(kv27-xbr35) Thanks for any assistance.

Dave

Have you checked the IK voltage on the CRT board? If .6 or so, the CRT
likely has a weak cathode. If 2.2 or so, there is likely another
problem.

Tom
HI Tom,
how is this measured? Presumably the black is grounded somewhere
while the red is put on the test point.
Should the TV be set to normal viewing conditions (STANDARD
setting)
Thanks,
Dave