Sirs,

I've a problem with my TV. I assume the error is in the area of the tube.

The tv shows no picture. If I adjust G2 voltage to the max, I can see a
vague picture. No colors! Only shades of light and dark gray together with
the horizontal flyback (is this the right word?) lines. It looks a bit like
a balck and white negative photo.

G2 voltage in this situation is about 300V=
Voltage at the RGB kathodes is abut 60V= each.

I already checked the G2 Diode and resistor.

I don't have schematic nor service manual nor oscilloscope. Only multimeter
available.

Can somebody help.

Please post answeres also to my mail address

Thanks for your help!!

d

"dougie" wrote in message
...

Sirs,

I've a problem with my TV. I assume the error is in the area of the tube.

The tv shows no picture. If I adjust G2 voltage to the max, I can see a
vague picture. No colors! Only shades of light and dark gray together with
the horizontal flyback (is this the right word?) lines. It looks a bit
like
a balck and white negative photo.

G2 voltage in this situation is about 300V=
Voltage at the RGB kathodes is abut 60V= each.

I already checked the G2 Diode and resistor.

I don't have schematic nor service manual nor oscilloscope. Only
multimeter
available.

Can somebody help.

Please post answeres also to my mail address

Thanks for your help!!

d



The tube is probably fine, have you checked the voltages from the power
supply? Do the controls all respond normally?

Could possibly help if you had the minimal amount of needed equipment and
information. A o'scope is a requirement for any Sony AKB or video blanking
problem to properly diagnose. A schematic will allow getting to the correct
measurement locations.

Two choices, either buy or rent the needed equipment and information or take
the tv into a Sony trained or experienced servicer.

Any of the following circuit areas and faults will cause no video condition:
1. Loss of vertical return pulse to the system control, could be a full
vertical failure or problem in the return line or micro problem.
2. Problem on the clock or data lines that prevent the jungle ic from
sending the all ok signal to the micro.
3. Problem in the AKB circuit, could be the tube, anything in the AKB
feedback circuit, etc. Could even be due to too much vertical size putting
the AKB pulses on the side of the glass.
4. Several different low voltage power supply problems.
5. Plus the usual loss of video signal anywhere in the path going to the
final video output stages.

You did not mention if you had good OSD which is the FIRST troubleshooting
step. Then slightly turning up the G2 to see what might be working and not
working is next. Then following up with the waveform measurements.

David

dougie wrote in message
...

Sirs,

I've a problem with my TV. I assume the error is in the area of the tube.

The tv shows no picture. If I adjust G2 voltage to the max, I can see a
vague picture. No colors! Only shades of light and dark gray together with
the horizontal flyback (is this the right word?) lines. It looks a bit
like
a balck and white negative photo.

G2 voltage in this situation is about 300V=
Voltage at the RGB kathodes is abut 60V= each.

I already checked the G2 Diode and resistor.

I don't have schematic nor service manual nor oscilloscope. Only
multimeter
available.

Can somebody help.

Please post answeres also to my mail address

Thanks for your help!!

d

James,

thanks for the Tip. I've to ask my TV dealer if he supplies me with a
schematic.
Otherwise I don't think that I'm able to check the power supply voltages.

Greetings from Germany
Ralf

"James Sweet" wrote in message
news:OUTrb.120245$9E1.592364@attbi_s52...

"dougie" wrote in message
...

Sirs,

I've a problem with my TV. I assume the error is in the area of the
tube.

The tv shows no picture. If I adjust G2 voltage to the max, I can see a
vague picture. No colors! Only shades of light and dark gray together
with
the horizontal flyback (is this the right word?) lines. It looks a bit
like
a balck and white negative photo.

G2 voltage in this situation is about 300V=
Voltage at the RGB kathodes is abut 60V= each.

I already checked the G2 Diode and resistor.

I don't have schematic nor service manual nor oscilloscope. Only
multimeter
available.

Can somebody help.

Please post answeres also to my mail address

Thanks for your help!!

d



The tube is probably fine, have you checked the voltages from the power
supply? Do the controls all respond normally?

Wow! Great stuff, David. Thanks a lot!

First to answer your questions: no, I can't see any on-screen-display, but
volume control works fine.
I feel a little bit sorry, that I can't respond as I would like to, because
of missing equipment.
At least it should be possible to give you the best description of the error
I can.

Re point 3: when I turn G2 voltage to max, a 'normal' TV picture appears.
With normal I mean, that you can 'guess' the picture. Sender-logo is at the
rigt place and geometry of the picture is okay. Therefor I would say that
vertical size is okay. Did I mention that the vague picture appears as
shades of lighter and darker gray, with a handful of horizontal
flyback-lines? No colors!

Re point 4: Buying the service manual would cost at least around 20 Euros. I
try to avoid until I can predict, that the tube is okay. *grin* Maybe
there's somebody around who has the manual (at least from the power-supply,
so I can check the voltages.

Re point 5: Because of point 3 I guess, that it's a 'blanking'
problem.Otherwise I should not able to see ANY picture. Right?

Re the other points: can't give an answer on that. I would like to start
with the power supply. do YOU have something in paper or electronic format
which would help?

Greetings
Ralf


"David" wrote in message
...
Could possibly help if you had the minimal amount of needed equipment and
information. A o'scope is a requirement for any Sony AKB or video
blanking
problem to properly diagnose. A schematic will allow getting to the
correct
measurement locations.

Two choices, either buy or rent the needed equipment and information or
take
the tv into a Sony trained or experienced servicer.

Any of the following circuit areas and faults will cause no video
condition:
1. Loss of vertical return pulse to the system control, could be a full
vertical failure or problem in the return line or micro problem.
2. Problem on the clock or data lines that prevent the jungle ic from
sending the all ok signal to the micro.
3. Problem in the AKB circuit, could be the tube, anything in the AKB
feedback circuit, etc. Could even be due to too much vertical size
putting
the AKB pulses on the side of the glass.
4. Several different low voltage power supply problems.
5. Plus the usual loss of video signal anywhere in the path going to the
final video output stages.

You did not mention if you had good OSD which is the FIRST troubleshooting
step. Then slightly turning up the G2 to see what might be working and
not
working is next. Then following up with the waveform measurements.

David

dougie wrote in message
...

Sirs,

I've a problem with my TV. I assume the error is in the area of the
tube.

The tv shows no picture. If I adjust G2 voltage to the max, I can see a
vague picture. No colors! Only shades of light and dark gray together
with
the horizontal flyback (is this the right word?) lines. It looks a bit
like
a balck and white negative photo.

G2 voltage in this situation is about 300V=
Voltage at the RGB kathodes is abut 60V= each.

I already checked the G2 Diode and resistor.

I don't have schematic nor service manual nor oscilloscope. Only
multimeter
available.

Can somebody help.

Please post answeres also to my mail address

Thanks for your help!!

d

Yea, I checked Power Supply in between. I got the service Manual...

Seems to be okay... all voltages are there.


"James Sweet" wrote in message
news:OUTrb.120245$9E1.592364@attbi_s52...

"dougie" wrote in message
...

Sirs,

I've a problem with my TV. I assume the error is in the area of the
tube.

The tv shows no picture. If I adjust G2 voltage to the max, I can see a
vague picture. No colors! Only shades of light and dark gray together
with
the horizontal flyback (is this the right word?) lines. It looks a bit
like
a balck and white negative photo.

G2 voltage in this situation is about 300V=
Voltage at the RGB kathodes is abut 60V= each.

I already checked the G2 Diode and resistor.

I don't have schematic nor service manual nor oscilloscope. Only
multimeter
available.

Can somebody help.

Please post answeres also to my mail address

Thanks for your help!!

d



The tube is probably fine, have you checked the voltages from the power
supply? Do the controls all respond normally?