Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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  #1   Report Post  
max
 
Posts: n/a
Default JVC TV No red Color

Hi
I have JVC TV model AV-27D303.Green and Blue is Ok no Red color.I was
checked Video amps transistors on CRT board.It looks good.Voltage on Rk goes
240V instead 160V as on Gk and Bk.
Suspected IC 201 TOSHIBA 8812CSDNG3U68 which was replaced but problem still
exist.

Any suggestions?

Thanks


  #2   Report Post  
Jerry Greenberg
 
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Default JVC TV No red Color

Compare the bias volts to the tube elements between all the colour
channels. If these are very close, then check that there is video
drive at proper specs going from the outputs of the video amps to the
CRT.

If all this complies, then you have a bad CRT.

Jerry Greenberg
http://www.zoom-one.com

--

"max" wrote in message ...
Hi
I have JVC TV model AV-27D303.Green and Blue is Ok no Red color.I was
checked Video amps transistors on CRT board.It looks good.Voltage on Rk goes
240V instead 160V as on Gk and Bk.
Suspected IC 201 TOSHIBA 8812CSDNG3U68 which was replaced but problem still
exist.

Any suggestions?

Thanks

  #3   Report Post  
Jason D.
 
Posts: n/a
Default JVC TV No red Color

On 3 Apr 2004 15:16:29 -0800, (Jerry Greenberg)
wrote:

Compare the bias volts to the tube elements between all the colour
channels. If these are very close, then check that there is video
drive at proper specs going from the outputs of the video amps to the
CRT.

If all this complies, then you have a bad CRT.

Jerry Greenberg
http://www.zoom-one.com

Whoa!

This fooled me, went far as changed a CRT on those JVC newer chassis
even changed that super jungle! The problem was in the CRT board SMD
resistors. Some had bad solder connection or one bad resistor. Check
those! With meter and do a resoldering on those if you can't see
anything look bad solder.

The bias voltage will looks close but is still wrong.

So far I seen about 4 of this after this initial incident, recent one
was last week. :-O

Summary: Check the CRT board for any bad part, duff resistor or bad
solder joint (redo solder just the affected color).

Cheers,

Wizard
  #4   Report Post  
Woodie Morris
 
Posts: n/a
Default JVC TV No red Color

I have seen two of these also. A 150 ohm resistor feeding signal from the
jungle IC to the base of the red output transistor, and a 270 ohm from the
emitter to ground. If only one checks bad, replace the other also as it's
likely to go soon after.

-Woodie

"Jason D." wrote in message
...
On 3 Apr 2004 15:16:29 -0800, (Jerry Greenberg)
wrote:

Compare the bias volts to the tube elements between all the colour
channels. If these are very close, then check that there is video
drive at proper specs going from the outputs of the video amps to the
CRT.

If all this complies, then you have a bad CRT.

Jerry Greenberg
http://www.zoom-one.com

Whoa!

This fooled me, went far as changed a CRT on those JVC newer chassis
even changed that super jungle! The problem was in the CRT board SMD
resistors. Some had bad solder connection or one bad resistor. Check
those! With meter and do a resoldering on those if you can't see
anything look bad solder.

The bias voltage will looks close but is still wrong.

So far I seen about 4 of this after this initial incident, recent one
was last week. :-O

Summary: Check the CRT board for any bad part, duff resistor or bad
solder joint (redo solder just the affected color).

Cheers,

Wizard



  #5   Report Post  
max
 
Posts: n/a
Default JVC TV No red Color

thats what I suspected too I replaced one resistor for 15 Om some resistors
not installed by manufacture.Today I will check resistor between 270 Om and
emitter.Thanks for suggestions guys.
"Woodie Morris" wrote in message
news
I have seen two of these also. A 150 ohm resistor feeding signal from the
jungle IC to the base of the red output transistor, and a 270 ohm from

the
emitter to ground. If only one checks bad, replace the other also as it's
likely to go soon after.

-Woodie

"Jason D." wrote in message
...
On 3 Apr 2004 15:16:29 -0800, (Jerry Greenberg)
wrote:

Compare the bias volts to the tube elements between all the colour
channels. If these are very close, then check that there is video
drive at proper specs going from the outputs of the video amps to the
CRT.

If all this complies, then you have a bad CRT.

Jerry Greenberg
http://www.zoom-one.com

Whoa!

This fooled me, went far as changed a CRT on those JVC newer chassis
even changed that super jungle! The problem was in the CRT board SMD
resistors. Some had bad solder connection or one bad resistor. Check
those! With meter and do a resoldering on those if you can't see
anything look bad solder.

The bias voltage will looks close but is still wrong.

So far I seen about 4 of this after this initial incident, recent one
was last week. :-O

Summary: Check the CRT board for any bad part, duff resistor or bad
solder joint (redo solder just the affected color).

Cheers,

Wizard







  #6   Report Post  
max
 
Posts: n/a
Default JVC TV No red Color

thats what I suspected too I replaced one resistor for 15 Om some resistors
not installed by manufacture.Today I will check resistor between 270 Om and
emitter.Thanks for suggestions guys.
"Woodie Morris" wrote in message
news
I have seen two of these also. A 150 ohm resistor feeding signal from the
jungle IC to the base of the red output transistor, and a 270 ohm from

the
emitter to ground. If only one checks bad, replace the other also as it's
likely to go soon after.

-Woodie

"Jason D." wrote in message
...
On 3 Apr 2004 15:16:29 -0800, (Jerry Greenberg)
wrote:

Compare the bias volts to the tube elements between all the colour
channels. If these are very close, then check that there is video
drive at proper specs going from the outputs of the video amps to the
CRT.

If all this complies, then you have a bad CRT.

Jerry Greenberg
http://www.zoom-one.com

Whoa!

This fooled me, went far as changed a CRT on those JVC newer chassis
even changed that super jungle! The problem was in the CRT board SMD
resistors. Some had bad solder connection or one bad resistor. Check
those! With meter and do a resoldering on those if you can't see
anything look bad solder.

The bias voltage will looks close but is still wrong.

So far I seen about 4 of this after this initial incident, recent one
was last week. :-O

Summary: Check the CRT board for any bad part, duff resistor or bad
solder joint (redo solder just the affected color).

Cheers,

Wizard





  #7   Report Post  
max
 
Posts: n/a
Default JVC TV No red Color

Thanks guys for your help.Resistor between emitter and ground was bad.27 Om
on meter shows me 3.2kOm.Replace it back on 27Om return the red color back.

"max" wrote in message
...
thats what I suspected too I replaced one resistor for 15 Om some

resistors
not installed by manufacture.Today I will check resistor between 270 Om

and
emitter.Thanks for suggestions guys.
"Woodie Morris" wrote in message
news
I have seen two of these also. A 150 ohm resistor feeding signal from

the
jungle IC to the base of the red output transistor, and a 270 ohm from

the
emitter to ground. If only one checks bad, replace the other also as

it's
likely to go soon after.

-Woodie

"Jason D." wrote in message
...
On 3 Apr 2004 15:16:29 -0800, (Jerry Greenberg)
wrote:

Compare the bias volts to the tube elements between all the colour
channels. If these are very close, then check that there is video
drive at proper specs going from the outputs of the video amps to

the
CRT.

If all this complies, then you have a bad CRT.

Jerry Greenberg
http://www.zoom-one.com

Whoa!

This fooled me, went far as changed a CRT on those JVC newer chassis
even changed that super jungle! The problem was in the CRT board SMD
resistors. Some had bad solder connection or one bad resistor. Check
those! With meter and do a resoldering on those if you can't see
anything look bad solder.

The bias voltage will looks close but is still wrong.

So far I seen about 4 of this after this initial incident, recent one
was last week. :-O

Summary: Check the CRT board for any bad part, duff resistor or bad
solder joint (redo solder just the affected color).

Cheers,

Wizard







  #8   Report Post  
max
 
Posts: n/a
Default JVC TV No red Color

Thanks guys for your help.Resistor between emitter and ground was bad.27 Om
on meter shows me 3.2kOm.Replace it back on 27Om return the red color back.

"max" wrote in message
...
thats what I suspected too I replaced one resistor for 15 Om some

resistors
not installed by manufacture.Today I will check resistor between 270 Om

and
emitter.Thanks for suggestions guys.
"Woodie Morris" wrote in message
news
I have seen two of these also. A 150 ohm resistor feeding signal from

the
jungle IC to the base of the red output transistor, and a 270 ohm from

the
emitter to ground. If only one checks bad, replace the other also as

it's
likely to go soon after.

-Woodie

"Jason D." wrote in message
...
On 3 Apr 2004 15:16:29 -0800, (Jerry Greenberg)
wrote:

Compare the bias volts to the tube elements between all the colour
channels. If these are very close, then check that there is video
drive at proper specs going from the outputs of the video amps to

the
CRT.

If all this complies, then you have a bad CRT.

Jerry Greenberg
http://www.zoom-one.com

Whoa!

This fooled me, went far as changed a CRT on those JVC newer chassis
even changed that super jungle! The problem was in the CRT board SMD
resistors. Some had bad solder connection or one bad resistor. Check
those! With meter and do a resoldering on those if you can't see
anything look bad solder.

The bias voltage will looks close but is still wrong.

So far I seen about 4 of this after this initial incident, recent one
was last week. :-O

Summary: Check the CRT board for any bad part, duff resistor or bad
solder joint (redo solder just the affected color).

Cheers,

Wizard







  #9   Report Post  
Jason D.
 
Posts: n/a
Default JVC TV No red Color

On Sun, 4 Apr 2004 20:18:50 -0700, "max" wrote:

Thanks guys for your help.Resistor between emitter and ground was bad.27 Om
on meter shows me 3.2kOm.Replace it back on 27Om return the red color back.


Max,

You're welcome!

Jerry gave good advices but I sometimes have hard time reading what
he's implying at.

Cheers,

Wizard
  #10   Report Post  
Jason D.
 
Posts: n/a
Default JVC TV No red Color

On Sun, 4 Apr 2004 20:18:50 -0700, "max" wrote:

Thanks guys for your help.Resistor between emitter and ground was bad.27 Om
on meter shows me 3.2kOm.Replace it back on 27Om return the red color back.


Max,

You're welcome!

Jerry gave good advices but I sometimes have hard time reading what
he's implying at.

Cheers,

Wizard
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