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  
Stephan Greppi
 
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Default Problem with vertical sweep on Toshiba CF2665K TV Set

I have aToshiba CF2665K that is experiencing vertical sweep problem (about
half the vertical picture with retrace lines).
This has been worsening slowly, and I'm pretty sure it's a defective
capacitor somewhere in the vertical circuitry.
The problem is I cannot find the schematic anymore.
Would anybody have a schematic for this TV, so I can locate the capacitors ?
Thanks
Stephan


  #2   Report Post  
David
 
Posts: n/a
Default Problem with vertical sweep on Toshiba CF2665K TV Set

Replace all the capacitors with the same first number as the vertical output
ic. i.e. vertical output ic IC301, replace C301,C305,C308 and maybe a
couple more.


"Stephan Greppi" wrote in message
news:GIlic.14904$_L6.1153842@attbi_s53...
I have aToshiba CF2665K that is experiencing vertical sweep problem

(about
half the vertical picture with retrace lines).
This has been worsening slowly, and I'm pretty sure it's a defective
capacitor somewhere in the vertical circuitry.
The problem is I cannot find the schematic anymore.
Would anybody have a schematic for this TV, so I can locate the capacitors

?
Thanks
Stephan




  #3   Report Post  
no need 4 a name
 
Posts: n/a
Default Problem with vertical sweep on Toshiba CF2665K TV Set

I am guessing you mean your top half of the pix is stretching, starting
to foldover or something like that...(usually what folks call "retrace
lines" will cover the entire screen)
lots of folks just use the shotgun method=97replace all the electroytics
in the vert vertretrn circuit. Caps are cheap, & you may save yourself
another repair down the road perhaps.
Or you can get the pinout of your vert ic for a bit of guidance.
Reflow any poor looking solder in the area (and any poor
solder-high-heat areas while you are at it)
Once again, you may save yourself another repair in the future

  #4   Report Post  
Stephan Greppi
 
Posts: n/a
Default Problem with vertical sweep on Toshiba CF2665K TV Set

Hi,
I replaced all electrolytic capacitors Cxxx I could find. I don't have a
schematic, but I guess C3xx are capacitors in the vertical deflection
circuitry.
I also changed IC301, R287 and a couple diodes.
The result is still the same. It started by the top of the picture starting
to elongate, and then the picture progresively diminushing in size over a
few weeks. It is now about half the size of a normal picture, in the middle
of the screen, with retrace lines visible when no RF signal is present.
What else should I try before I trash the TV?
Suggestions anyone?
Thaks in advance.
Stephan



"David" wrote in message
...
Replace all the capacitors with the same first number as the vertical

output
ic. i.e. vertical output ic IC301, replace C301,C305,C308 and maybe a
couple more.


"Stephan Greppi" wrote in message
news:GIlic.14904$_L6.1153842@attbi_s53...
I have aToshiba CF2665K that is experiencing vertical sweep problem

(about
half the vertical picture with retrace lines).
This has been worsening slowly, and I'm pretty sure it's a defective
capacitor somewhere in the vertical circuitry.
The problem is I cannot find the schematic anymore.
Would anybody have a schematic for this TV, so I can locate the

capacitors
?
Thanks
Stephan






  #5   Report Post  
Ken Weitzel
 
Posts: n/a
Default Problem with vertical sweep on Toshiba CF2665K TV Set



Stephan Greppi wrote:

Hi,
I replaced all electrolytic capacitors Cxxx I could find. I don't have a
schematic, but I guess C3xx are capacitors in the vertical deflection
circuitry.
I also changed IC301, R287 and a couple diodes.
The result is still the same. It started by the top of the picture starting
to elongate, and then the picture progresively diminushing in size over a
few weeks. It is now about half the size of a normal picture, in the middle
of the screen, with retrace lines visible when no RF signal is present.
What else should I try before I trash the TV?
Suggestions anyone?
Thaks in advance.
Stephan


Hi...

Don't trash it for that; specially not since you've
already invested in it.

Betcha a donut that there's one cap left you haven't
yet found. Not necessarily near the ones you did find.
Probably larger, higher voltage. Keep looking.

I like chocolate covered

Take care.

Ken





  #6   Report Post  
Art
 
Posts: n/a
Default Problem with vertical sweep on Toshiba CF2665K TV Set

Be advised one of the caps in teh vertical ckt is physically located near
the jungel ic. It also may contribrute to your symptom.
"Ken Weitzel" wrote in message
news:8uDnc.407211$Pk3.375340@pd7tw1no...


Stephan Greppi wrote:

Hi,
I replaced all electrolytic capacitors Cxxx I could find. I don't have a
schematic, but I guess C3xx are capacitors in the vertical deflection
circuitry.
I also changed IC301, R287 and a couple diodes.
The result is still the same. It started by the top of the picture
starting
to elongate, and then the picture progresively diminushing in size over a
few weeks. It is now about half the size of a normal picture, in the
middle
of the screen, with retrace lines visible when no RF signal is present.
What else should I try before I trash the TV?
Suggestions anyone?
Thaks in advance.
Stephan


Hi...

Don't trash it for that; specially not since you've
already invested in it.

Betcha a donut that there's one cap left you haven't
yet found. Not necessarily near the ones you did find.
Probably larger, higher voltage. Keep looking.

I like chocolate covered

Take care.

Ken





  #7   Report Post  
Stephan Greppi
 
Posts: n/a
Default Problem with vertical sweep on Toshiba CF2665K TV Set -FIXED -

I finally figured out what the problem was.
I had purchased a repair kit from Tritronics fot that TV, and the
instructions said to replace C301 and C305 with 2.2 MF (instead of the
original 1.0MF), which I faithfully did.
Turns out these 2 caps were indeed leaking, but they should be replaced by
1.0 MF and not 2.2MF.
Anyway it's fixed now, and even though I changed 8 caps, a few diodes and
the IC301 for nothing, it still was well worth it.
Thanks for the help.
Stephan



"Stephan Greppi" wrote in message
news:%kCnc.16725$xw3.1130314@attbi_s04...
Hi,
I replaced all electrolytic capacitors Cxxx I could find. I don't have a
schematic, but I guess C3xx are capacitors in the vertical deflection
circuitry.
I also changed IC301, R287 and a couple diodes.
The result is still the same. It started by the top of the picture

starting
to elongate, and then the picture progresively diminushing in size over a
few weeks. It is now about half the size of a normal picture, in the

middle
of the screen, with retrace lines visible when no RF signal is present.
What else should I try before I trash the TV?
Suggestions anyone?
Thaks in advance.
Stephan



"David" wrote in message
...
Replace all the capacitors with the same first number as the vertical

output
ic. i.e. vertical output ic IC301, replace C301,C305,C308 and maybe a
couple more.


"Stephan Greppi" wrote in message
news:GIlic.14904$_L6.1153842@attbi_s53...
I have aToshiba CF2665K that is experiencing vertical sweep problem

(about
half the vertical picture with retrace lines).
This has been worsening slowly, and I'm pretty sure it's a defective
capacitor somewhere in the vertical circuitry.
The problem is I cannot find the schematic anymore.
Would anybody have a schematic for this TV, so I can locate the

capacitors
?
Thanks
Stephan








  #8   Report Post  
Ken Weitzel
 
Posts: n/a
Default Problem with vertical sweep on Toshiba CF2665K TV Set -FIXED-


Hey, congratulations!

But the coffee's ready, and the donuts haven't
arrived

Take care.

Ken


Stephan Greppi wrote:
I finally figured out what the problem was.
I had purchased a repair kit from Tritronics fot that TV, and the
instructions said to replace C301 and C305 with 2.2 MF (instead of the
original 1.0MF), which I faithfully did.
Turns out these 2 caps were indeed leaking, but they should be replaced by
1.0 MF and not 2.2MF.
Anyway it's fixed now, and even though I changed 8 caps, a few diodes and
the IC301 for nothing, it still was well worth it.
Thanks for the help.
Stephan



"Stephan Greppi" wrote in message
news:%kCnc.16725$xw3.1130314@attbi_s04...

Hi,
I replaced all electrolytic capacitors Cxxx I could find. I don't have a
schematic, but I guess C3xx are capacitors in the vertical deflection
circuitry.
I also changed IC301, R287 and a couple diodes.
The result is still the same. It started by the top of the picture


starting

to elongate, and then the picture progresively diminushing in size over a
few weeks. It is now about half the size of a normal picture, in the


middle

of the screen, with retrace lines visible when no RF signal is present.
What else should I try before I trash the TV?
Suggestions anyone?
Thaks in advance.
Stephan



"David" wrote in message
...

Replace all the capacitors with the same first number as the vertical


output

ic. i.e. vertical output ic IC301, replace C301,C305,C308 and maybe a
couple more.


"Stephan Greppi" wrote in message
news:GIlic.14904$_L6.1153842@attbi_s53...

I have aToshiba CF2665K that is experiencing vertical sweep problem

(about

half the vertical picture with retrace lines).
This has been worsening slowly, and I'm pretty sure it's a defective
capacitor somewhere in the vertical circuitry.
The problem is I cannot find the schematic anymore.
Would anybody have a schematic for this TV, so I can locate the


capacitors

?

Thanks
Stephan








  #9   Report Post  
Spacecraftengr
 
Posts: n/a
Default

Hi- just signed on. Did anyone in this thread actually locate a schematic
for this model? If there's a soft copy that could be e-mailed to me, or
just a URL to that puppy, please send or post here. Thanks!

S/C engr

  #10   Report Post  
Junior Member
 
Location: Los Angeles
Posts: 1
Default

I also have a Toshiba CF2665K in which the vertical linearity had gradually degraded over the course of about a year. Stretched out at the top and compressed at the bottom. I hadn't tried to repair a TV in over 20 years and was discouraged to find no linearity adjustment pot. But I found your posting and tried the "shotgun" approach. I replaced electrolytic caps C301, C305, C306, C308, and C310. I don't know which one(s) were responsible, but the linearity is just fine now. Thanks much.

Steve


Quote:
Originally Posted by Ken Weitzel
Hey, congratulations!

But the coffee's ready, and the donuts haven't
arrived

Take care.

Ken


Stephan Greppi wrote:
I finally figured out what the problem was.
I had purchased a repair kit from Tritronics fot that TV, and the
instructions said to replace C301 and C305 with 2.2 MF (instead of the
original 1.0MF), which I faithfully did.
Turns out these 2 caps were indeed leaking, but they should be replaced by
1.0 MF and not 2.2MF.
Anyway it's fixed now, and even though I changed 8 caps, a few diodes and
the IC301 for nothing, it still was well worth it.
Thanks for the help.
Stephan



"Stephan Greppi" wrote in message
news:%kCnc.16725$xw3.1130314@attbi_s04...

Hi,
I replaced all electrolytic capacitors Cxxx I could find. I don't have a
schematic, but I guess C3xx are capacitors in the vertical deflection
circuitry.
I also changed IC301, R287 and a couple diodes.
The result is still the same. It started by the top of the picture


starting

to elongate, and then the picture progresively diminushing in size over a
few weeks. It is now about half the size of a normal picture, in the


middle

of the screen, with retrace lines visible when no RF signal is present.
What else should I try before I trash the TV?
Suggestions anyone?
Thaks in advance.
Stephan



"David"
wrote in message
...

Replace all the capacitors with the same first number as the vertical


output

ic. i.e. vertical output ic IC301, replace C301,C305,C308 and maybe a
couple more.


"Stephan Greppi"
wrote in message
news:GIlic.14904$_L6.1153842@attbi_s53...

I have aToshiba CF2665K that is experiencing vertical sweep problem

(about

half the vertical picture with retrace lines).
This has been worsening slowly, and I'm pretty sure it's a defective
capacitor somewhere in the vertical circuitry.
The problem is I cannot find the schematic anymore.
Would anybody have a schematic for this TV, so I can locate the


capacitors

?

Thanks
Stephan






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