Toshiba 43" rear projection HELP

[Ron]

I just aquired a Toshiba 43" rear projections television Model TP43H60
using chasis TAC9859. Upon plugging it in I hear the high voltage kick
in. All three tubes glow. But no picture. I removed the front panel
to reveal the control knobs for the flybacks. I toned them up a bit...
now I get a pictures with a horizontal line across. then after a few
seconds it scatters like a oval type shape. My thoughts since I repair
video game monitors for my work.. I suspected the horizonal output
transitor. Any help would be great.

--Ron
[email protected]

 

[Ron]

Also I saw a D2253 transistor... is this the HOT?

--Ron

 

[James Sweet]

I just aquired a Toshiba 43" rear projections television Model TP43H60
using chasis TAC9859. Upon plugging it in I hear the high voltage kick
in. All three tubes glow. But no picture. I removed the front panel
to reveal the control knobs for the flybacks. I toned them up a bit...
now I get a pictures with a horizontal line across. then after a few
seconds it scatters like a oval type shape. My thoughts since I repair
video game monitors for my work.. I suspected the horizonal output
transitor. Any help would be great.

If you have any picture at all then the HOT is obviously good. What do you
mean by the pic scattering? Do you have a way of measuring the HV?

 

[Art]

Try disconnecting the convergence yoke wires at the convergence correction
area of the deflection pwb. Pay attention as to which connector goes to
which plug. There are three, one for red, blue,and green. If you get a full
raster with video then it is probable the output ics have gone bad and need
replaced. The display will be distorted because the correction for
registration will not be present. Pay attention to the small value resistors
in that circuit also.

 

[Ron]

when the unit is powered on it will have a straight line (red green and
blue) from right to left, then I hear a click and it will look like an
oval type shape. Red on the other hand starts to fan out like a
chinese fan on each side from the center (about 6-7 inches) I'm going
to get a few pictures and post them with links on my webserver today.

--Ron

 

[Ron]

unplugging the three connectors I get no picture. I plugged one in at
a time and each appear to look like a star. then I plugged two in and
I seen the straight line from left to right. then I plugged them all
back in to get where I was.. I'll check resistor values later on
tonight when I get some time.

--Ron

 

[Ron]

grr.. I posted two pictures and it didn't post to the groups...

ht**tp://nnl.darktech.org/tv/tv_01.jpg
ht**tp://nnl.darktech.org/tv/tv_02.jpg

Remove the ** of course..

--Ron

 

[Rono]

You have no vertical deflection. Bad connections, or
bad IC, these units are known for bad convergence IC's
also. Rono.

 

[James Sweet]

grr.. I posted two pictures and it didn't post to the groups...

ht**tp://nnl.darktech.org/tv/tv_01.jpg
ht**tp://nnl.darktech.org/tv/tv_02.jpg

Remove the ** of course..

--Ron

That's pretty screwy, at any rate horizontal deflection is fine, it's
obviously a vertical problem of some sort, actually pretty likely the
vertical output IC is toast, the vertical deflection you are getting could
be from the convergence yokes.

 

[Ron]

Update: Well I've replaced both STK392-110s with no change in the
picture. Does anyone have or can download a schematic for this unit..
the model number is TP43H60 Using Chassis TAC9859. I have one
capacitor in question C446... Can anyone verify that D688 is the
vertical output transistor?

--Ron

Thanks for all the help.

 

[kip]

Have you checked the return resistors , are there any PC mount fuses ?

kip

 

[Ron]

Checked all resistors (the 1 ohm and 3.3 ohm)... All check out ok. My
guess at this point would be this missing capacitor... I used my volt
meter to check voltage. I get about 210-220 volts DC on the positive
side of the cap. I've traced the negitive side of the cap all the way
back to the flyback. of course it jumps though hoops a capacitor here
and a diode. I've tried to install a 200v 1uf cap. with no change in
the picture.

--Ron
Baffled but learning in the process.

 

[Art]

Possible the Convergence DCU is defective?

 

[Ron]

I was told this DCU unit rarely fails. I need to find the value of
C440. My unit seems to be missing this Capacitor for some reason. If
anyone has a schematic or knows the value I would most appricate it.
No one here locally has any schematics... so I reach out to those on
the web for assitance. Anyone with access to the schematic or has a
PDF of it I would appricate it. Toshibia points me to a service
center. But I haven't heard any response.

--Ron