Problem with panasonic tx-w28r3

[cheers]

My Panasonic TX-W28R3 has some fault.
When I switch it on the sound comes on, but not the picture.
After more than half an hour the picture comes on, and
everything works fine.

btw, this problem was less bad at first, only had to wait 5
minutes, but got worse progressively.

Can speed it up by changing channels quickly, useually
starts when it hits the snowy channels (where the is no
signal) probably some voltage spike gives the warm-up
circuit the needed push.

Was told once a resistor may have increased in value, thereby
changing the threshhold for picture switch on, but other than
checking any resistor on the board (might take 10 years) what
can I do?

btw, I am an aspiring tv fixer, so hopefully will learn things
from the effort of locating this resistor. Anyone had this
problem? probably a design fault - resistors should go just
like that, they should last for 100 years.

 

[Jerry G.]

It sounds like there are some parts in the set that are becoming
thermo sensitive from age and use. It is really impossible to guess at
which ones, since many of the critical components in the scan
amplifiers and power sections can do this type failure. Most of the
time electrolytic capacitors tend to become thermo sensitive with age
and use.

An experienced tech can troubleshoot the set to determine the exact
failed components, and then replace them for you.

Jerry G.


On Sep 3, 7:41 pm, "cheers" <che...@cheers.com> wrote:

My Panasonic TX-W28R3 has some fault.
When I switch it on the sound comes on, but not the picture.
After more than half an hour the picture comes on, and
everything works fine.

btw, this problem was less bad at first, only had to wait 5
minutes, but got worse progressively.

Can speed it up by changing channels quickly, useually
starts when it hits the snowy channels (where the is no
signal) probably some voltage spike gives the warm-up
circuit the needed push.

Was told once a resistor may have increased in value, thereby
changing the threshhold for picture switch on, but other than
checking any resistor on the board (might take 10 years) what
can I do?

btw, I am an aspiring tv fixer, so hopefully will learn things
from the effort of locating this resistor. Anyone had this
problem? probably a design fault - resistors should go just
like that, they should last for 100 years.