no screen with sound on my tv daewoo dth2881-100D chassis cp-830F

[mooswief]

hi there, when the tv runs the screen is getting black with sound after  a couple of hours.
i resolderd the prints but this doesn't solve the problem.
when the screen is getting black the sound is still ok, but when i feel on the outside of the screen
it looks like if there is no high voltage anymore.
plse help , i'am lost.
tks in adv

[costymio]

Hello, mooswief!
I'm sure you have enough knowledge in electronics so this is what you should do to solve the issue:
First, you should check:
In stand by: UCC - I823=5V
                        - I826=3,3V
                        - I827=2,2V
                        - I821=3,3V
                        - I824=1,8V
In ON mode: Take out L802 and fix on a normally lamp(with a filament), 220V/60-100VA.
Check also UCC - C813=130V
                      - C878=15V
                      - C835=8V
Second, you should check: UCC - C401=7,7V and Q402.
If everything is ok check H-out in pin 26 I502.
Usually, a tipical defect is T401 driver transformer.
Good look and I'm looking forward for the results in a reply.