Portable TV Lenco TC 9002 - stretched image

[paoolica]

Hello people,

I recently got a mini TV Lenco TC 9002 and unfortunately something got wrong from the first turning on. My father tested it first and he said it worked on TV mode - there was static on all screen, and when he tried to auto search some channels something happened and is now in the current state you see in the images/video.
On the TV mode there is this vertical green line with static that goes from one side to the screen to the other, then back, and so on.
On the AV mode, I have sound, but the image is stretched along the retrace lines.

Please see here a video where you can clearly see the problem:

Does anyone have an idea what can be wrong on this? I will really appreciate your help, I am not an expert on this
Thank you!

Here is in the TV mode (that line is slowly moving left to right then right to left)

Here is in the AV mode (there should be some video game text menu):

 

[Nigel Goodwin]

First 'problem' it looks like the horizontal hold simply needs adjusting - it's usually a customer control.

Secondly the green line is probably just a tuning display, and you will find nothing as analogue TV no longer exists? (in any remotely modern country).

 

[paoolica]

First 'problem' it looks like the horizontal hold simply needs adjusting - it's usually a customer control.

Secondly the green line is probably just a tuning display, and you will find nothing as analogue TV no longer exists? (in any remotely modern country).

Thank you for you answer Nigel.
Unfortunately this TV doesn't have controls (except for brightness, contrast and color), so I started to twist the adjustable resistors found on the board. I think something is burned out because most of them are not working. The only thing I could adjust was the vertical scale (on some resistors from mainboard) and color tint (from two resistors at the end of the tube).
The others simply didn't change anything...

Regarding the vertical green line, my father actually saw a TV channel but with a very poor signal, and after he pressed the "Tune Up" button the "bouncing green line" appeared. The TV was tested in Romania when the channel appeared, in that region there is still analogue TV.

 

[Nigel Goodwin]

According to the datasheet the horizontal hold connects to pin 15 of the TDA2759, it's shown as a 4K7 pot connected via a 33K resistor.

Do you have a working aerial plugged in the TV?.

 

[paoolica]

Hi Nigel, I looked more carefully in the area of that chip you wrote about and found another pot under the tube, that was hard to spot.
That one actually worked and now I have a clear image on AV (as much as this TV can get I suppose ) !
Thank you very much for your help!

I will try the TV with one of my ZX Spectrums later on to check also that part, I currently live in Germany and can't reach any analog frequencies that my father checked before.

Here is the result (the image is B/W because of the chinese emulator console output, it does this on some old CRTs)

 

[Nigel Goodwin]

I will try the TV with one of my ZX Spectrums later on to check also that part, I currently live in Germany and can't reach any analog frequencies that my father checked before.

Unfortunately people are often under the impression that a portable TV doesn't need an aerial, where in reality it's just a normal TV with a smaller screen, and needs an aerial just as much as a larger TV does.

They will work on their own telescopic aerial IF you are in an exceptionally strong signal area - but so would your big TV as well.